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Long-Term Effects of Appearance-Based Interventions on Sun ProtectionBehaviors

Heike I. M. MahlerUniversity of California, San Diego, and California State

University, San Marcos

James A. KulikUniversity of California, San Diego

Meg Gerrard and Frederick X. GibbonsIowa State University

Objectives: To examine the longer term efficacies of exposure to UV photographs andphotoaging information

(e.g., wrinkles and age spots) for increasing sun protection intentions and behaviors of young adults. Design:

Randomized controlled trial with 4- to 5-month and 12-month follow-ups. Main Outcome Measures:

Participants self-reported sun protection intentions assessed immediately after the interventions, and both

self-reported sun protection behaviors and an objective assessment (via spectrophotometry) of skin color

change measured at the end of summer (45 months following interventions) and 1 year following interven-

tions. Results: Both interventions resulted in immediate positive effects on future sun protection intentions.

Both interventions showed objective evidence of less skin darkening at the postsummer follow-up, with thosein the photoaging information condition also reporting more sun protective behavior and continuing to show

less skin darkening 1 year after intervention. There was also evidence that effects of photoaging information

on subsequent skin color change were mediated by the earlier positive effect photoaging information had on

participants intentions to sun protect and their subsequent sun protection behaviors. Conclusions: UV photo

and photoaging-information interventions each show promise as a brief and relatively inexpensive approach

for motivating sun protection practices that may reduce skin cancer risk.

Keywords: skin cancer, sun protection, photoaging, UV photos, spectrophotometry

Skin cancer is the most common type of cancer, with approxi-

mately 1.3 million new cases diagnosed annually in the United

States (American Cancer Society, 2004). The incidence of the

deadliest form of skin cancer (melanoma) is increasing morerapidly than that of any other type of cancer (Rigel, Friedman, &

Kopf, 1996; Weinstock, 1998), and sun exposure is implicated in

over 80% of all skin cancers (Parker, Tong, Bolden, & Wingo,

1997). Thus, interventions that decrease sun exposure or increase

sun protection behaviors have the potential for significant impact

on skin cancer incidence.

Although knowledge regarding the skin cancersun exposure

link and risk reduction behaviors has increased in the past 1520

years (Baum & Cohen, 1998; Robinson, Rigel, & Amonette,

1997), many Americans continue to receive large amounts ofintentional and incidental sun exposure without adequate protec-

tion (Hoegh, Davis, & Manthe, 1999; Robinson et al., 1997).

Because most intentional ultraviolet (UV) exposure is directed at

getting a tan to improve appearance (Hillhouse, Stair, & Adler,

1996; Hoegh et al., 1999; Jones & Leary, 1994; Miller, Ashton,

McHoskey, & Gimbel, 1990; Robinson et al., 1997; Turrisi, Hill-

house, & Gebert, 1998), interventions that focus exclusively on the

health risks of sun exposure may not be maximally effective.

Several recent studies have demonstrated the promise of

appearance-based interventions, which instead highlight the link

between sun exposure and appearance detractors such as wrinkles,

age spots, and uneven pigmentation, for motivating UV protection

behaviors (Gibbons, Gerrard, Lane, Mahler, & Kulik, 2005; Jones& Leary, 1994; Mahler, Fitzpatrick, Parker, & Lapin, 1997;

Mahler, Kulik, Gibbons, Gerrard, & Harrell, 2003; Mahler et al.,

2005). Compared with a health-based message, emphasizing neg-

ative appearance consequences may better counteract the primary

(appearance-based) motivation for sun exposure, namely, getting a

tan. Individuals also may feel more vulnerable to developing

wrinkles and age spots than to cancer, because the former are more

common and easily noticed.

UV photography has been used in several recent appearance-based

interventions to highlight the negative appearance consequences of

UV exposure (Gibbons et al., 2005; Mahler et al., 2003; Pagoto,

Heike I. M. Mahler, Department of Psychology, University of Califor-

nia, San Diego, and California State University, San Marcos (CSUSM);

James A. Kulik, Department of Psychology, University of California, San

Diego; Meg Gerrard and Frederick X. Gibbons, Department of Psychology,

Iowa State University.

This research was supported by grants from the Cancer Research and

Prevention Foundation, the National Cancer Institute, and CSUSM Research,

Scholarship, and Creative Activity grants to Heike I. M. Mahler. We thank

Jody Harrell, Kathy Herbst-Damm, Alma Correa, Emily Gray, Karen Lee,

Crystal Winters, Angela Gorezman, and Jaimi Martsoff for their help in

carrying out this project. We also thank Richard E. Fitzpatrick and Betsy

Fizpatrick for their advice and assistance with this project. Finally, we thank

John Homann of Neutrogena Corp. and Donna Gabriel of the Boston Derma-

tology and Laser Center who provided the sunscreen samples.

Correspondence concerning this article should be addressed to Heike

I. M. Mahler, Department of Psychology 0109, University of California,

San Diego, La Jolla, CA 92093. E-mail: [email protected]

Health Psychology Copyright 2007 by the American Psychological Association2007, Vol. 26, No. 3, 350 360 0278-6133/07/$12.00 DOI: 10.1037/0278-6133.26.3.350

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McChargue, & Fuqua, 2003). Chronic UV exposure can produce

uneven epidermal pigmentation that, when photographed through a

UV filter, appears as brown blotches. Viewing a photo of ones face

with such blotches can be quite dramatic and may make the negative

appearance consequences of sun exposure more salient, immediate,

and certain. In two studies, Gibbons et al. (2005) found that college

students who had versus had not viewed their UV photos reported lesstanning booth use 34 weeks later. In a study of beachgoers, Mahler

et al. (2003, Study II) also found that sun protection intentions were

greater if participants did versus did not view their UV photo, and

separately, if participants received versus did not receive photoaging

information about wrinkles and age spots caused by UV exposure;

both interventions either separately or in combination also increased

self-reported sun protection behaviors during the subsequent 12

months. These recent findings, although clearly promising, are limited

to immediate intentions and self-reported behaviors over brief periods

of time (e.g., 12 months). The primary purpose of the present study

therefore was to determine if appearance-based interventions also

affect more objective assessments of sun exposure over substantially

longer periods of time.1

Overview of Current Experiment

Participants were college students randomly assigned to one of

four conditions: control, UV photo, photoaging information, or UV

photo plus photoaging information. The first follow-up occurred

after a period of very high risk for sun exposure, namely, imme-

diately following the summer break (45 months after the inter-

vention). A second, final follow-up occurred 1 year after the

intervention. Objective assessment of skin color changes (i.e.,

tanning) was accomplished via skin reflectance spectrophotome-

try. Of primary interest was whether the two appearance-based

interventions (photoaging information and UV photo) would sep-

arately increase sun protection intentions and behaviors, and if so,

how long any such effects on behavior would last.

