Behav. Res. Thu. Vol. 31, No. 1, pp. 57-62, 1993 0005-7967/93 $5.00 + 0.00

Printed in Great Britain. All rights reserved Copyright 0 1992 Pergamon Press Ltd

EMOTIONALITY AND INTERFERENCE WITH COLOR-NAMING IN ANXIETY

ANDREW MATHEWS’* and FRED KLUG’

‘Applied Psychology Unit, IS Chaucer Road, Cambridge CB2 2EF, England and *Department of Psychology, Louisiana State University, Baton Rouge, LA 70803-5501, U.S.A.

(Received 14 January 1992)

Summary-The source of interference with color-naming emotional words in clinical anxiety was investigated using word sets that were varied in valence and in their judged relationship to the concerns of anxious patients. Results showed that neither valence nor general emotionality was of critical importance in predicting extent of interference. In contrast, words that were judged to be highly related to likely concerns or relevant threats caused more interference than those which were not, irrespective of their positive or negative valence. These results suggest the need to modify earlier formulations of emotional Stroop effects, and may help to explain the variable results obtained in previous investigations.

INTRODUCTION

In the original Stroop color-naming task (Stroop, 1935), Ss are required to name the color in which words are written, while ignoring the word meaning itself. As is now well known, if this meaning matches the color in which a word is written, performance is speeded, but if the meaning conflicts with the color, performance is slowed. This robust finding seems to imply that the internal representations of both word meaning and word color are accessed, and that the former interferes with response to the latter. There is strong evidence that the direction of interference arises because reading words is practised much more than naming colors (MacLeod, 1991), so that word meaning is accessed more rapidly than is the color name. Despite this evidence, there is continuing disagreement about whether interference is due to conflict at an early attentional stage of processing, at a late response output stage, or somewhere in between (e.g. Seymour, 1977).

Color-naming interference is not unique to conflict between word meaning and color names, but can also occur with words whose meaning has recently been primed (Warren, 1974), or is currently of personal or emotional significance (McKenna, 1986). This fact has given rise to a series of studies in which interference has been demonstrated in anxious and depressed individuals when required to color-name emotionally threatening and neutral control words. Thus, relative to normal controls, phobic individuals are slowed when color-naming words describing phobic stimuli (Watts, McKenna, Sharrock & Tresize, 1986), depressives are slower with negative self-descriptors (Gotlib & Cane, 1987; Williams & Broadbent, 1986; Segal & Vella, 1990), Ss with generalized anxiety states by words descriptive of danger (Mathews & MacLeod, 1985; Mogg, Mathews & Weinman, 1989), and panic disorder patients are slowed by physically threatening words (Ehlers, Margraf, Davies & Roth, 1988; McNally, Reiman & Kim, 1990). It therefore seems that interference effects occur in a range of emotional disorders. However, in all the above studies, slowing has been demonstrated only for negative or threatening words.

These results have been variously interpreted as evidence of group differences in schemata representing danger (Mathews & MacLeod, 1985), emotional construct accessibility (Gotlib & Cane, 1987), or attentional bias effects (McNally et al., 1990); although there are no convincing reasons for selecting or rejecting any of these explanations. One important assumption underlying all these proposals is that interference is specific to negative or threatening words, that match the content of emotional concerns (Mathews, 1990). An alternative view is that interference is a function of word “emotionality”; that is, interference can arise from any personally emotional word, including those of positive valence. This view has been put forward by Martin, Williams and Clark (1991), who have shown that anxious patients, but not controls, were slowed by both positive

*Author for correspondence.

57

58 ANDREW MATHEWS and FRED KLUG

and negative (threatening) words, in comparison to emotionally neutral words. In discussing these results, Martin et al. (199 1) note that in previous studies, threat value and emotionality have been confounded, since the sets of control words used have probably been lower in both emotionality and threat value. As a result, it remains unclear whether emotional interference in anxiety disorders arises from selective processing of threat cues only, or of any personally emotional stimulus.

