Motivation and Emotion, Vol. 23, No. 1, 1999
Self-Relevance of Performance, Task Difficulty, and Task Engagement Assessed as Cardiovascular Response1 Guido H. E. Gendolla2
Two experiments examined task engagement, quantified as cardiovascular (CV) response, under conditions of high self-relevance of performance (i. e., when performance had strong implications for the individual's self-definition and self-esteem). Experiment 1 involved a 2 (self-relevance) x 2 (task difficulty) design and revealed, in accordance with predictions derived from Brehm's energization model, that selfrelevance per se does not result in high engagement, but that high self-relevance bound up with high task difficulty does. Experiment 2 involved three difficulty conditions (very easy, moderate, very difficult) under highly self-relevant performance conditions and revealed a curvilinear difficulty/engagement relationship. In both studies CV responses were independent of feeling states.
It is reasonable to expect the process of motivation to be affected by the extent of demand implications for an individual's self-definition and self-esteem (cf. Baumeister, 1986; Wicklund & Gollwitzer, 1982; Tesser, 1989). In the psychological literature this assumption has been, for example, referred to as the motivational impact of individuals' ego-involvement (e.g., DeCharms, 1968; Klein & Schoenfeld, 1941; Nicholls, 1984) or the magnitude of demands' identityrelevance (Gendolla, 1998). A more comprehensive concept that captures selfrelated implications is self-relevance of performance, which refers to the interplay between the nature of demands (i.e., the area they stem from and for which they 1The
present research was conducted at the University of Bielefeld, Germany. I would like to thank Andrea Abele, Jack Brehm, Jan Krusken, and Rex Wright for numerous helpful suggestions and comments on previous versions of this writing, and I am especially indebted to Robert Wicklund for his interest, help, and support. Portions of the present research were presented as a poster at the Annual Meeting of the Society for Experimental Social Psychology in Toronto, Canada, October 23-25, 1997. 2Mailing address: Guido H. E. Gendolla, Universitat Erlangen, LS Sozialpsychologie, Bismarckstr. 6, D-91054 Erlangen, Germany, E-mail:
[email protected].
45 0146-7239/99/0300-0045$16.00/0 © 1999 Plenum Publishing Corporation
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have implications) and the self-definition of individuals who perform these tasks. Performance of a task from the area of music, for example, should have particularly strong implications for a musician, whereas the same task should have much weaker implications for other people, such as mathematics or architects. The present analysis focuses on the level of individuals' engagements when they perform self-relevant tasks. Intuitively, one may expect maximal engagement under highly self-relevant performance conditions and minimal engagement under self-irrelevant ones. But a recent experiment by Gendolla (1998) suggests a more complex process. This study highlighted only one specific self-related issue—the extent of performance quality's instrumentality for attaining an identity goal (a profession participants strived for). Though the focus of the present research—the general motivational impact of self-relevant performance conditions—is broader, the results of this instrumentality study are relevant because they may have implications for performance under self-relevant conditions in general. Student novices in psychology who had decided among professional self-definitions to be psychologists tried to memorize a list of names. For half of the participants, successful performance was highly instrumental for attaining their pursued professional identity goal. In these conditions the list consisted of the names of prominent psychologists that had to be learned in order to pass necessary examinations for a degree in psychology. The other half of the participants was not informed about the list's connection to psychology. Results showed that high task engagement was only mobilized when high identity relevance was bound up with high task difficulty. Another study by Wright, Tunstall, Williams, Goodwin, and Harmon-Jones (1995, Study 1) investigated the impact of performance evaluation through others on task engagement. Though this setting did not directly pertain to self-relevance of performance, the results are also relevant because performance under public conditions should have stronger implications for a performer's self-esteem than performance under private conditions. The results showed that social evaluation moderated participants' task engagement by defining the upper limit of effort that was justified for successful performance. Specifically, Wright et al. (1995) observed that performance under public conditions bound up with high task difficulty resulted in high engagement. Social evaluation and task difficulty per se, as well as other combinations of both variables, evoked only low effort. This effect was, however, much stronger for women than for men. Both studies (Gendolla, 1998; Wright et al., 1995, Study 1) tested predictions derived from Brehm's energization model (e.g., Brehm & Self, 1989; Brehm, Wright, Solomon, Silka, & Greenberg, 1983; Wright & Brehm, 1989) and quantified task engagement in terms of performance-related cardiovascular (CV) responses. The present research extended the analysis to the general motivational impact of self-relevant performance conditions and pursued two specific goals. These were (a) a test of the impact of self-relevance of performance on task engagement based on predictions derived from Brehm's energization model, and
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(b) a differentiated test of the impact of task difficulty in this process. Therefore, two experiments were conducted. Experiment 1 tested the interaction between selfrelevance of performance and task difficulty, and Experiment 2 further highlighted the impact of task difficulty.
