Estimating the Valence of Single Stimuli: A New ... - Hogrefe eContent

Estimating the Valence of Single Stimuli: A New Variant of the Affective Simon Task Andreas Voß,1 Klaus Rothermund,1 and Dirk Wentura2 1 University

of Trier, Germany and 2 University of Jena, Germany

Abstract. In this article, a modified variant of the Affective Simon Task (AST; De Houwer & Eelen, 1998) is presented as a measure of implicit evaluations of single stimuli. In the AST, the words “good” or “bad” have to be given as responses depending on the color of the stimuli. The AST was combined with an evaluation task to increase the salience of the valence of the presented stimuli. Experiment 1 investigated evaluations of schematic faces showing emotional expressions. In Experiment 2 we measured the valence of artificial stimuli that acquired valence in a game context during the experiment. Both experiments confirm the validity of the modified AST. The results also revealed a dissociation between explicit and implicit evaluations. Key words: Affective Simon Task, automatic evaluation

In this paper, an indirect method for estimating the valence of single stimuli is presented, which is a variant of the Affective Simon Task (AST; De Houwer & Eelen, 1998). In recent years, several response-time based paradigms have been developed to assess the valence of stimuli (e.g., attitude objects) indirectly, that is, without reference to scales and questionnaires. Most important is the Affective Priming Task (Fazio, Sanbonmatsu, Powell, & Kardes, 1986), the Implicit Association Test (IAT; Greenwald, McGhee, & Schwartz, 1998), and the Affective Simon Task (AST; De Houwer & Eelen, 1998; see also De Houwer, Crombez, Baeyens, & Hermans, 2001), as well as variants of them (e.g., Masked Affective Priming with Response Window, Draine & Greenwald, 1998; the Extrinsic Affective Simon Task, De Houwer, 2002; or the Go/No-Go Association Task, Nosek & Banaji, 2001). Frequently, the problem arises that an attitude object is best represented by a single stimulus: a brand name or logo in consumer research (e.g., Kokkinaki & Lunt, 1999), participants’ names or initials in The research reported in this article was supported by a grant from the Deutsche Forschungsgemeinschaft (DFG) to Klaus Rothermund and Dirk Wentura (RO 1272/ 2Ð1). The authors wish to thank Jan De Houwer for valuable comments on an earlier draft of this paper. DOI: 10.1027//1618-3169.50.2.86 Experimental Psychology 2003; Vol. 50(2): 86Ð96

self-esteem research (e.g., Bosson, Swann, & Pennebaker, 2000; Wentura, Kulfanek, & Greve, 2002), or a newly acquired group assignment in social psychology’s minimal group paradigm (e.g., Otten & Wentura, 1999), to name just a few examples. Additionally, in our own research, we were interested in the implicit valence of abstract symbols that acquired the function of danger and chance signals in a game context (Rothermund, Wentura, & Bak, 2001; see also Derryberry, 1993). Not all indirect measures of attitudes are equally apt for this purpose. For example, the most popular technique Ð the IAT Ð measures only attitudes towards categories and not the valence of single stimuli. The AST is a well-suited design for single-stimulus measurement. In a Simon Task, each stimulus is characterized by two dimensions (De Houwer, in press): The relevant dimension determines which of two alternative responses has to be given. The irrelevant dimension is not related to the task and should be ignored. However, the irrelevant dimension is either congruent or incongruent to the response. For example, in the original, that is, spatial, version of the Simon Task (Craft & Simon, 1970), the color of the stimulus (the relevant dimension) determined the response, which was either a left or right key press. The location of the stimulus on the screen (left vs. ” 2003 Hogrefe & Huber Publishers

