Sociability/impulsivity and attenuated dopaminergic arousal: critical flicker/fusion frequency and procedural learning

Two experiments examined the interaction of sociability (Soc) and impulsivity (Imp) components of extraversion and reduced dopamine activity (by haloperidol) on critical flicker/fusion frequency change scores (ACFFT) and procedural learning. In double-blind designs, subjects received either haloperidol (5 mg) or placebo; Soc and Imp were randomly sampled. In Experiment 1, Drug × Imp, and Drug × Imp × Soc interactions were found on ΔCFFT; in Experiment 2, a drug × Soc interaction was found on procedural learning. In both experiments, introverts seemed over-aroused under placebo (putatively due to the medical context), more optimally aroused under haloperidol; for procedural learning, extraverts seemed more optimally aroused under placebo, less optimally aroused under haloperidol. These data indicate that both Soc and Imp mediate the effects of arousal; Drug × Imp effects my conceal joint effects of Soc × Imp; and that Soc shows more consistent effects than Imp. These data complement a previous study of Soc/Imp and caffeine-induced arousal (Corr, Pickering & Gray, 1995), and lend support to H. J. Eysenck's (1967) arousal model of Extraversion.     

Dishabituation and spontaneous recovery of the electrodermal orienting response: Effects of extraversion,impulsivity, sociability,and caffeine

The relationship between extraversion and psychophysiological indices of arousal is not yet fully understood. The present study attempted to further clarify this relationship by using caffeine to systematically manipulate arousal. Subjects pretested on the Eysenck Personality Inventory were given caffeine or a placebo, then underwent habituation, dishabituation, and spontaneous recovery of the electrodermal OR. Separate analyses examined the main and interactive effects of extraversion, impulsivity, and sociability with caffeine. Several tonic and phasic measures showed group reversal effects, with introverts having higher tonic levels and larger phasic responses under placebo conditions and extraverts having larger phasic responses and higher tonic levels under caffeine. Although both tonic and phasic responses were differentially affected, the group reversal effects occurred at different points in time on tonic than they did on phasic measures relative to the theoretical buildup of inhibition. The findings for impulsivity were quite consistent with those for extraversion, and both sets of results were generally supportive of the Eysenck hypothesis.     

Extraversion: sociability and impulsivity?

The sociability and impulsivity components of extraversion were studied. Thirty experimental items were written to assess different aspects of sociability and impuslivity. These items, along with the 24 extraversion items of the MPI, were administered to 146 college students. Factor analyses of experimental items indicated that neither sociability nor impulsivity is unitary. Correlations among these sociability and impulsivity factors and the MPI extraversion items indicated that MPI extraversion is essentially a measure of one aspect of sociability: the quantity of social relationships. Extraversion touches on but does not adequately sample either the intensity (quality) of social relationships or aspects of impulsivity.     

Impulsivity/sociability and reinforcement in verbal operant conditioning

The present investigation was designed to study the relationship between impulsivity/sociability and modes of reinforcement in verbal operant conditioning. Two 2x3 randomized block designs, one each for impulsivity and sociability, were replicated ten times. One hundred and twenty undergraduate female students (60 for impulsivity and 60 for sociability) were individually subjected to Taffel's verbal conditioning procedure. When the conditioning scores of high and low scorers on the impulsivity and sociability scales were compared, it was found that under rewarding conditions ('good' and 'buzzer' in respect of sociability and 'good' in respect of impulsivity) the high scorers' score and under punishing conditions ('electric shock') the low scorers' score was the higher of the two. The study also revealed that the high scorers (on the impulsivity scale) conditioned more under rewarding conditions while the low scorers (both on the impulsivity and sociability scales) conditioned more under punishing ones.     

Differential relationships of extraversion,impulsivity, and sociability to study habits

Reanalysis of data on library study habits presented by J. B. Campbell and C. W. Hawley (Journal of Research in Personality, 1982, 16, 139–148) revealed differential utility for the EPI extraversion scale and its components, impulsivity and sociability. Individuals studying in locations that provided greater external stimulation had significantly higher extraversion and impulsivity, but not sociability, scores than individuals studying elsewhere in the library. Impulsivity was more strongly associated than sociability with preferred noise levels, frequency of study breaks, and importance and preferred levels of socializing opportunities, but less strongly associated with preferred levels of crowdedness. Findings are discussed in terms of the interpretation, reliabilities, and theoretical context of the subscales.     

