NEURAL AND BEHAVIORAL AGE DIFFERENCES IN EMOTIONAL BIASES

A Thesis

Submitted to the Faculty

in partial fulfillment of the requirements for the

degree of

Master of Arts

in

Experimental Psychology

by

Kristin Flanary

DARTMOUTH COLLEGE

Hanover, New Hampshire

May 2011

Examining Committee:

Catherine J. Norris, Ph.D. (Chair)

Paul J. Whalen, Ph.D.

Jeff T. Larsen, Ph.D.

_____________________ Brian W. Pogue, Ph.D. Dean of Graduate Studies

Abstract Research has demonstrated a “positivity effect” in aging, such that older adults remember

and attend to more positive than negative information, compared to their younger

counterparts. The underlying mechanisms of this effect, however, remain largely

unknown. One possibility is that the positivity effect arises from changes in the

negativity bias (the tendency for negativity to outweigh positivity at high levels of

emotional input) or the positivity offset (the tendency for positivity to outweigh negativity

at low levels of emotional input) over the lifespan. The current study aimed to compare

age differences in these emotional biases in order to assess whether the positivity effect is

related to a decreased negativity bias, an increased positivity offset, or both. To do this,

we examined younger (18-25) and older (65-80) females’ behavioral and neural

responses to pictures ranging from neutral and mildly emotional to moderately and

extremely emotional in content. The age groups demonstrated a similar negativity bias in

picture ratings, but older adults showed a larger positivity offset, which was driven by

higher positive and lower negative ratings of the mildly emotional pictures. Older adults

also took more time to rate the mildly unpleasant pictures, and the longer they took to

rate these pictures, the more positive they reported feeling about them. Neural responses

to the emotional pictures appeared to be characterized by prefrontal control regions acting

to down-regulate negative and up-regulate positive emotional responses to both mildly

and very emotional pictures. Results suggest that older adults use multiple emotion

regulation strategies with varying degrees of effectiveness, but appear to successfully

regulate their responses to mildly emotional stimuli in order to more fully appreciate the

simple things in life.

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Acknowledgments

First and foremost, many thanks are due to my advisor, Catherine Norris, PhD, for

the generosity, patience, support, and instruction she has extended throughout my time at

Dartmouth. I will always be grateful for all that I have learned from you. I would also

like to thank the members of my committee, Paul Whalen, PhD, and Jeff Larsen, PhD,

whose invaluable assistance, guidance, and support I have truly appreciated.

Thanks to the members of the Norris Lab for three great years of invigorating

discussions and patient hours of data entry and reduction. Special thanks are due to the

many people who have provided technical assistance and helpful discussions regarding

data analysis and interpretation of these data over the last three years: Zachary

Ingbretsen, Lisa Sprute, Ross O’Hara, Dylan Wagner, Kristina Caudle, and especially

Katie Powers, who has been my biggest cheerleader.

Many of my fellow graduate students have made the last three years remarkable

and full of smiles: John Kingsbury, Ross O’Hara, Megan Roberts, Lisa Sprute, Kristina

Caudle, Andrea Robinson, Katie Powers, and Robert Chavez. They have all been

amazing classmates and confidantes, and I am honored to call them friends.

Thanks to my parents, Phil and Eileen Wood, and my family, Ron, Candace,

Scott, and Shane for always believing in me and supporting my every decision. Most of

all, I would like to thank my husband, William Flanary, who has been my biggest

supporter and who reminds me daily why life is so much fun. I can’t imagine a better

partner to stand by my side.

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Table of Contents

Introduction ....................................................................................................................... 1 Methods .............................................................................................................................. 6 Participants ............................................................................................................... 6 Materials .................................................................................................................. 7 Procedure ................................................................................................................. 8 Behavioral Task ............................................................................................ 8 fMRI Image Acquisition .......................................................................................... 9 fMRI Preprocessing ................................................................................................. 9 Results .............................................................................................................................. 10 Emotional Biases in Picture Ratings ...................................................................... 10 Emotional Biases in Brain Function ...................................................................... 15 Discussion......................................................................................................................... 17 Emotion Regulation and Emotional Biases in Older Adults ................................. 20 Alternative Explanations ........................................................................................ 23 Limitations ............................................................................................................. 25 Conclusions and Future Research .......................................................................... 26 References ........................................................................................................................ 28 Tables ............................................................................................................................... 35 Figures .............................................................................................................................. 39

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List of Tables Table 1: Group activations for the mildly pleasant – mildly unpleasant contrast ............ 35 Table 2: Group activations for the mildly pleasant – mildly unpleasant contrast ............ 36 Table 3: Group activations for the older positivity offset – younger positivity offset

contrast .......................................................................................................................... 37 Table 4: Group activations for the older negativity bias – younger negativity bias contrast

....................................................................................................................................... 38

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List of Figures

Figure 1: Emotional biases predicted by the Evaluative Space Model. ............................ 39 Figure 2: Younger and older adults’ ratings of neutral and mildly, moderately, and

extremely emotional pictures. ....................................................................................... 40 Figure 3: Standardized reaction times to mildly unpleasant and mildly pleasant pictures

by age group. ................................................................................................................. 41 Figure 4: Negative and positive ratings of mildly unpleasant and mildly pleasant pictures

by age group. ................................................................................................................. 42 Figure 5: Z-scored response times as predictors of positive ratings of mildly unpleasant

pictures in older and younger adults. ............................................................................ 43 Figure 6: Figure 7: Figure 8: Figure 9:

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Introduction

American society often paints a dismal picture of aging, with images of

physiological systems shutting down, memories fading, and life ending. Despite

declining physical and cognitive functioning in later life, however, emotional functions

seem to remain intact, or even improve, with age. Across the life span, goals and

motivations shift, with younger adults focusing on broadening their horizons and seeking

new life experiences, and older adults focusing on strengthening close relationships and

seeking meaningful emotional interactions (Carstensen, Fung, & Charles, 2003).

Socioemotional selectivity theory posits that such motivational shifts result from

experiencing a sense of limited time (Carstensen, Isaacowitz, & Charles, 1999). Aging

inherently brings the realization of one’s remaining lifetime growing shorter, and this

sense of time running out in life may lead older adults to become increasingly motivated

to regulate their emotions in order to achieve more fulfilling daily emotional experiences

(Carstensen et al., 2003). Consistent with this theory, Gross and his colleagues (1997)

found that older adults in cultures all over the world report better emotion regulation than

their younger counterparts. Collectively, the emotion-focused motivation in later life

predicted by socioemotional selectivity theory combined with a lifetime of emotion

regulation experience may facilitate more favorable emotional responses with age.

Indeed, Carstensen and her colleagues have proposed a “positivity effect” in older

age, such that older adults respond more positively than younger adults across a variety

of domains (Mather & Carstensen, 2005). For example, older adults remember and

attend to more positive than negative information, and this bias toward positivity is larger

for older adults than for younger adults (Charles, Mather, & Carstensen, 2003;

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Isaacowitz, Wadlinger, Goren, & Wilson, 2006; Mather & Carstensen, 2003; Mather &

Carstensen, 2005). Additionally, older adults report experiencing less negative emotion

(Carstensen, Pasupathi, Mayr, & Nesselroade, 2000; Charles, Reynolds, & Gatz, 2001;

Gross et al., 1997) and utilizing greater emotional control (Gross et al., 1997) in daily life

than do younger adults. Consistent with these findings, older adults also show this

positivity effect in neural responses to emotional stimuli. For example, older adults show

decreased amygdala activation in response to unpleasant pictures but not in response to

pleasant pictures; younger adults do not show this pattern (Mather et al., 2004; Nashiro,

Sakaki, & Mather, in press). The cognitive control model proposes that older adults

achieve such reduction in amygdala responses to unpleasant stimuli by engaging

prefrontal control mechanisms in order to regulate their emotions in keeping with their

more positive motivational goals (Nashiro, Sakaki, & Mather, in press; Williams et al.,

2006). Indeed, older adults show an inverse relationship between ventromedial prefrontal

cortex (vmPFC) and the amygdala when instructed to decrease their negative emotional

responses (Urry et al., 2006). Increased activity in the medial prefrontal cortex (mPFC)

has also been associated with better control over negative emotional responses (Williams

et al., 2006). Taken together, this evidence supports the notion that older adults engage

prefrontal control mechanisms in order to decrease negative emotion. Moreover,

previous research has revealed a large amount of overlap between the brain regions that

are activated when older adults are instructed to regulate their responses to emotional

stimuli and when they are allowed to respond freely (Nashiro, Sakaki, & Mather, in

press). This suggests that older adults may naturally regulate their emotions, even when

given no instructions to do so.