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right; the irrelevant dimension) had to be ignored but nonetheless caused interference effects. De Houwer (De Houwer et al., 2001; De Houwer & Eelen, 1998) applied this task to the assessment of automatic evaluation (AST): According to an arbitrarily selected relevant dimension (e.g., letter case), stimuli now had to be categorized by valent responses, for example, saying “good” to uppercase stimuli and “bad” to lowercase stimuli. Stimulus valence was the irrelevant dimension in this type of task. It was shown that the positive response was given faster to positive stimuli than the negative response (and vice versa for negative stimuli). For stimuli with unknown valence, the difference between the mean latencies for trials with the response “bad” and trials with the response “good” can be interpreted as the implicit positivity of the stimuli. The AST is a very elegant task for the measurement of single-stimulus valence, but there is one problem as well: Duscherer, Holender, & Molenaar (2002) showed that the AST produces stronger and more reliable effects, if a large proportion of the presented stimuli have a clear valence, that is, if valence is a salient feature of the materials. This dependence on the overall salience of valence might be seen as a disadvantage of the task, because an indirect measure of valence is especially useful if the valence of the stimuli is not a priori evident. To provide more robust effects in assessing valence that is unknown or close to neutral, it is important to draw attention to the valence dimension, which should warrant an automatic evaluation of all stimuli. For that purpose, the original AST was combined with an additional evaluation task in our new variant of the AST. The new task has the following logic: If a colored (red vs. blue) stimulus is presented, the color determines whether the response “good” or “bad” is to be given. All stimuli presented in black, however, have to be categorized as positive or negative on the basis of the valence of the stimuli, using the same responses. Procter and Vu (2002) report evidence that spatial Simon effects are enlarged by increasing the proportion of compatible trials. In a similar way, including evaluation trials in our task yields a high proportion of trials in which stimulus valence corresponds to the valence of the response. Trials of both tasks are randomly intermixed, so that it is not possible to know in advance whether valence will be the relevant feature in the next trial. De Houwer (2002) recently created a similar task, the Extrinsic Affective Simon Task (EAST), which stimulated our work. The EAST and our variant of the AST will be compared in the Discussion. Two experiments were conducted using the new variant of the AST. In the first experiment, the valence of schematic faces showing different emotional expressions was measured. In the second study, we measured the implicit valence of abstract symbols that acquired valence in game-like parts of the experiment. ” 2003 Hogrefe & Huber Publishers

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Experiment 1 Experiment 1 applies the new variant of the AST to the evaluation of emotional facial expressions (i.e., to single stimuli with an a priori defined valence). We used four different stylized faces, a happy and a friendly one as positive stimuli, and a sad and a hostile one as negative stimuli (see Table 1). Thus, orthogonally to valence and for exploratory reasons, we manipulated the perspective of evaluation (see Peeters, 1983; Peeters & Czapinski, 1990; see also von Grünau & Anston, 1995). To be happy or to be sad (possessor relevant) is unconditionally positive or negative, respectively, for those who are happy or sad, but not (necessarily) for those interacting with them. By contrast, to be friendly or to be hostile (other-relevant) is unconditionally positive or negative, respectively, for those who interact with the friendly or hostile person, but not (necessarily) for those persons themselves. It is known from former studies that the distinction between possessor-relevant and other-relevant valence is a basic feature of the information-processing system (see Rothermund, Wentura, & Bak, 1996; Wentura, Rothermund, & Bak, 2000). In an emotional Stroop task, Wentura et al. (2000) found that attention is automatically drawn to other-relevant traits. Moreover, this effect is behavior-related: Negative other-relevant traits prepare for an avoidance reaction, while positive other-relevant traits facilitate an approach reaction. Indirect measures of valence might be susceptible to these basic differences between kinds of stimuli such that the AST effect might be more pronounced for otherrelevant faces compared to self-relevant ones.

Method Participants Twenty-four undergraduate students (18 women and 6 men) of psychology of the University of Trier (age 19 to 28 years; M = 22.25) participated for partial course credits. Materials Sixteen symbols were used: eight for the AST and eight for the evaluation task (see Table 1). All symbols were bounded by a circle with a diameter of approximately 3 cm. The AST symbols consisted of the four emotional faces (i.e., friendly, happy, sad, hostile). Besides these, we added two more symbols (gift and rain cloud) that were assumed to have a slightly positive and negative valence, respectively. Additionally, two abstract symbols were used that were assumed to have a neutral valance and served as a baseline to control for main effects of response. Experimental Psychology 2003; Vol. 50(2): 86Ð96

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Table 1. Means and Standard Deviations of Valence Ratings for the Symbols Used in the AST and in the Evaluation Task (Experiment 1) Affective Simon Task Symbols (happy)

(friendly)

(sad)

(hostile)

2.25 (0.68)

2.21 (0.66)

Ð1.63 (0.88)

Ð1.71 (0.95)

M SD

1.92 (0.93)

Ð1.42 (0.83)

Ð0.25 (0.79)

Ð0.21 (0.51)

Ð1.71 (1.16)

Ð2.24 (0.93)

Ð2.25 (1.03)

Evaluation Task Symbols

M SD

2.25 (0.68)

1.75 (0.79)

2.24 (0.88)

2.04 (0.95)

Ð2.42 (0.83)

Note. Ratings were given on a scale from Ð3 (“very bad”) to +3 (“very good”).

