A developmental-genetic analysis of aggressive behavior in mice: I. Behavioral outcomes

In order to investigate the proposal that modifications in developmental rate may mediate differences in aggressive behavior, two series of selective breeding studies were completed. Stable lines of mice that differed in the frequency and latency of attacks were rapidly established in two series (by S1 in the first series and S3 or S4 in the second series). For evaluation of the developmental-genetic proposal, an analysis was made of the ontogeny of aggressive expression in male mice of the two series, with a detailed report provided of the S1 and S4 generations of the second breeding series. Comparisons between the results of a longitudinal design and the results of a new type of cross-sectional design (involving only siblings, or co-sibial) indicated (a) a reliable developmental course of attack expression, with a sharp rise in early maturity and a slow decline thereafter; (b) a convergence in later maturity of the behavior of lines selectively bred for high or low aggressive behavior, if the animals had been assigned to the longitudinal design; (c) a strong effect of repeated testing on attack latency and frequency, even though the dyadic tests were brief in duration and separated by long intervals. In addition, cross-generational comparisons suggested that the selective breeding differences came about primarily by changes in the behavior of the low aggressive lines, in that these animals failed to show in early maturity the sharp increases in attack occurrence that were observed in earlier generations. Certain implications of these findings for developmental and evolutionary concepts (e.g., neoteny, acceleration, heterochrony) are discussed.     

Assessment of cognitive control in psychopathic and normal prisoners

It has been suggested that psychopaths exhibit specific deficits in cognitive processes associated with frontal lobe functioning. There is also evidence which indicates that level of intelligence may influence expression of impulse control among psychopaths. The present study investigated these hypotheses by comparing groups of 44 psychopaths and 14 normal controls selected from a sample of incarcerated male felons using Minnesota Multiphasic Personality Inventory (MMPI)-defined criteria. Dependent variables included several measures of cognitive flexibility, perseveration, and impulsiveness. Compared to normal controls, psychopaths showed no greater tendencies to persist in incorrect responding, disregard cues suggesting the need to modify behaviors, or proceed impulsively in problem solving. Level of intelligence was found to be a moderator variable influencing performance for psychopaths and normal controls. Results suggest that deficits in cognitive functioning are not necessarily characteristic of psychopaths across situations.     

The Pittsburgh Initial Neuropsychological Testing System (PINTS): A neuropsychological screening battery for psychiatric patients

This paper presents a new neuropsychological screening battery for psychiatric patients. It takes 1.5 to 2 hr to administer and briefly assesses general level of performance, memory, language skills, attention, and spatial-constructional abilities. Scoring and profiling are computerized. Initial validation based on discriminant analysis of a group of brain-damaged and non-brain-damaged psychiatric patients yielded a diagnostic accuracy level of 84.51%. Cross-validation on a different population led to a substantial attrition of classificatory accuracy, but cross-validation based on a comparison between two samples drawn from a homogeneous population yielded substantially less attrition. It was concluded that while the battery discriminates accurately in a homogeneous population, it is necessary to develop separate norms for populations varying in level of impairment.     

Behavior and personality assessment in men labeled adaptive sociopaths

Few efforts have been made to understand antisocial-prone individuals who maintain adaptive functioning. This study identified a sample of potentially deviant but adaptively functioning persons to determine whether they differed significantly from their more conforming peers. A small sample of men was selected by Minnesota Multiphasic Personality Inventory (MMPI)-defined criteria for sociopathy and compared with MMPI-defined normals of similar ages, backgrounds, and intelligence. Response variables were those cited in the literature as characteristic of sociopathic psychopathology and included measures of abilities to plan ahead and inhibit impulsiveness, sensation seeking, interpersonal performance and style, and behavior conformity. Men labeled adaptive sociopaths showed greater impulsiveness and needs for experience seeking, earned lower scores on measures of socialization and self-control, and admitted greater adolescent behavior deviance. They were not shown to be less empathetic or less able to relate interpersonally in interview. The potential role of socially constructive self-determined goals and tangible vocational rewards as mediators of adaptive behavior are discussed in terms of overcoming antisocial tendencies and attenuation of behavior disinhibition.     

Quest: A Bayesian adaptive psychometric method

An adaptive psychometric procedure that places each trial at the current most probable Bayesian estimate of threshold is described. The procedure takes advantage of the common finding that the human psychometric function is invariant in form when expressed as a function of log intensity. The procedure is simple, fast, and efficient, and may be easily implemented on any computer.     

Transfer of training of a new linguistic contrast in voicing

The present study examined the plasticity of the human perceptual system by means of laboratory training procedures designed to modify the perception of the voicing dimension in synthetic speech stimuli. Although the results of earlier laboratory training studies have been ambiguous, recently Pisoni, Aslin, Perey, and Hennessy (1982) have succeeded in altering the perception of labial stop consonants from a two-way contrast in voicing to a three-way contrast. The present study extended these initial results by demonstrating that experience gained from discrimination training on one place of articulation (e.g., labial) can be transferred to another place of articulation (e.g., alveolar) without any additional training on the specific test stimuli. Quantitative analyses of the identification functions showed that the new perceptual categories were stable and displayed well-defined labeling boundaries between categories. Taken together with the earlier findings, these results imply a greater degree of plasticity in the adult speech processing system than has generally been acknowledged in past studies.     

Expectation and autokinesis

The reported direction of autokinesis for naive observers is not biased by gaze deviations of 22.5 deg of arc. However, instructions to expect either “inward” or “outward” movement produce reports of autokinetic movement that are progressively biased in the expected direction. Instructions to expect “more” or “less” movement resulted in a decrease in the reported duration of apparent movement for the “less” group but no change for the “more” group. Response bias is not considered to play a role in these results. The results are discussed in terms of fixational bias and selective attention mechanisms of autokinesis.     

Scaling apparent distance in a large open field: some new data

Judged distance in a large open field, scaled by the method of magnitude estimation, is related to physical distance by a power function with an exponent smaller than unity. The exponents obtained with two ranges of distance were not affected by the availability of a standard. The mean exponent for all 80 individual power functions was 0.86, with a standard deviation of 0.11.     

Quantitative amino acid determination in the serum and cerebrospinal fluid in endogenous depressions

The levels of 20 amino acids were measured in the plasma and cerbrospinal fluid of 41 patients with endogenic depressions. The plasma levels of 12 amino acids were found to be significantly lower in the patients than in the control group, but cerebrospinal fluid levels were significantly lower only in the case of taurine, glutamine, phenylalanine and aginine. Comparison of the same amino acid levels in treated and non-treated patients showed that serine and alpha-aminobutyric acid serum concentrations were higher in the nontreated patients. The tyrosine and phenylalanine levels in the cerebrospinal fluid of the patients who had received medicamentous treatment were higher than in the other group.     

On the conflict between logic and belief in syllogistic reasoning

Three experiments are reported that investigate the weighting attached to logic and belief in syllogistic reasoning. Substantial belief biases were observed despite controls for possible conversions of the premises. Equally substantial effects of logic were observed despite controls for two possible response biases. A consistent interaction between belief and logic was also recorded; belief bias was more marked on invalid than on valid syllogisms. In all experiments, verbal protocols were recorded and analyzed. These protocols are interpreted in some cases as providing rationalizations for prejudiced decisions and, in other cases, as reflecting a genuine process of premise to conclusion reasoning. In the latter cases, belief bias was minimal but still present. Similarly, even subjects who focus primarily on the conclusion are influenced to an extent by the logic. Thus a conflict between logic and belief is observed throughout, but at several levels of extent.