The Future of Neuropsychology in Medical Specialties

Although neuropsychology continues to grow as a valued service in most medical specialties, because of its multiple uses with diverse populations, it is necessary to evaluate the specialty critically in order to ensure continued future success. This article reviews areas in which neuropsychology is most firmly established, potential growth areas, and likely obstacles to success in the future. Suggestions are provided for ways in which neuropsychology can be improved/adapted in clinical, business, research, and training areas. On sabattical at Bebek University, Instanbul, Turkey     

Abstraction Processes in Artificial Grammar Learning

Four experiments explored the extent to which abstract knowledge may underlie subjects' performance when asked to judge the grammaticality of letter strings generated from an artificial grammar. In Experiments 1 and 2 subjects studied grammatical strings instantiated with one set of letters and were then tested on grammatical and ungrammatical strings formed either from the same or a changedletter-set.Evenwith a change ofletter-set, subjects were found to be sensitive to a variety of violations of the grammar. In Experiments 3 and 4, the critical manipulation involved the way in which the training strings were studied: an incidental learning procedure was used for some subjects, and others engaged in an explicit code-breaking task to try to learn the rules of the grammar. When strings were generated from a biconditional (Experiment 4) but not from a standard finite-state grammar (Experiment 3), grammaticality judgements for test strings were independent of their surface similarity to specific studied strings. Overall, the results suggest that transfer in this simple memory task is mediated at least to some extent by abstract knowledge.     

Confirmatory factor analysis of The Aggression Questionnaire

A confirmatory factor analysis of the factor structure of The Aggression Questionnaire created by Buss and Perry (1992) [Journal of Personality and Social Psychology, 63, 452–459] was conducted to assess whether the scale's purported 4 factors emerged. The results generally supported the 4-factor model. However, the hostility factor may be improved if 2 items pertaining to suspicion are removed from the scale. These items had relatively low loadings on that factor and decreased the hostility scale's internal reliability.     

Me,us and them: Political identification and the third-person effect in the 1993 Australian federal election

Three days prior to the 1993 Australian federal election 54 Australian university students who identified with one of the two major political parties were surveyed regarding their perceptions of media campaign impact on self and others. Results provided evidence of a third-person effect (Davison, 1983) wherein respondents judged others us more influenced by the election campaign than themselves. Consistent with predictions derived from social identity theory and self-categorization theory (e.g. Turner, Hogg, Oakes, Reicher and Wetherell, 1987), political ingroup members were also judged as less injuenced by campaign content than political outgroup members. Respondents who identified strongly with their preferred party judged self and ingroup members as less influenced by campaign content than did other respondents, and showed more evidence of positive intergroup differentiation. At the same time, however, these respondents exaggerated self–ingroup differences, challenging the theoretical assumption that intergroup diferentiation is associated with ingroup assimilation. Judgements of media impact on self and other also depended on the direction of the campaign message. Respondents believed ‘voters in general’ were persuaded in line with the intent of campaign content, while outgroup members were seen to be persuaded by material favouring their own side but to be uninfluenced by counter-attitudinal content. Election propaganda, irrespective of direction, was seen to amplify existing party preferences in self and ingroup members. Hence the relative invulnerability of self to media impact was pronounced when respondents judged the impact of pro-outgroup messages. Results suggest that perceptions of self–other differences in media vulnerability are influenced by the subjectively salient social relationship between self and other, and are governed by motivational needs, such as self-esteem, social-identity, and differentiation from others (cf. Brewer, 1991; Hogs and Abrams, 1993).     

A possible genetic basis of accuracy in personality perception

An analysis was conducted to assess whether individuals are more accurate in perceiving those personality characteristics of other' that have a larger genetic component. Adult monozygotic (MZ) twins (63 pairs) and same-sex dizygotic (DZ) twins (35 pairs) completed the Personality Research Form-E (PRF) and the Sibling Evaluation of Personality Characteristics (SEPC) which consists of 20 sets of adjectives corresponding to the 20 trait scales of the PRF. Subjects also evaluated their co-twin with the SEPC. Self-other agreement correlations were then correlated with the heritability estimates of the PRF traits calculated on the same twin sample. The results suggest that accuracy in perceiving the co-twin's personality does increase with the heritability component of the personality dimension.     

