Kirby Gilliland

The personality theories of H.J. Eysenck and J.A. Gray: a comparative review

Abstract Hans J. Eysenck and Jeffrey A. Gray have proposed influential theories of the biological bases of personality traits. Eysencks theory concerns the extraversion, neuroticism and psychoticism traits, whereas Gray proposes the use of new, rotated axes of impulsivity and anxiety. Eysenck uses multiple arousal systems as the central explanatory constructs, whereas Gray describes more specific systems related to behavioural inhibition and activation. This article reviews the evidence relating to these theories provided by studies of c.n.s. and a.n.s. psychophysiology, subjective affect, conditioning and attention and performance. It discusses key predictive successes and failures and methodological problems which may impede theory-testing. It is concluded that there is a solid core of predictive support for the Eysenck theory in some paradigms, such as the moderator effect of stimulation level on individual differences in phasic electrodermal response and eyelid conditioning. In other settings, the theory fails to explain empirical data adequately, especially in studies of subjective response and attention and performance. Grays theory has advanced research through stimulating interest in moderation of personality effects by motivational variables. It also provides a better explanation than Eysencks theory for certain data, such as instrumental conditioning to reward stimuli and the positive affectivity of extraverts. Overall, however, Grays theory explains a narrower range of findings than Eysencks. There is little evidence that Grays revised personality axes are generally more predictive of psychophysiological and performance criteria than Eysencks original dimensions. Finally, it is suggested that the assumptions of the biological approach to personality are in need of reassessment. It is possible that the biological theories may be improved through developments in methodology or through discriminating multiple systems underpinning traits. For example, extraversion may have distinct “reticulo–cortical” and “dopaminergic” aspects. Alternatively, the biological approach may not in fact be adequate for explaining behavioural correlates of traits. In this case, trait research should place more emphasis on cognitive or social bases for personality.

Tactile stimulation of the human head for information display

A series of three studies was conducted to explore the use of tactile stimulation or light tapping of the human head to inform a pilot of possible threats or other situations in the flight environment. Study I confirmed that subjects could achieve 100% detection of the tactile stimuli. Localization performance, measured in Study 2, depended on the number of different stimulus sites and ranged from 93% accuracy for 6 sites to 47% accuracy for 12 sites across the parietal meridian of the head. In Study 3 we investigated the effect of performing the localization task simultaneously with a dual memory/tracking task or an air combat simulation task. These studies demonstrated that tactile information display could be an integral contributor to improved situation awareness, but not without cost to other task performance. The results of Study 3 were also examined with reference to popular models of attention and workload.

The interactive effect of introversion-extraversion with caffeine induced arousal on verbal performance

Abstract In a test of the arousal hypothesis of introversion-extraversion, subjects were pre- and post-tested on practice Graduate Record Examination verbal performance items while administered caffeine at either 0, 2, or 4 mg/kg of body weight. Introverts increased dramatically in performance between the 0 and 2 mg/kg conditions and then decreased even more dramatically between the 2 and 4 mg/kg conditions. Extraverts showed decrements in performance at the 0 mg/kg level, improved slightly at the 2 mg/kg level, and showed marked improvement at the 4 mg/kg level. Further analyses revealed that introverts increased in both speed and accuracy at low levels of stimulation but then decreased in both at higher levels of stimulation. Extraverts showed continued increases in speed and accuracy across the increasing arousal levels.

Automated neuropsychological assessment metrics (v4) traumatic brain injury battery: military normative data

The aim of the present study was to establish normative data for the Automated Neuropsychological Assessment Metrics (v4) Traumatic Brain Injury (ANAM4 TBI) battery in a military context. ANAM4 data from over 107,500 active duty service members ranging from 17 to 65 years of age were included in this study. The influence of the demographic variables of age and gender were also examined. These norms, stratified by age and gender, represent a more comprehensive set of norms than previously available and are provided as a representative set of norms for clinical practice. Additionally, base rates of below average performance in a normal population are provided to help inform clinical decision making.

Evidence for Added Value of Baseline Testing in Computer-Based Cognitive Assessment

CONTEXT Large-scale baseline cognitive assessment for individuals at risk for concussion is a common part of the protocol for concussion-surveillance programs, particularly in sports. Baseline cognitive testing is also being conducted in US military service members before deployment. Recently, the incremental validity of large-scale baseline cognitive assessment has been questioned. OBJECTIVE To examine the added value of baseline cognitive testing in computer-based neuropsychological assessment by comparing 2 methods of classifying atypical performance in a presumed healthy sample. DESIGN Cross-sectional study. SETTING Military base. PATIENTS OR OTHER PARTICIPANTS Military service members who took the Automated Neuropsychological Assessment Matrix (ANAM) before and after deployment (n = 8002). MAIN OUTCOME MEASURE(S) Rates of atypical performance in this healthy, active-duty sample were determined first by comparing postdeployment scores with a military normative database and then with each individuals personal baseline performance using a reliable change index. RESULTS Overall rates of atypical performance were comparable across these 2 methods. However, these methods were highly discordant in terms of which individuals were classified as atypical. When norm-referenced methods were used, 2.6% of individuals classified as normal actually demonstrated declines from baseline. Further, 65.7% of individuals classified as atypical using norm-referenced scores showed no change from baseline (ie, potential false-positive findings). CONCLUSIONS Knowing an individuals baseline performance is important for minimizing potential false-positive errors and reducing the risks and stresses of misdiagnosis.

