The influence of stimulus intensity and motivational differences on learned helplessness deficits

The influence of stimulus intensity and motivational differences on learned helplessness deficits

0191s8869/87 $3.00+ 0.00 Pergamon Journals Ltd Person. indiuid. Dr# Vol. 8, No. I, pp. 25-32, 1987 Printedin GreatBritain THE INFLUENCE OF STIMULUS ...

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0191s8869/87 $3.00+ 0.00 Pergamon Journals Ltd

Person. indiuid. Dr# Vol. 8, No. I, pp. 25-32, 1987 Printedin GreatBritain

THE INFLUENCE OF STIMULUS INTENSITY AND MOTIVATIONAL DIFFERENCES ON LEARNED HELPLESSNESS DEFICITS JAMES G.

BARBER*

Department

of Psychology,

and

ANTHONY

University

H. WINEFIELD

of Adelaide,

Australia

(Received 26 February 1986) Summary-Two experiments are reported which assess the moderating effects on learned helplessness deficits of individual differences in task-specific motivation and expectation of control. In Experiment 1 a neutral stimulus was used and in this case only high motivation subjects displayed helplessness deficits in response to noncontingency training. In addition, high motivation subjects demonstrated greater sensitivity to the noncontingency than did low motivation subjects. However, when an aversive stimulus was used in Experiment 2 the moderating effect of motivational differences was removed and this was accompanied by greater sensitivity to the noncontingency on the part of low motivation subjects. Indeed, the learned helplessness effect in Experiment 2 was more pronounced within the low motivation group. The theoretical significance of these findings is explored and directions for future research are suggested.

INTRODUCTION

The learned helplessness effect refers to the performance deficits that normally follow exposure to uncontrollable events. In both animals and humans, however, helplessness is not the inevitable result of exposure to uncontrollability. Indeed, some experiments have reported facilitation rather than interference, e.g. Roth and Kubal (1975). As a result, a number of researchers have begun turning their attention to the capacity of certain individual difference variables to moderate reactions to uncontrollable outcomes. Although the available evidence is not always consistent, it is clear that human helplessness is moderated by a range of such variables. For example, there is evidence to suggest that under certain circumstances noncontingency training impairs the performance of females more than males (Dweck and Bush, 1976), males more than females (Samuel, Baynes and Sabet, 1978), Type A (coronary-prone) individuals more than Type B (non-coronary-prone) individuals (Krantz, Glass and Snyder, 1974), introverts more than extraverts (Tiggemann, Winefield and Brebner, 1982), higher IQ more than lower IQ subjects (Winefield, Barnett and Tiggemann, 1984) and subjects low in learned resourcefulness more than subjects high in learned resourcefulness (Rosenbaum and Jaffe, 1983). Learned helplessness theory (Seligman, 1975) claims that exposure to uncontrollable events leads to the development of a generalized expectation that events are uncontrollable and this expectation is assumed to produce motivational and cognitive deficits that are manifested in impaired performance on a transfer task. As a result, Barber, Winefield and Mortimer (1986) have recently argued that the learned helplessness effect should also be moderated both by individual differences in motivation as well as by differences in the expectation of control prior to entering the laboratory. This led the authors to develop the Personal Interests Questionnaire (PIQ) as a task-specific measure of locus of control and motivation for use in learned helplessness research. The PIQ presents respondents with 9 tasks chosen for their similarity to instrumental tasks normally employed in learned helplessness research. In response to each task respondents are asked to report whether they do or do not enjoy performing the task (motivation) and whether they are or are not skilled at the task (ability). In the case of the ability scale, it was proposed that both a high ability self-perception and an internal locus of control involve the expectation of response-outcome contingency. Barber et al. (1986) found the PIQ to be an internally consistent measure, with KR-20 reliability coefficients of 0.71 and 0.70 for the motivation and ability scales *Present address: Department of Behavioural Sciences, James Qld. 4811; to where all correspondence should be addressed. 25