We also sought secondarily to examine possible mediators of

the anticipated intervention effects. Health behavior models such

as the health belief model (HBM; Becker, 1974), protection mo-

tivation theory (PMT; Rogers, 1983), and the theory of planned

behavior (TPB; Ajzen & Madden, 1986) posit various cognitions

that theoretically mediate the relationship between a prevention

message and a health behavior. For example, the HBM suggests

that engaging in a particular preventive behavior is determined by

perceived susceptibility to the health threat and by perceived costs

versus benefits of the recommended behavior (Becker, 1974). The

PMT likewise posits a role for perceived susceptibility (Rogers,

1983), whereas the TPB emphasizes behavioral intentions as aproximal determinant of behavior (Ajzen & Madden, 1986). Either

of our interventions might be expected to raise participants per-

ceived susceptibility to photoagingthe UV photo directly by

showing that underlying damage already exists, and the photoag-

ing information more indirectly by linking the majority of wrinkles

and age spots to chronic sun exposure. Seeing the underlying

brown blotches on ones face and learning that most wrinkles and

age spots are caused by sun exposure also could decrease the

perceived rewards of tanning and costs of sun protection. Thus, we

expected that the effects of either intervention on participants

subsequent sun-related behavior might be mediated by perceptions

of susceptibility to photoaging, sunbathing/tanning rewards, sun

protection costs, and sun protection intentions.

Method

Participants

Undergraduate students from the University of California, SanDiego (107 women, 26 men) received course credit for their

participation. Ages ranged from 18 to 44 years (M 20.13, SD

3.38), and 45% described themselves as Caucasian, 35.3% as

Asian, 11.3% as Hispanic, 1.5% as both Asian and Caucasian,

0.8% as both Hispanic and Caucasian, 0.8% as both Asian and

Hispanic, and 5.3% as other. At baseline, participants reported

sunscreen use on their face 74.2% and 45.1% of the time while

sunbathing and during incidental exposure (time in the sun en-

gaged in activities other than sunbathing), respectively. In contrast,

they used sunscreen on their body 58.3% and 21.5% of the time

while sunbathing and during incidental exposure, respectively.

Twenty-three percent reported spending at least 30 min sunbath-

ing, and 93.9% reported at least 3 hr of incidental sun exposureduring the prior week. None had a personal history but 27.1% had

a positive family history of skin cancer.

Intervention Materials

Photoaging information. Photoaging information was pre-

sented via an 11-min videotaped slide show that had been devel-

oped and evaluated previously (Mahler et al., 1997). The video

depicted photoaging (including graphic photos of extreme cases of

wrinkles and age spots), described how sun exposure and UV

radiation from any source leads to photoaging, and discussed

effective practices for minimizing photoaging (e.g., wearing pro-

tective clothing and applying a sunscreen with a sun protection

factor [SPF] of at least 15 to protect against both UVB and UVArays). The video also provided general information about sun-

screen, such as the meaning of the SPF number, when to use

sunscreen, and how much to apply.

UV photographs. UV facial photographs were taken with an

instant Polaroid camera modified to include a 315- to 390-mm UV

filter. Because filtered UV light is selectively absorbed by the

melanin in the skin, a photograph taken with a UV filter dramat-

ically highlights the nonuniform epidermal pigmentation that re-

sults from chronic sun exposure (Fulton, 1997). Each person who

had a UV photo taken also had a natural-light, instant photograph

taken for comparison. In all cases, participants were first shown

the natural-light, black-and-white photograph and were told that it

depicted what can be seen with the naked eye. Then the UV

1 Although no previous appearance-based interventions have assessed

longer term outcomes, we were able to locate one health-based intervention

that included a 1-year follow-up (Robinson, 1990) and a multicomponent

intervention that included both a 1- and a 2-year follow-up (Weinstock,

Rossi, Redding, & Maddock, 2002). Both of these studies demonstrated

improved long-term sun protection efforts in the intervention group com-

pared with controls. However, both studies relied exclusively on self-

reported outcomes and also included boosters for the intervention group

(i.e., provision of additional information during the follow-up period),

making interpretations of the long-term effects of the interventions some-

what problematic.

351APPEARANCE-BASED INTERVENTIONS


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photograph was placed adjacent to the natural-light photo. Partic-

ipants were told that any dark, freckled, or pitted areas in the UV

photo that did not appear in the natural-light photo indicate exist-

ing underlying skin damage that would continue to get worse if

they continued their current sun exposure levels without additional

sun protection.

Procedure

Initial session. The initial session was conducted during the

spring term (AprilMay; average temperatures 62 F [16.7 C]

and 64.1 F [17.8 C], respectively). Participants signed up for a

study titled Health Attitudes through the Psychology Depart-

ment human participant pool. The sign-up sheet specified only that

participants had to be at least 18 years old and should not be

graduating seniors (to ensure they would be more readily available

for the follow-ups). Participants were tested individually or in pairs

(separated by a partition), and each session was assigned randomly

to a 2 (photoaging video vs. no video) 2 (UV photo vs. no UV

photo) factorial design (resulting in 30 participants in the photo

video, 35 in the photo-only, and 34 each in the video-only andcontrol conditions). On arrival, participants completed a consent

form that described the study as an attempt to learn more about

college students sun exposure and sun protection behaviors. Par-

ticipants were further informed that they might be contacted for a

follow-up study in the fall and were asked to provide their current

telephone number and e-mail address as well as a permanent

contact (e.g., parents) telephone number. All of the participants

then completed a questionnaire that assessed demographic infor-

mation and baseline UV exposure and protection behaviors. De-

pending on condition, participants then either did or did not view

the photoaging videotape and, separately, either did or did not have

their UV photo taken and shown to them. All of the participants

then completed a questionnaire that assessed their future intentionsto use sun protection and several additional potential cognitive

mediators, after which their baseline skin color was measured

using skin reflectance spectrophotometry (described below).