Effects of Military Deployment on Cognitive Functioning

Military deployment poses many risks for cognitive functioning. When deployed individuals are compared to a nondeployed control group, there is some evidence that deployment may be associated with declines in cognitive functioning. The current study examined cognitive performance before and following deployment in a large sample of active duty military personnel (N = 8002) who reported no traumatic brain injury (TBI). Cognition was assessed using the Automated Neuropsychological Assessment Metrics version 4 TBI Military (ANAM4 TBI-MIL) battery, a computer-based battery of tests measuring attention, processing speed, and general cognitive efficiency. Pre- and postdeployment scores were compared using repeated measures analyses. Although statistically significant differences were observed for all tests (with 5 of 7 tests demonstrating performance improvement), effect sizes were very small for all but 1 test, indicating that performance differences had minimal clinical significance. Likewise, determination of change for individuals using reliable change indices revealed that a very small percentage (<3%) of this presumed healthy sample showed meaningful decline in cognition following deployment. Analyses indicated that despite risks for cognitive decline while in theater, deployment had minimal to no lasting effect on cognition as measured by ANAM4 TBI-Mil upon return from deployment.

Personality, biology and cognitive science: a reply to Corr (2001)

Abstract Corr’s (2000) commentary on the Matthews and Gilliland (1999) review article provides a useful account of the current status of Gray’s personality theory, and the prospects for theory development. In this reply, we find some common ground with Corr (2000) . We agree that it is important to articulate and test biological models of personality. Likewise, the moderator effects of reinforcement factors, which may be controlled by brain motivation systems, are an important focus for empirical study. We differ from Corr (2000) , at least in emphasis, in two respects. First, Gray’s Reinforcement Sensitivity Theory does not seem to have accommodated the multiplicity of brain systems which may relate to personality, including attentional systems which may modulate motivation. Second, the evidence from studies of personality and performance, suggests that cognitive models of trait action are often more successful in explaining behavioral data than theories of Gray and Eysenck. Cognitive and biological approaches may be integrated within a cognitive science framework which distinguishes multiple, complementary levels of explanation.

Initial Clinical Validation of an Embedded Performance Validity Measure within the Automated Neuropsychological Metrics (ANAM)

The measurement of effort and performance validity is essential for computerized testing where less direct supervision is needed. The clinical validation of an Automated Neuropsychological Metrics-Performance Validity Index (ANAM-PVI) was examined by converting ANAM test scores into a common metric based on their relative infrequency in an outpatient clinic sample with presumed good effort. Optimal ANAM-PVI cut-points were determined using receiver operator characteristic (ROC) curve analyses and an a priori specificity of 90%. Sensitivity/specificity was examined in available validation samples (controls, simulators, and neurorehabilitation patients). ANAM-PVI scores differed between groups with simulators scoring the highest. ROC curve analysis indicated excellent discriminability of ANAM-PVI scores ≥5 to detect simulators versus controls (area under the curve = 0.858; odds ratio for detecting suboptimal performance = 15.6), but resulted in a 27% false-positive rate in the clinical sample. When specificity in the clinical sample was set at 90%, sensitivity decreased (68%), but was consistent with other embedded effort measures. Results support the ANAM-PVI as an embedded effort measure and demonstrate the value of sample-specific cut-points in groups with cognitive impairment. Examination of different cut-points indicates that clinicians should choose sample-specific cut-points based on sensitivity and specificity rates that are most appropriate for their patient population with higher cut-points for those expected to have severe cognitive impairment (e.g., dementia or severe acquired brain injury).

Traditional neuropsychological correlates and reliability of the Automated Neuropsychological Assessment Metrics-4 battery for Parkinson’s disease

BACKGROUND The automated neuropsychological assessment metrics battery-4 for PD offers the promise of a computerized approach to cognitive assessment. METHODS To assess its utility, the ANAM4-PD was administered to 72 PD patients and 24 controls along with a traditional battery. Reliability was assessed by retesting 26 patients. RESULTS The cognitive efficiency score (CES; a global score) exhibited high reliability (r = 0.86). Constituent variables exhibited lower reliability. The CES correlated strongly with the traditional battery global score, but displayed weaker relationships to UPDRS scores than the traditional score. Multivariate analysis of variance revealed a significant difference between the patient and control groups in ANAM4-PD performance, with three ANAM4-PD tests, math, tower, and pursuit tracking, displaying sizeable differences. In discriminant analyses these variables were as effective as the total ANAM4-PD in classifying cases designated as impaired based on traditional variables. Principal components analyses uncovered fewer factors in the ANAM4-PD relative to the traditional battery. ANAM4-PD variables correlated at higher levels with traditional motor and processing speed variables than with untimed executive, intellectual or memory variables. CONCLUSIONS The ANAM4-PD displays high global reliability, but variable subtest reliability. The battery assesses a narrower range of cognitive functions than traditional tests, and discriminates between patients and controls less effectively. Three ANAM4-PD tests, pursuit tracking, math, and tower performed as well as the total ANAM4-PD in classifying patients as cognitively impaired. These findings could guide the refinement of the ANAM4-PD as an efficient method of screening for mild to moderate cognitive deficits in PD patients.

Development of the Criterion Task Set Performance Data Base

The initial phase of a large-scale experimental study was conducted involving the training and testing of fifty human subjects on the Criterion Task Set (Version 1.0). Testing was performed under baseline conditions and the stressors of noise and sleep loss. The resulting data base includes CTS performance data and subjective ratings obtained using the Subjective Workload Assessment Technique (SWAT) for each task, along with information on subject individual differences. This paper presents the methodology used for the data collection and analysis efforts and provides a summary of the performance and subjective assessment information. In general, no performance differences were found under the noise stress condition. Following sleep loss, response times for the central processing tasks deteriorated as did performance on the Unstable Tracking and Interval Production tasks.