Comparison of EPI and psychoticism scales with measures of the five-factor model of personality

The need for a comprehensive model of personality traits acceptable to the entire community of personality researches has often been acknowledged. In this article, two such models are compared. Eysenck scales measuring neuroticism, extraversion, psychoticism and lie are correlated with self-report and peer-rating measures of the five-factor model—neuroticism, extraversion, openness to experience, agreeableness and conscientiousness—in a sample of adult men and women. Findings suggest that: (1) neuroticism and extraversion factors from the two systems match well; (2) sociability and impulsivity are distinguishable traits, but both fall within the broad domain of extraversion; (3) the EPI L scale measures aspects of several substantive traits rather than a response bias; (4) openness to experience is not well-represented in the Eysenck system; and (5) psychoticism corresponds most closely to the low poles of agreeableness and conscientiousness.     

A quantitative review of the relations between the “Big 3” higher order personality dimensions and antisocial behavior

In this meta-analytic review, Hans J. Eysenck’s theory of criminality (Eysenck, 1964, Eysenck, 1977) serves as a theoretical framework for examining the relations between higher order personality dimensions and antisocial behavior (ASB). The three higher order dimensions examined are referred to as extraversion/sociability, neuroticism/emotionality, and impulsivity/disinhibition (see Sher & Trull, 1994), and they are likened to Eysenck’s dimensions of extraversion (E), neuroticism (N), and psychoticism (P), respectively (Eysenck & Eysenck, 1975) and Tellegen’s dimensions of positive emotionality (PEM), negative emotionality (NEM), and constraint (reversed) (CON), respectively (Tellegen, 1982). Ninety-seven samples, from 52 published and unpublished studies, were reviewed. The results indicated that among the “Big 3” personality dimensions, impulsivity/disinhibition is most strongly related to ASB and extraversion/sociability is least strongly related to ASB. Additional variables, including age and methodological differences, were found to moderate the associations between the personality dimensions and ASB.     

The role of R-S1 expectancy in discrimination and discrimination reversal learning

Four experiments assessed the role of response-reinforcement (R-S¹) expectancy as rats either learned a discrimination or a discrimination reversal. Experiment 1 showed that the higher the percentage of reinforcement during nondiscriminative pretraining the more quickly a subsequent discrimination is learned. Experiment 2 demonstrated that the overlearning reversal effect (ORE) can be obtained even though the overtraining phase consists of responses to a single neutral card. In Experiment 3 subjects were again overtrained on a single neutral stimulus under conditions of varying reinforcement. ORE was apparent under reinforcement of a high percentage of responses but was not apparent under reinforcement of a low percentage. Experiment 4 revealed that the fewer errors a subject makes prior to reversal the better its reversal performance is. Results of these studies were discussed in terms of generalized attention theories and the expectancy notions of Bolles (Psychological Review, 1972, 79(5), 394–409.     

Reinforcing effects of caffeine in coffee and capsules.

In a residential research ward the reinforcing and subjective effects of caffeine were studied under double-blind conditions in volunteer subjects with histories of heavy coffee drinking. In Experiment 1, 6 subjects had 13 opportunities each day to self-administer either a caffeine (100 mg) or a placebo capsule for periods of 14 to 61 days. All subjects developed a clear preference for caffeine, with intake of caffeine becoming relatively stable after preference had been attained. Preference for caffeine was demonstrated whether or not preference testing was preceded by a period of 10 to 37 days of caffeine abstinence, suggesting that a recent history of heavy caffeine intake (tolerance/dependence) was not a necessary condition for caffeine to function as a reinforcer. In Experiment 2, 6 subjects had 10 opportunities each day to self-administer a cup of coffee or (on different days) a capsule, dependent upon completing a work requirement that progressively increased and then decreased over days. Each day, one of four conditions was studied: caffeinated coffee (100 mg/cup), decaffeinated coffee, caffeine capsules (100 mg/capsule), or placebo capsules. Caffeinated coffee maintained the most self-administration, significantly higher than decaffeinated coffee and placebo capsules but not different from caffeine capsules. Both decaffeinated coffee and caffeine capsules were significantly higher than placebo capsules but not different from each other. In both experiments, subject ratings of "linking" of coffee or capsules covaried with the self-administration measures. These experiments provide the clearest demonstrations to date of the reinforcing effects of caffeine in capsules and in coffee.     