Thereafter participants were partially debriefed and received a

sunscreen sample as a thank-you gift.

Postsummer follow-up. At the beginning of the following fall

term (late September; average temperature 71.4 F [21.9 C]),

participants were contacted by telephone or e-mail, reminded of

their participation during the previous spring term, and offered

course credit or $10 to return to the lab. Eighty-five percent of the

original sample participated in this follow-up, which occurred an

average of 20.30 (SD 2.56) weeks following the intervention

and 2.79 (SD 2.13) days after being contacted. Of the 15% who

did not participate, half were studying abroad or no longer livingin the area, 40% were not reachable, and 10% refused. Current skin

color was assessed via spectrophotometry, and both sun exposure

and sun protection behaviors during the summer months were

assessed by questionnaire.

1-year follow-up. The 1-year follow-up occurred on average

54.12 (SD 2.69) weeks after the intervention and 4.83 (SD

3.42) days after being reached to schedule the follow-up. Partici-

pants were unaware that there would be a 1-year follow-up. Eighty

percent of our original sample participated in this surprise

follow-up, during which current skin color and self-reported sun

exposure and sun protection behaviors (for the previous month)

were assessed.2 Most of those who did not participate in this

follow-up were not reachable because of incorrect telephone num-

bers and e-mail addresses (78%). The remainder were studying

abroad or no longer living in the area.

Measures

Cognitions. Immediately following administration of the in-

tervention conditions, several scales were used to assess potential

cognitive mediators of interest (see Mahler et al., 1997, 2003). On

separate 5-point scales (1 strongly disagree, 5 strongly

agree), perceived rewards of sunbathing/tanning were indexed by

averaging 10 items ( .90; e.g., I have more self-confidence

when I have a tan), costs of using sun protection by averaging 12

items ( .72, e.g., Using sunscreen regularly is just too much

trouble), perceived susceptibility to photoaging by averaging 9

items ( .70; e.g., I dont spend enough time in the sun to be

concerned about getting wrinkles and age spots; reverse scored),

and sun protection intentions by averaging 18 items ( .91; e.g.,

I plan to always use sunscreen on my face when I sunbathe and

I plan to avoid being outdoors between the hours of 10 a.m. and2 p.m. whenever possible).

Skin color. Skin color was assessed at baseline and at both

follow-ups using skin reflectance spectrophotometry, which en-

ables objective, reliable, in vivo quantification of human skin color

(Bjerring & Andersen, 1987). The Minolta CM-2600d spectropho-

tometer used is a handheld instrument that measures the color of

objects on three dimensions, two of which, L* and b*, are sensitive

to tanning (Levine et al., 1991; Seitz & Whitmore, 1988).3 L*

indexes lightness from black to white, with higher values indicat-

ing lighter coloring (i.e., less tan), whereas b* indexes saturation in

terms of blue to yellow, with higher values indicating more yellow

(i.e., more tan). At each assessment period, three consecutive

readings of L* and of b* were taken from one higher exposure site(4 in. [10.16 cm] above the wrist on outer side of the forearm) and

from one lower exposure site (4 in. above the wrist on underside

[palm side] of the same forearm). The three readings from each site

were averaged for analysis.

Sun exposure and protection behaviors. Previous work has

indicated that intentional (e.g., sunbathing) and incidental sun expo-

sure involve distinguishable behaviors (e.g., Mahler et al., 2003), as

do sun exposure and sun protection behaviors (e.g., Jackson & Aiken,

2001). Prior to the interventions, we therefore assessed baseline in-

tentional and incidental UV exposure in addition to sun protection

behaviors. Specifically, we asked participants to indicate their number

of hours of sunbathing during the previous week and weekend. These

items, as in other work (e.g., Mahler et al., 2003), were only modestly

2 Ten percent of the sample for the surprise 1-year follow-up had to be

interviewed by telephone, because they no longer lived in the area. For

these people, self-reported sun protection reports were obtained but not

spectrophotometry readings.3 Like others (e.g., Buller, Buller, Beach, & Ertl, 1996; Mayer et al.,

1997), we did not use a third (a* scale) measure, because it indicates skin

erythema or redness (i.e., sunburn). Skin darkening is considered a better

measure of cumulative UV exposure from baseline to follow-up, because

cumulative exposure is more likely to produce changes in tanning. Also,

skin reddening (sunburn) typically subsides within 4872 hr following UV

exposure (Muizzuddin, Marenus, Maes, & Smith, 1990).

352 MAHLER, KULIK, GERRARD, AND GIBBONS


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interrelated, but for simplicity they were separately z scored and

averaged to index baseline intentional exposure ( .50).4 We also

assessed participants number of hours of sun exposure while doing

other (nonsunbathing) activities during the previous workweek and

weekend. These items too were separately z scored and averaged to

index baseline incidental exposure ( .84). Finally, to assess

baseline sun protection behaviors, we asked participants to indicatetheir frequencies of sunscreen use on face and body during both

intentional and incidental exposure (on scales ranging from 0% to

100%) and also the SPF levels of sunscreen they used on face and

body during both intentional and incidental exposure, respectively. A

baseline sun protection index was then created by z scoring and

averaging these 8 items ( .72), with higher values indicating

greater protection.

Postsummer follow-up sun exposure and protection questions were

asked in reference to the past summer (June 15September 15),

whereas the 1-year follow-up questions were asked in reference to the

preceding month (April 15May 15). To index intentional exposure,

participants estimated the number of hours they spent sunbathing

during the relevant period. For comparability, these values were

separately z scored within the follow-up period for analyses. Partici-pants also indicated the number of hours they had spent in the sun

doing other (nonsunbathing) activities on a typical weekday and

weekend day. These items were separately z scored and averaged

within the follow-up period to index incidental exposure ( .70 and

.75 for the postsummer and 1-year follow-ups, respectively). Finally,

participants indicated the frequencies of sunscreen use on their face

and body during intentional and, separately, during incidental sun

exposure (ranging from 0% to 100%), in addition to the SPF levels of

sunscreen used on their face and body during both intentional and

incidental sun exposure. Separate postsummer and 1-year sun protec-

tion indices were created subsequently by z scoring and averaging

these items ( .85 and .88, respectively), with higher values

indicating greater protection.Manipulation checks. Finally, participants completed three