THE ROLE OF CARDIOVASCULAR ACTIVITY IN MOTIVATION Based on pioneering work by Obrist (1976; 1981) there is cumulative evidence that CV activity reflects not only physical (e.g., Wood & Hokanson, 1965) but also cognitive effort expenditure (see Blascovich & Tomaka,1996; Wright, 19%, for reviews). Customary indices of CV activity are heart rate (HR, i.e., the frequency of pulse beats within a specific period of time), systolic blood pressure (SBP, i.e., the maximum pressure against the vessel walls following a heart beat), and diastolic blood pressure (DBP, i.e., the minimum pressure between two heart beats). As discussed by Wright (1996), these indices differ in their reliability as indicators of energization. SBP is mainly determined by the force with which the heart muscle pumps (Obrist, 1981). This intensity is directly linked to B-adrenergic discharge of the sympathetic nervous system (SNS) and the mobilization of energy. HR is affected by the independent impacts of both sympathetic and parasympathetic arousal (Berntson, Cacioppo, & Quigley, 1993). Accordingly, HR reflects energization only sometimes—when the SNS impact is stronger than the PNS impact. DBP is mainly dependent on the total peripheral flow resistance in the blood vessels. Though this is affected by SNS arousal, DBP is no reliable indicator of SNS activity because sympathetic discharge results in both a-adrenergic constriction in some vascular beds and B-adrenergic dilatation in others. Consequently, among the CV indices discussed so far, performance-related SBP responses are the most sensitive measures of engagement, though increases in SNS activity may also result in elevations of SBP, HR, and DBP (e.g., Smith, Baldwin, & Christensen, 1990). Self-report measures of engagement, for instance, are much less reliable because they proved to be sensitive for self-protective strategies (e.g., Pyszczynski & Greenberg, 1983; Rhodewalt & Fairfield, 1991). That is, reporting to withdraw effort (e.g., when failure has negative consequences for self-esteem) does not mean that effort is actually not mobilized during task performance. But how is the level of task engagement determined? An answer to this question is provided by the energization model formulated by Brehm.
ENERGIZATION THEORY Brehm (e.g., Brehm et al., 1983; Brehm & Self, 1989; Wright & Brehm, 1989) posits that task engagement, which is treated equivalently to energy mobilization, energization, or effort expenditure, is a nonlinear function of demand's momentary
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difficulty. Task engagement rises proportionally to task difficulty up to a point where (a) deterrents are so high that success is actually impossible or (b) the magnitude of necessary energy is no longer justified by an outcome's importance. This second limit is defined by the level of potential motivation that reflects the maximum energy a person is willing to expend for goal attainment. This level of maximal justified effort is determined, for instance, by the importance of success.3 It follows from these predictions that high engagement is elicited in the pursuit of highly important outcomes that are difficult to attain. The pursuit of outcomes that are unimportant as well as outcomes that are important but easily attainable elicits only low energization (Biner, 1987; Brehm & Self, 1989; Wright & Brehm, 1989). Furthermore the model predicts that energy should be mobilized in face of a challenge directly prior to and during task performance. Wright and his colleagues have integrated Brehm's energization model with Obrist's (1981) active coping approach and demonstrated high increases in SBP (and in some studies also of HR) directly prior to and while individuals performed highly important and difficult tasks (see Wright, 19%, for a review). Other importance/difficulty combinations elicited lower engagement. TASK ENGAGEMENT UNDER SELF-RELEVANT AND SELF-IRRELEVANT PERFORMANCE CONDITIONS Potential motivation can be operationalized in terms of self-relevance of performance. Accordingly, individuals should be more willing to expend high effort under self-relevant than under self-irrelevant performance conditions. Whether they do so depends, however, on the level of task difficulty. Consequently, individuals should be generally less engaged if a task is self-irrelevant because high effort is not justified under this condition. Furthermore, they should also be less engaged if a task is easy because performing easy tasks requires only low effort regardless of the magnitude of self-relevance. High effort should only be mobilized when performance is high in both self-relevance and difficulty. These predictions were tested in the first experiment. EXPERIMENT 1 Overview and Hypotheses Participants performed a memory task that was manipulated in terms of selfrelevance and task difficulty. In the self-relevant conditions participants were told 3
There is only one condition under which effort expenditure is directly related to the importance of an outcome. This condition is when performers have no idea about a demand's difficulty (Wright & Brehm, 1989; Roberson & Wright, 1994).