Individual differences in circadian activity rhythm and personality

Individual differences in circadian activity rhythms were assessed in terms of peak activity time, rising time and retiring time reported every day for 84 consecutive days. A 19-item Morningness-Eveningness Questionnaire (MEQ) was found to significantly correlate with time-of-day effects on these three circadian activity measures, as well as with parental report of the S's peak activity time. Several measures of extraversion were also found to correlate significantly with the MEQ, as well as with rising and retiring time, suggesting that extraverts are evening types. However, when the differential effects of sociability and impulsivity were examined it was found that the sociability component of extraversion was most responsible for the time-of-day differences. This result diverges somewhat from previous findings that suggest impulsivity is the component responsible for time-of-day effects. This apparent contradiction is discussed in terms of arousal being a non-urinary construct, with different indices of circadian arousal allowing for differential correlates with specific personality components.     

The interactive effect of personality, time of day, and caffeine: a test of the arousal model

The personality dimension of introversion/extraversion is one of the few personality dimensions that can be reliably identified from study to study and investigator to investigator. The importance of this demension within personality theory is due both to the stability of the trait and the influential theory of H. J. Eysenck. The basic assumption in Eysenck's theory of introversion/extraversion is that the personality differences between introverts and extraverts reflect some basic difference in the resting level of cortical arousal or activation. Assuming that there is a curvilinear relationship (an inverted U) between levels of stress and performance leads to a test of this arousal theory. That is, moderate increases in stress should hinder the performance of introverts who are presumably already highly aroused. However, the same moderate increase in stress might help the performance of the presumably underaroused extraverts. Revelle, Amaral, and Turriff reported that the administration of moderate doses of caffeine hindered the performance of introverts and helped the performance of extraverts on a cognitive task similar to the verbal test of the Graduate Record Examination. Assuming that caffeine increases arousal, this interaction between introversion/extraversion and drug condition supports Eysenck's theory. This interaction was explored in a series of experiments designed to replicate, extend, and test the generality of the original finding. The interaction between personality and drug condition was replicated and extended to additional cognitive performance tasks. However, these interactions were affected by time of day and stage of practice, and the subscales of introversion/extraversion, impulsivity, and sociability, were differentially affected. In the morning of the first day, low impulsives were hindered and high impulsives helped by caffeine. This pattern reversed in the evening of the first day, and it reversed again in the evening of Day 2. We concluded that the results from the first day of testing require a revision of Eysenck's theory. Instead of a stable difference in arousal between low and high impulsives, it appeared that these groups differed in the phase of their diurnal arousal rhythms. The result is that low impulsives are more aroused in the morning and less aroused in the evening than are the high impulsives. A variety of peripheral or strategic explanations (differences in caffeine consumption, guessing strategies, distraction, etc.) for the observed performance increments and decrements were proposed and tentatively rejected. It seems probable that some fundamental change in the efficiency with which information is processes is responsible for these performance changes.     

A Psychometric Investigation of the Usefulness of the Easi-III Temperament Survey in the Australian General Population

The psychometric properties of Buss and Plomin's EASI-III Temperament Survey were examined for a random sample of 290 respondents from the Australian general population. These data support the use of the emotionality, activity and sociability scales with some minor modifications, but cast doubt on the impulsivity scale. Not only did impulsivity emerge as a multidimensional construct, but its components related to other temperaments in markedly different ways. The preliminary analyses also suggested that the EASI-III could be used to measure other constructs, the most important of which are neuroticism and extraversion. The advantages offered by the EASI-III over currently available instruments are discussed: in particular, the simplicity and clarity of the items and the well-articulated sampling framework for their selection.     