manipulation-check items at both follow-ups. Specifically, partic-

ipants rated their agreement with the statement I currently have

significant underlying sun damage to my face (1 strongly

disagree, 5 strongly agree), and they provided open-ended

responses to questions asking What percentage of wrinkles and

age spots are caused by the sun (or other UV exposure) rather than

the natural aging process? and How much sunscreen should be

used to cover the entire body? We expected that those who had

versus had not seen their UV photo would more strongly agree that

they had significant sun damage. Separately, we also expected that

viewers compared with nonviewers of the photoaging video would

be more accurate in their estimates of the percentage of wrinkles

and age spots caused by sun exposure and of how much sunscreenshould be used (because both pieces of information were twice

mentioned in the video but are not common knowledge).5

Results

Preliminary Analyses

Group equivalence. To determine the initial equivalence of the

groups, we performed separate 2 (photoaging video) 2 (UV

photo) analyses of variance (ANOVAs) on the demographic and

baseline sun protection variables. The results indicated no signif-

icant differences or trends in age, gender, ethnicity, or education

level. There also were no differences in terms of intentional or

incidental sun exposure at baseline, skin type (Fitzpatrick, 1988),

personal history of skin cancer, or the frequencies of sunscreen use

on either the face or body during incidental or intentional sun

exposure. We did find that those assigned to the UV photo con-

dition compared with those assigned to the no-photo conditionreported having fewer family members with a history of skin

cancer (Ms 0.34 vs. 0.85, p .02). To statistically control for

its potentially confounding influence, we included family history

of skin cancer as a covariate in the analyses of any outcome with

which it was at least marginally related (p .10).

Manipulation checks. The manipulation checks collected at

both follow-ups indicate that the interventions provided differen-

tial information as intended. Separate Photoaging Video UV

Photo ANOVAs indicated that participants who did versus did not

view their UV photo believed they had significantly more under-

lying skin damage from the sun: M 3.27, SD 0.91 versus M

2.77, SD 1.03, F(1, 106) 7.06, p .01, for postsummer; M

3.40, SD 0.75 versus M 2.69, SD 1.07, F(1, 87) 12.94,

p .001, for 1-year follow-ups. As expected, there were noseparate or interactive effects with the photoaging video condition

for this item at either time. In addition, viewers of the photoaging

video compared with nonviewers provided higher (i.e., closer to

correct) estimates of the percentage of wrinkles caused by sun

exposure: M 74.48, SD 19.95 versus M 61.69, SD 21.58,

p .002, for postsummer follow-up; M 71.26, SD 17.53

versus M 57.36, SD 21.24, p .001, for 1-year follow-up. As

expected, there were no significant effects involving the UV photo

on this item. Finally, participants who had viewed the photoaging

video also were significantly more likely than their nonviewer

counterparts to indicate accurately (0 incorrect, 1 correct) the

amount of sunscreen necessary to cover the body: M 0.25, SD

0.44 versus M 0.09, SD 0.28, p .03, for postsummerfollow-up; M 0.32, SD 0.47 versus M 0.14, SD 0.35, p

.05, for 1-year follow-up. Again, as expected, there were no UV

photo main effects or interactions for this item at either time.

Primary Analyses

None of the primary analyses indicated any significant interac-

tions between the two interventions. For simplicity, therefore, all

tables and figures are presented in terms of the respective inter-

vention main effects. To assist in interpretation of the significance

of primary findings of interest, we also list effect sizes using

Cohens d statistic (small 0.20, medium 0.50, large 0.80;

Cohen, 1988). In addition, in all instances in which analysis of

covariance (ANCOVA) is used, preliminary analyses indicatedthat all assumptions were met.

4 Analyses that use the intentional exposure items individually yield the

exact same conclusions as those involving the composite index.5 Responses regarding the amount of sunscreen needed to cover the body

were coded as either incorrect (0) or correct (1). Because the goal was to

determine whether participants had paid attention to the information pro-

vided in the photoaging video, we adopted a very strict accuracy criterion.

Specifically, for an answer to be coded as correct, participants had to

indicate one of the following: (a) 1.2 ounces, (b) one shot-glass full, or (c)

a palm full.



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Immediate cognition outcomes. The proposed cognitive medi-

ators that were assessed immediately after the interventions (per-

ceived susceptibility to photoaging, perceived rewards of sunbath-

ing, perceived costs of sun protection, and sun protection

intentions) were analyzed using a Photoaging Video UV Photo

multivariate analysis of variance (MANOVA). The MANOVA

results indicated that the overall effect of the photoaging video wassignificant, F(4, 126) 4.25, p .003, whereas the overall UV

photo condition effect was not (p .13). Subsequent univariate

analyses indicated that those who viewed compared with those

who did not view the photoaging video had significantly greater

intentions to engage in sun protective behavior, F(1, 129) 15.65,

p .001, d 0.70, and felt marginally more susceptible to

photoaging, F(1, 129) 2.98, p .09, d 0.30, but did not differ

with respect to perceived rewards of tanning or costs of sunscreen

use. These univariate analyses separately indicated that those who

viewed their UV photo compared with those who did not also had

significantly greater intentions to engage in sun protective behav-

ior, F(1, 129) 4.59, p .03, d 0.38, and felt more susceptible

to photoaging, F(1, 129) 4.64, p .03, d 0.38, but did notdiffer in perceived rewards of tanning or costs of sun protection

(see Table 1 for means).

Longer term outcomes. To enable direct comparisons of

changes over time in longer term outcomes, we focus here on the

participants (n 84) who completed both follow-ups. Analyses of

participants who did versus did not complete both follow-ups

revealed no significant differences in age, education, gender, eth-

nicity, skin type, personal skin cancer history, family history of

skin cancer, perceived susceptibility to photoaging, perceived

costs of sun protection, sun protection intentions, baseline hours of

intentional and incidental sun exposure, frequencies of sun pro-

tection behaviors during intentional and incidental sun exposure,

or spectrometer readings. The only significant difference found

was for those lost to follow-up to perceive the rewards of tanningas somewhat greater than did those who completed both follow-

ups, Ms 2.64 versus 2.33, F(1, 129) 4.64, p .04, d 0.38.