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the task was a test of their mnemonic abilities that were essential for academic success. Under self-irrelevant performance conditions, participants believed the task was just a filler without any achievement character. Task difficulty was manipulated through the number of items participants tried to memorize within a defined period of time. The success criterion was the correct memorization of the whole list of items. Task engagement, the dependent variable, was quantified in terms of performance-related CV response. Additionally, affect measures were taken to control for alternative explanations for the predicted effects on the physiological responses. Subjectively perceived activation was measured exploratively, and participants' achievement was assessed to get a full picture of achievement behavior. High increases in SBP were only expected for the self-relevant-difficult condition. According to previous research (Gendolla, 1998), high increases in HR were also expected. Because of the inconsistent relationship between effort expenditure and DBP response, no specific hypothesis was formulated for this measure, which was taken for the sake of completeness of participants' blood pressure (BP) responses. Method Participants Sixty-four university students with various majors (psychology majors excluded) volunteered in the present study and received seven Deutsche Marks (about $4) for their participation. Respondents were randomly assigned in a 2 (selfrelevance: irrelevant vs. relevant) x 2 (task difficulty: easy vs. very difficult) factorial between subjects design. Seven participants who did not meet the baseline criteria for the physiological measures (see below) had to be excluded. Thus, the data of 57 participants (31 women, 26 men, mean age 24 years) were submitted to the analysis. Procedure Announcements in the university hall described the study as an investigation in task performance and BP. Due to the laboratory arrangement, one prerequisite for participation was right-handedness. To obtain reliable physiological measures, we told participants not to drink coffee or tea, not to smoke, not to exercise, and not to eat a heavy meal one hour before they were scheduled. Participants, who attended the experimental session individually, were seated at a prepared table whose top was divided by a 70 cm high screen. Then the experimenter placed a BP cuff around the student's left wrist. The experimenter took a seat behind the screen where the BP and HR monitor was fixed. Both the displayed measures and the experimenter were thus invisible to the participants.
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Physiological Measures. The experimental session started with a habituation period to determine the physiological baselines. Participants received instructions to sit still and to relax for about five to ten minutes during which they could read a popular magazine. The physiological measures (each took about 20 to 30 seconds), were obtained with an automatic BP and HR monitor (Hestia Visomat 300). The BP cuff was pumped up automatically each time a measure was taken. HR (in beats per minute, bpm), SBP, and DBP (both in millimeters of mercury, mmHg) were obtained via the oscillometric method. The determinations were repeated in intervals of two minutes during the baseline period and directly prior to and during task performance. During the baseline period the physiological measures were repeated until at least six minutes had passed and two successive determinations of SBP were relatively constant (i.e., did not differ more than +/-5 mmHg). Participants who did not meet this criterion after 10 minutes were excluded from the analysis. The averages of the last two measures of SBP, HR, and DBP, respectively, constituted the baselines. Manipulation and Manipulation Checks. After the baseline measures were taken, participants received written instructions to memorize within five minutes a list of random letter series, each consisting of four letters (e.g., A B C D). Furthermore they were instructed to recall the list afterward and to tell the letter series to the experimenter. The level of task difficulty was manipulated through the number of letter series. These were four in the easy vs. 20 in the very difficult conditions (the first four letter series in the very difficult conditions were identical with the letter series in the easy cells). The level of self-relevance was varied by providing participants with manipulated information about the task (see Appendix). In the self-irrelevant conditions participants read that the memory task was just a filler without any achievement character that was just run to bridge the time to the next experimental demand. Participants in the self-relevant conditions received, in contrast, the bogus information that the memory task would be conducted in