Differences in the transmission of sensory input into motor output between introverts and extraverts: Behavioral and psychophysiological analyses

The present study was designed to investigate extraversion-related individual differences in the speed of transmission of sensory input into motor output. In a sample of 16 introverted and 16 extraverted female volunteers, event-related potentials, lateralized readiness potentials (LRPs), and electromyogram (EMG) were recorded as participants performed a visual choice reaction time task. As additional behavioral indicators of performance, measures of reaction time (RT) and response dynamics were obtained. Although extraversion-related differences were found neither for behavioral measures nor for the N1 and P3 components of the evoked potential, introverts showed a reliably shorter latency in stimulus-locked LRP than extraverts. This latter finding supports the notion of faster stimulus analysis in introverts compared to extraverts. Furthermore, there was no indication of extraversion-related individual differences in speed of response organization and response execution as indicated by response-locked LRP and EMG latencies, respectively. However, a significantly higher EMG amplitude observed with introverts pointed to a less accurately adjusted motor output system of introverts compared to extraverts.     

人格特质对选择性加工偏向的影响

采用词性辨别和注意探测任务,考察了神经质和外倾性对选择性加工偏向的影响。结果表明：（1）放试在选择信息时存在特质一致性倾向;（2）在单一刺激条件下,当刺激词呈现时间为0．5s时,高神经质对所有效价词的RT均快于低神经质;而当呈现时间为1．0s时,外倾者比内倾者的反应潜伏期更短4（3）双重刺激条件下的选择性加工偏向比单一刺激条件更明显;（4）在词性辨别任务中．刺激词呈现时间只影响了神经质被试对情绪词的RT;在注意探测任务中,呈现时间对内外倾被试的加工偏向影响不显著。     

双作业任务中人格特质对选择性加工的影响

运用双操作任务,该研究考察了人格的神经质和外倾性特质对选择性加工的影响。实验结果表明：(1)对各类词性的辨别速度,低神经质普遍快于高神经质,外倾者普遍快于内倾者．选择性加工偏向在RT指标上并不明显;(2)从词性辨别的正确率指标分析,高神经质被试对负性词存在明显的反应偏向;对于特质词与中性词的判断,内、外倾被试之间不存在显著差异;(3)在自由回忆任务中,各类被试均存在明显的回忆偏向及特质一致性倾向。     

Identification of sensorimotor components accounting for individual variability in Zahlen–Verbindungs-Test (ZVT) performance

The Zahlen–Verbindungs-Test (ZVT) represents a highly feasible measure of information-processing speed that correlates quite highly with standard psychometric tests of intelligence. The present study was designed to identify specific stages of the sensorimotor processing system that may account for individual differences in overall variability of ZVT performance. For this purpose, ZVT, reaction time (RT), lateralized readiness potential (LRP), and electromyogram (EMG) measures were obtained in 48 female participants. While faster RT, smaller intraindividual variability in RT, shorter response-locked LRP and EMG latencies were associated with superior ZVT performance, speed of stimulus analysis, as reflected by stimulus-locked LRP latency, was unrelated to ZVT performance. Additional commonality analyses suggested a functional relationship between ZVT performance and the time course of central aspects of response organization rather than the time required for execution of the overt motor response. These findings provide converging evidence for the general notion of an association between speed of motor processing and intelligence.     

An event-related potential analysis of extraversion and individual differences in cognitive processing speed and response execution

Individual differences in cognitive processing speed and response execution were examined in relation to extraversion. Event-related potentials (ERPs) were recorded concurrently with reaction time and movement time (MT) measures as participants (N = 67) performed simple reaction time and stimulus-response compatibility tasks. Slower processing speed for extraverts, as indicated by longer latency of a late positive ERP wave, P3, was only evident in conditions in which stimulus information was in conflict with response selection demands. As previously reported, the salient effect in all conditions of both tasks was faster MT for extraverts, an effect that is indicative of differences in fundamental motor processes. On the simple reaction time task, amplitudes of the N1 component, an early negative ERP wave, were smaller for extraverts than for introverts in response to auditory tones, an effect that affirms the enhanced sensory reactivity of introverts to punctate physical stimuli.     

Television distraction and the performance of introverts and extroverts

An experiment was run to test the effect on reading comprehension of distraction by a television programme, which was presented while reading took place. Respondents, classified in terms of extroversion or introversion, carried out two reading comprehension tests in silence and in the presence of a television drama programme. As predicted, extroverts and introverts both performed better in silence, but there was a significant interaction that showed that extroverts performed better than introverts in the presence of television distraction. The findings are discussed in relation to previous research on this subject.     

Personality correlates of assertive behavior

The present research studied the relationships between assertive behavior and two personality variables: extroversion and need for approval (nApp). Assertive behavior was measured in two role-play situations: an authority situation and an equal situation. It was found that extroverts behaved more assertively than introverts. nApp was negatively related to assertive behavior for females, while for males no correlation was found between nApp and assertive behavior in the authority situation and a positive correlation was found in the equal situation. It was concluded that extroversion and nApp are contributing factors in assertive behavior and that nApp moderates assertiveness differentially for males and females.     