Intercorrelations among the primary outcome measures are pre-

sented in Table 2.6

Skin color changes. Separate 2 (photoaging video) 2 (UV

photo) 2 (follow-up time, postsummer vs. 1 year) ANCOVAs,

with repeated measures on the last factor and controlling for the

relevant baseline skin color assessment, were performed on the

change (follow-up minus baseline) in L* and b* readings at the

higher and lower exposure sites, respectively.7 As would be ex-

pected, each of these analyses revealed strong effects of time

period, such that controlling for baseline skin assessments, partic-

ipants skin colors were significantly darker (L* readings) and

more yellow saturated (b* readings) immediately after the summer

months than they were 1 year after the springtime interventions (all

Fs 61.47, ps .0001, ds 1.852.10). No separate effects of

the interventions on b* readings were significant (ps .12; see

Table 3 for means), whereas analyses of the change in L* readings

at the higher exposure site indicated that the skin of those who

viewed the photoaging video was significantly lighter than the skin

of those who had not viewed the photoaging video, F(1, 79)

7.34, p .01, d 0.61; this effect was consistent across both

follow-up periods, as evidenced by the lack of any interaction with

time period (F 1) and by subsequent analyses that revealed

significant differences both at the postsummer and 1-year follow-

ups (ps .02, ds 0.56 and 0.57, respectively; see Figure 1).

Separately, the higher exposure skin sites of those who viewed

their UV photos also tended to be lighter than those of their

non-UV photo counterparts, F(1, 79) 3.58, p .06, d 0.43,

but this effect was qualified by a significant UV Photo Time

effect, F(1, 80) 4.54, p .04, d 0.48. Subsequent analysesindicated the UV photo participants were lighter at both follow-ups

but that the difference was significant at the postsummer follow-up

(p .01, d .60) but not at the 1-year follow-up ( p .39, d

0.19; see Figure 1).

Analyses of change in L* readings at the lower exposure site of

the arm revealed very similar effects of the photoaging video, in

that those who had viewed the video had significantly lighter skin

than those who had not, F(1, 79) 5.24, p .03, d 0.52. Again,

this difference was consistent and significant at both follow-up

periods (ps .04, ds .49 and .47, respectively; see Figure 2).

Separately, those who viewed their UV photo were also lighter at

this skin site, but the difference was not significant (p .15, d

0.33; see Figure 2). No other effects involving L* readings ap-proached significance. When the 7.6% of participants who pur-

chased sunless tanning lotion during the follow-up period were

6 Correlations of these outcomes that include everyone who participated

in either the postsummer follow-up (n 110) or the 1-year follow-up (n

91), but not necessarily both, yielded results that are virtually identical to

those reported; therefore, they are not presented to avoid redundancy.7 ANCOVAs performed on change scores yield statistical tests that are

identical to ANCOVAS performed on the raw outcome values but have the

desirable advantage here of also conveying the direction (lighter or darker)

of skin color changes from baseline.

Table 1

Means (and Standard Deviations) of Cognitions as a Function of Phototaging Video and UV

Photo Conditions

MeasurePhotoaging video

(n 64)No video(n 69)

UV photo(n 65)

No photo(n 68)

Intentions to sun protecta,b

3.30 (0.69) 2.79 (0.75) 3.18 (0.76) 2.91 (0.69)Susceptibility to photoaginga 3.70 (0.53) 3.54 (0.55) 3.72 (0.47) 3.52 (0.61)Rewards of tanningc 2.35 (0.92) 2.55 (0.72) 2.46 (0.82) 2.44 (0.81)Costs of sun protection 2.87 (0.60) 2.98 (0.51) 2.90 (0.52) 2.95 (0.59)

a UV photo main effect: p .05. b Photoaging video main effect: p .001. cControlling for a significant effectof skin cancer in family history (p .03).



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removed from the analyses of skin color change reported above,

the pattern of findings remained the same and all significant effects

remained significant.

Sun exposure and protection behavior. Because the follow-upindices of reported sun exposure and protection behaviors were not

identical to their respective baseline indices, direct change scores

could not be computed. Therefore intentional exposure, incidental

exposure, and sun protection behavior reports were analyzed with

separate 2 (photoaging video) 2 (UV photo) 2 (follow-up

time, postsummer vs. 1 year) ANCOVAs, with repeated measures

on the last factor and controlling for the relevant baseline index.

The analyses of intentional exposure indicated that people who

reported higher intentional exposure levels at baseline also re-

ported higher levels across the follow-up assessments, F(1, 78)

14.34, p .001, d 0.86. Separately, those who did versus those

who did not view their UV photo reported somewhat more inten-

tional exposure (z-score Ms 0.13 vs. 0.17), but this differencewas not significant, F(1, 78) 2.95, p .09, d 0.39. No other

effects involving intentional exposure approached significance

(see Table 3).

More interesting, the analyses of incidental exposure indicated

that controlling again for a significant positive relationship with

relevant baseline exposure, F(1, 78) 5.46, p .025, d 0.53,

participants who had viewed the photoaging video reported sig-

nificantly lower incidental sun exposure levels than did those who

had not viewed the video, F(1, 78) 6.62, p .02, d 0.58

(z-score Ms 0.20 vs. 0.25). This effect held across follow-up

periods (see Table 4 for means), as indicated by the absence of any

interaction involving time period (Fs 1.21). Separately, there

was a significant UV Photo Time effect, F(1, 79) 4.96, p

.03, d 0.50, which indicated that those who viewed their UVphoto reported less incidental exposure at the postsummer

follow-up but more incidental exposure at the 1-year follow-up

than their non-UV photo counterparts (see Table 3). Analyses

within follow-up periods indicated that these differences were not

individually significant, however, either at postsummer (p .15,

d 0.33) or at 1 year (p .29, d 0.24).

Finally, analyses of the sun protection behavior index indicated

that, controlling for a highly significant positive relationship with

baseline sun protective behavior, F(1, 78) 66.06, p .001, d

1.84, there was a marginal Video Time effect, F(1, 79) 3.12,

p .08, d 0.40. Analyses of the individual follow-ups indicated

that those who had versus those who had not viewed the photo-

aging video reported significantly more sun protective behavior at

the initial postsummer assessment, F(1, 78) 4.15, p .045, d

0.46, but there were no differences at the 1-year follow-up (F 1,d 0.00; see Table 3). No effects involving the UV photo

condition were significant for this measure.