order "to test students' mnemonic abilities." Furthermore they received the information that numerous students would have to terminate their course of studies without a degree and that, according to recent research, the main reason for these failures would be their inability to learn under time pressure. The instructions in the selfrelevant conditions ended with the bogus notion that the memory task would test this basic ability. Thus, good performance was particularly relevant for students. Success ostensibly indicated an ability that was important for academic mastery which in turn allowed a positive self-definition as capable student. To underline the manipulation's credibility, the instructions in the self-relevant conditions were printed on an official letter of the university, whereas participants in the irrelevant conditions received their instructions printed on a neutral sheet of paper. After having received the instructions, the participants informed the experimenter when they were ready to start memorizing. Once so informed, the experimenter said "a moment please, the task will follow immediately." In parallel fashion to studies by Wright, Shaw, and Jones (1990)
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and Gendolla (1998), the anticipatory determinations of SBP, DBP, and HR were taken 20 seconds later.4 After these measures the experimenter said "before we will start with the memory task, please answer these questions about your impressions of the task" and handed out a brief questionnaire designed to check the manipulations and to assess participants' feelings of activation and their momentary affective experiences. On the first page participants indicated their impressions of task difficulty (extremely easy = 0, extremely difficult = 10), and the likelihood of success (extremely certain = 0, extremely unlikely = 10). On the next page followed a German version of the General Activation Scale (G Act, e.g., full of pep, vigorous) from Thayer's (1978) Activation-Deactivation Adjective Check List. Participants rated each item in regard to their momentary feeling on scales ranging from not at all (0) to extremely (10). Additionally, participants rated the states helpless, angry, and depressive (not at all = 0, extremely = 10). Following previous research (e.g., Wright, Contrada, & Patane, 1986) these measures were taken in order to control for the potential influence of these feeling states on CV activity. Once having filled out the questionnaire, the participants received the condition-corresponding list of letter series. In the self-relevant conditions the list was entitled "memory test for students," whereas it was untitled in the selfirrelevant conditions. During task performance, the physiological measures were taken repeatedly—0.5, 2.5, and 4.5 minutes after participants had started to perform. After five minutes participants gave the list back to the experimenter and told him the letter series they could recall. The number of correctly recalled items indicated the participant's objective achievement. Then all participants received their payment, were interviewed and probed for suspicion about the manipulations, and were extensively debriefed about the experiment's purpose and the manipulations. Those who participated in the very difficult conditions were explicitly informed that it was impossible to memorize the whole list of letter series within the defined period of time and that they had performed quite well as compared to other participants. Results Manipulation Checks The data were submitted to 2 (self-relevance) x 2 (task difficulty) between subjects analyses of variance (ANOVAs). Two significant main effects of task difficulty indicated the effectiveness of the task difficulty manipulation. In the easy conditions the task difficulty ratings were significantly lower than in the difficult ones (Ms = 3.52 vs. 6.36), F(1, 53) = 35.46, p < .001. The probability of success ratings, which had been recorded so that high values indicate high probability, were 4
As stated before, Brehm's energization model predicts that effort will be mobilized directly prior to and during performance. Consequently, task engagement was measured at these times.
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Table I. Means (M) and Standard Deviations (SD) of the Cardiovascular Baselines in Experiment 1a Easy Task
Very Difficult Task c
Self-Irrelevant*
Self-Irrelevantc
Self-Relevantc
116.36 (9.65)
119.07 (13.36)
115.61 (9.85)
75.25 (5.24)
77.39 (6.72)
76.64 (5.45)
76.18 (11.98)
67.71 (13.43)
70.89 (6.89)
Self-Relevant
Systolic Blood Pressure (mmHg) M 121.10 (SD) (11.15) Diastolic Blood Pressure (mmHg) M 78.97 (SD) (8.57) Heart Rate (bpm) M 77.13 (SD) (7.46) a
mmHg = millimeters of mercury; bpm = beats per minute. The mean square errors of the baselines of SBP, HR, and DBP are 123.76, 129.97, and 43.59, respectively. n = 15. c n = 14.
