The effects of anxiety on intellectual performance: When and why are they found?

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    The Effects of Anxiety on Intellectual Performance: When and Why Are They Found?


    University of Cambridge

    An experiment tested the effects on intelligence and creativity test performance of two 16PF primary anxiety traits, and general mood and activation components of state anxiety. Two attentional theories of the deleterious effects of anxiety on performance were also tested. Subjects were 80 male students. Trait and state components of anxiety appeared to affect creativity test performance independently. Intelligence test performance was insensitive to anxiety variables. The 0 anxiety primary factor was significantly negatively correlated with creativity test per- formance, but the unique variance of the other anxiety primary (Q4) was associated with higher levels of performance. Neither specific attentional theory was supported, but data were generally compatible with dual-mechanism theories of anxiety, which posit separate detrimental and sometimes facilitative effects of anxiety on performance. 0 1986 Academic Press, 113~.


    The effects of anxiety on complex cognitive or intellectual tasks are notoriously inconsistent. Adverse effects of anxiety on intelligence test performance have only modest replicability (see review by Matarazzo, 1972). Three studies have shown (deleterious) main effects of trait anxiety or neuroticism on creativity test or verbal fluency performance (Tapasak, Roodin, & Vaught, 1978; Upmanyu, Gill, & Singh, 1982, White, 1968); two others have not (Di Scipio, 1971; Leith, 1972). Two approaches to resolving these inconsistencies have been followed. One line of research, which often involves correlational methods, is directed toward identifying different types or components of anxiety and determining which affect performance. The other approach is to investigate the dependency of anxiety effects on other factors, such as extraversion (Gupta, 1977), time

    This research was carried out in partial fulfillment of the requirements for the University of Cambridge Ph.D. degree, while the author was supported by an SSRC grant. Contributions to research expenses were made by the Perrott-Warwick Studentship and the 23 Club. 1 am grateful to Carl Sargent for supervising this research. I also thank an anonymous referee for comments made about a previous draft of this paper. Requests for reprints should be sent to Dr. Gerald Matthews, Applied Psychology Division, Aston University, Aston Triangle, Birmingham BA 7ET, England.

    385 OO92-6566/86 $3.00

    Copyright 0 1986 by Academic Press, Inc. All rights of reproduction in any form reserved.


    pressure (Siegman, 1956), and the nature of the task (see M. W. Eysenck, 1982). This approach suggests an experimental approach to test for in- teractive effects of anxiety and other variables on performance.

    The research reported on here was part of a wider investigation of the effects of personality traits and states on intellectual performance (Mat- thews, 1983). The experimental procedure was designed to provide both correlational and experimental data on effects of anxiety-related variables on performance. The remainder of this section discusses the dimensions and modifying variables investigated, and identifies unresolved issues to which the present research was directed.

    Two separate distinctions between different types of anxiety are of interest here, that between trait and state anxiety, and that between worry and emotionality. According to Spielberger (1966, 1972), state anxiety may be characterized as a transitory emotional state, while trait anxiety reflects a stable predisposition to respond to stimuli threatening to self-esteem with state anxiety. It is clear that state but not trait anxiety consistently impairs working memory (M. W. Eysenck, 1981), and the- oretically effects of trait anxiety are often said to be wholly dependent on state anxiety. Since working memory may be an element of intelligence test performance (see Humphreys & Revelle, 1984). it is plausible that intelligence test performance should be more susceptible to effects of state than trait anxiety. There are few empirical tests of this hypothesis, though the insensitivity of IQ to trait anxiety provides circumstantial evidence for it. Leon and Revelle (1985) obtained significant deleterious effects of state but not trait anxiety on analogical reasoning. Conversely, Samuel (1980) found a small but significant negative correlation (r = - .27) between trait anxiety and IQ, but no effect of state anxiety on IQ (r = - . IO). Unfortunately this study measured state variables post- task rather than pretask, which raises interpretational difficulties. Also, effects of trait anxiety might be expected to the extent that ability testing acts as an ego threat (see Sarason, 1975), and so induces higher state anxiety in trait anxious subjects (see Hodges, 1968).

