Personality and belief in Capital Punishment: a replication and extension

Male and female Canadian undergraduates identified as high or low on Extraversion and Psychoticism on the basis of the Eysenck Personality Questionnaire completed the Questionnaire on Capital Punishment. In a replication of a previous study, males and extraverts reported more favourable attitudes towards Capital Punishment than females and introverts. In contrast, there were no significant differences in attitude between subjects classified as high and low on Psychoticism, a result which may be due to the difficulty of finding normal subjects with absolutely high scores on this trait.     

Memory scanning,introversion-extraversion,and levels of processing

Individual differences in information processing were studied in the form of the hypothesis that arousal, as indexed by a personality measure of introversion-extraversion, affects the speed with which certain kinds of processing are completed. The Sternberg paradigm was used, and the results suggested that introverts and extraverts scanned for physical features equally rapidly, but that introverts were slower than extraverts at scanning for the semantic features of category membership. There was limited support for the hypothesis that introverts, thought to be more aroused than extraverts, are less able to engage in shared or parallel processing. It was concluded that information processing in introverts and extraverts may differ qualitatively as well as quantitatively.     

Individual differences in components of slow cortical potentials: implications for models of information processing

Individual differences in the effects of pharmacological and behavioural manipulations on slow cortical potentials (SCP), may reflect personality differences in type of informational control under attentional stress. Two experiments were conducted to examine SCP component differences in extraverts and introverts under different attentional tasks and with and without nicotine smoking ‘stressor’ conditions. In an initial experiment a decrease in late negativity for introverts and an increase in late negativity for extraverts suggested that smoking enhanced introverts' stimulus set and extraverts' motor set. In a second experiment, personality differences in SCP were examined again, but within a signal-detection paradigm, which allows separate assessment of the contribution of sensory sensitivity and response bias factors to performance. Smoking increased sensitivity in both personality groups, but response bias (caution) increased in introverts only. Extraverts showed an increase in central negativity during smoking whilst introverts showed a decrease in negativity and a decrease in positive wave components. The results are explained in terms of a motor model of attentional control whereby smoking regulates inhibitory controlled actions in introverts, but activates general motor processes for extraverts.     

Extraversion and reactions to cognitive inconsistency

Two studies are reported which test the hypothesis that extraverts are more tolerant of cognitive inconsistency than are introverts. The first study tested this prediction in the context of Heider's balance model. While degree of extraversion did not moderate reactions to imbalance, extraverts did show less aversion to interpersonal disagreement than introverts. When coupled with other recently published data this suggests that extraverts find arousing social situations less aversive than introverts. In support of the main hypothesis, the second experiment showed that extraverts changed their attitudes less than introverts as a result of writing an essay which was counter to their own attitude under conditions where they had high perceived freedom of choice.     

Introversion-extraversion,tempo, and guided imagery

This research tested the hypotheses that (a) introverts would produce more vivid imagery than would extraverts, and (b) introverts would produce better mental imagery if the background auditory tempo was slow, and extraverts would produce better mental imagery of the background auditory tempo was fast. Participants (N=240) were classified as introverts or extraverts and were randomly assigned one of three tempo conditions: slow, fast, or none. They were instructed to form mental images while listening individually to one of two stories. Clicks (slow or fast) sounded in the background during the stories. All participants then completed detailed questionnaires about the vividness of their mental imagery. Analysis showed that introverts reported significantly more vividness in their imagery than did extraverts. The hypothesized interaction between personality and tempo was not found. Implications were drawn for therapeutic applications of mental imagery.     

Time perception: effects of introversion/extraversion and task interest.

32 extraverted and 32 introverted college students rated the interest value and estimated the duration of 3-min. intervals filled with reading. There were 3 dull and 3 interesting readings. It was hypothesized that time perceptions of extraverts and introverts would differ when their interest in the task was dissimilar. But no personality differences in time perception and few in interest were found; both extraverts and introverts judged the intervals to be shorter when the reading was interesting.     

Actual and stereotyped speech tempos of extraverts and introverts

The study examined the actual speech tempos of extraverts and introverts and stereotyped notions about the tempos of extraverts and introverts. Forty-six female undergraduates were divided on the basis of the Eysenck Extraversion Scale into equal groups of extraverts and introverts. Each was asked to talk in a natural manner about $$ TAT pictures, to talk as if she were an extravert or an introvert, and to speak rapidly or slowly. The results indicate that the actual speech tempo of extraverts is faster than that of introverts and suggest that the stereotypes of the speech rates of extraverts and introverts somewhat exaggerate their actual rates.     

Lay conceptions of personality: Eliciting tiers of a scientific conception of personality

Two studies are reported which examine the availability of scientific propositions of personality in lay conceptions of personality. It is argued from a social constructivist perspective that models of personality must derive from and refer to lay conceptions of persons. Eysenck's trait-type model of introversion-extraversion, containing specific propositions about phenotypic and genotypic differences between extraverts and introverts, was utilized as the scientific model of personality and its availability in lay conceptions of personality was examined in two studies. In the first study, subjects were presented with a genotypic characterization of either an introvert or an extravert target person and asked to infer corresponding phenotypic differences. In the second study, the inference process was reversed with subjects being asked to infer genotypic characteristics of introverts versus extraverts on the basis of phenotypic target person desecrations of the two types. Results from both studies show a high degree of accuracy in subjects' inferences, suggesting that laypersons have well-formed conceptions about personality containing ‘higher-order’ psychogenetic propositions corresponding to Eysenck's trait-type model. The implications of the findings for theory construction are discussed.     