b
significantly higher in the easy than in the difficult cells (Ms = 5.86 vs. 3.38), F(1, 53) = 10.29, p < .002. Self-relevance had no impact on these measures, neither as main effect nor in interaction (all Fs < 1.15). Cardiovascular Baselines Cell means are presented in Table I. According to 2 (self-relevance) x 2 (task difficulty) ANOVAs, the baselines of SBP and DBP did not differ between the conditions (all Fs < 1.96). But the HR baselines in the easy conditions were higher than those in the very difficult cells, F(1, 53) = 7.32, p< .01. This finding will be considered below in the analysis of the HR responses during task performance. Cardiovascular Responses Change (delta) scores (Llabre, Spitzer, Saab, Ironson, & Schneiderman, 1991) were computed for each participant by subtracting baseline values from performance-related values. The averages of the four change values (20 sec. after the instructions, 0.5, 2.5, and 4.5 minutes after starting to memorize) of each participant constituted the performance-related physiological change scores. It is noteworthy that the change scores were highly consistent. Cronbach's As were .91 for SBP, .94 for HR, and .89 for DBP. Preliminary ANOVAs revealed no significant sex effect on any CV index, and preliminary analyses of covariance (ANCOVAs) revealed no significant relationship between the baselines and the reactivity scores of SBP and DBP. Thus these indices were analyzed with 2 (self-relevance) x 2 (task difficulty)
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Fig. 1. SBP responses in the experimental conditions of Experiment 1; mmHg=millimeters of mercury. The mean square error of the SBP responses is 26.57. The standard deviations are as follows: self-irrelevanteasy 6.88, self-relevant-easy 4.67, self-irrelevant-very-difficult 3.29, selfrelevant-very-difficult 4.97.
ANOVAs. The ANCOVA of the HR data revealed a significant baseline effect and is reported in further detail below. Reactivity of SBP. There were significant main effects of both task difficulty, F(1, 53) = 4.30, p < .04, and self-relevance, F(1, 53) = 9.09, p< .004, which were qualified by the expected significant two-way interaction, F(1,53) = 4.63, p < .04. As depicted in Fig. 1, the highest systolic responses were observed, as predicted, in the self-relevant-difficult condition. Follow-up contrasts between the experimental conditions revealed, as expected, significantly higher systolic responses in this cell than in each of the other three conditions, all ts(53) > 2.99, ps < .004,5 whereas the latter three cells did not differ from one another, all ts(53).50. Reactivity of HR. A preliminary ANCOVA revealed that the HR baselines were significantly related to the change scores, F(1, 52) = 5.90, p< .01, r = — .31, p < .02. Furthermore there was a reliable main effect of self-relevance, F(1, 52) = 9.74, p < .003. The main effect of task difficulty (F < 1) and the two-way interaction, F(1,52) = 1.82, p 2.53, ps < .02. The task difficulty ratings assessed after performance revealed the same pattern as those assessed prior to performance. The manipulation had a significant effect, F(2, 42)= 50.91, p < .001, and
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Moderate
Very Difficult
Systolic Blood Pressure (mmHg) M 120.97 122.47 (SD) (12.40) (12.07) Diastolic Blood Pressure (mmHg) M 78.27 87.97 (SD) (8.80) (4.50) Heart Rate (bpm) M 75.73 74.93 (SD) (8.21) (14.19)
120.47 (8.49) 78.07 (5.75) 70.63 (11.01)
a
mmHg = millimeters of mercury; bpm = beats per minute. The mean square errors of the baselines of SBP, HR, and DBP are 123.76, 129.97, and 43.59, respectively. b n = 15 in each cell.