Mediation Analyses

Finally, we conducted a series of analyses to identify possible

mediators of the obtained intervention effects on L* readings, the

outcome of primary interest to us. Following Baron and Kenny

(1986), evidence that a variable serves as a mediator is obtained

when, in separate regression analyses, (a) the independent variable

significantly affects the dependent variable; (b) the independent

variable significantly affects the hypothesized mediator; and (c)

the mediator has a significant unique effect on the dependent

variable and reduces the previously significant effect of the inde-

pendent variable on the dependent variable. With respect to pos-

sible mediators, we did not find that either intervention signifi-

cantly affected the perceived rewards of tanning or the perceived

costs of sun protection, but both interventions did increase imme-

diate sun protection intentions. The UV photo condition addition-

ally produced higher immediate perceptions of susceptibility to

photoaging, whereas the photoaging video produced lower inci-

dental exposure across follow-ups and greater sun protection be-

havior as assessed at the postsummer follow-up. We therefore

explored the extent to which these immediate cognitions and later

behaviors may have mediated the effects of the interventions on

participants subsequent L* readings.8

Because the effects of the photoaging video on L* readings at

the higher and lower exposure sites were both consistent across

follow-ups, at each site we first separately averaged the L* differ-

8 As noted previously, the effect of UV photo condition on L* level was

primarily evident at the higher exposure skin site at the postsummer

follow-up (Figure 2). We found no evidence that either immediate sun

protection intentions or perceived susceptibility to photoaging mediated

this effect of UV photo condition. In the interest of space, therefore, we

present only the specific mediation analyses of the photoaging video

condition.

Table 2

Correlations Between Primary Outcome Measures (n 84)

Variable 1 2 3 4 5 6 7 8

1. Sun protection intentions .36*** .31** .28** .24* .29** .19 .37***

2. L* higher exposure .31** .85*** .33** .58*** .08 .07 .42***

3. L* lower exposure .21

*

.81

***

.43

***

.80

***

.07 .18 .32

**

4. b* higher exposure .23* .55*** .46*** .73*** .29** .18 .075. b* lower exposure .19 .64*** .82*** .75*** .15 .12 .166. Sunbathing hours .23* .25* .22* .29** .19 .13 .047. Incidental exposure hours .03 .06 .03 .21 .12 .34** .22*

8. Sun protection index .35*** .11 .03 .08 .05 .06 .08

Note. Sun protection intentions were assessed immediately after the interventions. With that exception, correlations above the diagonal depict postsummerfollow-up relationships, whereas those below the diagonal depict 1-year follow-up relationships. Higher values of L* indicate lighter skin color; highervalues of b* indicate greater yellow saturation. Sites were higher (outer side of the forearm) and lower exposure (underside of the same forearm) areas.*p .05. **p .01. ***p .001.



7/11

ence score readings for the two follow-up periods and then sepa-

rately regressed these averaged L* readings on photoaging video

condition (and baseline L*). As can be seen in Table 4 (Step 1),

and in accord with the results of the ANCOVAs previously re-

ported, these analyses indicated that the photoaging video signif-

icantly affected subsequent L* levels both at the higher ( p .009)

and the lower exposure sites (p .03). Also consistent with

previously reported results, separate regressions of each potential

mediator (sun protection intentions, incidental exposure averaged

over follow-ups, and sun protection behavior reported at the post-

summer follow-up, respectively) on the photoaging video condi-

tion indicated that each was significantly influenced by the pho-

toaging video (see Table 4, Step 2). The critical analyses then

involved separate regressions of the L* readings simultaneously on

photoaging video condition and each possible mediator. The re-

sults indicated that participants immediate sun protection inten-

tions significantly predicted subsequent L* levels at both the

higher and the lower exposure sites and that controlling for these

immediate intentions reduced the photoaging video effect on L*

readings at both sites to nonsignificance (Table 4, Step 3). The

reduction was significant by Sobel z test (Preacher & Leonardelli,

2001) for L* readings at the higher exposure site (Sobel z 2.25,

p .02) and borderline at the lower exposure site (Sobel z 1.87,

p .06). These analyses suggest then that the effects of the

photoaging video intervention on subsequent L* levels at both the

higher and the lower exposure sites were mediated at least partially

Figure 1. Change in higher exposure site L* readings at postsummer and 1-year follow-ups as a function of

photoaging video and UV photo conditions, controlling for baseline status (n 84). L* indexes lightness from

black to white, with higher values indicating lighter coloring (i.e., less tan). Bars represent standard errors of the

means.

Table 3

Spectrometer (b* Scale), Self-Reported Intentional and Incidental Exposure, and Sun Protection Means (and Standard Errors) at

Postsummer Follow-Up and 1-Year Follow-Up as a Function of Photoaging Video and UV Photo Condition

Measure

Postsummer 1 year

Photoaging

video No video UV photo No photo

Photoaging

video No video UV photo No photo

Higher exposure site b* scalea 2.12(0.28)

2.34(0.25)

2.24(0.26)

2.23(0.26)

0.82(0.28)

0.90(0.25)

1.03(0.26)

0.69(0.26)

Lower exposure site b* scalea 2.07(0.28)

2.08(0.25)

2.23(0.26)

1.88(0.26)

0.32(0.28)

0.39(0.25)

0.51(0.26)

0.21(0.26)

Intentional exposureb 0.13(0.16)

0.09(0.14)

0.06(0.15)

0.10(0.15)

0.12(0.16)

0.10(0.14)

0.21(0.15)

0.24(0.15)

Incidental exposureb 0.17(0.16)

0.22(0.15)

0.14(0.15)

0.19(0.15)

0.23(0.16)

0.28(0.15)

0.15(0.15)

0.11(0.15)

Sun protection indexb 0.14(0.10)

0.11(0.09)

0.02(0.09)

0.02(0.09)

0.02(0.10)

0.07(0.09)

0.05(0.09)

0.03(0.09)

Note. Photoaging video (n 38) versus no video (n 46); UV photo (n 42) versus no photo (n 42).a Higher values of b* indicate greater change toward yellow color. bValues are z scores adjusted for baseline status.



8/11

by the effects of the photoaging video on immediate intentions to

sun protect.