2

Thus, emotion regulation may be an important mechanism underlying the

positivity effect in aging. However, there are many ways in which older adults may

regulate their emotions. The process model of emotion regulation (Gross, 1998) proposes

that people can regulate emotions through such strategies as situation selection (choosing

one’s situation so as to avoid circumstances that may produce unwanted emotional

responses), situation modification (changing one’s situation in ways that are consistent

with one’s emotional goals), attentional deployment (directing one’s attention to certain

aspects of an emotional stimulus and away from other aspects), cognitive reappraisal

(changing one’s interpretation of an emotional stimulus), or response modulation

(changing one’s response to an emotional stimulus). Any of these strategies or others

may contribute to the positivity effect in aging, though the specific regulation strategies

employed by older adults in response to pleasant and unpleasant stimuli remain unclear

(Urry & Gross, 2010).

Moreover, the extant research fails to specify whether older adults respond to

emotional stimuli with more positivity, less negativity, or both. The Evaluative Space

Model (ESM; Cacioppo & Berntson, 1994; Cacioppo, Gardner, & Berntson, 1997) can

address this issue by examining positivity and negativity separately but simultaneously.

According to the ESM, positivity and negativity are partially separable and functionally

independent, such that increasing positivity does not necessarily decrease negativity, and

vice versa. That is, positivity and negativity are not confined to a reciprocal relationship,

but can vary independently of one another. As a result, the ESM predicts differential

activation functions for positivity and negativity (Figure 1). At high levels of emotional

input, it predicts a negativity bias, such that responses to extremely negative events and

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information (e.g., losing $100) are stronger than to equally positive (e.g., winning $100).

However, at low levels of emotional input, the ESM predicts a positivity offset, such that

responses to mildly positive events and information (e.g., finding a quarter) are stronger

than to equally negative (e.g., losing a quarter; Norris, Larsen, Crawford & Cacioppo, in

press).

These biases in emotional responding may have served evolutionarily adaptive

purposes. The negativity bias may have helped our early ancestors detect threatening

stimuli in the environment and facilitated avoidance-related behavior (e.g., running away)

in order to escape from potential harm. Given that a potentially harmful stimulus has

stronger implications for survival than an opportunity unpursued, the negativity bias may

have evolved to promote fitness. Conversely, the positivity offset may have promoted

exploration and approach-related behavior (e.g., searching for food) in more neutral

environments in order to encourage the pursuit of basic needs. Together, these emotional

biases encourage exploration while maintaining vigilance for aversive stimuli.

If these emotional biases serve adaptive purposes, then experience over time may

shape emotional responses in such a way as to enhance the adaptive aspects of the biases.

Thus, it is possible that the positivity effect seen in older adults may result from changes

in these emotional biases. One possibility is that the effect is due to a decreased

negativity bias (driven by responses to high levels of emotional input). Indeed, Wood

and her colleagues used event-related brain potentials (ERPs) to investigate the negativity

bias in younger and older adults. In an oddball paradigm, older adults exhibited smaller

amplitude late positive potentials (LPPs) than did younger adults, especially in response

to negative images (Kisley, Wood, & Burrows, 2007; Wood & Kisley, 2006). These data

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suggest a possible elimination of the negativity bias in older age. However, a decreased

negativity bias could be maladaptive, as it could reduce vigilance for or responses to

threatening stimuli in the world. In contrast to Wood and colleagues, Mather and Knight

(2006) found that the ability to detect threatening stimuli (e.g., angry faces) more quickly

than non-threatening stimuli (e.g., neutral faces) is maintained in older adulthood. This

finding indicates that the negativity bias may remain intact with age.

An alternative possibility is that the positivity effect in aging could be due to an

increased positivity offset (driven by responses to low levels of emotional input).

Consistent with this possibility, van Reekum and her colleagues (2010) found age

differences in psychophysiological responses to neutral stimuli. Older adults showed

decreased activity over corrugator supercilli (the brow muscle, which shows increased

activity during the experience of negative affect and decreased activity during the

experience of positive affect; Larsen, Norris & Cacioppo, 2003) and attenuated startle-

potentiated eye-blink responses (marking less negative affect; e.g., Lang, Bradley &

Cuthbert, 1990) to neutral pictures compared to younger adults. In other words, older

adults exhibited psychophysiological responses that indicated more positive affect and

less negative affect toward neutral stimuli. These responses suggest that the positivity

offset may be larger in older adults.

Taken together, these patterns of responding provide mixed evidence for changes

in emotional biases over the lifespan. The current study aimed to systematically compare

age differences in these emotional biases in order to assess whether the positivity effect is

related to a decreased negativity bias, an increased positivity offset, or both. To do this,

we examined age differences in behavioral and neural responses to emotional pictures

5

ranging from low levels of emotional input (i.e., neutral and mildly emotional pictures) to

high levels of emotional input (i.e., moderately and extremely emotional pictures). If

older adults exhibit a decreased negativity bias, we would expect them to respond more

favorably (i.e., more positively or less negatively) to the moderately or extremely

emotional pictures. Conversely, if older adults exhibit an increased positivity offset, we

would expect them to respond more favorably (i.e., more positively or less negatively) to

the neutral or mildly emotional pictures. Given older adults’ natural tendency to regulate

their emotions (Nashiro, Sakaki, & Mather, in press), we may also expect older adults to

show increased activation in prefrontal control regions implicated in emotion regulation,

such as the dorsomedial prefrontal cortex (dmPFC) or anterior cingulate cortex (ACC;

Goldin, McRae, Ramel & Gross, 2008; Ochnser, Bunge, Gross & Gabrieli, 2002;

Schaefer et al., 2002), or decreased activation in limbic structures, such as the amygdala

(Mather et al., 2004; Urry et al., 2006). The specific patterns of neural activation that

older adults demonstrate in response to both the milder and more extreme emotional

pictures may help shed light on the particular regulation strategies that may contribute to

the positivity effect.

Methods

Participants

Nineteen younger adults aged 18-22 (M = 19.0, SD = 1.05) and 23 older adults

aged 65-80 (M = 73.26, SD = 5.22) participated in the current study. Data from five older

adults were dropped from all analyses due to failure to follow task instructions. Data

from an additional seven younger adults and two older adults were dropped from the

imaging analyses due to excessive noise in the imaging data; an additional 11 older adults

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who participated in the behavioral task did not participate in the imaging task. This

resulted in final samples of 19 younger (M = 19.0, SD = 1.05) and 18 older adults (M =

72.72, SD = 5.61) included in the behavioral analyses and 12 younger (M = 19.08, SD =

1.31) and five older adults (M = 71.80, SD = 3.63) included in the imaging analyses.

Younger adults were undergraduates at Dartmouth College and received either course

credit or payment; older adults were recruited from the surrounding community and

received payment. All participants were right-handed females with normal or corrected-

to-normal vision and no history of neurological disorder. All participants provided oral

and written informed consent, and the study was approved by the Dartmouth College

Committee for the Protection of Human Subjects.