To compare the indirect indices of valence with rating data, an independent sample (N = 24) rated the symbols on a scale from Ð3 (“very bad”) to +3 (“very good”). Means are given in Table 1. The pattern of evaluation corresponds to the predicted valences of the stimuli. Importantly, there are no differences with regard to explicit valence between possessor-relevant and other-relevant stimuli. During the experiment, all AST symbols were presented in either dark red (RGB color values: 170, 20, 20; range: 0Ð255) or dark blue (RGB color values: 20, 20, 170) color on a white background. The eight symbols of the evaluation task included four positive and four negative stimuli (see Table 1). The symbols were selected in pilot studies so that fast and accurate valence estimations were made. These symbols were always presented in black color. Design Essentially, the design comprised three within-subjects factors: (1) valence of response (positive vs. negative), (2) valence of symbol (positive vs. negative), and (3) direction of relevance (possessor vs. other). Additionally, we counterbalanced the assignment of stimulus colors and responses (red Ð “good” and blue Ð “bad” vs. red Ð “bad” and blue Ð “good”) between participants. Procedure Participants completed the experiment on an individual basis. The experiment (including instructions) Experimental Psychology 2003; Vol. 50(2): 86Ð96

was implemented on an IBM-compatible Pentium computer using a Turbo Pascal 7.0 program. After reading the instructions, each participant started with a first practice block consisting of 24 evaluation trials, that is, each symbol of the evaluation task was presented three times in random order. In a second practice block, the AST was introduced: Each of the eight AST symbols appeared once in red and once in blue color. The trials were presented in random order. Thereafter, both tasks were intermixed. The trials followed a random sequence with three constraints: (1) the same symbol was not presented in consecutive trials; (2) sequences of trials of the same task (i.e., AST or evaluation) were restricted to a maximum of three trials; (3) half of the AST trials followed an evaluation trial and half followed another AST trial, respectively. The main phase started with 20 practice trials followed by 384 experimental trials. Each of the 16 symbols was presented 24 times (the AST symbols were presented 12 times in red color and 12 times in blue color). In case of either an erroneous response or a failure of the voice key, trials were repeated at the end of the experiment. The experiment took about 20 minutes. In each trial, a symbol was presented in the center of the screen. It disappeared as soon as a verbal response was given. A voice key recorded the reaction time to the nearest millisecond. Rules of responding depended on the color of the symbol: If it was black (i.e., evaluation trial) the participant had to indicate the valence of the symbol using the words “gut” (good) or “böse” (bad, evil). For the negative reaction, we used “böse” (evil) instead of “schlecht” (low/poor quality), because measuring verbal response times with the initial sound of the latter word ” 2003 Hogrefe & Huber Publishers

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is inaccurate. If a colored symbol was presented, its valence had to be ignored, and the correct answer depended on the color: Participants had to give either the positive response to all red stimuli and the negative response to all blue stimuli or vice versa depending on the condition (see Design). In each trial, the correct response was presented on a second CRT screen allowing the experimenter to register incorrect responses (i.e., incorrect naming or false triggering of the voice key). Feedback for errors, slow responses (i.e., latencies of more than three seconds), or voice key failures were presented on the participant’s screen for 800 ms. Following a blank screen for 250 ms, the next trial started.

Results Analyses were restricted to the correct AST trials only (3.45 % of these trials had been repeated because of errors; see above). Response time outliers (0.65%) were excluded from all analyses. For each participant an upper and a lower outlier criterion were calculated according to Tukey (1977, “far out values”), using the distribution of all AST latencies of this person. For each participant, mean reaction times were calculated separately for each symbol and for both responses. For all analyses, latencies were log-transformed. Table 2 shows the mean reaction times, as well as the difference score between positive and negative responses. In all cases (but one) the sign of the difference score corresponds to the expectation. Only the “gift” symbol has a difference near zero. Response time differences between both reactions concerning the two neutral symbols are quite small and clearly not significant. Corrections for baseline effects do not alter the described analyses substantially. Only for the sad face does the

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analysis with the corrected times not provide a significant AST effect. Our main hypothesis concerned the valence of the emotional faces. A 2 (stimulus valence) ¥ 2 (direction of relevance) ANOVA with the difference score as the dependent variable yielded a main effect of stimulus valence, F(1, 23) = 28.05, p ⬍ .001. For the positive faces, a positive affective Simon effect of 45 ms (SD = 58 ms) was found, t(23) = 4.24, p ⬍ .001. For the negative faces, a negative affective Simon effect of Ð60 ms (SD = 83 ms) was evident, t(23) = Ð3.65, p = .001. The interaction between stimulus valence and direction of relevance was also significant, F(1, 23) = 4.51, p = .05. Affective Simon effects were larger for the other-relevant faces compared to the possessor-relevant faces. However, the interaction is ordinal: simple main effects of stimulus valence are significant for the other-relevant stimuli, t(23) = 4.99, p ⬍ .001, as well as for the possessorrelevant stimuli, t(23) = 2.90, p ⬍ .01. Three out of the four faces show a difference score that is significantly different from zero, t(23) = 4.24, p ⬍ .001, for the friendly face, t(23) = Ð3.76, p = .001, for the hostile face, and t(23) = Ð2.29, p ⬍ .05, for the sad face. Only the affective Simon effect for the happy face fails to reach significance, t(23) = 1.67, p = .11. All other symbols did not show a significant AST effect, all t ⱕ 1. In the following section, explicit and implicit evaluations are compared: The correlation of the mean explicit and implicit valence measures across the eight symbols is r = .85, p ⬍ .01. A more specific test compares the influence of the direction of relevance between the explicit and the implicit data. To make data comparable, all evaluation measures for the four face symbols were standardized. A 2 (data source: explicit vs. implicit) ¥ 2 (face valence: positive vs. negative) ¥ 2 (direction of relevance: self vs. other) ANOVA with the evaluation values as de-

