Validity and structure of a self-report measure of youth psychopathy

An interest in early identification of youth who may be at risk of psychopathy has generated measures for age-appropriate screening and assessment. This study examines the structural, concurrent, and divergent validity of the Psychopathy Content Scale, a 20-item self-report instrument derived from the Millon Adolescent Clinical Inventory (MACI). Data for 481 youths who had taken the MACI, the Child Behavior Checklist Youth Self-Report (YSR), and the Massachusetts Youth Screening Instrument, Second Version (MAYSI-2), were analyzed. Results showed that the PCS is best described by a two-factor model and that analyses of the two factors offer limited support for convergent and divergent validity. High scores on both factors were associated with high YSR and MAYSI-2 scales, suggesting that the measure identified youth who were distressed on several measures of emotional, psychological, and behavioral disorder.     

Common processes may contribute to extinction and habituation

Psychologists routinely attribute the characteristics of conditioned behavior to complicated cognitive processes. For example, many of the characteristics of behavior undergoing extinction have been attributed to retrieval from memory. The authors argue that these characteristics may result from the simpler process of habituation. In particular, conditioned responding may decrease during extinction partially because habituation occurs to the stimuli that control responding when those stimuli are presented repeatedly or for a prolonged time (e.g., the experimental context, the conditioned stimulus in classical conditioning). This idea is parsimonious, has face validity, and evokes only processes that are well established by other evidence. In addition, behavior undergoing extinction shows 12 of the fundamental properties of behavior undergoing habituation. However, this model probably cannot provide a complete theory of extinction. It provides no obvious explanation for some of the other characteristics of extinguished behavior.     

Walking,looking to the side,and taking curved paths

In two experiments, viewers judged heading from displays simulating locomotion through tree-filled environments, with gaze off to the side. They marked their heading with a mouse-controlled probe at three different depths. When simulated eye or head rotation generally exceeded 0.5 deg/sec, there was reliable curvature in perceived paths toward the fixated object. This curvature, however, was slight even with rotation rates as great as 2.6 deg/sec. Best-fit paths to circular arcs had radii of 1.8 km or greater. In a third experiment, pedestrians walked with matched gaze to the side. Measured curvature in the direction of gaze corresponded to a circular radius of about 1.3 km. Thus, at minimum, vision scientists need not worry about perceived path curvature in this situation; real path curvatures are about the same. However, at present, we can make no claim that the same mechanisms necessarily govern the two results.     

Reading aloud begins when the computation of phonology is complete

Naming latency experiments in which monosyllabic items are read aloud are based on the assumption that the vocal response is not initiated until the phonology of the entire syllable has been computed. Recently, this assumption has been challenged by A. H. Kawamoto, C. T. Kello, R. Jones, and K. Bame (1998), who argued instead that the reading-aloud response begins as soon as the initial phoneme is computed. This view would be refuted by evidence of anticipatory coarticulation effects on the initial phoneme due to the nature of the following vowel in the speeded reading-aloud task. The authors provide such evidence.     

Seeking one’s heading through eye movements

A study of eye movements during simulated travel toward a grove of four stationary trees revealed that observers looked most at pairs of trees that converged or decelerated apart. Such pairs specify that one’s direction of travel, calledheading, is to the outside of the near member of the pair. Observers looked at these trees more than those that accelerated apart; such pairs do not offer trustworthy heading information. Observers also looked at gaps between trees less often when they converged or diverged apart, and heading can never be between such pairs. Heading responses were in accord with eye movements. In general, if observers responded accurately, they had looked at trees that converged or decelerated apart; if they were inaccurate, they had not. Results support the notion that observers seek out their heading through eye movements, saccading to and fixating on the most informative locations in the field of view.     

A test of object permanence in a new-world monkey species,cotton top tamarins (<Emphasis Type="Italic">Saguinus oedipus</Emphasis>)

Cotton top tamarins were tested in visible and invisible displacement tasks in a method similar to that used elsewhere to test squirrel monkeys and orangutans. All subjects performed at levels significantly above chance on visible (n=8) and invisible (n=7) displacements, wherein the tasks included tests of the perseverance error, tests of memory in double and triple displacements, and "catch" trials that tested for the use of the experimenter's hand as a cue for the correct cup. Performance on all nine tasks was significantly higher than chance level selection of cups, and tasks using visible displacements generated more accurate performance than tasks using invisible displacements. Performance was not accounted for by a practice effect based on exposure to successive tasks. Results suggest that tamarins possess stage 6 object permanence capabilities, and that in a situation involving brief exposure to tasks and foraging opportunities, tracking objects' movements and responding more flexibly are abilities expressed readily by the tamarins. Electronic Publication     

Human navigation in nested environments

Navigation in humans and many other animals relies on spatial representations of their environments. Three experiments examined how humans maintain sense of orientation between nested environments. Subjects can acquire new spatial representations easily without integrating them into their existing spatial knowledge system. While navigating between nested environments, subjects seemed to constantly switch between the currently processed environment by reorienting to approaching environments and losing track of old environments at given spatial regions. These results suggest that spatial updating in naturalistic, nested environments does not occur for all environments at the same time. Implications for the hierarchical theory of spatial representations and the path integration theory of navigation are discussed.     

Within-session rates of responding when reinforcer magnitude is changed within the session

In the present experiment, the authors investigated the idea that within-session changes in operant response rates occur because subjects sensitize and then habituate to the reinforcer. If that is true, then altering an aspect of the reinforcer within the session should alter the observed within-session responding. The authors tested that idea by having rats press a lever for 2 food-pellet reinforcers delivered by a variable-interval 120-s schedule during 60-min baseline sessions. In treatment conditions, the magnitude of the reinforcer was halved (1 pellet) or doubled (4 pellets) 10, 20, 30, 40, or 50 min into the session. That magnitude of reinforcement then remained in effect for the rest of the session. Altering reinforcer magnitude altered the rates of responding within the session in a fashion consistent with the habituation explanation, that is, response rates increased, relative to baseline, when the magnitude of reinforcement was increased. They decreased when the magnitude was decreased. Those results were seemingly inconsistent with the competing idea that within-session decreases in responding rates are produced by satiation.     

Metatraits and assessment of attributional style

Some personality trait dimensions may not be equally applicable to all people. The degree of applicability of a given trait, or traitedness, is conceptually distinct from trait level. In this study, 3 ways of assessing traitedness--interitem variance (R. F. Baumeister & D. M. Tice, 1988), scalability (K. Lanning, 1988), and construct similarity (W. F. Chaplin, 1991)--were applied to attributional style. A nonclinical sample (N = 123) completed measures of attributional style and depressive symptoms. In a series of multiple regression analyses, none of the traitedness indicators significantly moderated the relation of attributional style with depressive symptoms. The authors discuss several methodological and conceptual explanations for these null results.