Materials

One hundred sixty-eight color pictures1 were chosen from the International

Affective Picture System (IAPS; Lang, Bradley, & Cuthbert, 2005) based on female-only

normative ratings to fill seven different categories, including neutral (low in arousal and

close to the midpoint of normative valence ratings) and a 2 (valence: unpleasant,

pleasant) x 3 (extremity: mild, moderate, extreme) design. Pictures were matched on

social content, with half of each category containing at least one person, and half

containing no people. Unpleasant and pleasant pictures at each extremity level were

1 IAPS stimuli numbers: 1220, 1230, 1280, 1463, 1617, 1661, 1670, 1731, 1811, 1942, 1945, 1947, 1999, 2055.1, 2102, 2110, 2153, 2190, 2209, 2210, 2221, 2230, 2235, 2271, 2305, 2344, 2346, 2372, 2383, 2393, 2394, 2396, 2397, 2435, 2441, 2442, 2513, 2515, 2520, 2593, 2700, 2752, 2830, 2840, 2850, 2870, 2880, 3061, 3160, 3220, 4233, 4250, 4532, 4537, 4621, 4623, 4624, 4625, 4626, 4640, 5260, 5270, 5480, 5530, 5700, 5740, 5910, 5970, 5973, 6312, 6561, 6838, 6930, 7000, 7031, 7036, 7039, 7130, 7140, 7192, 7217, 7234, 7236, 7247, 7250, 7270, 7281, 7282, 7330, 7350, 7351, 7460, 7472, 7475, 7481, 7491, 7493, 7495, 7500, 7501, 7502, 7503, 7504, 7508, 7510, 7550, 7595, 7700, 7920, 7950, 8010, 8090, 8120, 8130, 8170, 8210, 8220, 8241, 8380, 8420, 8465, 8467, 8470, 8499, 8502, 8510, 8531, 8600, 9005, 9007, 9008, 9045, 9046, 9110, 9140, 9171, 9190, 9270, 9280, 9290, 9320, 9340, 9373, 9390, 9400, 9401, 9404, 9421, 9424, 9429, 9440, 9470, 9471, 9472, 9495, 9560, 9561, 9584, 9600, 9611, 9620, 9621, 9622, 9830, 9900, 9902, 9911, and 9912.

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matched on normative arousal and extremity (i.e., distance from the midpoint of the

normative valence rating scale), and all categories were matched on RGB values, hue,

saturation, luminance, and spatial complexity.

Procedure

Once situated in the scanner, participants were instructed to view each picture for

the entire time it was displayed and think about whether it was positive or negative.

Pictures appeared in one of two predetermined pseudorandom orders, counterbalanced

across participants. An angled mirror attached to the head coil allowed participants to

view the pictures projected onto a panel at the end of the scanner bore; a PC using E-

Prime version 2.0 Professional software (Psychology Software Tools, Inc., Pittsburgh,

PA) presented the pictures. Each trial consisted of a white fixation cross displayed on a

black background for 1 s, followed by a picture displayed for 4 s; jittered intertrial

intervals consisting of a black background ranged from 1 to 13 s (mean = 5 s), which

allowed for deconvolution of the hemodynamic response.

Behavioral Task. Participants viewed each picture again outside of the scanner,

this time rating how they felt about each picture using the Evaluative Space Grid (ESG;

Larsen, Norris, McGraw, Hawkley & Cacioppo, 2009). The ESG is a 5x5 grid that

allows for independent assessments of negativity and positivity. Negativity is measured

on the y-axis and positivity on the x-axis, with ratings on each axis ranging from not at all

negative/positive (coded as 0) to very negative/positive (4). Participants used the grid to

select the cell that most appropriately represented their positive and negative feelings

about each picture. A PC using E-Prime version 2.0 Professional software (Psychology

Software Tools, Inc., Pittsburgh, PA) presented the pictures and recorded negative

8

ratings, positive ratings and response times for each picture. On each trial, the ESG

appeared immediately below the picture. Pictures appeared in random order at a rate

controlled by participants, such that each picture remained visible until participants made

a rating.

fMRI Image Acquisition

Functional magnetic resonance images were acquired on a 3.0 Tesla Philips

Achieva Intera scanner (Philips Medical Systems, Bothell, WA), with an eight-channel

SENSE head coil. Functional T2*-weighted echo-planar images were acquired in six runs

with 36 contiguous 3.5mm axial interleaved slices with a 0.5mm gap (TR = 2000 ms, TE

= 35 ms, flip angle = 90°, field of view = 24 cm, 80x80 matrix size, fat suppressed).

High-resolution T1-weighted anatomical images were acquired in 160 1-mm sagittal

slices (TR = 9.8 ms, TE = 4.6 ms, flip angle = 8°, field of view = 24 cm).

fMRI Preprocessing

We used AFNI software (Cox, 1996) for processing and analysis of fMRI data.

For each participant, the data were despiked, corrected for slice timing, realigned using a

six-parameter, rigid-body transformation, and converted to percent signal change.

Individual-participant deconvolution analyses then removed variance due to motion as

well as constant and linear trends, and the voxel-wise standard deviation of the residual

signal was calculated in order to assess the signal-to-noise ratio. Output from the

deconvolution analyses underwent spatial smoothing using a 6-mm FWHM Gaussian

kernel.

A second individual-participant deconvolution analysis isolated contributions of

each condition to the fMRI signal by generating impulse response functions (IRFs) of the

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signal for each condition of a 2 (valence: unpleasant, pleasant) x 2 (extremity: mild,

extreme) design, with a filler condition comprised of responses to the remaining

pictures2. The analysis used a sine function, with 15 regressors per condition (i.e., one

regressor for each second of the estimated hemodynamic response) to model the

hemodynamic response to each condition. Each participant’s data were then normalized

to Talairach stereotaxic coordinate space (Talairach & Tournoux, 1988), and a measure

of the area under the curve (AUC; seconds 5-10) was calculated for use in group analysis;

each condition’s AUC was used as a measure of neural activation to that condition. All

group analyses were thresholded at p < .001, uncorrected, with a minimum cluster size of

50 voxels.

Results

Emotional Biases in Picture Ratings

The positivity offset refers to the tendency for positivity to outweigh negativity at

low levels of input to the affect system. Conversely, the negativity bias refers to the

tendency for negativity to outweigh positivity at high levels of input (Figure 1). We

examined the positivity offset and negativity bias by comparing positive ratings of

pleasant pictures with negative ratings of unpleasant pictures (i.e., “dominant ratings”).

Specifically, we sought to determine whether older and younger adults differed in the

positivity offset and negativity bias. To this end, we conducted a 2 (Age: younger, older)

x 2 (Picture Valence: unpleasant, pleasant) x 4 (Picture Extremity: neutral, mild,

2 The model was limited to these conditions in order to increase power in group analyses designed specifically to investigate neural responses underlying the positivity offset and negativity bias. The mildly emotional pictures were used instead of neutral pictures to investigate the positivity offset, as the positivity offset must be calculated by comparing two conditions (i.e., pleasant – unpleasant) at relatively low levels of emotional input. The mildly emotional pictures offered two such conditions (mildly pleasant, mildly unpleasant), while the neutral pictures did not.

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moderate, extreme) repeated measures general linear model (GLM) analysis on dominant

ratings (i.e., negative ratings of unpleasant pictures and positive ratings of pleasant

pictures).3 This analysis allowed several manipulation checks in addition to addressing

our primary question of interest.

First, there was a main effect of Extremity, F(3, 33) = 280.50, p < .001, ηp2 = .96;

this was a manipulation check that showed that dominant ratings increased as a function

of the extremity of the picture (i.e., distance from the midpoint of the normative valence

scale); all ps < .001. There was no main effect of Age, F(1, 35) < 1, p = .99, ηp2 < .001,

indicating that older and younger adults did not differ in their overall ratings of the

pictures. There was also no main effect of Valence, F(1, 35) < 1, p = .41, ηp2 = .02,

demonstrating that participants rated unpleasant and pleasant pictures equally intensely.

More importantly, we examined whether participants demonstrated a positivity

offset and a negativity bias in response to the pictures. A significant Valence x Extremity

interaction, F(3, 33) = 50.31, p < .001, ηp2 =.82, verified that participants responded with

both a positivity offset and a negativity bias. Pairwise comparisons revealed that

participants showed higher positive (M = 1.07, SE = .09) than negative ratings (M = .57,

SE = .06) of neutral pictures, p < .001, ηp2 = .49, as well as higher dominant ratings of

mildly pleasant (M = 1.91, SE = .08) than of mildly unpleasant (M = 1.65, SE = .08)

pictures, p =.02, ηp2 = .16 (i.e., both findings are consistent with the functioning of a

positivity offset). They also showed higher dominant ratings of moderately unpleasant

(M = 2.72, SE = .07) than moderately pleasant (M = 2.28, SE = .09) pictures, p < .001, ηp2

= .41, and higher dominant ratings of extremely unpleasant (M = 3.28, SE = .07) than of

3 Positive and negative ratings of neutral pictures were used as a measure of unpleasant and pleasant valence.

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extremely pleasant (M = 2.70, SE = .09) pictures, p < .001, ηp2 = .56 (i.e., both findings

are consistent with the functioning of a negativity bias; Figure 2).