心算对内外倾者的心率、T波幅度和呼吸频率的影响

该文旨在探讨内、外倾者在三种不同难度心算时,心率、Ｔ波幅度、呼吸频率变化的差异。通过艾森克个性问卷筛选出１５名内倾者和１５名外倾者作为被试,让其完成三种不同难度的心算任务。实验结果表明,心算时两组被试心率均显著上升,内倾组上升幅度大于外倾组;Ｔ波幅度显著降低,内倾组降低幅度大于外倾组但差异不显著;呼吸频率显著上升,但两组上升幅度差异不显著。此外,从心率变化上看,两组被试对心算均表现出适应,内倾组的适应速度比外倾组慢。本实验表明,焦虑性精神紧张比智力操作性精神紧张对心率的影响更大。     

外倾性和正性情绪关系的研究述评

人格特质与情绪关系的研究表明外倾性与正性情绪存在一定相关,主要表现为以下几方面：（1）外倾个体在日常生活中体验到更多的正性情绪;（2）外倾个体对正性刺激有更为强烈的愉悦体验和情绪反应;（3）外倾个体对正性刺激有注意等认知加工偏向;（4）外倾程度与皮层及皮层下某些组织的激活程度相关。随着认知神经科学的发展,ERP及fMRI技术逐步被引入到这方面的研究中,进而从脑机制等方面更加客观的揭示了外倾性与正性情绪的关系。通过整合近年来的研究成果,分析现阶段的研究疑点,从人格理论假设,人格测量方法和实验方法这个三个方面探悉了疑点存在的原因,并在此基础上展望未来发展趋势     

Psychological refractory period in introverts and extraverts

The present study was designed to explore extraversion-related differences in the psychological refractory period (PRP). PRP refers to a bottleneck of information processing that becomes evident when participants are required to respond to two signals (S1 and S2) presented in rapid succession. If this capacity limit of premotor information processing is essential for differences in speed of information processing between introverts and extraverts, magnitude of the PRP effect should vary as a function of extraversion. Due to the failure of previous attempts to establish extraversion-related differences in the PRP effect, we also obtained lateralized readiness potentials (LRPs). For this purpose, 63 introverted and 63 extraverted female participants were tested with a standard PRP design. Extraverts responded faster to S2 and exhibited shorter stimulus-locked LRP latencies compared to introverts. Although a general PRP effect could be shown at the behavioral and psychophysiological level, there was no indication for any extraversion-related differences in PRP. Thus, extraversion-related differences in speed of information processing at the premotor level appear unlikely to originate from individual differences in the capacity limits underlying the PRP phenomenon. Furthermore, our findings provide converging evidence for the notion that extraversion-related individual differences in processing speed depend on specific task demands.     

奖惩线索条件下内外倾个体的自主唤醒和行为反应

将停止信号任务和金钱激励延迟任务相结合,使用16导生理记录仪记录被试的生理指标,探讨内外倾者在动机凸显情景下的生理唤醒特点以及反应调节能力。结果发现,隐含奖励和惩罚线索呈现之后,内外倾者的心率增快,内倾者的皮肤电活动显著增强。在停止信号任务中的优势反应阶段,内外倾者表现为对奖励凸显线索刺激的反应时缩短;而在非优势反应阶段,和外倾者相比较,内倾者的抑制反应错误率增高。表明内外倾者在奖惩线索条件下表现出不同的生理唤醒特点和行为反应。     

Depth of facial expression processing depends on stimulus visibility: Behavioral and electrophysiological evidence of priming effects

Participants performed a priming task during which emotional faces served as prime stimuli and emotional words served as targets. Prime-target pairs were congruent or incongruent, and two levels of prime visibility were obtained by varying the duration of the masked primes. To probe a neural signature of the impact of the masked primes, lateralized readiness potentials (LRPs) were recorded over motor cortex. In the high-visibility condition, responses to word targets were faster when the prime-target pairs were congruent than when they were incongruent, providing evidence of priming effects. In line with the behavioral results, the electrophysiological data showed that high-visibility face primes resulted in LRP differences between congruent and incongruent trials, suggesting that prime stimuli initiated motor preparation. Contrary to the above pattern, no evidence for reaction time or LRP differences was observed in the low-visibility condition, revealing that the depth of facial expression processing is dependent on stimulus visibility.     

The temporal selectivity of additive factor effects on the reaction process revealed in ERP component latencies

An experiment was conducted to relate individual components of the event-related brain potential to specific stages of information processing in a two-choice reaction time (RT) task in a group of undergraduate students. Specifically, the latency of the P300 component and the lateralized readiness potential (LRP) were studied as a function of variations in stimulus degradation and response complexity. It was hypothesized that degrading the stimulus would delay the P300 and LRP to the same extent as RT, and that increasing response complexity would affect RT but not P300 latency. The extant literature did not permit any hypothesis regarding the effect of response complexity on LRP latency. The two task variables were found to have additive effects on RT. As predicted, variations in stimulus degradation influenced the latencies of both components, whereas alterations in response complexity had no effect on P300 latency. A significant new finding was that the onset latency of the LRP remained unchanged across levels of response complexity. The overall pattern of results supports the notion of temporal selectivity of stage manipulations that is derived from discrete stage models of human information processing. Furthermore, these results refine the functional interpretation of the LRP by indicating that within the conceptual framework of a stage model the processes this component indexes succeed the start of response choice but precede the start of motor programming.     