    The research on creativity and anxiety referred to above was confined to trait measures of anxiety or neuroticism. Idzikowski and Baddeley (1983) found a small but significant deleterious effect of situational anxiety prior to public speaking on verbal fluency (one component of creativity: Cattell, 1971), but found no significant effect on logical reasoning. This study suggests that state anxiety might be more consistently related to creativity test performance than trait anxiety. Further research comparing effects of trait and state anxiety on intellectual task performance is clearly desirable.

    The most important component of self-report anxiety is displeasure, with high arousal or activation making a lesser contribution (Russell & Mehrabian, 1977). If anxiety effects are considered to be dependent on


    state anxiety, it becomes important to determine whether such effects are determined by the pleasure-displeasure and/or activation components of the state.

    Morris and Liebert (1969) have shown that (time-pressure dependent) adverse effects of general anxiety on intelligence depend on worry rather than emotionality items. It would be desirable to extend this distinction to psychometrically more rigorous traits. H. J. Eysencks (1967) neuroticsm (N) variable is indivisible, but Cattell (e.g., 1973) has claimed that several primary traits contribute to the anxiety factor ap- proximately equivalent to N and to other trait anxiety measures (see Cattell & Kline, 1977, chap. 5). Two Cattell anxiety primaries appear to correspond approximately to worry and emotionality-0 and Q4, re- spectively. The high-0 subject is said to be apprehensive, self-reproaching, insecure, worrying, and troubled. The high-Q4 subject is tense, frustrated, driven, and overwrought (Cattell & Kline, 1977). A preliminary experiment (Matthews, 1983), suggested that only 0 seemed to be consistently neg- atively associated with performance. Table 1 shows correlations between 16PF anxiety primaries in groups run in quiet and noise. The experiment used a repeated-measures Latin square design, with 18 subjects run in noise followed by quiet, and 18 run in quiet followed by noise. The two testing sessions were a week apart. The Table 1 quiet and noise data were pooled across testing session.


    Theoretically anxiety is said to induce a generalized attentional deficit (Sarason, 1972; Wine, 1971) due to the tendency of anxious subjects to divert attention toward self-deprecatory cogitation. Attempts to account for effects of anxiety on performance in more detail have led to several dual-mechanism theories of anxiety. Such theories posit one mechanism



    Trait anxiety variable

    Group 0

    Intelligence test Quiet -33* Noise -22

    Creativity test Quiet -29 Noise -35*

    Note. All correlations are Pearson r. * P < .OS. two-tailed test.

    Q4 Anxiety

    -06 - 18 09 05

    -04 - 15 -20 - 33*


    deleterious to performance and one which may sometimes be facilitatory . The second mechanism accounts for improvements with anxiety sometimes found with easy tasks (see M. W. Eysenck, 1981). The mechanisms of three such theories are shown in Table 2. The difference in the effects of anxiety on effort according to the M. W. Eysenck (1981) and Humphreys and Revelle (1984) theories may be more apparent than real. Eysenck sees effort as related to the intensity of motivation, while Humphreys and Revelle associate on-task effort with the direction of motivation. Two of these theories were tested here, those of Hamilton (1975) and M. W. Eysenck (1981). Because effects of anxiety on intellectual per- formance, where found, tend to be detrimental, empirical tests were directed toward those components of anxiety said to impair performance.

    Hamilton (1975) sees anxiety as increasing task-irrelevant information load in a limited capacity processing system. If information load exceeds a fixed capacity, then performance decrements will result. Different sources of information load are additive, so tasks with a high rate of information processing would be most sensitive to deleterious effects of anxiety. Facilitative effects of anxiety are accounted for in terms of increased drive. Similarly, M. W. Eysenck (1981) considers that (state) anxiety has both cognitive and motivational/physiological effects. Cognitively, anxiety reduces working memory capacity by generating task-irrelevant cognitions. Motivationally, anxiety is considered to increase effort, such that anxious subjects are often able to maintain performance efficiency at the cost of increased effort. On simple tasks this expenditure of effort may allow anxious subjects to outperform those low in anxiety. There have been few direct tests of these models (though see M. W. Eysenck, 1982). According to Hamilton, though, anxiety decrements should be enhanced primarily by manipulations increasing total information input, regardless of requirements to retain information, while according to M. W. Eysenck, such decrements should be enhanced by conditions reducing working memory capacity.