Finally, our primary question of interest concerned whether younger and older

adults differ with respect to the positivity offset and negativity bias. A significant Age x

Valence x Extremity interaction, F(3, 33) = 9.53, p < .001, ηp2 = .46, revealed an age

difference in these emotional biases. Compared to younger adults, older adults rated

neutral (older: M = .46, SE = .09; younger: M = .70, SE = .08) and mildly unpleasant

pictures (older: M = 1.51, SE = .11; younger: M = 1.79, SE = .11), as marginally less

negative, ps < .07, and mildly pleasant pictures as more positive (older: M = 2.10, SE =

.11; younger: M = 1.72, SE = .11), p = .02. These ratings show a larger positivity offset

among the older adults. Specifically, younger adults demonstrated a positivity offset only

in response to neutral pictures, but older adults showed a positivity offset in response to

both neutral and mildly emotional pictures. However, there were no age differences in

responses to moderately or extremely emotional pictures, ps > .21, resulting in no age

differences in the negativity bias. In sum, the age groups did not differ in the negativity

bias, but older adults showed a larger and extended positivity offset as compared to

younger adults (Figure 2).

Since this analysis revealed significant age differences involving only the mildly

emotional pictures, further analyses focused on that category. We next sought to explore

the nature of the processes underlying the extended positivity offset in older adults.

Specifically, we wondered whether this effect appeared to be the result of more automatic

or effortful processes. For example, if older adults’ extended positivity offset occurs by

relatively automatic processes, then older adults should rate the mildly emotional pictures

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as quickly, or even more quickly, than younger adults. However, if older adults’

extended positivity offset occurs by more effortful processes, then they should rate the

mildly emotional pictures more slowly than younger adults, since longer response times

may suggest that effortful processes have been recruited.

To investigate these questions, we conducted a 2 (Age: younger, older) x 2

(Picture Valence: mildly unpleasant, mildly pleasant) repeated measures GLM on z-

scored response times (RTs), trimmed to exclude the fastest and slowest 10% of

responses (Bush, Hess, & Wolford, 1993). This analysis yielded no main effects of Age,

F(1, 35) = .62, p = .44, ηp2 = .02, or Valence, F(1, 35) = 1.74, p = .20, ηp

2 = .05, but did

reveal a significant Age x Valence interaction, F(1, 35) = 5.95, p = .02, ηp2 = .15.

Pairwise comparisons showed that older adults (M = .24, SE = .05) took longer than

younger adults (M = .06, SE = .05) to rate the mildly unpleasant pictures, p = .02, but RTs

to the mildly pleasant pictures did not differ by age (Molder = .02, SEolder = .06; Myounger =

.12, SEyounger = .06), p = .20. Furthermore, older adults took longer to rate mildly

unpleasant (M = .24, SE = .05) compared to mildly pleasant pictures (M = .02, SE = .06),

p = .01, while younger adults showed no differences in RTs, p = .43 (Figure 3). In sum,

older adults took longer to respond to mildly unpleasant pictures than did younger adults.

One possible explanation for this pattern of RTs is that older adults were

distracted by the unpleasant pictures, and subsequently took longer to rate them.

However, this explanation seems unlikely given previous research demonstrating greater

attention to and memory for positive (i.e., pleasant) than negative (i.e., unpleasant)

stimuli in older adults (e.g., Mather & Carstensen, 2005). A second possibility is that this

pattern reflects an effortful process on the part of older adults to feel more favorably

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toward mildly emotional stimuli. If this is accurate, then older adults should a) assign

lower negative and/or higher positive ratings to mildly emotional pictures than younger

adults, and b) rate mildly emotional pictures as increasingly more positive and/or less

negative as picture viewing time increases.

To examine these hypotheses, we first looked at whether older adults rated mildly

emotional pictures less negatively and/or more positively. Four independent-samples t-

tests were conducted to compare older and younger adults’ positive and negative ratings

of mildly unpleasant and mildly pleasant pictures. 4 These analyses revealed that older

adults rated mildly pleasant pictures as less negative (M = .26, SE = .06) and more

positive (M = 2.10, SE = .13) than younger adults (negative: M = .47, SE = .06; positive:

M = 1.72, SE = .09), ts(35) = -2.41 and 2.41, respectively, ps = .02. There was also a

trend for older adults to rate mildly unpleasant pictures as less negative than younger

adults (older: M = 1.50, SE = .13; younger: M = 1.79, SE = .08), t(35) = -1.89, p = .07

(Figure 4). Taken together, these data support the conclusion that older adults did indeed

respond more favorably to mildly emotional pictures than younger adults.

Finally, we examined whether older adults’ more positive and less negative

responses to the mildly emotional pictures may be the result of effortful processes. As

outlined above, we expected that if older adults were engaging effortful self-control

processes, we should see that longer RTs predict better regulation (i.e., more positive,

less negative ratings) in older but not younger adults. Since older adults showed longer

RTs only to the mildly unpleasant pictures, analyses focused on those pictures. Negative

and positive ratings of the mildly unpleasant pictures were separately regressed on Age

4 This is in contrast to the omnibus GLM, which included only dominant ratings (i.e., negative ratings of unpleasant pictures and positive ratings of pleasant pictures).

14

(younger, older), RTs to the mildly unpleasant pictures (RTs), and the interaction (Age x

RT). For negative ratings, the model was not significant, R2 = .11, F(3, 33) = 1.35, p =

.28; that is, none of the variables predicted negative ratings of the mildly unpleasant

pictures, ps > .08. For positive ratings, however, the model was significant, R2 = .28,

F(3, 33) = 4.37, p = .01. There was a trend for RTs to predict positive ratings, b = .47,

t(33) = 2.03, p = .05. However, this was qualified by a significant Age x RT interaction,

b = -.69, t(33) = -2.94, p < .01. Bivariate correlations revealed that longer RTs predicted

higher positive ratings of the mildly unpleasant pictures among older, r = .58, p = .01, but

not younger adults, r = -.20, p = .42. That is, the more time that older adults took to rate

the mildly unpleasant pictures, the more positively they rated them (Figure 5). Taken

together, these data suggest that older adults may have effortfully attempted to feel more

positive when viewing mildly unpleasant pictures.

Emotional Biases in Brain Function

We next examined whether participants exhibited a positivity offset and

negativity bias in neural activity by comparing neural responses to pleasant pictures with

neural responses to unpleasant pictures across all participants. To examine the positivity

offset, a whole-brain paired-sample t-test compared neural activation to mildly pleasant

pictures with activation to mildly unpleasant pictures (i.e., mildly pleasant – mildly

unpleasant). No regions demonstrated greater activation to the mildly pleasant than the

mildly unpleasant pictures. However, several regions of the prefrontal cortex

demonstrated greater activation to the mildly unpleasant pictures (Table 1, Figure 6).

These regions included bilateral clusters in the dorsomedial prefrontal cortex (dmPFC;

BA 9), right ventrolateral prefrontal cortex (vlPFC; BA 47), left medial prefrontal cortex

15

(mPFC; BA 9), right supplementary motor area (SMA; BA 6), and left frontal eye fields

(BA 8).

To examine the negativity bias, a second whole-brain paired-sample t-test

compared activation to very unpleasant pictures with activation to very pleasant pictures

(i.e., very unpleasant – very pleasant). No regions demonstrated greater activation to the

very unpleasant than the very pleasant pictures. However, clusters in the left medial

prefrontal cortex (mPFC; BA 10) and left parahippocampal gyrus demonstrated greater

activation to the very pleasant pictures (Table 2, Figure 7).

As our primary question of interest concerned whether younger and older adults

differ with respect to the positivity offset and negativity bias, we next directly compared

the age groups’ emotional biases in neural activity. To examine age differences in the

positivity offset, we first calculated contrasts comparing neural activation to mildly

pleasant pictures with activation to mildly unpleasant pictures (mildly pleasant – mildly

unpleasant; i.e., a positivity offset) for each individual participant. These contrasts were

then submitted to an independent-samples t-test comparing older and younger adults’

neural positivity offset. This analysis revealed three regions exhibiting significant age

differences (Table 3, Figure 8). Older adults demonstrated a greater positivity offset than

younger adults in the vlPFC (BA 47) and fusiform gyrus. That is, older adults showed

greater activation of these areas in response to the mildly pleasant pictures than the

mildly unpleasant. In contrast, younger adults demonstrated a greater positivity offset in

the subgenual anterior cingulate cortex (sgACC; BA 25). That is, younger adults showed

greater activation of the sgACC to mildly pleasant than unpleasant pictures, while older

adults showed the opposite pattern of activation (Figure 8).