Infant temperament and the brainstem auditory evoked response in later childhood.

Brainstem auditory evoked responses (BAERs) were evaluated on 10-12-year-old children (N = 56) who had been classified as high or low reactive to unfamiliar stimuli at 4 months of age. BAER measurement was selected because high reactive infants tend to become inhibited or fearful young children, and adult introverts have a faster latency to wave V of the BAER than do extroverts. Children previously classified as high reactive at 4 months had larger wave V components than did low reactive children, a finding that possibly suggests greater excitability in projections to the inferior colliculus. The fact that a fundamental feature of brainstem activity differentiated preadolescent children belonging to two early temperamental groups supports the value of gathering physiological data in temperament research.     

Neuroticism, extroversion, and response to stress

The study evaluated the role of dispositional determinants in the mediation of response to stress. Thirty-five undergraduate females were assigned to one of four groups according to scores on the neuroticism and extroversion scales of the Eysenck Personality Inventory. The Induced Affect research paradigm was adapted as a stress analog procedure and, following a baseline phase, subjects were run in alternating relaxation and arousal phases. Both univariate and multivariate analyses were completed. Neurotic introverts tended to label IA generated arousal as fear whereas neurotic extroverts tended to label arousal as anger.     

Time pressure effects on information processing in overlapping tasks: evidence from the lateralized readiness potential

Information processing is impaired when two tasks are performed concurrently. The interference between the tasks is commonly attributed to structural bottlenecks or strategic scheduling of information processing. The present experiment investigated the effects of time pressure for the second of two responses on information processing in overlapping tasks by recording the lateralized readiness potential (LRP). Time pressure shortened the latency of the second response by diminishing the time devoted to motoric processing. In addition, task interference decreased under time pressure, which is probably due to the relatively early availability of the central bottleneck stage rather than to increased overlap of central stages. The LRP also provided direct evidence for an additional bottleneck following response selection, possibly due to supramodal refractoriness of response initiation.     

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.     

Bisecting RT with lateralized readiness potentials: Precue effects after LRP onset

Recent work has sought to use the time at which the Lateralized Readiness Potential (LRP) first develops (LRP onset) as a temporal landmark to bisect experimental effects on reaction time (RT). Many studies have found experimental effects on the time between the signal and LRP onset, but few have found effects on the time between LRP onset and RT (LRP-RT interval). The primary goal of this study was to produce an effect on the LRP-RT interval. We employed precuing, a manipulation likely to influence motor-programming processes at the end of the RT interval. Subjects performed a 4-alternative choice-RT task in which a signal prompted a button-press with the index or middle finger on the left or right hand. Precues preceded the signals and were either informative, reducing the set of response alternatives from four to two, or uninformative. Besides RT and LRP, we also measured electromyographic (EMG) activity and the P300 ERP component. RT, P300 latency, and the interval between the signal and LRP onset were all shorter with informative than uninformative precues, but the timing of EMG activity relative to RT remained the same. Most importantly, precuing affected the LRP-RT interval. Implications for bisecting RT with LRPs and the identity of processes affected by precuing are discussed.     

Brain-potential evidence for the time course of access to biographical facts and names of familiar persons

On seeing familiar persons, biographical (semantic) information is typically retrieved faster and more accurately than name information. Serial stage models explain this pattern by suggesting that access to the name follows the retrieval of semantic information. In contrast, interactive activation and competition (IAC) models hold that both processes start together but name retrieval is slower because of structural peculiarities. With a 2-choice go/no-go procedure based on a semantic and a name-related classification, the authors tested differential predictions of the 2 alternative models for reaction times (RTs) and lateralized readiness potentials (LRP). Both LRP (Experiment 1) and RT (Experiment 2) results are in line with IAC models of face identification and naming.     

The epistemic benefits of trait-consistent mood states: an analysis of extraversion and mood

One must consider both trait and state affect to predict individual differences in emotional processing. The present results document a novel trait-state interaction that is consistent with proposals concerning the epistemic functions of affect (A. R. Damasio, 1994). Four studies tested the effects of extraversion and mood on motivation-relevant processing. Study 1 measured naturally occurring mood, whereas Studies 2-4 manipulated mood. Extraverts were faster to link events to their personal motivations when in a positive mood state, whereas introverts were faster to do so in a neutral or negative mood state. Further findings indicate that this interaction affects attitude accessibility rather than event elaboration. Overall, the authors suggest that there are pragmatic benefits to trait-consistent moods, particularly for processing motivation-relevant stimuli.