Table 2. Mean Reaction Times (Standard Deviations in Parentheses) for the Verbal Responses “Gut” (Good) and “Böse” (Bad) for all Symbols of the AST Trials (Experiment 1)

Positive reaction Negative reaction AST effect Effect size

677 (101) 697 (102)

676 (121) 746 (112)

727 (127) 678 (96)

749 (150) 679 (90)

720 (135) 718 (123)

731 (143) 703 (111)

708 (108) 697 (94)

707 (132) 705 (120)

20 .34

71** .87

Ð49* .47

Ð71** .77

Ð2 .01

Ð27 .21

Ð12 .11

Ð3 .00

Note. The AST effect is the difference between the latencies for the negative and the positive reactions. All tests were conducted with log-transformed data. *p ⬍ 05; **p ⬍ 01 ” 2003 Hogrefe & Huber Publishers

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pendent variable reveals a marginally significant three-way interaction, F(1, 46) = 3.80, p = .06: Stronger evaluations for other relevant emotions are found with the implicit measure (see above), but not with the explicit measure, F ⬍ 1 for the valence ¥ direction of relevance interaction.

attitude change rather than stable stimulus valence. Therefore we used abstract symbols that should acquire a positive or negative valence in game-like parts of the experiment (Rothermund et al., 2001; see also Derryberry, 1993).

Method Discussion

Participants

In Experiment 1, the new variant of the Affective Simon Task was tested using emotional facial expressions as stimuli. Our results reveal that the new task is well suited for measuring the valence of single stimuli. The AST effects, calculated as response time differences between negative and positive reactions, point in the a priori expected direction for seven out of eight symbols. Only the absence of a positive valence of the gift symbol is surprising. Perhaps the three-dimensional structure of this stimulus is too complex for a fast automatic evaluation. Interestingly, for the faces the perspective of evaluation (possessor-relevant vs. other-relevant) moderated the AST effect. As argued above, this difference indicates a dissociation between explicit valence (as measured by the rating scale) and implicit valence (as assessed by the AST). Implicit valence might more strongly reflect automatic behavioral tendencies of approach behavior (in case of positive other-relevant stimuli) and avoidance behavior (in case of negative other-relevant stimuli), respectively (Wentura et al., 2000). Possibly, the strong affective Simon effect for the hostile face might partially be due to the fact that the response “böse” (evil) is semantically connected to hostility, but this cannot explain the difference in Simon effects for the friendly and the happy face.

Twenty-four students (18 women, 6 men) from various faculties at the University of Trier (age 19 to 28 years; M = 22) participated in the experiment. Depending on performance, they received up to five Euro (M = 3.75 Euro) for their participation (see below). Materials Sixteen symbols of the same size as in Experiment 1 were used. The eight evaluation symbols were identical to the stimuli of Experiment 1. The AST symbols are shown in Figure 1. Four symbols were used in the game (“game stimuli”) and should acquire different valences according to the rules of the game. The names “Kah,” “Teh,” “Peh,” and “Ah” were assigned to the four symbols during a verbal naming task. The assignment of meanings (i.e., chance, danger, and neutral) to the stimuli was counterbalanced across participants (see Design). Additionally, four more AST stimuli were used: To allow for a comparison of the newly acquired valence to a priori valences, we adopted two of the faces (i.e., friendly and hostile) of Experiment 1. For a baseline measurement, two neutral symbols (i.e., a square and a triangle) were used.

Experiment 2 Design With Experiment 2, the sensitivity of the new task for more subtle, short-term and newly acquired valence was tested. The measurement of recently acquired valence is an important problem in attitude research, because it is often more interesting to show

Again the factor valence of response (positive vs. negative) was the most important independent variable. For the analyses concerning the game stimuli, a second factor was manipulated within-subjects:

Game Stimuli

“Kah”

“the”

“Peh”

“Ah”

Figure 1. The symbols used in the AST trials of Experiment 2. The game symbols were used also in other parts of the experiment. A syllable was assigned as a name to each of the four game symbols (see text for further explanations). Experimental Psychology 2003; Vol. 50(2): 86Ð96