Cook

University

of North

Queensland,Townsville,

26

JAMES G. BARBER and ANTHONY H. WINEFIELD

respectively. Test-retest reliabilities, based on a separation of 16 weeks, were 0.80 for the motivation and 0.65 for the ability scale. In the case of the motivation scale, discriminant and construct validity were demonstrated by a modest but significant positive correlation (r = 0.34) with Burger and Cooper’s (1979) ‘Desirability of Control’ scale which is a more general measure of the individual’s desire to control events. In the case of the ability scale, discriminant validity was demonstrated by the absence of a significant correlation (r = 0.10) with the NowickiStrickland ‘Locus of Control’ scale (Nowicki and Duke, 1974). Finally, the predictive validity of both scales was assessed in an experiment in which subjects were asked to rate their motivation and confidence immediately prior to undertaking an instrumental task. Correlations between these ratings and PIQ scores were positive and significant: the correlation between motivation ratings and PIQ motivation scores was 0.25 and the correlation between confidence ratings and PIQ ability scores was 0.23. In the experiments that follow, the PIQ was used to assess the potential moderating effects of individual differences in the expectation of response-outcome contingency and motivation on reactions to an uncontrollable stimulus. To date, the evidence relating to both variables is mixed. Although Albert and Geller (1978) and Dweck and Reppucci (1973) have produced evidence to support the greater susceptibility of ‘externals’ to helplessness manipulations, Hiroto (1974) found that both internals and externals were impaired by noncontingency training. Gregory, Chartier and Wright (1979) have even reported performance deficits following uncontrollability among internals but not externals. Finally, Pittman and Pittman (1979) found that small amounts of helplessness training produced greater deficits in externals but large amounts produced greater deficits in internals. Concerning motivation differences, Buys and Winefield (1982), Jardine and Winefield (1981), and Winefield (1983) have not discovered any significant differences in response to uncontrollability between subjects high and low in achievement motivation. However, a more recent study by Jardine and Winefield (1984) suggests that helplessness deficits may be greater among subjects high in achievement motivation when the uncontrollable outcome is also unpredictable. Moreover, Burger and Arkin (1980) have reported that subjects high in the desire for control performed more poorly than low desire for control subjects irrespective of whether the outcomes were controllable or uncontrollable. A second aim of the present experiments was to explore the influence of stimulus intensity on helplessness deficits. Although the original animal experiments exposed subjects to aversive stimuli, the theory applies equally to non-aversive stimuli. Indeed, Tiggemann and Winefield (1978) and Tiggemann (1981) have reported strong helplessness effects using neutral tones. The following experiments sought to replicate the learned helplessness effect using both aversive and nonaversive stimuli and to assess whether the moderating effects of the individual difference variables under investigation were identical in both cases. METHOD

Experiment

I

Experimental design. The experiment took the form of a 3 x 2 x 2 factorial arrangement of pretreatment (escapable tones, inescapable tones, no pretreatment) x motivation level (high, low) x ability level (high, low). Subjects. Forty-eight subjects were drawn from a sample of 151 first year psychology students who completed the PIQ. Scores on both the motivation and ability scales of the PIQ can range between O-9 and on the basis of a median split of the original 151 respondents, the 48 experimental subjects were assigned to ‘high’ and ‘low’ motivation and ability subgroups. Median scores for both scales fell between 6 and 7. Each experimental condition comprised equal numbers of high and low motivation subjects (8 of each) and equal numbers of high and low ability subjects (8 of each) in a balanced 2 x 2 arrangement of motivation x ability level. Apparatus. Approximately 55 db, 2 kHz tones were presented to the subject through stereo headphones. This was the identical stimulus to that used by Tiggemann and Winefield (1978) and Tiggemann (198 1) which was found to produce a strong helplessness effect despite being rated by subjects as nonaversive. The tones were generated by computer which was programmed to operationalize all experimental manipulations as well as record all dependent response measures. Maximum tone duration was set at 10 sec.