all conditions differed significantly from one another (Ms = 0.67 very easy vs. 4.33 moderate vs. 7.87 very difficult), all ts(42) > 4.95, ps < .001. Cardiovascular Baselines No differences existed between the conditions in any of the three physiological baseline measures (all Fs < 1). The cell means are presented in Table II. Cardiovascular Responses As in the first experiment, the single CV change scores showed high internal consistency. Cronbach's as were .94 for SBP, .96 for DBP, and .86 for HR. Preliminary ANOVAs revealed no sex effects on the reactivity of HR and DBP. But there was a sex main effect, F(1, 39) = 5.61, p < .03, on the SBP responses (Ms = 10.85 men, 5.84 women). However, given that there was no interaction with task difficulty (F = 1.03), this is of minor interest. Preliminary ANCOVAs revealed no significant relationships between CV baselines and reactivity scores. Consequently, the reactivity scores were submitted to one-way ANOVAs. Reactivity of SBP. The manipulation had a significant effect, F(2, 42) = 9.87, p < .001. Follow-up contrasts revealed, as expected, significantly lower SBP responses in the very easy condition than in both the very difficult, t(42) = 2.38, p < .03, and the moderately difficult, t(42)=4.44, p < .001, cells. But in contrast to the prediction, the strongest responses were, as depicted in Fig. 3, observed in the moderately difficult cell where they were even stronger than in the very difficult condition, t(42) = 2.05, p < .05. The observed curvilinearity of the relationship
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Fig. 3. SBP responses in the experimental conditions of Experiment 2; mmHg = millimeters of mercury. The mean square error of the SBP responses is 42.11. The standard deviations are as follows: very-easy 4.83, moderate 7.41, very-difficult 6.94.
between task difficulty and the systolic responses was further confirmed by a highly significant quadratic trend, F(1, 42) = 14.05, p < .001. Reactivity of HR. The manipulation had a significant effect, F(2, 42) = 10.36, p < .001. As depicted in Fig. 4 and supported by the results of follow-up contrasts, the lowest performance-related responses existed in the very easy cell. Here, the responses were significantly lower than in both the very difficult, t(42) = 2.88, p < .006, and the moderately difficult, t(42) = 4.49, p < .001, cells. The difference between the moderately and very difficult cells did not reach the conventional significance level, t(42) = 1.62, p < .11. But, as depicted in Fig. 4, HR reactivity
Fig. 4. HR responses in the experimental conditions of Experiment 2; bpm=beats per minute. The mean square error of the HR responses is 35.80. The standard deviations are as follows: very-easy 3.66, moderate 6.34, very-difficult 7.07.
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described a curvilinear function of task difficulty, which was further evidenced by a highly significant quadratic trend, F(1, 42) = 12.45, p < .001. Reactivity of DBP. A one-way ANOVA, that was conducted without specific predictions, revealed a significant manipulation effect, F(2, 42)=5.96, p < .005. A Tukey-test,7 which is an appropriate instrument for the post-hoc comparison of cell means (Winer, 1971), revealed significant cell differences between the very easy (M = 1.57) and the moderate (M = 7.68) conditions on the p < .05 level. The diastolic responses in the very difficult condition (M = 5.52) fell between these values. A significant quadratic trend, F(1, 42) = 7.09, p < .01, further proved that the DBP responses were a curvilinear function of task difficulty. Felt Activation and Affect In parallel fashion to the first experiment, no differences existed in participant ratings of felt activation (F = 1.08) measured with the G-Act Scale. The manipulation had only an effect on one feeling state—helplessness, F(2, 42) = 4.41, p < .02. According to a Tukey-test, there was a reliable difference between the moderate (M = 0.40) and the very difficult conditions (M= 1.73; p < .05). The very easy cell (M = 1.07) fell between these two conditions. Given these differences in felt helplessness, the physiological determinations were submitted to ANCOVAs that controlled for the impact of rated helplessness on the CV responses. However, helplessness was not related to any of the physiological measures (all Fs < 1) and all of the effects previously identified via ANOVAs remained stable.8 Memory Performance Because all participants in the very easy condition memorized both letter series correctly, memory performance was analyzed via nonparametric testing. Participants in the very easy condition memorized fewer letter series (M = 2.00) than those in the moderately difficult (M =5.73) and very difficult conditions (M=4.60). All conditions differed significantly from one another according to Mann-Whitney tests (all Us < 59.5, ps < .02). Interestingly, that reflects that participants in the very difficult condition memorized fewer letter series correctly than did those in the moderately difficult condition. 7
Post-hoc comparisons between cell means of measures for which no hypotheses had been formulated were performed via Tukey-tests. 8 There was only one significant correlation between rated affect and CV responses. This was a negative correlation between anger and the systolic responses, r = -.29, p < .05. The correlations between anger and the HR responses, r = —.25, p> .09, and between anger and the diastolic responses, r = —. 19, p > .22, were not significant. There were no significant correlations at all between the other affect ratings and the physiological responses. The correlations between the respective states and the SBP, HR, and DBP responses, respectively, were as follows: helpless: rs = -.01, .00, -.07, all ps > .50; depressive: rs = -.07, -.17, -.09, all ps > .26; fearful: rs = -.03, .04, -.13, all ps > .38; threatened: rs = .07. .19, -.02, all ps > .22; sad: rs= -.16, -.14, -.13, all ps > .29.
