Development of the visual placing response in the human infant

The development of the visual placing response was studied in the human infant using an apparatus that controlled the visual stimulus (texture density of patterns) and the depth at which stimuli were presented. The visual placing response was found to be nearly an all-or-none response having an acute onset at between 170 and 190 days of age. The response is identified in the human infant by rigid extension of the hands and arms, characteristically with the fingers fanned. Shortly after it develops, the response appears to be visually mediated and is well differentiated with respect to increasing depth. In contrast, the older infants showed less well differentiated visual placing, tending to respond to all depths equally. The results suggest that there are two phases in the development of the response. The first phase is the initial acquisition of the response and is determined largely by visual depth. The second phase occurs later in development, near the time of walking, and seems to be determined by several factors, including both texture density and depth.     

The lickometer: A simple device for the analysis of licking as an operant

A lickometer for recording dry (unreinforced) tube licking in rats is described. As opposed to the conventional drinkometer, where each lick produces fluid, the lickometer provides the possibility for automatically programmed intermittent reinforcement of (dry) licking, and it does not involve electrical connections through the chamber floor. Comparison of licking and leverpressing with equivalent reinforcers and under equivalent schedules of reinforcement is thus feasible.     

Incremental validity of the Psychopathy Checklist facet scores: predicting release outcome in six samples

The incremental validity of the 4 facet scores (Interpersonal, Affective, Lifestyle, Antisocial) of the Psychopathy Checklist-Revised (PCL-R; R. D. Hare, 1991, 2003) and the Psychopathy Checklist: Screening Version (PCL:SV; S. D. Hart, D. N. Cox, & R. D. Hare, 1995) was evaluated in 6 forensic/correctional samples with average follow-ups ranging from 20 weeks to 10 years. Results indicated that whereas Facet 4 (Antisocial) achieved incremental validity relative to the first 3 facets (Interpersonal, Affective, and Lifestyle) in predicting recidivism in all 6 samples, a block of the first 3 facets achieved incremental validity relative to the 4th facet in only 1 sample. Thus, although there was consistent support for the incremental validity of Facet 4 above and beyond the first 3 facets, there was minimal support for the incremental validity of Facets 1, 2, and 3 above and beyond Facet 4. The implications of these findings for the psychopathy construct in general and the PCL-R/SV in particular are discussed.     

The latent structure of psychopathy: a taxometric investigation of the Psychopathy Checklist Revised in a heterogeneous sample of male prison inmates

A taxometric analysis of the Psychopathy Checklist-Revised (PCL-R) is conducted on a group of 409 male maximum-, medium-, and minimum-security federal prison inmates using the four PCL-R facet scores (interpersonal, affective, impulsive lifestyle, and antisocial behavior) as indicators. Results obtained from three quasi-independent taxometric procedures-mean above minus below a cut, maximum eigenvalue, and latent mode factor analysis-reveal consistent support for a dimensional interpretation of the psychopathy concept in a moderately heterogeneous sample of participants. On the basis of these results, it is concluded that psychopathy falls along a continuum and that high and low scores on the PCL-R reflect quantitative differences in degree rather than qualitative differences in kind.     

Response style versus crime-specific cognition: predicting disciplinary adjustment and recidivism in male and female offenders with the PICTS

Four samples were used to evaluate the incremental validity of the Psychological Inventory of Criminal Thinking Styles (PICTS) General Criminal Thinking (GCT) score and Proactive (P) and Reactive (R) composite scales vis-á-vis response style in predicting disciplinary adjustment and recidivism. Purified Confusion (Cf(p)) and Defensiveness (Df(p)) validity scales were constructed by eliminating items from the PICTS Confusion and Defensiveness scales that overlapped with GCT, P, and R. The four-item Cf(p) and Df(p) scales were employed as measures of response style and entered into binomial probit regression analyses alongside GCT, P, and R. The GCT score consistently predicted disciplinary adjustment and recidivism in male and female offenders when included in regression equations with Cf(p) and Df(p). The P scale only displayed incremental validity relative to Cf(p) and Df(p) in large groups of participants, whereas the R scale was incapable of predicting recidivism in female offenders when paired with Cf(p) and Df(p).