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meaning of symbol (chance, danger, or neutral). As in Experiment 1, the assignment of stimulus colors and responses was counterbalanced across participants. Additionally, the meanings of the game symbols were varied in 12 groups, so that each possible pair out of the four symbols (i.e., 12 pairs) received the meanings chance and danger for one group of participants. Procedure The experiment consisted of a series of different practice blocks followed by a sequence consisting of the naming task (valence induction) and the combined evaluation and Affective Simon Task (valence measurement) that was repeated four times. Table 3 gives an outline of the procedure of Experiment 2. In the first and second block, participants practiced the evaluation task (ET) and the Affective Simon Task (AST) separately. A third block included both tasks. Up to this point the procedure was essentially the same as in Experiment 1. Then participants were taught the names of the four game symbols in block 4 by performing a simple naming task. If more than five errors were made, this block had to be repeated. In block 5, the meanings of the four game symbols were introduced. Again, the naming task was used, but this time with a distractor present: On each trial, two of the four game symbols were presented next to each other, one in gray and one in black color. The gray symbol had to be named, while the black one had to be ignored. (Distractors were presented for analyzing effects of automatic attentional capture of stimuli signaling dangers and chances. These effects are not important for this paper and will not be described further.) Each response was categorized as either fast or slow, using the median of the last twelve responses for the respective target symbol as a criterion. If the target was the chance symbol, then 10 points were won if the reaction was faster than the “chance criterion”. If the target was the danger symbol, then 10 points were lost if the reaction was slower than the “danger criterion” or if the reaction was wrong. All correct answers were additionally rewarded with a gain of two points; for each error two points were lost. If participants got more than 50 points in a block, they received 1 Euro. Following block 5, a “rule comprehension check” was made in which participants had to answer four questions concerning the rules of the game. If any errors were made, block 5 was repeated (without the chance of winning money). The experimental blocks consisted of four naming task blocks and four AST blocks (see Table 3). In each naming task block, there was again the chance of winning 1 Euro. Valence assessment was almost identical to the method introduced in Experiment 1 and con” 2003 Hogrefe & Huber Publishers

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Table 3. Sequence of Task Blocks (Experiment 2) No. of trials Practice Blocks: Evaluation task (ET) Affective Simon Task (AST) ET + AST Simple naming of game stimuli Naming game with point rules Rule comprehension check Experimental Blocks Game ET + AST Game ET + AST Game ET + AST Game ET + AST

16 16 96 40 48

48 48 48 48 48 48 48 48

sisted of 48 experimental trials plus 20 warm-up trials (plus repetition trials if any errors were made). The only change compared to Experiment 1 was the introduction of a fixation point, which was presented for 250 ms at the beginning of each trial. In total, the experiment lasted about 45 minutes.

Results Only the results for the AST are reported. Error trials (2.21%) were repeated and outlier latencies (0.96%) were ignored for all analyses. Individual outlier criterions were calculated for each participant and for each of the four experimental AST blocks separately. This was done because there was a strong main effect of block, F(3, 21) = 13.73, p ⬍ 001, indicating faster responses in the later blocks. For all analyses, latencies were log-transformed. Mean response times and AST effects for all AST stimuli are shown in Table 4. As predicted, the mean AST difference score for the chance stimulus is larger than the mean score for the danger symbol, t(23) = 2.09, p ⬍ .05, indicating a more negative valence for the danger signal compared to the chance signal. Simple tests revealed that the mean AST difference is significantly below zero for the danger stimulus, t(23) = -2.16, p ⬍ .05, whereas there is no significant deviation from zero for the chance stimulus and the neutral stimulus, both t(23) ⬍ 1. Replicating the results from Experiment 1, the mean AST difference score for the friendly face is larger than the mean score for the hostile face, t(23) = 4.83, p ⬍ 001. Both mean scores deviate significantly from zero, t(23) = 2.79, p ⬍ .01, for the friendly face; t(23) = Ð2.84, p ⬍ .01, for the hostile face. Experimental Psychology 2003; Vol. 50(2): 86Ð96

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Table 4. Mean Reaction Times and Standard Deviations for the Verbal Responses “Gut” (Good) and “Böse” (Bad) for all Symbols of the AST (Experiment 2) Chance Positive reaction Negative reaction AST effect Effect size (d)

Game stimuli Danger Neutral

Friendly Face

Hostile Face

Square & Triangle

646 (71) 650 (89)

666 (81) 634 (80)

650 (83) 647 (89)

635 (70) 682 (94)

696 (115) 627 (79)

635 (86) 633 (71)

4 .07

Ð32* .44

Ð3 .06

48** .57

Ð69** .58

Ð2 .06

Note. The AST effect is the difference between the latencies for the negative and the positive reactions. All tests were conducted with log-transformed data. *p ⬍ 05; **p ⬍ 01