Learned helplessness deficits

27

In the pretreatment phase, the response device was a hand-held switch. For the Escapable group, pressing the switch 4 times would terminate the tone while in the Inescapable condition, the switch did not influence the tone presentations. The test phase apparatus consisted of 2 buttons 12 cm apart set into a metal plate. Pressing the left button once and the right button twice in any order (except simultaneously) terminated the tone. Procedure. Subjects in the Escapable and Inescapable groups were yoked according to scores on the PIQ and each replication comprised a triad which was a matched PIQ subgroup. Thus, a High motivation-High ability subject, for example, was always yoked to another High motivation-High ability subject. The pretreatment task was introduced by the following instructions: “From time to time a tone will be presented to you. When that tone comes on there may be something you can do to stop it”. Pretreatment consisted of 30 unsignalled tone presentations with intertrial intervals ranging between 10-25 sec. Following pretreatment, subjects in the 2 experimental groups rated the level of control they had exercised over the tone on 7-point scales extending from ‘(1) No control’ to ‘(7) Complete control’. Test trials were preceded for all 3 groups by the following instructions: “You will now be given some trials in which tones will be presented to you. You can stop the tones by discovering a certain pattern”. The test phase comprised 20 unsignalled presentations of the tone with intertrial intervals again ranging from 10-25 sec. RESULTS

Table 1 presents the mean scores of the high and low motivation and ability subgroups on the 3 response measures: mean response latency over the 20 trials, number of failures to escape the tone, and trials to criterion. Criterion for solving the pattern was set at 3 consecutive trials in which the subject managed to terminate the tone. Table 1 also presents subjects’ ratings of the control they experienced over the tones during pretreatment. Because of the positively skewed distributions and non-homogeneity of variances, all statistical analyses of response measures were performed on log-transformed data. A 3 x 2 x 2 (Treatment x Motivation x Ability) multivariate analysis of variance (MANOVA) performed on the response measures produced a significant main effect of treatment (F(6,66) = 4.13, P < O.OOl), and a significant treatment x motivation interaction (F(6,66) = 3.21, P < 0.01). No other main effects or 2 or 3-way interactions were significant. In order to clarify the main effect of treatment condition, two orthogonal planned contrasts were carried out on each of the three response measures. The planned contrasts were: (1) Escapable group against No pretreatment control group, and (2) Inescapable group against Escapable and No pretreatment control group combined. An adequate demonstration of the learned helplessness effect requires that comparison 1 should not be statistically significant, while comparison 2 should be significant. Both conditions were satisfied for all three response measures. Escapable and No pretreatment control groups did not differ on mean latency (t = 0.32, df = 45, P > O.lO), failures (t = 0.53, df = 45, P > 0.10) or trials to criterion (t = 0.09, df = 45, p > 0.10). However, Escapable and No pretreatment control groups performed significantly better on all response measures than the Inescapable group: for mean latency, t = 2.64, df = 45, P = 0.01; for failures, t = 2.64, df = 45, P < 0.01; for trials to criterion, t = 3.49, df = 45, P < 0.001. Thus a clear overall learned helplessness effect was observed. The interaction between the treatment and motivation factors was Table

1. Experiment

1: means and standard

Mean response

latency

deviations ko.

(in parentheses) of failures

of the three response

measures

Trials to criterion

and control

ratings

Control

ratings

High abil.

Low abil.

High abil.

Low abil.

High abil.

Low abil.

High abil.

Low abil.

Escapable Inescapable No LoWpretreatment motivation

2.04 (0.49) 3.64 (1.51) I .88 (0.52)

1.52 (0.93) 2.47 (1.30) 1.60(0.44)

0.67 (1.21) 11.33 (14.61) 0.83 11.60)

0.00 (0.00) 2.00 (0.60) 0.00 (0.00)

3.67 (1.21) 9.00 (5.93) 3.83 (1.60) ~ ,

3.00 (0.00) 5.50 (0.71) 3.00 (0.00) . ,

6. I7 (0.98) 3.33 (1.37) -

7.00 (1.80) 1.00 (1.10) -

Escapable Inescapable No pretreatment

I .40

I .89 (0.76) 2.18 (0.67) 2.17 (0.75)

0.00 (0.00) I .oo(0.2 I) 0.33 (0.57)

0.00 (0.00) 2.00 (6.45) 0.00 (0.00)

3.00 (0.00) 4.00 (1.30) 3.00 (0.00)

3.33 (0.52) 3.17 (0.41) 3.33 (0.52)

6.50 (0.71) 4.50 (3.54) -

6.50 4.40

Group High motivation

(0.32) 1.63 (0.38) 1.46 (0.44)