The impact of Eysenck's extraversion-introversion personality dimension on prospective memory

Prospective memory (PM) is memory for future events. PM is a developing area of research (e.g., Brandimonte, Einstein & McDaniel, 1996) with recent work linking personality types and their utilisation of PM (Goschke & Kuhl, 1996; Searleman, 1996). The present study compared 28 extraverts and 28 introverts on their short- and long-term prospective memory using the Prospective Memory Scale developed by Hannon, Adams, Harrington, Fries-Dias & Gibson (1995). The main finding was that extraverts reported significantly fewer errors on short- and long-term PM than introverts, and this difference could not be explained in terms of the number of strategies used to support prospective remembering. These findings are discussed in relation to differences between the personality types.     

Associational social capital and psychological type: an empirical enquiry among cathedral Friends in England

A sample of 1131 members of the Friends associations of six English cathedrals (616 women and 515 men) completed the Francis Psychological Type Scales (FPTS) and a modified version of the Williams Religious Social Capital Index (WRSCI). The data demonstrated that higher levels of religious social capital were found among extraverts (compared with introverts), sensing types (compared with intuitive types), and feeling types (compared with thinking types). No significant differences were found between judging types and perceiving types. The finding that extraverts displayed higher levels of religious social capital poses a challenge for the cathedrals, given that introverts outnumbered extraverts by nearly 2:1 in the Friends groups. Since religious social networks are known to influence generosity with time and money, it is suggested that cathedrals not only develop strategies to recruit more extravert Friends but also devise novel ways of encouraging introvert types to participate in associational activities where social capital will be generated.     

Personality and the topography of the conditioned eyelid response

One-hundred and four women were tested on an eyelid conditioning paradigm in a 2 x 2 x 2 factorial design where two levels of US intensity (1 vs 3 p.s.i.) were balanced against two rest pause interpolations (after 25 and after 50 trials), and the presence or absence of a warning stimulus prior to CS-US presentation. Subjects were later classified as high, low or intermediate extraverts on the basis of a personality questionnaire. A very detailed analysis of conditioned responses was carried out, using both simple and composite measures including work-ratio, utility-ratio, CR frequency, peak latency, peak amplitude, response area and effective response area, degree of avoidance amplitude and latency, etc. Major findings related to similar effects of high intensity US vs low intensity US, and introversion vs extraversion; introverts react as if they were responding to more intense stimuli than extraverts. This finding cuts across other parameter variables, and supports Eysenck's formulation of personality-conditioning relationships in terms of higher cortical arousal in introverts as compared with extraverts.     

The influence of introversion-extraversion on activity choice and satisfaction among the elderly

The present study investigated the optimum theory of aging. This theory predicts that individuals with different personality types will react differentially to the aging process. In the present study, 60 nursing-home residents were administered the Eysenck Personality Inventory and then randomly assigned to one of two experimental manipulations. Elderly subjects classified as extraverts showed a high level of satisfaction to an experimental manipulation which was of a high activity, interpersonal type; those classified as introverts evidenced more satisfaction with a low activity, non-interpersonal type manipulation. Inspection of records documenting actual participation in programs within the nursing home indicated that introverts were more often involved in low activity, non-interpersonal events whereas extraverts participated more often in high activity, interpersonal events. Implications of these results are discussed in relation to the optimum theory of aging.     

Extraversion and positive affect: A day reconstruction study of person–environment transactions

Extraversion is robustly correlated with positive affect, but the reasons for this correlation remain unclear. One possibility is that extraverts and introverts both enjoy interacting with others, but extraverts do so more frequently. Another possibility is that extraverts enjoy social interactions more. Both hypotheses were tested using the Day Reconstruction Method. Subjects reported on interactions with others and positive affect experienced during all of the episodes from a single day. Results were consistent with the first hypothesis: the relation between extraversion and positive affect was partially mediated by extraverts’ greater social participation. The findings support a transactional approach to personality, in which traits like extraversion are seen as styles of actively engaging with the environment.     

Differential effects of personality on access to various long-term memory codes

Arousal, as indexed by personality measures, has been related to memory encoding, organization, and retrieval. In an attempt to investigate one of the component information-processing mechanisms underlying both encoding and retrieval, the effects of introversion-extraversion on performance in a simultaneous matching task was investigated. As predicted from earlier research, personality did not influence performance on a physical identity matching task but extraverts were faster than introverts in making taxonomic category matches (a semantic task). Somewhat unexpectedly, extraverts were also faster at making “homophone” identity matches. Arousal, then, appears to influence access to long-term memory codes of any type—a characteristic that may be reflected in tests of both encoding and retrieval.     