Discussion Experiment 2 shows that abstract symbols that function as chance and danger signals in a game-like context acquire corresponding valences: The estimation of valence for the danger symbol is negative compared to the estimation of the chance signal. However, in our design the chance signal did not acquire a positive valence. This might be due to the rules of the game: Because correct answers were rewarded, it was quite easy to reach the critical amount of 50 points (and therefore to earn the monetary reward). So participants probably activated a prevention focus (Higgins, 1996) in which the information processing system is tuned to defend the current status. In this state the danger stimulus will be especially salient, resulting in a strong negative valence (Rothermund et al., 2001). In a follow-up study, a modified version of the game task was used in which it was more difficult to attain the monetary rewards. This modification should induce a promotion focus. With this variant of the game, we observed a significant positive valence for the chance signal, whereas the negative valence of the danger signal was no longer significant. Additionally, the results for the emotional faces replicated the findings of Experiment 1: A positive affective Simon effect emerged for the friendly face, whereas a negative affective Simon effect was present for the hostile face. Reliability of the Implicit Valence Estimations A further set of analyses was conducted to estimate the reliability of the implicit valence measures of Experiments 1 and 2. In personality research, reliability coefficients give an estimate of the relative amount of systematic interindividual variance of a measure; that is, they indicate whether a certain test or variable can be used to measure reliable interindividual differences on a latent dimension. This concept of reliabilExperimental Psychology 2003; Vol. 50(2): 86Ð96

ity, however, is not an apt measure to evaluate the psychometric quality of the Affective Simon Task in our studies, because we do not expect systematic interindividual differences in the evaluations of the symbols: The variance of our data is due to differences in the symbol valences and measurement errors, but not Ð or only to a very small degree Ð to stable interindividual variance regarding the evaluation of the stimuli. Therefore, reliability estimates that are based on interindividual differences are not very informative in our case. Besides, a low amount of trials per symbol prevents a reliable estimation of interindividual differences. In line with this expectation, split-half reliability coefficients were low (M = .28 in Experiment 1 and M = .23 in Experiment 2; see Table 5). It appears that reliability is higher for ambivalent symbols (especially for the neutral game stimuli) and lower for stimuli with clear valences. Possibly, there is more systematic interindividual variance concerning the ambiguous symbols and, in turn, reliability is increased. A better estimate of the psychometric quality of our task is obtained by comparing the patterns of affective Simon effects across symbols between two test halves. We divided all Simon trials into two subsets by using an odd-even algorithm: For each symbol and each response type, trials were alternatively assigned to the two sets. Additionally, we balanced both sets for the type of the pre-trial (i.e., task-switch vs. task-repetition in the current trial) in Experiment 1, and controlled statistically for effects of task shifting in Experiment 2. In Experiment 2, it was not possible to balance trial type (task switch vs. task repetition) in each trial set, because there were an unequal number (three) of trials for each symbol and each response in each subset. Instead we calculated the mean response time difference between task switch and task repetition trials for each participant and adjusted each response time for this effect. If our variant of the AST is reliable, then both “subtests” should reveal a similar pattern of valence estimates. To assess the degree of correspondence of ” 2003 Hogrefe & Huber Publishers

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Table 5. Summary of Syntactic Manipulations and Results Symbol Happy face Friendly face Sad face Hostile face Gift Rain cloud Abstract 1 Abstract 2

Experiment 1 Trial set 1 Trial set 2 9 53 -49 -67 -10 -23 0 16

32 90 -49 -77 9 -31 Ð22 -20

Rel(I)b .31 .08 .14 .56 .26 .56 .16 -c

Rel(S)a = .94

Experiment 2 Trial set 1 Trial set 2

Symbol Game: chance Game: danger Game: neutral 1 Game: neutral 2 Friendly face Hostile face Square Triangle

20 -35 0 -21 85 -73 -16 5

-16 -50 -11 11 16 Ð69 -34 5

Rel(I)b .17 .05 .52 .40 -c .35 .14 .21

Rel(S)a = .84

Note. The affective Simon effect is the difference between the latencies for the negative and the positive reactions. Reliability coefficients and ICC’s were calculated with log-transformed data. a Reliability of inter-stimulus variance (intra-class correlation coefficient; see text for further explanation) b Reliability of inter-individual variance (split-half reliability, corrected according to Spearman-Brown) c Reliability could not be calculated, because of negative correlations between test halves (r = Ð.05 for the “abstract 2” Symbol in Exp. 1, and r = Ð.10 for the “happy face” symbol in Exp. 2, respectively)

results between the two test halves, the intra-class correlation (ICC) was used. The ICC coefficient is often used to estimate reliability in observational studies by analyzing observer consistency (see, e.g., Greve & Wentura, 1997). It indicates the proportion of variance that is due to the observed object. The Pearson coefficient should not be used in this case, because it is not independent of the allocation of the effect measures to the test. Table 5 shows the effect measures (mean response-time differences for negative minus positive responses) across symbols for both trial sets. As can be seen, the reliability of interstimulus variance is quite high. The lower coefficient in Experiment 2 is probably due to the smaller number of Simon trials (96 trials, or 3 trials in each trial subset for one symbol and one response) compared to Experiment 1 (192 trials, or 6 trials in each trial subset for one symbol and one response). The ICC coefficients reveal that differences in the implicit valence of different stimuli can be reliably estimated with our variant of the Affective Simon Task.