(I .22) (I .95) -

28

JAMESG. BARBERand ANTHONY H. WINEFIELD

examined, using Keppel’s (1973) method for the analysis of simple main effects. In the present case this involved conducting two univariate analyses of variance. One tested for the significance of treatment at the first (low) level of the motivation factor and the second for the significance of treatment at the second (high) level of motivation. Proceeding in this way, treatment was found to have no effect at the low level of motivation on any of the three response measures: for mean latency, F(2,20) = 0.12, P > 0.10; for failures, F(2,20) = 0.88, P > 0.10 and for trials to criterion, F(2,20) = 0.24, P > 0.10. On the other hand, a significant effect of treatment on all response measures was found at the high motivation level: for mean latency, F(2,20) = 4.99, P < 0.05, for failures, F(2,20) = 2.54, P < 0.01, and for trials to criterion, F(2,20) = 9.36, P < 0.01. A 2 x 2 x 2 analysis of variance was performed on subjects’ ratings of the control they experienced over pretreatment tones. Results indicated a significant main effect of treatment (F( 1,22) = 22.34, P < O.OOOl),with subjects in the Escapable condition rating control much higher than Inescapable subjects. Table 1 reveals that Inescapable subjects rated control over the tone below the midpoint of the scale, while subjects in the Escapable group rated their degree of control well above the midpoint. Although no other significant main effects or interactions were discovered, the 2-way interaction between treatment condition and PIQ motivation level approached significance (F( 1,22) = 3.8 1, 0.05< P < 0.06). Indeed, only Inescapable subjects high in PIQ motivation rated their control over the tone below the midpoint of the scale. Thus, although the resultant F did not quite reach significance, only highly motivated subjects appear to have been aware of the noncontingency. DISCUSSION

The present experiment confirms that helplessness deficits can be produced using nonaversive stimuli. However, there was no evidence of helplessness deficits within the low motivation group, with the effect of pretreatment being confined entirely to high motivation subjects. This finding leads to the conclusion that unless individuals possess a certain minimum level of motivation to begin with, noncontingency training will not affect them. As a result, the experiment goes some way towards accounting for the biomodality of response that is commonly observed within the helpless group. The present experiment also raises an interesting possibility concerning the means by which motivational differences influence performance. Learned helplessness theory proposes that the recognition of noncontingency is not an all-or-none affair and that the extent of the deficit will depend on the certainty of noncontingency (Abramson, Seligman and Teasdale, 1978). In line with this proposition, post-treatment control ratings showed high motivation subjects to be more aware of the noncontingency than were low motivation subjects. This finding suggests that the level of initial motivation may exert its influence on helpless behaviour via the differential perception of noncontingency. Because the interaction between the treatment and PIQ motivation factors did not quite reach significance, this proposal must be put forward tentatively but a similar (significant) interaction has been reported in the literature by Jardine and Winefield (1984) who found that subjects high in achievement motivation reported awareness of noncontingency while low achievement motivation subjects did not. On the other hand, the predicted difference due to ability perceptions did not occur. Subjects with a ‘high’ ability self-perception were no less likely to display helplessness deficits following noncontingency training than ‘low’ ability subjects. This finding conforms with other studies of human helplessness which suggests that “the expectation of noncontingency only interferes with the initiation of responses (the motivational deficit of helplessness) and not with the perception of response-outcome relationships” (Alloy, 1982, pp. 449450). Because motivational differences accounted so successfully for the bimodality of responses to uncontrollability, the present experiment questions the necessity of postulating an additional cognitive component. One way of approaching this issue is suggested by Jackson, Maier and Rappaport’s (1978) experiments with rats. In these experiments the authors tested rats in a shuttle box escape-avoidance task using three intensities of shock. At the most intense level rats previously exposed to inescapable shock displayed no performance deficit relative to Escapable and No pretreatment control rats. Only subjects that were tested using less intense shocks exhibited the

Learned helplessness deficits

29

learned helplessness effect. This led the authors to conclude that the shuttle box task is sensitive only to the activity or motivational deficit and that the motivational deficit can be overcome by using aversive stimuli in test trials. Thus a second experiment was run in which tones were set at an aversive level. Based on Jackson et al.‘s (1978) findings it was predicted that the moderating effect of motivational differences would be removed by this manipulation. If, as in Jackson et al’s experiments, performance deficits were removed in the process it would suggest either that exposure to uncontrollable noise does not produce a separate cognitive deficit or that the button-press test task is insensitive to the cognitive component. METHOD