The present study represents an attempt to clarify this question, and contrasts two related (but conceptually distinct) explanations of the results reported by Martin et aI. (1991). The first is that interference can be attributed to the emotionality of the words used, irrespective of valence. The second is that interference depends on the extent to which the words are semantically linked to a personal threat or concern. Inspection of the positive words that Martin er al. found to elicit interference effects suggested that at least some of them described mood states that were directly opposite in meaning to descriptions of anxiety symptoms (e.g. carefree, peaceful). This raises the possibility that such words might have automatically primed their opposites, such as “worried” or “anxious” (Small & Robins, 1988). Alternatively, anxious patients might consciously elaborate on the meaning of the positive words, and conclude that they describe a state they desire, but fear that they will never achieve. In either case, it could be argued that the positive words used were a special subset that can (paradoxically) be seen as threatening by anxious patients. To test this idea, the present experiment was carried out with clinically anxious patients, using word sets chosen to be either emotionally positive or negative (threatening), but with each set further sub-divided into those considered related or unrelated to the likely concerns of anxious patients.

METHOD

Twenty anxious patients a.nd the same number of matched controls were required to color-name five sets of words: negative-related and -unrelated, positive-related and -unrelated, and emotionaliy neutral; given in balanced order. Word sets were matched for frequency and length, and the emotional sets were selected after being rated for relevance to the concerns of anxious patients.

Materials

Sets of positive and negative emotional words drawn from a larger pool were rated by 7 judges, clinical psychologists and graduate students familiar with DSM III-R criteria for anxiety disorders, and with the typical concerns expressed by such patients. Judges were asked to read each word and decide how much it might relate to a likely concern or worry of patients with an anxiety disorder, including Generalized Anxiety Disorder, Panic Disorder or Social Phobia. They were instructed to disregard the positive or negative valence of the words for the purpose of this rating. Ratings were made on a scale from 1 (not relevant) to 7 (extremely relevant). The ratings on the finally selected sets (see Table 1) were subjected to ANOVA for repeated measures, which showed that the planned differences in relevance ratings were highly significant, P < 0.001. Both sets of “related” words were given high ratings (negative mean = 6.4, positive = 5.8) that were not significantly different from one another on post-hoc Bonferroni adjusted “t” tests (P < O.OS), but were significantly higher than all other sets (negative-unrelated = 3.2, positive-unrelated = 1.8, and neutral = 1 .O). These latter three means all differed significantly from each other, so that the “unrelated” words, particularly the negative-unrelated set, were judged as being more related to anxiety than were the neutral words. Word sets, shown in Table 1, were presented on cards with 96 words on each (see Mathews & MacLeod, 1985).

Subjects

The anxious 5s were selected from referrals to the Psychological Services Center at Louisiana State University. All were screened using the ADIS, a standardized interview schedule for anxiety disorders (DiNardo, Barlow, Cerny, Vermilyea, Vermilyea, Himadi & Waddell, 1983), given by a clinical graduate student under supervision. To be accepted into the study, clients had to receive a primary diagnosis of Generalized Anxiety (1 l), Panic Disorder (6) or Social Phobia (3): most met criteria for more than one such diagnosis. Control Ss were community volunteers, who were matched for gender, age and educational status, but had no history of anxiety disorder.

Color-naming and anxiety 59

Table I. Emotional word sets used in the experiment

Postitiw-related Fearless

competent Relaxed

Safe Controlled

Courage Confidence

Assured

Positiue-unrelated Beauty

Brilliant Splendid

Pride Mercy

Romantic Delightful

HUIIKX

Negative-related Shaking Crazy

NerVOUS Fear

Dying Tense

Frightened Panic

Ne,eatiw -unrelated Negative

Sin Warfare Murder Quarrel

Destructive Controversy

Warning

Table 2. Mean for S characteristics (SDS in parentheses)

Anxious patients Normal controls

Sex ratio (males/females) SjlS 6/14

Age in years 36.3 (1 I .8) 36.8 (12.3) Trait anxiety 55.0(15.2) 34.9 (8.6) Beck depression 10.6 (8.5) 4.6 (3.6)

Procedure

Anxious Ss first attended an assessment session in which the ADIS interview was given, prior to acceptance for anxiety management treatment. Those who were accepted were asked to attend for a further experimental session before treatment began, during which the color-naming task was carried out. In the test session, all Ss (including controls) were instructed that the color-naming task was a test of mental speed, that they should ignore word content and name the ink color of each word card as fast as they could without making mistakes. They were first given a practice card with (unmatched) neutral words, which was followed by the five matched experimental cards, given in balanced order. Time taken to complete each card was recorded using a stopwatch. All Ss were then given a list of the words used, presented in random order, and asked to rate each for emotional impact on them, and for how often they thought that they used the word, both using O-10 visual analog rating scales. Finally, the Spielberger Trait Anxiety Inventory and the Beck Depression Inventory were administered.