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Discussion In contrast to the initial predictions, the results of Experiment 2 indicate a curvilinear relationship between task difficulty and task engagement under the condition of high self-relevance of performance. The highest engagement was observed on a moderately high difficulty level and the large increase in this condition strongly suggests that potential motivation was, as expected, high under the present self-relevant performance conditions. Given that in the first study the highest engagement existed in the self-relevant-very-difficult condition, the curvilinear pattern was unexpected. If the difficulty ratings are interpreted literally, they indicate that participants in the very difficult cell did not believe that effort expenditure would be senseless because success was impossible and that participants in the moderately difficult condition performed on an intermediate difficulty level. This would fit with approaches positing that performance on intermediately high difficulty levels elicits the highest engagement (e.g., Atkinson, 1957; Berlyne, 1960; Helson, 1964; Hoppe, 1930; Meyer & Hallermann, 1977). However, given the nonmanipulation of potential motivation, it remains open whether the present study's pattern of results contradicts the predictions of Brehm's energization model. It is also possible that participants in the present study learned while performing that the very difficult condition was impossible to meet for them and that this caused a drop in engagement as demonstrated in several previous studies (e.g., Wright et al., 1986; 1990; in press). This latter process would fit with the predictions of Brehm's energization model. Furthermore, given that an inspection of the standard deviations in the self-relevant-difficult cell (see Fig. 3 and 4 captions) suggests no higher variance in this cell than in the two other conditions, it is unlikely that the curvilinear pattern is due to a drop in engagement of only some individuals. However, referring to the topic of the present research—task engagement under self-relevant performance conditions—Experiment 2 demonstrated, again, that task difficulty plays a critical role. Besides the physiological engagement data, there were additional relevant results of Experiment 2. Replicating findings of the first study, the observed effects on CV activity were not attributable to participants' feeling states and there was no correspondence between actual and perceived arousal. Consequently, the present findings do not appear to reflect emotion effects, such that the high probability to fail on a difficulty task under self-relevant conditions elicited high fear or threat. However, this does not mean that emotions have nothing to do with motivation. According to several authors (e.g., Brehm & Brummett, 1998; Frijda, 1986; Izard, 1977; Lazarus, 1991) emotions—at least the so called active or acute ones—have strong motivational implications. The present findings do not cast doubt on that. They just suggest that the CV adjustments observed here were not mediated by emotional response. The memory performance data are also of interest. Memory performance was higher in the moderately than in the highly difficult condition. Thus, participants
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in the moderately difficult condition performed better though those in the difficult condition had the opportunity to memorize more letter series correctly. This suggests a drop in performance on a high task difficulty level (e.g., Atkinson, 1958) and is not supportive of the assumption of an increase in performance with task difficulty (e.g., Locke & Latham, 1990). These findings are moreover not in line with the Yerkes-Dodson (1908) law according to which cognitive performance is an inverted U-function of an organism's arousal level (see also Easterbrook, 1959). Participants in the moderately difficult condition were more aroused, according to all physiological measures, but performed better than those in the very difficult condition. GENERAL DISCUSSION The present experiments examined the joint impact of self-relevance of performance and task difficulty on task engagement assessed as CV response. Applying predictions of Brehm's energization theory (Brehm et al., 1983; Brehm & Self, 1989; Wright & Brehm, 1989) it was predicted that self-relevance of performance would not per se determine the extent of effort individuals mobilize. Rather, it was expected that self-relevance of performance would moderate the effect of task difficulty on task engagement. The results of Experiment 1 were in full support of these predictions. Participants expended great effort only when both self-relevance and difficulty were high. Most of the previous studies on the energization model were conducted in achievement settings in which participants could actively attain concrete positive outcomes or actively avoid concrete negative consequences (cf. Wright, 1996). This research has provided cumulative evidence in support of Brehm's model—as did the first of the two present studies and the experiment on