Experiment

2

overview. The experiment involved the same 3 x 2 x 2 factorial arrangement of pretreatment (escapable tones, inescapable tones, and no pretreatment) x motivation level (high, low) x ability level (high, low). However, in this experiment the tones were designed to be aversive. Subject. Thirty-six subjects participated in the experiment. As in Experiment 1, subjects were assigned to pretreatment conditions on the basis of PIQ scores with scores of 7 or more on both scales again being assigned to ‘high’ groups. Once again there as a balanced 2 x 2 arrangement of motivation x ability levels with 6 subjects in each level of the 2 factors. Apparatus. The apparatus was identical to that used in Experiment 1 except that the nonaversive tone was replaced by a more intense stimulus. The tone used was set at 85 db was made to go through a frequency sweep from 2.5 kHz to 3.5 kHz 9 times/set. In fact, the stimulus was a modification of a commercially produced burglar alarm and it has elsewhere been shown to be rated by subjects as aversive (Barber and Winefield, 1986). Procedure. On arrival at the laboratory subjects completed the PIQ before being assigned to pretreatment conditions. Following pretreatment experimental subjects again rated the degree of control they had experienced over the tone from ‘(1) No control’ to ‘(7) Complete control’. After testing, all subjects rated the aversiveness of the tone from ‘( 1) Extemely pleasant’ to ‘(7) Extremely unpleasant’. Subjects were debriefed and paid $4 for participating. Experimental

RESULTS

Table 2 presents the mean scores of the performance measures together with the questionnaire items for the high and low motivation and ability groups. Because 3 subjects failed to escape at least one tone after reaching criterion, the trials to criterion performance measure had to be dropped from the analysis. A 3 x 2 x 2 (pretreatment x motivation x ability) multivariate analysis of variance (MANOVA) performed on log-transformed performance data revealed a significant main effect of pretreatment only [F(4,44) = 3.60, P < 0.011. No other main effects or interactions produced significance. Of particular interest was the absence of an interaction between pretreatment and motivation factors [F(4,44) = 0.23, P > 0. lo] implying that the effect of pretreatment occurred equally in the high and low motivation groups. To clarify the effect of pretreatment on performance, the same planned contrasts carried out in Experiment 1 were repeated here. The first contrast, between the Escapable group and the No pretreatment group was nonsignificant both for mean response latency (t = 0.61,

Table 2. Experiment

2: means and standard Mean response

deviations

latency

(in parentheses) Failures

of the two performance

to solve

Control

measures

over tone

and the two questionnaire Aversiveness

items

of tone

High abil.

Low abil.

High abil.

Low abil.

High abil.

Low abil.

High abil.

Low abil.

Escapable Inescapable No pretreatment Low motivation

1.25 (0.14) 2.73 (2.12) I .72 (0.18)

2.90 (0.91) 3.41 (0.69) I .82 (0.28)

0.00 (0.00) 4.25 (7.85) 0.75 (1.50)

0.00 (0.00) 5.50 (7.78) 0.50 (0.71)

6.50 (0.58) 1.00 (0.00) -

4.50 (3.54) 3.00 (2.71) -

4.25 (0.50) 5.00 (0.82) 4.00 (0.82)

4.50 (0.71) 4.53 (0.81) 5.00 (9.00)

Escapable Inescapable No pretreatment

2.64 (I S6) 2.66 (0.08) I .48 (0.62)

I .63 (0.28) 3.22 (0.91) 2.56 (0.65)

2.00 (2.83) 8.50 (4.95) 0.50 (0.71)

0.50 (0.58) 3.50 (4.04) 1.00 (1.41)

7.00 (0.00) 2.50 (2.38) -

6.00 (0.82) 1.00 (0.00) -

4.75 (0.96) 4.51 (0.70) 5.00 (I .4l)

4.67 (0.82) 4.50 (0.58) 4.50 (1.00)