16

To examine age differences in the negativity bias, we calculated contrasts

comparing neural activation to very unpleasant pictures with activation to very pleasant

pictures (very unpleasant – very pleasant; i.e., a negativity bias) for each individual

participant. These contrasts were then submitted to an independent-samples t-test

comparing older and younger adults’ neural negativity bias. Older adults showed a

greater negativity bias in two regions of prefrontal cortex (Table 4, Figure 9). The largest

cluster extended from the left frontal eye fields into the SMA (BA 8 / BA 6); a second

cluster was located in the right dorsolateral prefrontal cortex (dlPFC; BA 9). That is,

older adults showed greater activation of these prefrontal regions to the very unpleasant

pictures than the very pleasant. Younger adults did not show a greater negativity bias

than older adults in any region.

Discussion

In the current study, older adults showed a larger and extended positivity offset in

ratings of emotional pictures compared to younger adults. Both age groups demonstrated

a positivity offset to neutral pictures, as predicted by the ESM; however, older adults

continued to show a positivity offset in response to mildly emotional pictures, while

younger adults did not. This extended positivity offset in older adults was driven by

higher positive and lower negative ratings of the mildly emotional pictures. Older adults

also took more time to rate the mildly unpleasant pictures, and the longer they took to

rate these pictures, the more positive they reported feeling about them. In contrast, there

were no age differences in the negativity bias. Taken together, these findings suggest that

older adults may effortfully regulate their responses to mildly emotional stimuli in order

to feel more favorably about them. That is, older adults may regulate their emotions to

17

feel more positively (and less negatively) toward a wider range of emotional stimuli than

younger adults.

The current study also investigated the neural mechanisms underlying the

positivity offset and negativity bias across the life span. Neural response patterns were

consistent with the behavioral response patterns in that several prefrontal control regions

demonstrated greater activation to the mildly unpleasant pictures than the mildly pleasant,

including the dmPFC, vmPFC, and vlPFC. Previous work has implicated the dmPFC in

the appraisal and experience of negative emotion (Etkin, Egner, & Kalisch, 2011), as well

as in making inferences about one’s feelings (Wager et al., 2008), whereas the vmPFC

and vlPFC have been shown to be involved in the regulation of negative emotion (Etkin

et al., 2011; Wager, Davidson, Hughes, Lindquist, & Ochsner, 2008) and the selection or

inhibition of information (Aron & Poldrack, 2005). These results suggest that the

dmPFC may detect the valence of the mildly unpleasant pictures and signal the need for

the vmPFC and vlPFC to down-regulate any negative emotional responses.

In contrast to this down-regulation of negative emotional responses to the mildly

unpleasant pictures, neural responses to the more extreme pictures suggested that

participants may have been attempting to engage with the very pleasant pictures or even

up-regulate their responses to them. Specifically, the mPFC showed greater activation to

the very pleasant pictures than the very unpleasant. Previous work has demonstrated that

this region is activated when increasing positive emotion (Kim & Hamann, 2007) and is

sensitive to the self-relevance of a stimulus (Kelley et al., 2002). Additionally, the

parahippocampal gyrus, a region involved in emotion perception (Wager et al., 2008),

showed greater activation to the very pleasant pictures than the very unpleasant. Taken

18

together, these results suggest that participants may have utilized the mPFC in an attempt

to upregulate positivity by focusing on the perceptual and self-relevant aspects of the

very pleasant pictures. In sum, neural responses to the emotional pictures appeared to be

characterized by the down-regulation of responses to the mildly unpleasant pictures, and

the up-regulation of responses to the very pleasant pictures.

This approach may have been particularly effective among the older adults, as

they demonstrated these sorts of patterns to a greater extent than did younger adults. For

example, Urry, van Reekum, Johnstone, & Davidson (2009) demonstrated that the

sgACC is involved in the cognitive reappraisal of emotion. In the current study, older

adults (compared to younger adults) showed greater activation of the sgACC in response

to the mildly unpleasant than mildly pleasant pictures, suggesting that older adults may

have been down-regulating negative responses to the mildly unpleasant pictures.

Moreover, older adults showed a greater positivity offset (i.e., greater activation to the

mildly pleasant than mildly unpleasant pictures) in the vlPFC and fusiform gyrus than did

younger adults. As previously discussed, the vlPFC works to generate and regulate

emotional responses (Wager et al., 2008), and the fusiform gyrus is a relatively low-level

perceptual region that is sensitive to emotional content (Norris, Chen, Zhu, Small, &

Cacioppo, 2004). These patterns of vlPFC and fusiform gyrus activity suggest that older

adults may have utilized the vlPFC in an attempt to upregulate positivity, in part by

focusing on the positive aspects of the mildly pleasant pictures. Taken together, these

results suggest that older adults may have been down-regulating their responses to the

mildly unpleasant pictures and up-regulating their responses to the mildly pleasant

pictures to a greater extent than younger adults.

19

Finally, older adults showed a similar pattern in neural responses to the very

emotional pictures. Specifically, older adults showed a greater negativity bias (i.e.,

greater activation in response to very unpleasant than very pleasant pictures) than did

younger adults in two regions of the PFC: the dmPFC and a region including the frontal

eye fields. As the dmPFC is involved in the appraisal of negative emotion (Etkin et al.,

2011) and making inferences about one’s feelings (Wager et al., 2008), it is possible that

the dmPFC may have detected the valence of the very unpleasant pictures and signaled

the need for regulation. The older adults may then have attempted to down-regulate their

emotional responses to the pictures by looking away from the negative aspects of these

pictures (e.g., Urry, 2010; van Reekum et al., 2007), as suggested by the activation of the

frontal eye fields (Leichnetz & Goldberg, 1988). It should be noted that we did not have

a measure of eye movement, so our dataset does not allow us to be certain that older

adults looked away from the very unpleasant pictures; however, the patterns of neural

activation are consistent with this possibility.

Emotion Regulation and Emotional Biases in Older Adults

Taken together, the behavioral and neural data from the current study suggest that

older adults may be effortfully regulating their emotional responses in order to increase

positivity and decrease negativity. Socioemotional selectivity theory proposes that a

sense of limited time left in life may motivate older adults to pursue more emotionally

gratifying experiences (Carstensen, Fung, & Charles, 2003; Carstensen, Isaacowitz, &

Charles, 1999). This motivation to seek out emotionally meaningful experiences

combined with a lifetime of emotion regulation experience may result in more effective

and refined emotion regulation in older age (e.g., Gross et al., 1997; Larcom &

20

Isaacowitz, 2009). Indeed, our findings are consistent with this refined emotion

regulation. Specifically, our data demonstrate that older adults may attempt to create

more gratifying emotional experiences by regulating their emotional responses to even

mildly evocative stimuli or events. Older adults also appear to employ multiple regulation

strategies in order to achieve more effective regulation. Much emotion regulation

research focuses on the strategy of cognitive reappraisal (e.g., Goldin et al., 2008;

Ochsner, Bunge, Gross, & Gabrieli, 2002; Urry et al., 2009; Urry 2010); however,

reappraisal-related processes require cognitive resources that may deteriorate as we age,

potentially rendering cognitive reappraisal a less effective emotion regulation strategy for

older adults. To compensate for this loss of cognitive resources, older adults may employ

other types of strategies to supplement or use instead of cognitive reappraisal (Urry &

Gross, 2010).

For example, our data suggest that older adults may regulate their emotions to

very emotional stimuli by attempting to engage with pleasant content and look away or

divert their attention from unpleasant content. As it is likely easier to enhance an active

emotional response than reduce one, this may be a more feasible option when faced with

diminishing cognitive resources. However, reappraisal may remain an effective strategy

for regulating responses to milder emotional stimuli, since it likely requires fewer

cognitive resources to down-regulate the less intense emotional responses these stimuli

elicit. Consistent with this idea, our data suggest that older adults may successfully

regulate their emotions to mildly emotional stimuli by reappraising unpleasant content in

addition to attempting to engage with pleasant content. In sum, older adults may employ

strategies that require fewer cognitive resources in order regulate responses to more

21

intense emotional stimuli, while reserving more resource-demanding strategies (e.g.,

cognitive reappraisal; Urry & Gross, 2010) for regulating responses to milder emotional

stimuli.