Similar evaluations of the possible mediational roles of inciden-

tal exposure and sun protective behavior revealed more differen-

tiated patterns. Incidental exposure levels did not, but sun protec-

tion behavior did, significantly predict L* readings at the higher

exposure site; further, controlling for sun protection levels reduced

the effect of the photoaging video, though not to nonsignificance

(Table 4, Step 3; Sobel z 1.60, p .11). In some contrast, sun

protection behavior did not, but incidental exposure did, signifi-

Figure 2. Change in lower exposure site L* readings at postsummer and 1-year follow-ups as a function ofphotoaging video and UV photo conditions, controlling for baseline status (n 84). L* indexes lightness from

black to white, with higher values indicating lighter coloring (i.e., less tan). Bars represent standard errors of the

means.

Table 4

Mediational Analyses of Photoaging Video Condition Effects on Higher and Lower ExposureSite L* Readings

Step SEb t p Sobel z, p

Step 1Video-higher exposure L* .21 .78 2.68 .0089Video-lower exposure L* .20 .76 2.28 .025

Step 2Video-sun protection intentions .45 .15 4.52 .0001Video-incidental exposure .23 1.39 2.14 .035Video-sun protection behavior .27 .15 2.57 .012

Step 3L* higher exposure

Intentions .23 .58 2.60 .011Video .11 .85 1.30 .20 2.25, p .02

Incidental exposure .09 .06 1.13 .26Video .19 .81 2.35 .02Sun protection .17 .59 2.03 .045Video .16 .81 2.00 .049 1.60, p .11

L* lower exposureIntentions .19 .57 2.06 .04Video .11 .83 1.14 .26 1.87, p .06Incidental exposure .21 .06 2.38 .02Video .15 .76 1.76 .08 1.59, p .11Sun protection .12 .58 1.30 .20Video .16 .80 1.74 .086

Note. Step 1 regression of L* levels on photoaging video condition (df 81); Step 2 regression of mediatoron video condition (df 82); Step 3 regression of L* levels simultaneously on video condition and mediator(df 80).



9/11

cantly predict L* readings at the lower exposure site while reduc-

ing the photoaging video effect to nonsignificance (Table 4, Step

3; Sobel z 1.59, p .11). Thus, this set of analyses suggests that

the effect of the photoaging video on subsequent L* levels at the

higher exposure site was also mediated somewhat by subsequent

sun protection behavior, whereas the photoaging video effect on

L* levels at the lower exposure site was mediated partially by theeffect of the photoaging video on subsequent incidental sun expo-

sure levels.

Discussion

Few prior studies have focused specifically on the effect of

using UV photographs to show individuals their current, not-yet-

visible skin damage from UV exposure, but the existing evidence

suggests that doing so significantly increases future sun protection

intentions (Mahler et al., 2003) and self-reported sun or UV

protection 12 months later (Gibbons et al., 2005; Mahler et al.,

2003). This study replicates the effects on intentions and extends

these UV photo results by showing longer term (4 5 month)beneficial effects on objectively assessed changes in skin darkness

(L* levels) following the summer months, the time when UV

radiation from the sun is most intense. Participants who had

viewed their UV photo continued to have lighter skin than their

no-photo counterparts 1 year after the original intervention, but

this difference was no longer reliable.

The separate impact of the photoaging video information was

even more impressive. Exposure to this information significantly

increased immediate intentions to sun protect, reduced reported

incidental sun exposure during the subsequent year, increased

self-reported sun protection behaviors that occurred during the

summer months following the intervention, and, most important,

produced spectrophotometric evidence of significantly less skin

darkening at higher and lower exposure areas of the arm at thepostsummer follow-up and also a year after the original interven-

tion.

Possible Mechanisms

The specific mechanism(s) by which the UV photo produced

its effects on postsummer skin darkness remains unknown.

Although the UV photo significantly affected sun protection

intentions and perceptions of photoaging susceptibility, we

found no evidence that these cognitions directly mediated the

UV photo effects on postsummer skin darkness. Like other

studies (e.g., Mahler et al., 2003), ours found no evidence that

the perceived rewards of tanning or costs of sun protectionmediated the UV photo effects on subsequent skin darkness. In

a study of tanning booth use, Gibbons et al. (2005) found that

UV photos influenced a tanning cognitions index (more neg-

ative general attitudes toward tanning; more negative views of

the prototypical tanning booth user; less willingness to engage

in impromptu risky UV exposure) and that this index partially

mediated reductions in booth use during the subsequent 3

weeks. It is possible but unknown whether a similar index

would likewise play a mediational role in the context of sun

exposure over the longer durations involved in the present

study. However, given the promise of the UV photo approach,

more work to understand these elusive mediational mechanisms

certainly is warranted.

Like the UV photo intervention, the photoaging intervention

produced significantly greater sun protection intentions. However,

for the photoaging intervention, there was fairly strong evidence

that these immediate sun protection intentions significantly medi-

ated the effects of photoaging information on skin darkness levelsassessed during the subsequent year at both exposure sites. Imme-

diate perceptions of the costs of sun protection, benefits of tanning,

and personal susceptibility were not significantly influenced by the

photoaging intervention and thus were not implicated as mediators

either directly or through their possible effects on intentions to sun

protect. There was, however, additional evidence to suggest the

photoaging video also affected subsequent skin darkness through

its beneficial effects on subsequent sun protective behavior and

incidental sun exposure (but not through intentional exposure, such

as sunbathing). Specifically, there were indications that the effects

of the photoaging video on subsequent sun protective behavior

partially mediated skin lightness at the higher sun exposure site,

whereas the photoaging video effect on subsequent incidental

exposure partially mediated the effect on skin lightness at thelower sun exposure site. These patterns make sense in that sun

protective behaviors (particularly the application of sunscreen)

tend to be directed at relatively high exposure sites (i.e., people

typically apply sunscreen directly to the outer side of the arm, but

the underside of the arm only receives the small amount that

remains on the palm after the outer arm has been covered), leaving

lower exposure sites perhaps to be influenced more by the amount

of incidental exposure one receives. That said, the strength of these

mediational pathways was modest, so future work will need not

only to try to replicate these important relationships but also to

continue to identify additional mediators.