Group High motivation

30

JAMESG. BARBERand ANTHONY H. WINEFIELD

df = 33, P > 0.10) and for failures to solve (t = 0.22, df = 33, P > 0.10). These two groups were then combined and compared with the Inescapable group. This contrast confirmed the existence of a performance deficit in the Inescapable group, with significant results being obtained for both mean latency (t = 3.26, df = 33, P < 0.01) and failures to solve (t = 3.44, df= 33, P < 0.01). Although the absence of a significant interaction between the motivation and pretreatment factors distinguishes the present experiment from Experiment 1, this result may simply have been due to the smaller sample used in the present case. In other words, the sample may have been large enough to produce a significant learned helplessness effect overall but not large enough to show up the interaction between the motivation and pretreatment factors. To assess this possibility, the planned contrasts that were performed to demonstrate the overall learned helplessness effect were repeated for high and low motivation groups separately. Results of the contrasts confirmed the existence of performance deficits within both Inescapable groups. In fact, in marked contrast to Experiment 1, the learned helplessness effect was stronger within the low motivation group than the high motivation group. Within the high motivation group, the contrast between the Escapable and No pretreatment groups was not significant in the case of mean response latency (t = 0.27, df = 15, P > 0.10) or in the case of failures to solve (t = 0.39, df = 15, P > 0.10). On combining these 2 groups and comparing them with high motivation Inescapable subjects, a significant result was obtained for mean response latency (t = 2.14, df = 15, P < 0.05) but not for failures to solve (t = 1.89, df = 15, 0.05 < P < 0.10). In the case of low motivation subjects, the contrast between Escapable and No pretreatment controls was again nonsignificant for mean response latency (t = 0.50, df = 15, P > O.lO), and for failures to solve (t = 0.11, df = 15, P > 0.10). However, when these groups were combined and compared with low motivation Inescapable subjects results were significant both for mean response latency (t = 2.44, df = 15, P < 0.05) and for failures to solve (t = 2.89, df = 15, P < 0.01). A 2 x 2 x 2 analysis of variance performed on ratings of control over the tone during pre-treatment produced a significant main effect of pretreatment condition only [F(1,16) = 27.02, P < 0.001). Ratings of the aversiveness of the tone were subjected to a 3 x 2 x 2 analysis of variance. This procedure produced no significant main effects or interactions. All groups reported finding the tone mildly unpleasant.

GENERAL

DISCUSSION

Results of Experiment 2 confirm the prediction that the moderating effect of motivational differences on learned helplessness deficits is removed by an aversive stimulus. It is also significant that as well as displaying similar performance deficits to ‘high’ motivation subjects, ‘low’ motivation subjects in Experiment 2 were sensitive to the noncontingency operating during pretreatment. This finding contrasts with Experiment 1 in which only high motivation subjects reported awareness of the noncontingency and only they displayed performance deficits. It is possible only to speculate as to the reason for these results, but it may be that when a neutral stimulus is used, (as in Experiment l), high motivation subjects explore a wider range of operant responses than low motivation subjects. If so, then high motivation subjects should also be more likely than low motivation subjects to discover the absence of a reliable association between any one response and termination of the tone. On the other hand, low motivation subjects would be more likely to display superstitious learning of one variably reinforced response. In fact, during debriefing following Experiment 1 a number of Inescapable subjects who rated controllability above the midpoint on the scale also reported that they believed a particular response was sometimes successful so they kept repeating it. However the intense stimulus used in Experimeqt 2 may have increased the urgency felt by low motivation subjects to exert control over the stimulus and this, in turn, should have increased the amount of responding during pretraining. This interpretation of the data is consistent with Jackson et al.‘s (1978) contention that performance deficits using uncontrollable aversive stimuli can be attributed solely to the associative deficit postulated by learned helplessness theory. As in Experiment 1, Experiment 2 again found no evidence to support the prediction that subjects with a high ability self-perception would be more resistant to helplessness manipulations