Despite neural evidence that older adults were attempting to regulate their

responses to both mildly and very emotional pictures, the current study revealed

behavioral age differences only in response to the mildly emotional pictures. The more

positive responses to mildly emotional information exhibited by older adults suggest that

the positivity effect (e.g., Mather & Carstensen, 2005) may be driven in part by responses

to mildly emotional stimuli in particular. Interestingly, responding more positively to

mildly emotional information (i.e., an increased positivity offset) may serve as a highly

efficient way to increase overall positive daily emotional experiences, as daily life

involves many more mild emotional experiences than extreme. If the positivity effect in

older adults were due to a decreased negativity bias, then older adults would presumably

demonstrate a shift in responses to extreme stimuli (i.e., respond with less negativity or

more positivity to extremely emotional events.) However, extremely emotional events,

such as having a baby or losing a loved one, occur relatively infrequently in daily life,

thereby limiting the effectiveness of using a decreased negativity bias as a regulation

strategy. Rather, it is much more common to encounter mildly emotional events in daily

life, such as enjoying a cup of coffee in the morning or being stuck in a traffic jam.

Regulating emotional responses to these more frequent events would presumably serve as

an effective mechanism for generating the more emotionally meaningful experiences

predicted by the socioemotional selectivity theory. For example, older adults may seek

22

pleasure by savoring their morning cup of coffee or choosing to appreciate the

opportunity provided by a traffic jam to converse with fellow passengers.

Although older adults’ neural response patterns suggest that they may be

attempting to regulate their emotions to the very emotional content, the current study

revealed no age differences in the negativity bias in picture ratings. This suggests that

their attempts at regulation may not be successfully influencing their behavioral

responses. As previously discussed, it may be inherently more difficult to reduce

emotional responses to very unpleasant stimuli, especially when faced with the loss of

cognitive resources (Urry & Gross, 2010). Moreover, it may be difficult to overcome a

negativity bias in emotional responding since such a bias is evolutionarily adaptive.

Indeed, the emotional response patterns exhibited by the older adults are

consistent with the adaptive functions of the emotional biases predicted by the ESM. For

example, the maintained negativity bias demonstrated by older adults suggests that the

affect system may preserve vigilance for more extreme emotional stimuli in older age,

facilitating avoidance of potentially dangerous stimuli throughout the lifespan. However,

the enhanced positivity offset in older age promotes the strengthening of approach

behavior to more innocuous stimuli. This mechanism may further facilitate older adults’

continued pursuit of emotionally meaningful relationships and experiences. In sum, the

emotional biases demonstrated by older adults facilitate the avoidance of very negative

emotional events and the pursuit of mildly positive emotional events in later life.

Alternative Explanations

Although our findings suggest that the positivity effect in aging may be driven

primarily by responses to mildly emotional information (i.e., an increased positivity

23

offset), other evidence suggests that there may be more substantial age differences in the

negativity bias than were revealed in the current study. For example, previous research

found that older adults exhibited smaller amplitudes in the late positive potential (LPP)

component of the event-related potential (ERP) response to emotional pictures, especially

if the pictures were negative in valence (Kisley, Wood, & Burrows, 2007 ; Wood &

Kisley, 2006;). These data suggest that there may be a diminished negativity bias with

age, at least in terms of initial neural reactivity (e.g., 400 milliseconds after stimulus

onset). However, the processes reflected by this relatively early neural activity may be

quite different from the processes involved in more deliberate tasks, such as our ratings

task. Indeed, van Reekum and colleagues (2010) found EMG evidence that older adults

showed decreased recovery from unpleasant pictures (i.e., maintained corrugator

supercilii activation following the offset of unpleasant pictures) but responded more

positively (i.e., decreased startle response and corrugator superciliii activation) in

response to neutral pictures than did younger adults. These patterns suggest a maintained

negativity bias and increased positivity offset with age, consistent with the current study.

Further evidence supporting the notion of an increased positivity offset with age

indicates that older adults attempt to maintain or increase positivity in daily emotional

experiences (most of which are presumably fairly mild). Riediger, Schmiedek, Wagner,

and Lindenberger (2009) found that while performing such typical daily activities as

watching TV, having a conversation, or running errands, adolescents sought to maintain

or enhance negative affect and attenuate positive affect; whereas older adults showed the

reverse pattern, seeking to attenuate negative and maintain positive affect.

24

The brain regions activated to mildly emotional pictures in the current study also

seem to be consistent with this enhanced positivity offset in older adults. Specifically,

older adults showed greater activation of several PFC regions to mildly unpleasant than

mildly pleasant pictures. Though this pattern of neural activation is consistent with

emotion regulation, the functions of the PFC are complex, and these regions may have

been engaging in other processes. Given that the neural responses were all greater to the

mildly unpleasant pictures, it is possible that these regions were actually more involved in

the appraisal and experience of mildly unpleasant emotion than its regulation (e.g., Etkin

et al., 2011). For example, Mayberg and her colleagues (2005) have demonstrated that

the sgACC is hyperactive in patients with major depressive disorder (MDD), suggesting

that this region may be sensitive to unpleasant emotion. However, this interpretation is

unlikely in the current study, given the greater positivity and decreased negativity

underlying the enhanced positivity offset demonstrated by older adults. Moreover, even

if the sgACC and other PFC regions were demonstrating sensitivity to the negative

valence of the mildly unpleasant pictures, older adults’ ratings of these pictures suggest

that this sensitivity may have served to signal the need for regulation.

Limitations

Interpretations of older adults’ neural and behavioral responses to the mildly

emotional pictures have focused on the notion that older adults were regulating their

responses to these pictures. However, participants in this study were not instructed to

regulate their emotions; rather they were allowed to respond freely to each picture.

Therefore, any inferences about regulation processes may be limited. Still, other neural

evidence and the socioemotional selectivity theory support the possibility that older

25

adults chronically regulate their emotions, even when not instructed to do so (Carstensen

et al., 2003; Nashiro, Sakaki, & Mather, in press). Therefore, it is likely that the older

adults in this study were automatically regulating their emotional responses. In this way,

the specific neural mechanisms underlying age differences in emotional biases can also

shed light on the particular regulation strategies that may contribute to the positivity

effect in aging.

Interpretations regarding how older adults’ neural responses affected their

behavioral responses should also be made with caution, as there are several issues with

directly comparing the two types of responses. First, the imaging and behavioral tasks

were slightly different and may not be directly comparable. In the fMRI task,

participants were simply asked to view each picture and think about whether it made

them feel negative or positive. The behavioral task was slightly more complex, as

participants were instructed to simultaneously rate both how negative and how positive

each picture made them feel. Moreover, these two tasks were performed at different

times, with the fMRI task always preceding the behavioral task. Accordingly,

participants always viewed each picture for the second time during the behavioral task.

Finally, pictures were always presented for only four seconds during the imaging task,

requiring participants to respond relatively (though reasonably) quickly to each picture.

In contrast, picture duration was self-paced in the behavioral task, allowing more time for

emotional responses and regulation processes to unfold. For all these reasons, the

processes involved in the two tasks are likely not identical, so any direct inferences about

the ways in which these processes interact are limited.

Conclusions and Future Research

26

The literature examining emotional responses across the life span demonstrates

that older adults seek to increase positivity in general, but the underlying mechanisms of

this positivity effect have received relatively little attention. The current study provided

evidence that older adults show a larger and extended positivity offset compared to

younger adults, driven by increased positivity and decreased negativity to mildly

emotional stimuli. Patterns of neural activation and response times to these mildly

emotional stimuli suggest that this effect may result from more effective emotion

regulation and more varied emotion regulation strategies employed by older adults.