Methodological/Interpretive Issues

The present research has several important strengths. We were

able to evaluate the separate effects that two orthogonally manip-

ulated, appearance-based interventions have on the cognitions and

subsequent sun protection behaviors and tanning of an important,

at-risk group (college students). Unlike most previous sun protec-

tion interventions, which have assessed only immediate or short-

term effects of interventions (e.g., 1 month), our study also as-

sessed longer term outcomes, first 4 5 months after the

intervention and following the period of greatest sun intensity, and

then again in an unanticipated, 1-year postintervention assessment.

Also, unlike most previous sun protection interventions, which

have relied on self-reports of intentions or behavior, our study used

objective assessments of skin color changes at both follow-ups.One interpretive wrinkle that warrants comment concerns the

fact that the UV photo and photoaging video interventions both

had significant effects on L* readings (lightness in terms of black

white) but not b* (saturation in terms of blueyellow) readings. As

noted previously, prior work has indicated that L* and b* readings

are sensitive to tanning (Levine et al., 1991; Seitz & Whitmore,

1988), and one might therefore also have expected significant

effects on the b* readings. Consistent with our results, however, at

least one other study that used a very different intervention and a

shorter follow-up period likewise found effects on L* but not b*

readings (Buller et al., 1996). Perusal of the correlations (Table 3)



10/11

indicates that L* and b* levels in the present study were related

negatively to each other as expected, although the magnitude of

their correlations suggests they do indeed tap different aspects of

skin color. We are not in a position to resolve the question of why

our interventions reliably affected L* but not b* aspects of skin

color change. It is worth noting, however, that some experts on

skin reflectance spectrophotometry now believe that L* readingsare more sensitive than b* readings to change in UV exposure

levels (personal communication, Nikiforos Kollias, Senior Re-

search Fellow, Johnson & Johnson Consumer Products World-

wide, July 20, 2005), and others have noted that although b*

readings may contribute to a tanning effect, the L* values are the

most important to show darkness of skin due to tanning (Muiz-

zuddin et al., 1990, p. 377).

Additional caveats to note are that our study was conducted at

only one site (San Diego, where the sun shines approximately 263

days per year), the volunteer sample was largely made up of

women and included no African Americans, and the follow-up

analyses included only individuals who returned for both follow-

ups. Thus, it is not possible to determine whether the interventions

would have similar effects in areas with different climates or withdifferent populations. Also, participants were aware at least of the

possibility that there would be a follow-up at the end of summer.

Thus, we cannot rule out the possibility that participants altered

their sun exposure and protection behaviors in anticipation of that

follow-up. However, participants were not told exactly when the

follow-up would occur (only sometime in the fall), and when

contacted many spontaneously remarked that they had forgotten

about the follow-up. Further, all of the participants were sensitized

to the issues being investigated. That is, even controls completed

all of the measures of baseline sun exposure and sun protection,

risk perceptions, and rewards of tanning and were debriefed re-

garding the general purpose of the study following the initial

session.

Practical Implications

Given the role of sun exposure in the increasing incidence of

skin cancer (American Cancer Society, 2004; Parker et al., 1997),

an intervention that is effective in decreasing sun exposure has the

potential for significant impact on skin cancer incidence. To the

extent that any such intervention is not terribly expensive, it of

course becomes all the more attractive from a costbenefit stand-

point. The fact that single exposures to the UV photo and the

photoaging video interventions separately demonstrated efficacy

following the summer months, the period of greatest risk of harm-

ful UV exposure, is therefore very encouraging. The fact that the

photoaging video intervention continued to exert significant ef-fects a full year later is even more remarkable. As we have noted

previously (Mahler et al., 2003), both the photoaging video infor-

mation and the UV photo intervention are relatively inexpensive,

brief, and do not require trained staff to administer; in fact, both

could be self-administered and could be made widely available in

health clinics, physicians offices, and perhaps even pharmacies

(much like automated blood pressure monitoring devices).

We think there are also theoretical and anecdotal reasons to

believe the measured results may actually have underestimated the

impact of the interventions. We were able to assess a variety of

outcomes that might be affected by the interventions, but it is never

possible to measure all potential effects. This may be particularly

relevant for studies, such as this one, that involve potential behav-

ior change. According to the transtheoretical model of behavior

change (Prochaska & DiClemente, 1986), change in risk behavior

progresses through a series of stages: precontemplation (no inten-

tion to alter behavior), contemplation (seriously considering alter-

ing target behavior), preparation (preparing to take action), action(currently modifying some aspect of target behavior), and main-

tenance (continuation of the modified behavior). Participants in

this experiment were likely at various stages when first exposed to

the interventions, but the measures used would only allow detec-

tion of intervention effects among individuals who were moved to

action (or possibly to a higher form of action) or maintenance.

Effects of the interventions that moved individuals from precon-

templation to contemplation would not have been detected. As one

participant remarked during debriefing,

Before this experiment I never even took a bottle of sunscreen when

I went to the beach. Now I always take a bottle with me, but I dont

always put it on. But I feel guilty when I dont put it onthat never

would have happened before.

Coupled with these issues, it has been our experience that both

interventions generate considerable interest and curiosity, and that

individuals tend to share the information learned with friends and

family members (Mahler et al., 2003, 2005). Whether such vicar-

ious exposure to UV photo or photoaging information might also

influence the contemplation or behavior of others is itself an

interesting question, but regardless, we believe these interventions

have considerable potential utility, perhaps even more than we

were able to document.

Conclusions

The results of this experiment add to the growing literaturedemonstrating the efficacy of an appearance-based approach in

general, and of separate photoaging information and UV photo

interventions in particular, for motivating UV protection behaviors

that may reduce skin cancer risk (Gibbons et al., 2005; Mahler et

al., 1997, 2003). This is the first experiment to investigate the

longer term effects of these interventions and to do so with

objective indices of skin color change. Given the brevity of the

interventions, their impact during the UV-intensive summer

months is particularly remarkable and important. We believe it

also may be possible to enhance the impact and duration of the

intervention effects, without greatly undermining their practical

utility. For example, it seems quite conceivable that if individuals

were allowed to keep the intervention material for future reference

(which would be particularly feasible in the case of the UV photo),

even stronger, longer lasting effects could be realized with mini-

mal increased cost. Likewise, combining the interventions with

information about safe alternatives for obtaining a tan might en-

hance their benefits while maintaining their practicality (see

Mahler et al., 2005).

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