General discussion In this article, we introduced a new variant of the Affective Simon Task. The new task deals with a problem of the original AST (De Houwer & Eelen, 1998) reported by Duscherer et al. (2002). Their results show a decline in the size of the affective Simon effect with an increasing proportion of neutral stimuli. To gain robust effects even in the absence of valence as a salient feature of the game stimuli, it seems to be important to draw attention to the stimu” 2003 Hogrefe & Huber Publishers

lus valence. To reach this goal, the AST was combined with an evaluation task. In Experiment 1 we used schematic emotional expressions as stimuli. Results show positive affective Simon effects for positive emotional expressions and negative affective Simon effects for negative emotional expressions. Additionally we find that faces expressing other-relevant states (Peeters 1983; Peeters & Czapinski, 1990; Rothermund et al., 1996; Wentura et al., 2000) were associated with more extreme evaluations compared to faces expressing possessor-relevant states. This is also in accordance with our hypothesis: Other-relevant facial expressions may necessitate an immediate reaction towards or away from another person, and the automatic evaluation may facilitate the preparation of an adequate reaction (see Wentura et al., 2000). Experiment 2 was conducted to investigate whether the new variant of the AST provides a sensitive measure for the analysis of newly acquired valence. A game-like task was adopted to assign the meanings chance, danger, and neutral, respectively, to different abstract symbols prior to the valence measurement. The application of abstract materials has two major advantages: (1) Participants do not have a priori attitudes towards the stimuli; therefore any affective Simon effect must be due to an attitude change as a consequence of treatment. (2) Graphic stimulus features can be excluded as confounding variables because each meaning (i.e., chance, danger, and neutral) was assigned to each of the four stimuli across participants. Results revealed that the danger stimulus was evaluated more negatively compared to the chance symbol, but a significant valence was only found for the danger symbol. Experimental Psychology 2003; Vol. 50(2): 86Ð96

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In the following sections, our variant of the AST will be compared with other implicit measures of attitudes, like the original AST (De Houwer et al. 2001; De Houwer & Eelen, 1998), the EAST (De Houwer, 2002), the IAT (Greenwald et al, 1998), and the GNAT (Nosek & Banaji, 2001).

Affective Simon Task (AST) The main disadvantage of the AST (De Houwer et al. 2001; De Houwer & Eelen, 1998; DeHower, Hermans, & Eelen, 1998) has been mentioned before: At least in some situations, (see Duscherer et al., 2002) only weak effects are obtained. So the major goal of our further development of the AST was to increase effect sizes. Our results reveal medium to large effects (Cohen, 1977) for emotional expressions, but only small to medium effects concerning artificial symbols that acquire valence in a previous game context. A direct comparison of effect sizes between methods is only possible if the same materials are used, so an appraisal can only be preliminarily: Our data indicate that the new variant of the AST is able to provide detectable effects even for material with a recently acquired implicit valence.

Extrinsic Affective Simon Task (EAST) Recently, De Houwer (2002) developed the Extrinsic Affective Simon Task (EAST), which is a variant of the AST that has in fact stimulated the development of our variant. The procedural difference between the EAST and our variant of the AST lies in the fact that in the EAST, all responses have to be given by a priori neutral key presses. For example, valent stimuli (presented in white color) have to be categorized as positive by pressing a right key or as negative by pressing a left key. In Simon trials, the color of stimuli has to be categorized by the same key responses (e.g., green stimuli by the right key, yellow stimuli by the left key). By assuming that the keys acquire an extrinsic valence during the evaluation trials, the difference (possibly adjusted for overall differences in pressing left or right) between mean response times for the same stimulus presented in yellow or green, respectively, can be considered as its implicit positivity. With that, the EAST has two features that distinguish the task from the original Affective Simon Task. First, attitude-related stimuli are not overtly categorized by intrinsic valent responses (i.e., to say “positive” or “negative”). Certainly, this is an elegant and intriguing feature for indirect (or implicit) attitude research, because for participants the intention to assess the valence of attitude objects is somewhat more concealed. In fact, De Houwer (2002) highlights this feature. Second, to ensure that the key responses acquire extrinsic valence, Experimental Psychology 2003; Vol. 50(2): 86Ð96