Extraversion and the ability to decode nonverbal communication

This study examined the relationship between extraversion, as measured by the Eysenck Personality Inventory (EPI), and skill at decoding nonverbal forms of communication. Prior research has had mixed success in establishing this relationship. Because extraverts have more experience in social settings than introverts, and because extraverts have a greater desire for sensory stimulation than introverts, it was hypothesized that extraverts would decode nonverbal cues in social interaction more accurately than introverts. The data supported this hypothesis. Extraverts were significantly more accurate in interpreting the meaning of nonverbal communication than introverts; in addition, extraverts were more confident that they were accurate decoders than introverts. The results are discussed in terms of cognitive processing style: the ‘extravert advantage’ in decoding nonverbal communication may be due to extraverts' superior attentive/perceptual skills; their superior interpretive/attributional skills; or both. In addition, the results are discussed in terms of methodological issues in the nonverbal decoding literature and their impact on research on extraversion. The nonverbal decoding task used in the present study differed from that of prior research by presenting scenes of natural, spontaneous, dyadic interactions for which an objective criterion for accuracy existed.     

Extraversion and sleep: A psychophysiological study of the arousal hypothesis

In order to examine Eysenck's (1967) hypothesis concerning the relationship between extraversion and arousal, autonomic measures were taken from introverts and extraverts immediately before sleep and during 6 hr of sleep. Introverts and extraverts did not differ in heart rate (HR) or skin-potential response rate (SPR) during the pre-sleep period. A variety of sleep-related measures of arousal provided no strong support for the hypothesis that introverts are more aroused than extraverts. The only consistent autonomic difference between introverts and extraverts during sleep was a tendency for introverts to have higher SPRs in the second 3 hr of the night. The results are discussed in terms of the level of environmental stimulation present in the experimental conditions, and suggestions are made for future sleep studies of the relationship between extraversion and arousal.     

Study habits and Eysenck's theory of extraversion-introversion

Predictions derived from Eysenck's theory of personality were tested in two samples by relating extraversion scores to library study locations, frequency of study breaks, and self-report of factors which influence study location. The predicted main effects for study location were found, with extraverts occupying locations that provided greater external stimulation. Positive correlations were consistently found between extraversion and preferred level of noise, preferred level of socializing opportunities, and rated importance of socializing opportunities. The prediction that extraverts would take more frequent study breaks was supported in Sample 1 but not replicated in Sample 2. The data are interpreted as providing direct support for Eysenck's theory of behavioral differences and mixed indirect support for his theory of neurological differences between introverts and extraverts.     

Do extraverts get more bang for the buck? Refining the affective-reactivity hypothesis of extraversion

One of the most robust observations in personality and emotion research is the finding that extraverts are happier than introverts. Some theorists have attributed this to differential reactivity of the brain reward system, which is central to many biologically inspired models of extraversion. This affective-reactivity hypothesis, which suggests that extraverts should be more susceptible to the induction of positive affect, has so far received very mixed empirical support. In this article, we consider a more biologically plausible account of extraverts' affective-reactivity. Over 5 experiments, we demonstrate that extraverts show greater affective-reactivity only in response to clearly appetitive stimuli and situations (e.g., where rewards are being pursued). Conversely, after merely pleasant stimuli and situations (without any reward-approach element), extraverts and introverts respond similarly. We also show that it is specifically activated affect (e.g., feelings of alertness), rather than pleasantly valenced affect (e.g., feelings of contentment), that characterizes the affective-reactivity of extraverts. Such reactions may potentially facilitate the reward-seeking behavior associated with extraversion, but they seem unlikely to explain the broadly happy disposition of extraverts.     

Attention and personality in augmenting/reducing of visual evoked potentials

Earlier research has shown that extraverts tend to increase their visual evoked potential amplitudes with increasing light intensity (augmenting), while introverts reach their maximum amplitude at lower intensities (reducing). The evoked response has normally been measured from association areas of the brain (at the vertex). The present study measured VEP amplitudes over visual cortex and at the vertex, using four light intensities in two conditions, where attention was either directed towards the light stimuli, or away from them by a concurrent auditory task. Forty subjects were classified as extraverts or introverts based on the Eysenck Personality Inventory. The results show that attention interacted significantly with extraversion. Introverts exhibited a narrower focus of attention, while higher amplitudes and amplitude-intensity functions when attending to the light flashes and lower when distracted. Extraverts showed smaller differences between conditions, indicating a more evenly distributed attention. Higher arousal in introverts is the probable cause of their narrower focus of attention. There were marked differences in the distribution of activity between vertex and occipital cortex. Introverts showed relatively stronger occipital responses and extraverts stronger vertex responses across all intensities and in both conditions. The predisposition for mainly perceptual responses to aversive stimuli in introverts, and for general alerting and motor preparatory responses in extraverts, are interpreted as supportive of Brebner and Cooper's hypothesis that introverts are ‘geared to inspect’ and extraverts are ‘geared to respond’.     

Personality changes with ageing

This paper is concerned with the integration of research on ageing with Eysenck's personality theory and in particular the personality dimension of introversion-extraversion. It is argued that older people behave like extraverts on a number of laboratory tests but like introverts in their behaviour patterns. A solution is offered for these paradoxical tendencies.