Future research should focus on investigating the psychological mechanisms

underlying the positivity effect in older age. Specifically, it remains uncertain under

which circumstances the positivity effect is due to decreased negativity, increased

positivity, or both. Additionally, more attention needs to be paid to the emotional

intensity (e.g., mild versus extreme) of the stimuli used in studies of emotional responses

across the life course, as we have demonstrated that age differences in emotional

responding may be limited to relatively mild stimuli. Finally, careful research is needed

to investigate the multiple regulation strategies that may contribute to the positivity

effect. For example, questions remain regarding the circumstances under which any

particular strategy is employed, which strategies older adults use most effectively, and

which they use most often.

Although the positivity effect is likely the result of a complex interplay of

processes, the current study indicates that at least one mechanism by which older adults

become more positive with age is through an increased positivity offset. This increase

may be due in part to multiple regulation strategies employed by older adults, including

27

cognitive reappraisal and attentional deployment. In this way, older adults respond more

positively to mildly emotional stimuli, perhaps allowing them to more fully appreciate

the simple things in life.

28

References

Aron, A. R. & Poldrack, R. A. (2005). The cognitive neuroscience of response inhibition:

Relevance for genetic research in ADHD. Biological Psychiatry, 57, 1285-92.

doi:10.1016/j.biopsych.2004.10.026

Bush, L. K., Hess, U., & Wolford, G. (1993). Transformations for within-subject designs:

A Monte Carlo investigation. Psychological Bulletin, 113, 566-579.

doi:10.1037/0033-2909.113.3.566

Cacioppo, J. T., & Berntson, G. G. (1994). Relationship between attitudes and evaluative

space: A critical review, with emphasis on the separability of positive and

negative substrates. Psychological Bulletin, 115, 401-423. doi:10.1037/0033-

2909.115.3.401

Cacioppo, J. T., Gardner, W. L., & Berntson, G. G. (1997). Beyond bipolar

conceptualizations and measures: The case of attitudes and evaluative space.

Personality and Social Psychology Review, 1, 3-25.

doi:10.1207/s15327957pspr0101_2

Carstensen, L. L., Fung, H. H., & Charles, S. T. (2003). Socioemotional selectivity theory

and the regulation of emotion in the second half of life. Motivation & Emotion,

27, 103-123. doi:10.1023/A:1024569803230

Carstensen, L. L., Isaacowitz, D. M., & Charles, S. T. (1999). Taking time seriously: A

theory of

socioemotional selectivity. American Psychologist, 54, 165–181.

doi:10.1037/0003-066X.54.3.165

29

Carstensen, L. L., Pasupathi, M., Mayr, U., & Nesselroade, J. R. (2000). Emotional

experience in everyday life across the adult life span. Journal of Personality and

Social Psychology, 79, 644-655. doi:10.1037/0022-3514.79.4.644

Charles, S. T., Mather, M., & Carstensen, L. L. (2003). Aging and emotional memory:

The forgettable nature of negative images for older adults. Journal of

Experimental Psychology: General, 132, 310-324. doi:10.1037/0096-

3445.132.2.310

Charles, S. T., Reynolds, C. A., & Gatz, M. (2001). Age-related differences and change

in positive and negative affect over 23 years. Journal of Personality and Social

Psychology, 80, 136-151. doi:10.1037/0022-3514.80.1.136

Cox, R. W. (1996). AFNI� Software for Analysis and Visualization of Functional

Magnetic Resonance Neuroimages. Computers and Biomedical Research, 29,

162-173.

Etkin, A., Egner, T., & Kalisch, R. (2011). Emotional processing in anterior cingulate and

medial prefrontal cortex. Trends in Cognitive Neuroscience, 15, 85-93.

doi:10.1016/j.tics.2010.11.004

Goldin, P. R., McRae, K., Ramel, W., & Gross, J.J. (2008). The neural basis of emotion

regulation: Reappraisal and suppression of negative emotion. Biological

Psychiatry, 63, 577-586. doi:10.1016/j.biopsych.2007.05.031

Gross, J. J. (1998). Antecedent- and response-focused emotion regulation: Divergent

consequences for experience, expression, and physiology. Journal of Personality

and Social Psychology, 74, 224-237.

30

Gross, J. J., Carstensen, L. L., Pasupathi, M., Tsai, J., Skorpen, C. G., & Hsu, A. Y. C.

(1997). Emotion and aging: Experience, expression, and control. Psychology and

Aging, 12, 590-599. doi: 10.1037/0882-7974.12.4.590

Isaacowitz, D. M., Wadlinger, H. A., Goren, D., & Wilson, H. R. (2006). Is there an age-

related positivity effect in visual attention? A comparison of two methodologies.

Emotion, 6, 511-516. doi:10.1037/1528-3542.6.3.511

Kelley, W. M., Macrae, C. N., Wyland, C. L., Caglar, S., Inati, S., & Heatherton, T. F.

(2002). Finding the self? An event-related fMRI study. Journal of Cognitive

Neuroscience, 14, 785-794. doi:10.1162/08989290260138672

Kim, S. H., & Hamann, S. (2007). Neural correlates of positive and negative emotion

regulation. Journal of Cognitive Neuroscience, 19, 776-798. doi:

10.1162/jocn.2007.19.5.776

Kisley, M. A., Wood, S., & Burrows, C. L. (2007). Looking at the sunny side of life.

Psychological Science, 18, 838-843. doi:10.1111/j.1467-9280.2007.01988.x

Lang, P. J., Bradley, M. M., & Cuthbert, B. N (1990). Emotion, attention, and the startle

reflex. Psychological Review, 97, 377-395. doi:10.1111/j.1469-

8986.1990.tb01966.x

Lang, P. J., Bradley, M. M., & Cuthbert, B. N. (2005). International affective picture

system (IAPS): Instruction manual and affective ratings. Technical Report A-6,

The Center for Research in Psychophysiology, University of Florida.

Larcom, M.J. & Isaacowitz, D.M. (2009). Rapid emotion regulation after mood

induction: Age and individual differences. Journal of Gerontology: Psychological

Sciences, 64B, 733-741. doi:10.1093/geronb/gbp077.

31

Larsen, J.T., Norris, C.J., McGraw, A.P., Hawkley, L.C., & Cacioppo, J.T. (2009). The

evaluative space grid: A single-item measure of positivity and negativity.

Cognition and Emotion, 23, 453-480. doi: 10.1080/02699930801994054

Leichnetz, G. R., & Goldberg, M. E. (1988). Higher centers concerned with eye

movement and visual attention: Cerebral cortex and thalamus. In Neuroanatomy

of the Oculomotor System, J. A. Buttner-Ennever (Editor), pp. 365-429, Elsevier,

New York.

Mather, M., Canli, T., English, T., Whitfield, S., Wais, P., Ochsner, K., …Carstensen, L.

L. (2004). Amygdala responses to emotionally valenced stimuli in older and

younger adults. Psychological Science, 15, 259-263. doi: 10.1111/j.0956-

7976.2004.00662.x

Mather, M., & Carstensen, L. L. (2003). Aging and attentional biases for emotional faces.

Psychological Science, 14, 409-415. doi:10.1111/1467-9280.01455

Mather, M., & Carstensen, L. L. (2005). Aging and motivated cognition: The positivity

effect in attention and memory. Trends in Cognitive Sciences, 9, 496-502.

doi:10.1016/j.tics.2005.08.005

Mather, M., & Knight, M. R. (2006). Angry faces get noticed quickly: Threat detection is

not impaired among older adults. The Journals of Gerontology Series B:

Psychological Sciences and Social Sciences, 61, 54-57.

Mayberg, H. S., Lozano, A. M., Voon, V., McNeely, H. E., Seminowicz, D., Hamani, C.,

…Kennedy, S.H. (2005). Deep brain stimulation for treatment-resistant

depression. Neuron, 45, 651-660. doi:10.1016/j.neuron.2005.02.014

32

Nashiro, N., Sakaki, M., & Mather, M. (in press). Age differences in brain activity during

emotion processing: Reflections of age-related decline or increased emotion

regulation? Gerontology.

Norris, C. J., Chen, E. E., Zhu, D. C., Small, S. L., & Cacioppo, J. T. (2004). The

interaction of social and emotional processes in the brain. Journal of Cognitive

Neuroscience, 16, 1818-1829. doi:10.1162/0898929042947847

Norris, C. J., Larsen, J. T., Crawford, L. E., & Cacioppo, J. T. (in press). Better (or

worse) for some than others: Individual differences in the positivity offset and

negativity bias. Journal of Research in Personality.