identity-relevance of performance by Gendolla (1998). Accordingly, the predictions of Brehm's energization model apply to the role of self- and identity-relevance of performance. However, Experiment 2 was addressed to a more differentiated test of the impact of task difficulty on engagement under self-relevant conditions and revealed an unexpected curvilinear relationship between task difficulty and task engagement. But whether this curvilinear pattern fits better with approaches positing that engagement is highest on intermediate difficulty levels (e.g., Atkinson, 1957; Berlyne, 1960; Helson, 1964; Hoppe, 1930; Meyer & Hallermann, 1977) or with Brehm's energization model remains open from these data because the non-manipulation of potential motivation allows no clear answers to this question. However, the present studies were conducted to illuminate the impact of self-relevance of performance on task engagement. In contrast to what might be intuitively assumed—that self-relevance directly determines engagement—both experiments revealed that task difficulty plays the critical role in determining the engagement level. This is the most relevant finding of the present research because it suggests that task difficulty is a critical variable and that it should be considered in any analyses of human motivation dealing with self-processes.
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The whole pattern of results of both experiments is tentatively also explicable in terms of the impact of unfixed and fixed challenges on effort expenditure. Wright el al. (1995, Study 2) observed low task engagement when performance was socially evaluated and the success criterion was easy and fixed as well as when there was no social evaluation, irrespective of the success criterion. But task engagement was high when the success criterion was unfixed and performance happened under social evaluation conditions. It is also possible that the present studies' moderately and very difficult conditions varied not only in task difficulty, but—for the participants—also in the extent of specificity of their success criteria. According to this tentative assumption participants in the moderately difficult condition of Experiment 2 performed a task that was challenging, but not too difficult to succeed in. Given that success was defined as the correct memorization and recall of the whole list of letter series, the success criterion was relatively fixed. Formally, the same conditions were provided in the very difficult conditions. But it could have been the case that participants in these conditions learned that it was impossible for them to memorize the whole list of 20 letter series within five minutes, though a literal interpretation of the difficulty ratings suggests that they did not believe that it was generally impossible to meet this success criterion. Given that failure on a test of basic abilities for academic success would coincide with very bad consequences for their self-esteem they did, however, not give up. Rather, they may have redefined the tasks into an unfixed "do your best" challenge. Consequently, they tried to make the consequences of performance for their self-definition and their self-esteem as positive as possible. According to Locke and Latham (1990) "do your best" challenges are less moderating than difficult but possible to attain fixed challenges. This interpretation is, however, a tentative one. What the present findings clearly reflect is that task difficulty is a central and critical motivational variable; it is also so under self-relevant performance conditions. APPENDIX Memory Task Instructions in the Self-Irrelevant Conditions The next demand is a memory task. You will receive a list of letter series. The letter series consist of four letters each, e.g., A B C D. It is your task to memorize this list. You will get five minutes for that. Afterwards, you will have to tell the list to the experimenter. The list consists of 4 (20, respectively) letter series. This is no memory test! Your performance is not indicative of your learning abilities. Memory Task Instructions in the Self-Relevant Conditions More and more students have problems to meet their study requirements. Recent investigations have revealed that the main problem of many students is their
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inability to learn under time pressure. Due to this problem many students cannot adequately cope with their course of studies and break off without a degree. In the present investigation we would like to test students' learning abilities. The ability to learn under time pressure is a basic and necessary skill for a successful course of study and represents a problem for many students. In order to test your learning abilities you will receive a list of letter series. The letter series consist of four letters each, e.g., A B C D. It is your task to memorize this list. You will get five minutes for that. Afterwards, you will have to tell the list to the experimenter. The list consists of 4 (20, respectively) letter series.
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