    TABLE 2


    Theory Deleterious Potentially facilitative Mechanism mechanism

    Hamilton (1975)

    Eysenck (1981) Humphreys and Revelle


    Information overload

    Working memory overload

    Reduced on-task effort





    Aims Two approaches to anxiety have been outlined above: the isolation of

    the component(s) of anxiety responsible for performance decrements, and the construction of precise attentional theories of anxiety able to predict how anxiety effects on performance will interact with task and situational variables. The first aim of the study was to compare the following components of anxiety as predictors of intellectual performance: activation and general mood (pleasure-displeasure) components of state anxiety, and 16PF 0 and Q4 anxiety primary trait factors. The second aim was to test Hamiltons (1975) and M. W. Eysencks (1981) theories of anxiety, by determining how other theoretically relevant variables (noise and time of day) modified effects of anxiety on performance.

    Hypotheses Existing research suggests the following hypotheses concerning rela-

    tionships between anxiety-related trait and state variables and performance. First, state variables (mood and activation) should be stronger predictors than trait variables (0 and 44). However, of the two trait variables 0 should be a stronger predictor of performance deficits than Q4. These hypotheses were tested by correlational and multiple regression analyses.

    To derive hypotheses from the Hamilton (1975) and M. W. Eysenck (1981) theories it is necessary to find manipulations which have differing effects on external information load and on working memory capacity. Noise vs quiet and late vs early time of day were used for this purpose. Clearly noise but not time of day affects information load. There is strong evidence, from a variety of paradigms, that working memory efficiency peaks in the late morning, and declines during the rest of the day (see Folkard, 1983). White noise tends to reduce working memory capacity (see M. W. Eysenck, 1976, 1982, chap. 8). though the effects may be more complex than a simple capacity loss. In particular, effects of noise on memory are modified by strategy use and the extent to which per- formance depends on order information (see M. W. Eysenck, 1982, chap. 8).

    In general, then, the Hamilton (1975) model predicts that noise but not later time of day should enhance anxiety decrements. while on the M. W. Eysenck (1981) model both time of day and noise should enhance anxiety decrements, with these two variables interacting to produce poorest performance in noise in the evening. Both tasks required speeded responses, the intelligence items because time pressure was imposed, the creativity tests because scores depend on the number of responses produced in a given time interval. Thus, on Hamiltons (1975) model, both tasks should require high rates of information processing, and so would be affected by extraneous information load. The probable role of working memory in intelligence test performance has been referred to above (see Humphreys


    & Revelle, 1984). M. W. Eysenck (1974a, 1974b) argues that one process on which creativity test performance depends is retrieval from semantic memory. Since items retrieved from long-term memory presumably have to be retained in working memory before being output, it is plausible that creativity test performance will be affected by working memory capacity. Baddeley, Lewis, Eldridge, and Thomson (1985) report that speed of retrieval from semantic memory is sensitive to attentional re- sources, though it is unclear whether this effect involves working memory.

    Interactive effects between anxiety and experimental manipulations could also reflect an activation-dependent mechanism obeying the Yerkes- Dodson Law (Broadhurst, 1959). Here the relationship between trait anxiety and activation could be checked. Activation is a component of state anxiety (Russell & Mehrabian, 1977), but analyses of interactive effects of mood and activation on performance were not performed, to prevent overanalysis of the data.

    To summarize, the correlational analyses indicated which components of anxiety were linearly related to intellectual task performance. The interactive effects of variables related to anxiety, and noise and time of day distinguished between the cognitive anxiety theories of M. W. Eysenck (1981) and Hamilton (1975).


    Subjects The subjects were 80 male Cambridge University student...


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