Neurobehavioral deficits,adolescent traumatic brain injury,and transition to college

Outcome following traumatic brain injury (TBI) has been frequently evaluated for adults, although there has been minimal research on adolescents with TBI. It has been argued that TBI sequelae may be more difficult for adolescents to adjust to given developmental changes in physical (puberty), interpersonal (self-concept), and environmental domains (transition to college). In addition, it is commonly acknowledged that moderator variables such as psychiatric history, family functioning, substance use, and sexuality impact functional outcome following TBI, although it is often difficult to objectively evaluate these variables. The current study examined relationships among TBI-related deficits, moderator variables, and academic outcomes for six adolescents transitioning to college. The findings suggest that it may not be appropriate to predict functional outcome based solely on objective neuropsychological results. However, moderator variables appear to have a more direct relationship with outcome, depending on the moderator variable and the individual.     

Human Signal-detection Performance: Effects Of Signal Presentation Probabilities And Reinforcer Distributions

University students participated in one of four standard two-choice signal-detection experiments in which signal presentation probability was varied and the reinforcement distribution was held constant and equal. In Experiments 1, 3 and 4, subjects' performance showed a systematic response bias for reporting the stimulus presented least often. Experiments 1 and 4 showed that this effect was reliable with extended training and monetary, rather than point, reinforcement. In Experiment 2, all correct responses were signaled in some way, and this produced the opposite relationship between signal presentation probability and response bias. Experiments 1 and 3 found that explicitly deducting money (intended as punishment) for equal numbers of incorrect responses on each alternative, or varying the obtained overall rate of reinforcement, produced no clear change in response bias. The bias, shown by humans, for reporting the stimulus presented least often remains a challenge for theories of stimulus detection.     

Is Speech Arrest during Wada Testing a Valid Method for Determining Hemispheric Representation of Language?

Background and objective: The intracarotid amobarbital procedure, or Wada test, is the method of choice to determine hemispheric representation of language, and is routinely used in the presurgical evaluation for intractable epilepsy. Some investigators perform comprehensive language assessments, but others base language lateralization solely on speech arrest. This study sought to determine whether speech arrest alone during Wada testing provides valid data regarding language lateralization. Methods: The subjects (previously reported) were 21 patients evaluated for intractable epilepsy, who underwent language lateralization by Wada testing and functional MRI (FMRI). For each patient, language representation was determined by calculating: (1) a Wada laterality index based exclusively on speech arrest; (2) a Wada laterality index based on comprehensive language assessment; and (3) an FMRI laterality quotient. Correlation coefficients and categorical classifications were analyzed. Results: There was no significant correlation between the Wada laterality quotient derived from duration of speech arrest and either the comprehensive Wada language laterality score (r= .35,p= .12) or FMRI language laterality score (r= .32,p= .16). Categorical classification as left, right or bilateral language also showed marked discordance between speech arrest and the other two methods. Conclusion: Duration of speech arrest during Wada testing is not a valid measure of language dominance.     

Social-Cognitive and Behavioral Correlates of Aggression and Victimization in Boys' Play Groups

A contrived play group procedure was utilized to examine the behavioral and social-cognitive correlates of reactive aggression, proactive aggression, and victimization via peers. Eleven play groups, each of which consisted of six familiar African-American 8-year-old boys, met for 45-min sessions on five consecutive days. Social-cognitive interviews were conducted following the second and fourth sessions. Play group interactions were videotaped and examined by trained observers. High rates of proactive aggression were associated with positive outcome expectancies for aggression/assertion, frequent displays of assertive social behavior, and low rates of submissive behavior. Reactive aggression was associated with hostile attributional tendencies and frequent victimization by peers. Victimization was associated with submissive behavior, hostile attributional bias, reactive aggression, and negative outcome expectations for aggression/assertion. These results demonstrate that there is a theoretically coherent and empirically distinct set of correlates associated with each of the examined aggression subtypes, and with victimization by peers.