RESULTS

S characteristics are shown in Table 2. As expected, patients had higher mean scores than controls on the Spielberger Trait Anxiety measure [55 vs 35, F(1,38) = 29, P < O.OOl]. However, patients also scored more highly on the Beck Depression Inventory [lo.6 vs 4.6, F(1.38) = 8.3, P < 0.0071. Thus, although none of the patients met criteria for depressive disorder, some of them must be regarded as being mildly depressed as well as anxious.

Time to complete each card was analyzed using a 2 by 5 repeated measure analysis of variance, with one between S factor (group: anxious vs control), and one within-S factor (word type). There was no main effect of group, F(l,38) = 0.84, but the differences between word type were highly significant overall, F(4,152) = 4.53, P < 0.01. More importantly, there was also a near-significant trend for group to interact with word type, F(4,152) = 2.28, P -C 0.07. Analysis of covariance, using the time to color-name the neutral words as a covariate to adjust the remaining times, resulted in the interaction of group by wordtype reaching significance, F(3,113) = 3.12, P < 0.03. Inspection of the mean values given in Table 3 shows that the most striking differences between the two groups concern the two related word types. Whether positive or negative in valence, the related words interfered more with the performance of anxious patients than did unrelated words.

To test the main hypotheses under consideration, two additional analyses were performed. In the first, the overall effect of valence was tested by averaging times to color-name the two negative sets (related and unrelated), and the times for the two positive sets. These collapsed negative and positive scores were then submitted to ANOVA for repeated measures to test the hypothesis that negative (threatening) words would cause more interference than positive words. Although there was an overall effect of valence, F( 1,38) = 5.6, P < 0.03, the interaction between valence and group did not approach significance, F(1,38) = 1.52, P = 0.23. That is, there was no evidence to support the hypothesis that the interference from negative vs positive words overall was greater in anxious patients than in the controls. In fact, inspection of the difference between color-naming times

60 ANDREW MATHEWS and FRED KLUG

Table 3. Mean color-naming x word sets in seconds. divided bv erou~ and tvue of word

Unrelated

Positive Negative

73. I 72.9 70.3 72.4

2.8 0.5

Related

Positive Negative Neutral

76.4 78.4 74.9 70.3 73.4 71.6

6.1 5.0 3.3

suggested that the greater slowing due to negative words overall was slightly more pronounced in controls (2.6 set) than it was in patients (0.8 set).

In the second analysis, the hypothesis that related words lead to more interference was tested. The times for the two “related” sets were averaged and compared to the average for the two “unrelated” sets, thus comparing two scores that were independent of valence. In the repeated measure ANOVA of these scores, there was a main effect for relatedness, with “related” words causing more interference overall, F(1,38) = 8.9, P < 0.001. However, this was qualified by an interaction between relatedness and group, F( 1,38) = 4.7, P < 0.04. On separate analyses by group, the relatedness factor was not significant for controls, F( 1,19) = 0.65, but it was for anxious patients, F( 1,19) = 8.9, P < 0.01. Related words caused more interference than “unrelated” words for anxious patients (77 vs 73 set), but not for controls (71.9 vs 71.2 set).

Ss emotionality and usage ratings are shown in Table 4. Averaged ratings for positive words were compared with those for negative words using “t” tests (alpha set at P < 0.01): both anxious and control groups rated negative words as more emotional. However, while anxious Ss also rated composite related words as more emotional than unrelated, the control Ss did not. For usage ratings, anxious Ss rated negative and related words as being used more frequently, while controls rated positive words as more frequent but did not differ on related versus unrelated.