participants work through a mixture of evaluation trials and Simon trials. Our variant of the AST uses the second feature but not the first one. From our point of view, the main consequence of interspersing evaluation trials in a sequence of Simon trials (with intrinsically valent responses) is not to associate responses with valence but to ensure that Simon stimuli are automatically evaluated, even if their valence is not blatant. It might be that the automaticity of evaluation that is revealed in the Simon task might be of the conditional type of automaticity (see Bargh, 1992): If most of the Simon stimuli are clearly positive or negative, then it might be sufficient to trigger automatic evaluation if participants are urged to utter intrinsically valent responses. If not, however, it might be necessary to intersperse evaluation trials. The use of key responses (with extrinsic valence) in the EAST might carry some advantages and disadvantages compared to our task. As was already written above, the advantage lies in the fact that Simon stimuli in the EAST are not responded to with intrinsically valent responses. For example, in research on prejudices it might be easier for participants to comply with instructions if they have to respond with (intrinsically) neutral key presses to faces of black people and not with an explicit “negative.” Not using intrinsically valent response, however, might result in a loss of effect size. An advantage of the EAST is certainly that in some circumstances (e.g., groupwise participation) manual responses are easier to use than vocal responses.

Implicit Association Test (IAT) The IAT (Greenwald et al, 1998) is probably the bestknown task for implicit attitude assessment, primarily because it typically yields large and robust effects, and because it is quite easy to implement. On the other hand, the IAT has its limitations: (1) It allows only an estimation of relative valence of two competing categories, and gives no absolute measures. (2) The IAT was designed for category valence estimation; in principle, single stimulus assessment is possible, but in this case the test stimulus would have to be presented in one out of four trials, which has not been tested yet. (3) Some results challenge the validity of the IAT (e.g., Brendl, Markman, & Messner, 2001; Rothermund & Wentura, 2001, 2002).

Go/No-Go Association Task (GNAT) The GNAT (Nosek & Banaji, 2001) is a new development that deals with at least one problem of the IAT: It allows absolute valence estimations for single categories. In the task, a series of targets and distractors is ” 2003 Hogrefe & Huber Publishers

Valence of Single Stimuli

presented. Each target requires a fast reaction within a response window; distractors do not require any reaction at all. In the standard version of the GNAT, there are four categories of stimuli: (1) words whose valence is in question, (2) distractor words, (3) positive adjectives, and (4) negative adjectives. Between experimental blocks it is varied whether categories (1) and (3) or (1) and (4), respectively, are targets. The GNAT effect is calculated as the difference in performance (d’ or response speed) between blocks. The results of Nosek and Banaji (2001) are quite encouraging. The GNAT effects are moderated but not reversed by the distractor words used. So, possibly, the validity problems of the IAT might be avoided by using the GNAT. Nonetheless, the GNAT is no possible alternative to our task, because (like the IAT) it is designed for valence estimation for categories but not for assessing the valence of single stimuli.

Affective Priming (Fazio et al., 1986) In the affective priming task, participants have to categorize positive and negative adjectives as quickly as possible. Shortly before each target, a prime word is presented. In the case of strongly valenced prime words, a congruency effect emerges, that is, performance (relatively) increases if the prime valence matches the target valence and (relatively) decreases if there is a nonmatch. Using attitude-related stimuli as primes allows for assessing the valence of attitude objects (e.g., Fazio, Jackson, Dunton, & Williams, 1995). The technique is also suited for estimating the valence of single stimuli, especially in its subliminal version (e.g., Draine & Greenwald, 1998; Otten & Wentura, 1999). Thus, in principle, the affective priming task is a possible alternative to our task. Further research will show whether effect sizes are comparable to those found with our version of the AST. To sum up, our variant of the AST has been validated in two experiments with encouraging results. The AST effects point in the a priori expected direction for nearly all stimuli, including nonverbal stimuli and artificial stimuli whose valence was acquired only recently. In addition, the AST revealed an interesting dissociation between explicit and implicit evaluations, e.g., with regards to the face stimuli.

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Rothermund, K., Wentura, D., & Bak, P. (2001). Automatic attention to stimuli signaling chances and dangers: Moderating effects of positive and negative goal and action contexts. Cognition and Emotion, 15, 231Ð248. Tukey, J. W. (1977). Exploratory data analysis. Reading, MA: Addison-Weasley. von Grünau, M. W., & Anston, C. (1995). The detection of gaze direction: A stare-in-the-crowed effect. Perception, 24, 1297Ð1313. Wentura, D., Kulfanek, M., & Greve, W. (2002). Masked affective Priming by name letters: Evidence for a correspondence of explicit and implicit self-esteem. Unpublished manuscript. Wentura, D., Rothermund, K., & Bak, P. (2000). Automatic vigilance: The attention-grabbing power of approachand avoidance-related social information. Journal of Personality and Social Psychology, 78, 1024Ð1037. Received June 17, 2002 Revision received October 4, 2002 Accepted October 11, 2002 Andreas Voß Department of Psychology University of Trier D-54286 Trier Germany Tel.: +49 651 201 2964 Fax: +49 651 201 2971 E-mail: [email protected]

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