Ochsner, K. N., Bunge, S. A., Gross, J. J., & Gabrieli, J .D. E. (2002). Rethinking

feelings: An fMRI study of the cognitive regulation of emotion. Journal of

Cognitive Neuroscience, 14, 1215-1229. doi:10.1162/089892902760807212

Riediger, M., Schmiedek, F., Wagner, G.G., & Lindenberger, U. (2009). Seeking

pleasure and seeking pain: Differences in prohedonic and contra-hedonic

motivation from adolescence to old age. Psychological Science, 20, 1529-1535.

doi: 10.1111/j.1467-9280.2009.02473.x

Schaefer, S.M., Jackson, D.C., Davidson, R.J., Aguirre, G.K., Kimberg, D.Y., &

Thompson-Schill, S.L. (2002). Modulation of amygdalar activity by the conscious

regulation of negative emotion. Journal of Cognitive Neuroscience, 14, 913-921.

doi:10.1162/089892902760191135

Talairach, J., & Tournoux, P. (1988). Co-planar stereotaxic atlas of the human brain: 3D

proportional system: An approach to cerebral imaging. New York: Georg

Thieme Verlag.

33

Urry, H. L. (2010). Seeing, thinking, and feeling: Emotion-regulating effects of gaze-

directed cognitive reappraisal. Emotion, 10, 125-135. doi:10.1037/a0017434

Urry, H. L., & Gross, J. J. (2010). Emotion regulation in older age. Current Directions in

Psychological Science, 19, 352 – 357. doi: 10.1177/0963721410388395

Urry, H. L., van Reekum, C. M., Johnstone, T., & Davidson, R. J. (2009). Individual

differences in some (but not all) medial prefrontal regions reflect cognitive

demand while regulating unpleasant emotion. NeuroImage, 47, 852-863.

doi:10.1016/j.neuroimage.2009.05.069

Urry, H. L., van Reekum, C. M., Johnstone, T. Kalin, N. H., Thurow, M. E., Schaefer, H.

S., …Davidson, R. J. (2006). Amygdala and ventromedial prefrontal cortex are

inversely coupled during regulation of negative affect and predict the diurnal

pattern of cortisol secretion among older adults. The Journal of Neuroscience, 26,

4415-4425. doi:10.1523JNEUROSCI.3215-05.2006

Van Reekum, C. M., Johnstone, T., Urry, H. L., Thurow, M. E., Schaefer, H. S.,

Alexander, A. L., & Davidson, R. J. (2007). Gaze fixations predict brain

activation during the voluntary regulation of picture-induced negative affect.

NeuroImage, 36, 1041-1055. doi:10.1016/j.neuroimage.2007.03.052

Van Reekum, C. M., Schaefer, S. M., Lapate, R. C., Norris, C. J., Greischar, L. L., &

Davidson, R. J. (2010). Aging is associated with positive responding to neutral

information but reduced recovery from negative information. Social Cognitive

and Affective Neuroscience. Advance online publication.

doi:10.1093/scan/nsq031

34

Wager, T. D., Feldman Barrett, L., Bliss-Moreau, E., Lindquist, K. A., Duncan, S.,

Kober, H., …Mize, J. (2008). The neuroimaging of emotion. In M. Lewis, J. M.

Haviland-Jones & L. Feldman Barrett (Eds.), Handbook of Emotions (pp. 249-

267). New York: The Guilford Press.

Wager, T. D., Davidson, M. L., Hughes, B. L., Lindquist, M. A., & Ochsner, K. N.

(2008). Prefrontal-subcortical pathways mediating successful emotion regulation.

Neuron, 59, 1037-1050. doi:10.1016/j.neuron.2008.09.006

Williams, L. M., Brown, K. J., Palmer, D., Liddell, B. J., Kemp, A.H., Olivieri, G.,

…Gordon, E. (2006). The mellow years? Neural basis of improving emotional

stability over age. The Journal of Neuroscience, 26, 6422-6430.

doi:10.1523/JNEUROSCI.0022-06.2006

Wood, S., & Kisley, M. A. (2006). The negativity bias is eliminated in older adults: Age-

related reduction in event-related brain potentials associated with evaluative

categorization. Psychology and Aging, 21, 815-820. doi:10.1037/0882-

7974.21.4.815

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Table 1 Group activations for the mildly pleasant – mildly unpleasant contrast

Region of activation BA Hemisphere Coordinates Volume (mm3) t-value

x y z Mildy pleasant > Mildly unpleasant None

Mildly unpleasant > Mildly pleasant Medial frontal gyrus 9 R -5 -44 29 200 -4.29 Superior frontal gyrus 8 L 3 -22 49 165 -4.03 Superior frontal gyrus 9 L 7 -50 30 111 -4.05 Superior frontal gyrus 6 R -2 -18 54 110 -4.03 Lentiform nucleus/claustrum/putamen R -27 -12 -3 93 -4.12 Inferior frontal gyrus 47 R -49 -18 2 80 -4.32 Medial frontal gyrus 9 L 3 -52 20 59 -4.15

Note. Clusters listed consist of 50 or more contiguous voxels with a t-threshold of 4.00, p < .001 uncorrected. Coordinates are in Talairach stereotaxic space (RAI format).

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Table 2 Group activations for the very unpleasant – very pleasant contrast

Region of activation BA Hemisphere Coordinates Volume (mm3) t-value

x y z Very unpleasant > Very pleasant None Very pleasant > Very unpleasant

Superior frontal gyrus 10 R -4 -61 -2 69 -4.06 Parahippocampal gyrus 28 L 19 13 -14 54 -4.21

Note. Clusters listed consist of 50 or more contiguous voxels with a t-threshold of 4.00, p < .001 uncorrected. Coordinates are in Talairach stereotaxic space (RAI format).

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Table 3 Group activations for the older positivity offset – younger positivity offset contrast

Region of activation BA Hemisphere Coordinates Volume (mm3) t-value

x y z Older > Younger Inferior frontal gyrus 47 R -47 -28 -14 90 4.06 Fusiform gyrus 37 R -59 50 -20 78 4.58

Younger > Older Subcallosal gyrus 25 L 0 -16 -12 188 -4.52

Note. Clusters listed consist of 50 or more contiguous voxels with a t-threshold of 4.05, p < .001 uncorrected. Coordinates are in Talairach stereotaxic space (RAI format).

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Table 4 Group activations for the older negativity bias – younger negativity bias contrast

Region of activation BA Hemisphere Coordinates Volume (mm3) t-value

x y z Older > Younger Superior frontal gyrus 8 L 2 -38 44 1119 4.23 Precentral gyrus 9 R -42 -16 34 399 4.15

Younger > Older None

Note. Clusters listed consist of 50 or more contiguous voxels with a t-threshold of 4.05, p < .001, uncorrected. Coordinates are in Talairach stereotaxic coordinate space (RAI format).

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Figure 1. Emotional biases predicted by the Evaluative Space Model. The positivity

offset is reflected by greater positivity than negativity at low levels of emotional input;

the negativity bias is reflected by greater negativity than positivity at high level of

emotional input. Adapted from Norris, Larsen, Crawford & Cacioppo (in press).

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Figure 2. Younger and older adults’ ratings of neutral and mildly, moderately, and

extremely emotional pictures. Dominant ratings refer to negative ratings of unpleasant

pictures and positive ratings of pleasant pictures. Compared to younger adults, older

adults show a larger positivity offset observed in responses to both neutral and mild

pictures.

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Figure 3. Standardized reaction times to mildly unpleasant and mildly pleasant pictures

by age group. Older adults responded more slowly than younger adults to mildly

unpleasant pictures; they also responded more slowly to mildly unpleasant than to mildly

pleasant pictures.

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Figure 4. Negative (a) and positive (b) ratings of mildly unpleasant and mildly pleasant

pictures by age group. Compared to younger adults, older adults rated mildly pleasant

pictures as less negative and more positive, and exhibited a trend to rate mildly

unpleasant pictures as less negative.

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Figure 5. Z-scored response times (separated into short and long RTs, representing 1 SD

below and above the mean, respectively) as predictors of positive ratings of mildly

unpleasant pictures in older and younger adults. As response times increased, older

adults rated mildly unpleasant pictures more positively, while younger adults did not.

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