Effects of caffeine on persuasion and attitude change: The role of secondary tasks in manipulating systematic message processing

Two experiments are reported that examine the effects of caffeine consumption on attitude change by using different secondary tasks to manipulate message processing. The first experiment employed an orientating task whilst the second experiment employed a distracter task. In both experiments participants consumed an orange‐juice drink that either contained caffeine (3.5 mg/kg body weight) or did not contain caffeine (placebo) prior to reading a counter‐attitudinal communication. The results across both experiments were similar. When message processing was reduced or under high distraction, there was no attitude change irrespective of caffeine consumption. However, when message processing was enhanced or under low distraction, there was greater attitude change in the caffeine vs. placebo conditions. Furthermore, attitudes formed after caffeine consumption resisted counter‐persuasion (Experiment 1) and led to indirect attitude change (Experiment 2). The extent that participants engaged in message‐congruent thinking mediated the amount of attitude change. These results provide evidence that moderate amounts of caffeine increase systematic processing of the arguments in the message resulting in greater agreement. Copyright © 2006 John Wiley & Sons, Ltd.     

Impulsive motor behavior: effects of personality and goal salience

This experiment used a circle tracing paradigm to extend our recent theoretical development concerning the contributions of extraversion and neuroticism to impulsive performance on continuous motor tasks. Subjects (N = 137) completed the Eysenck Personality Questionnaire and were randomly assigned to 1 of 2 circle conditions: The goal condition provided subjects with a salient behavioral end point for their tracings, whereas the no-goal condition promoted behavioral uncertainty. In both conditions, Ss were asked to trace the circle under neutral and inhibition instructions. Using Gray's impulsivity and anxiety dimensions to group subjects, impulsive subjects under inhibition instructions displayed significantly faster tracing speed than nonimpulsive subjects in the presence of a salient goal, whereas anxious subjects appeared behaviorally impulsive in a situation promoting uncertainty and response conflict. Conceptualizing impulsivity and anxiety in terms of extraversion and neuroticism, with impulsive Ss as neurotic extraverts and anxious Ss as neurotic-introverts, it is proposed that Ss' level of extraversion determines the type of stimuli to which they are responsive, and that level of neuroticism influences the magnitude of this reaction.     

Arousal and recognition memory: The effects of impulsivity,caffeine and time on task

Systematic changes in performance on memory tasks have been observed as a function of the number of prior items or lists learned. In an attempt to determine whether this was an ‘attentional’ phenomenon the effect of arousal (as indexed by Impulsivity and manipulated by caffeine) on memory performance was examined. One hundred college students were given either 4 mg of caffeine/kg body weight or a placebo and then shown four lists (two 24-item and two 80-item) of four letter words. A forced-choice recognition test for the last 20 items was given immediately after each list. The performance of the high impulsives who were given a placebo (least aroused subjects) declined as a function of the number of prior lists learned. Low impulsives (more aroused) showed significantly less decline. Caffeine significantly improved recognition memory especially on the final lists. Decrements in memory performance, as a function of number of prior litsts, are thus reduced by the same variables which reduce vigilance decrements. It is suggested that common explanations will be required.     

Low-dose caffeine discrimination and self-reported mood effects in normal volunteers.

A caffeine versus placebo discrimination procedure was used to determine the lowest caffeine dose that could produce discrimination and self-reported mood effects in normal volunteers. During daily sessions under double-blind conditions, caffeine-abstinent subjects orally ingested a capsule containing 178 mg caffeine or placebo. Before beginning discrimination training, the compounds were identified to subjects by letter codes. Fifteen, 30, and 45 min after capsule ingestion, subjects guessed the capsule's letter code. Correct guesses at 45 min earned money. After each session, subjects received a supplementary capsule containing caffeine or placebo to ensure that, within each phase of the study, subjects received the same daily dose of caffeine equal to the training dose. Five of the 15 subjects acquired the caffeine versus placebo discrimination within the first 20 sessions (greater than or equal to 75% correct); 6 other subjects acquired the discrimination with additional training. Nine subjects who acquired the discrimination were subsequently trained at progressively lower caffeine doses. In general, the lowest dose to produce discrimination (greater than or equal to 75% correct) was also the lowest dose to produce self-reported mood effects: 4 subjects showed discrimination and self-reported mood effects at 100 mg caffeine, 2 at 56 mg, 1 at 32 mg, and 1 at 18 mg. One of these subjects also showed self-reported mood effects at 10 mg. The present study documents discriminative stimulus and self-reported mood effects of caffeine at doses below those previously shown to affect any behavior in normal volunteers.     