Additional exploratory correlational analyses were carried out using interference scores calcu- lated by subtracting the time taken by each S to color-name the neutral words, from that taken to complete each of the other sets. Averaged emotionality and usage ratings made by each S for each word set were correlated with the corresponding interference scores across the whole group, without finding any significant relationships (all Ps > 0.05). Similarly, no significant correlations were found within the anxious group alone. Within the control group. the only significant correlation found indicated that interference from negative-unrelated words was greater the lower their usage estimates (Y = -0.48, P < 0.03). In general therefore, neither emotionality nor usage ratings proved a useful predictor of interference in color-naming.

DISCUSSION

In one sense the present results support the conclusions of Martin et al. (1991). Positive emotional words can cause as much interference with the color-naming performance of anxious patients as negative (threatening) words. At first sight, this implies that it is no longer tenable to account for the interference effects previously reported in anxious patients (for example by Mathews & MacLeod, 1985; and Mogg et al., 1989) as being due only to the threatening quality of the words used. Rather, the present results are consistent with the idea that interference effects are attributable to the extent to which the words used are related to the likely emotional concerns of that patient.

The distinction between the “emotionality” and “threat-value” hypotheses is not quite so clear-cut as this would imply, however. Rather, it depends on whether the threat value of a word

Table 4. Mean emotionality and usage ratings

Unrelated Related

Positive Negative Positive Negauve Neutral

Anxious Controls

AIlXiOUS Controls

4.8 5.0

2.2 3.9

Emofionolit~ ratings

6.3 5.4 6.4 4.7

Frequenc_v qf usage ratings 2.6 3.0 1.6 3.5

1.8 1.0 6.6 I.1

4.9 1.2 2.4 2.1

Color-naming and anxiety 61

is taken to correspond only to its surface meaning, or whether one allows the possibility that some apparently positive words can have a threatening meaning for anxious individuals. As indicated earlier, one way that this is particularly likely to arise is if the positive words are near antonyms of threatening words (Small & Robins, 1988; Martin et al., 1991). This explanation may help to resolve the problem of distinguishing the two hypotheses, provided that circular reasoning can be avoided by identifying such paradoxically “threatening” positive words in advance, using criteria other than their interfering properties. In the present experiment, positive words judged in advance as being related to the likely concerns of anxious patients caused interference effects, while other positive words that were judged to be almost as emotional, caused no more interference than did neutral words. This result favors the view that interference can arise due to semantic associations between some apparently positive words and the emotional concerns of anxious Ss.

Although quite similar to the conclusions of Martin et al. (1991) this view does lead to somewhat different implications. For example, it may be misleading to identify “emotionality” as the primary quality that causes material to selectively attract processing resources in anxious patients. As understood and rated by our Ss, “emotionality” estimates did not provide reliable predictions of interference. Presumably this was because words may be judged to be emotional in a general sense, despite being unrelated to one’s current concerns. For this reason we would prefer to attribute the interference effects seen in anxious patients to the extent that the words used are semantically linked with that individual’s current emotional concerns. If this is so, then judgements of how closely material matches or is related to personal emotional concerns should be a better predictor of interference than judgements of emotionality in general.

While this hypothesis needs to be tested further, the general view advanced here may help to explain the occasional failure to find interference with apparently threatening words in non-clin- ically anxious Ss. Martin et al. (1991) found no evidence of interference from either positive or threatening words in non-clinical Ss with trait anxiety scores matched to those of patients, and speculated that this may be because only the anxious patients perceived threat in predominantly non-threatening stimuli. However, in a related study by Mogg and Marden (1990), high anxious normals did show interference effects, although these were present with both positive and threatening words. Furthermore, Richards and Millwood (1989) had previously found interference effects in high anxious normals for threatening, but not for positive words.

While it is not possible to come to any firm conclusions, the view advanced here would suggest that these mixed results can be attributed to varying degrees of match with the concerns of the anxious Ss being tested. Since the concerns of (for example) high anxious students may differ considerably from those of a clinical sample, words chosen to describe the likely concerns of patients may not always be an appropriate match with those of other groups. Equally, the variable results obtained with positive words may have arisen because little attention has been paid in the past to the semantic associates of the supposedly non-threatening stimuli used. The present results suggest that when positive words have been found to cause interference this may be because at least some of them were semantically linked with a perceived threat or current concern.

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