Learned

helplessness

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31

than subjects with a low ability self-perception. This finding casts some doubt on the proposal that the initial expectation of uncontrollability (‘low ability’) renders the individual susceptible to helplessness manipulations. Moreover, although the PIQ was originally designed as a task-specific measure of locus of control, we now recognise that it actually provides a more valid measure of the expectation of control than locus of control measures do. As defined by Rotter (1966), the locus of control concept refers to the extent to which individuals perceive events to be contingent upon their own responses and such a notion is logically distinguishable from the expectation of control. In other words, it is possible for subjects to believe that performance is contingent upon their responses without expecting to succeed. The PIQ, on the other hand, measures the expectation of control quite directly by asking subjects to report how capable they believe themselves to be. For this reason we now prefer to think of the PIQ ability scale as a task-specific measure of the expectation rather than the locus of control. And the expectation of control should entail greater immunity to helplessness than mere internality. Thus the absence of any reliable association between PIQ ability and performance decrements raises a potentially important issue for learned helplessness research. In summary, the present experiments have a number of implications for learned helplessness research. At the most general level they imply that future studies should give careful consideration to the type of stimulus employed as the precise psychological effects are likely to be different depending on whether the stimulus is neutral or aversive. More specifically, research is needed into the effects of varying the stimulus from pretreatment to test trials. It is likely that such manipulations will influence the capacity of motivational differences to moderate helplessness deficits and these findings may cast further light on the mechanism(s) underlying the learned helplessness effect. REFERENCES Abramson L. Y., Seligman M. E. P. and Teasdale J. D. (1978) Learned helplessness in humans: Critique and reformulation. J. abnorm. Psychol. 87, 49-74. Albert M. and Geller E. S. (1978) Perceived control as a mediator of learned helplessness. Am. J. Psych& 91, 389400. Alloy L. B. (1982) The role of perceptions and attributions for reponseoutcome noncontingency in learned helplessness: A commentary and discussion. J. Person. 50, 443479. Barber J. G. and Winefield A. H. (1986) Learned helplessness as conditioned inattention to the target stimulus. J. exp. Psychol. Gen. In press. Barber J. G., Winefield A. H. and Mortimer K. (1986) The personal interests questionnaire: A task-specific measure of locus of control and motivation for use in learned helplessness research. Person. indiuid. D$ 7, 31 l-318. Burger J. M. and Arkin R. M. (1980) Prediction, control and learned helplessness. J. Person sot. PsychoI. 38, 48249 1. Burger J. M. and Cooper H. M. (1979) The desirability of control. Mar. Emof. 3, 381-393. Buys N. J. and Winefield A. H. (1982) Learned helplessness in high school students following experience of noncontingent rewards. J. Res. Person 16, 118-127. Cohen S., Rothbart M. and Phillips S. (1976) Locus of control and the generality of learned helplessness in humans. J. Person sot. Psychol. 34, 1049-1056. Dweck C. S. and Bush E. S. (1976) Sex differences in learned helplessness: 1. Differential debilitation with peer and adult evaluators. Dev. Psychol. 12, 147-156. Dweck C. S. and Reppucci N. D. (1973) Learned helplessness and reinforcement responsibility in children. J. Person sot. Psychol. 25, 109-l 16. Gregory W. L., Chartier G. M. and Wright M. H. (1979) Learned helplessness and learned effectiveness: Effects of explicit response cases on individuals differing in personal control expectancies. J. Person sot. Psychol. 37, 1982-1992. Hiroto D. S. (1974) Locus of control and learned helplessness. J. exp. Psychol. 102, 187-193. Jackson R. L., Maier S. F. and Rappaport P. M. (1978) Exposure to inescapable shock produces both activity and associative deficits in the rat. Learning Mot. 9, 69-98. Jardine E. and Winefield A. H. (1981) Achievement motivation, psychological reactance and learned helplessness. Mot. Emot. 5, 99-l 13. Jardine E. and Winefield A. H. (1984) Performance differences following exposure to predictable and unpredictable noncontingent outcomes in high and low achievers. J. Res. Person. 18, 508-521. Keppel G. (1973) Design and Analysis: A Researchers’ Handbook. Prentice-Hall, New Jersey. Krantz D. S., Glass D. C. and Snyder M. L. (1974) Helplessness, stress level, and the coronary-prone behavior pattern. J. Exp. sot. Psychol. 10, 284-300. Nowicki S. and Duke M. F. (1974) A locus of control scale for college as well as noncollege adults. J. Person. Assess. 38, 136137. Pittman N. L. and Pittman T. S. (1979) Effects of amount of helplessness training and internal-external locus of control on mood and performance. J. Person sot. Psychol. 37, 39-47. Rosenbaum M. and Jaffe Y. (1983) Learned helplessness: The role of individual differences in learned resourcefulness. Br. J. Sot. Psychol. 22, 215-225. Roth S. and Kubal L. (1975) Effects of noncontingent reinforcement on tasks of differing importance: Facilitation and learned helplessness. J. Person sot. Psychol. 32, 680-691.

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