The relationship between the EPI extraversion score and impulsiveness on a perceptual-motor task

This paper describes an investigation of the relationship between extraversion and impulsiveness. These two traits were measured respectively by the Eysenck Personality Inventory (EPI) and the IES Arrow-Dot test. The subjects were 50 males and 50 females matched for age. Arrow-Dot impulsiveness was found to correlate significantly with extraversion in both samples. In the female sample Arrow-Dot impulsiveness correlated only significantly with the ‘impulsiveness’ component of extraversion. In the male sample both the ‘impulsiveness’ and ‘sociability’ components of the extraversion factor contributed about equally to its variance.     

Impulsivity, caffeine, and proofreading: a test of the Easterbrook hypothesis

Easterbrook's (1959) suggestion that arousal is inversely related to the range of cue utilization has been frequently cited as an explanation for the curvilinear relationship between arousal and performance. There is very little empirical support for this position, however. As a test of the Easterbrook hypothesis, 60 undergraduates who varied in their impulsivity level were given caffeine or placebo and then asked to proofread several passages. Estimates of sensitivity were calculated using signal detection techniques. It was predicted that high arousal would reduce sensitivity to interword errors, which require a broad range of cue utilization, but that the observed levels of arousal would not affect sensitivity to intraword errors, which require a minimal range of cue utilization. A significant crossover interaction between impulsivity and drug for interword errors indicated that caffeine increased the error detection rate of the (less aroused) more impulsive subjects but lowered the error detection rate of the (more aroused) less impulsive subjects. The results of this study support the suggestion that arousal has direct effects on the capacity for simultaneous information processing, independent of its effects on performance speed.     

Impulsivity,neuroticism, and caffeine: Do they have additive effects on arousal?

The personality dimensions of impulsivity and neuroticism have been linked to differences in basal arousal. The hypothesis tested was whether these personality variables and caffeine have additive effects on arousal. All subjects received three paired-associate trials on each of two neutral control lists, two lists with semantically similar stimuli, and two lists with acoustically similar stimuli. Half of the subjects received caffeine and half placebo. Although significant interactions with personality and drug condition were obtained, the ordering of the conditions was inconsistent with the assumption that the arousal performance curve is single peaked. Further, S. Schwartz's (Journal of Research in Personality, 1975, 9, 217–225) hypothesis that in paired-associate learning high arousal and low arousal subjects process semantic and physical information differentially was not supported. The general issue of how to determine whether individual differences in performance are caused by differences in arousal is discussed.     

Adult ADHD: Associations with Personality and Other Psychopathology

The goals of this study were to explicate adult ADHD’s relations with personality at both the domain and facet levels and to examine its associations with other psychological symptoms. Community members (N?=?294) completed measures assessing ADHD inattentive and hyperactive/impulsive symptoms, five-factor model personality domains and facets, and other internalizing and externalizing symptoms. Inattentiveness showed strong negative relations with conscientiousness and extraversion and strong positive relations with neuroticism; in contrast, hyperactivity/impulsivity related negatively to agreeableness, positively to extraversion, and weakly to neuroticism. Whereas inattentiveness emerged as a positive predictor of internalizing psychopathology—and depression in particular—hyperactivity/impulsivity related weakly to internalizing but more strongly to externalizing psychopathology. Thus, inattentive and hyperactive/impulsive symptoms showed differential relations with personality—at both the domain and facet levels—and with other psychological symptoms. These results demonstrate the value in examining ADHD’s relations with personality facets and with a wide range of psychopathology within the same study.