Factor structure of the Hare Psychopathy Checklist: Youth Version (PCL: YV) in incarcerated adolescents

Two studies are reported on the underlying dimensions of the psychopathy construct in adolescents as measured by the Hare Psychopathy Checklist-Youth Version (PCL: YV; Forth, Kosson, & Hare, 2003). In Study 1, the PCL: YV item ratings for 505 male adolescents incarcerated in 5 different settings in North America were used to test the fit of 3 models that have been hypothesized to represent the structure of psychopathy in adults. A 4th model based on parceling PCL: YV items was also tested. In Study 2, these models were tested with a sample of 233 male adolescents incarcerated in 2 facilities in the United Kingdom. Model fit results indicated that the 18-item 4-factor model developed by Hare (2003) and a modified version of a 13-item 3-factor model developed by Cooke and Michie (2001) were associated with generally good fit. Because the 4-factor model is a less saturated model than the 3-factor model (better parameter to data point ratio), it survived a riskier test of disconfirmation. Implications for the nature of psychopathy in youth are discussed.     

Forgetting of prior remembering in persons reporting recovered memories of childhood sexual abuse

Case studies of individuals reporting recovered memories of childhood sexual abuse suggest that some overestimate their prior forgetting of the abuse. People reporting recovered or continuous memories of childhood sexual abuse and control subjects reporting no history of abuse participated in two experiments examining this "forgot it all along" phenomenon. Participants in Experiment 1 were more likely to forget that they had previously recalled a studied item if they were cued to think of it differently on two recall tests than if they were cued to think of it in the same way on the two tests. This effect was stronger for recovered-memory participants than for continuous-memory and control participants. In Experiment 2, participants recalled autobiographical events three times over a period of 4 months. Much as in Experiment 1, they underestimated prior remembering when the events had been recalled in a different emotional frame (positive vs. negative) on the previous occasion. This underestimation was more pronounced for recovered-memory participants than for continuous-memory and control participants.     

The effects of lead stimulus and reflex stimulus modality on modulation of the blink reflex at very short, short, and long lead intervals

The blink reflex is modulated if a weak lead stimulus precedes the blink-eliciting stimulus. In two experiments, we examined the effects of the sensory modality of the lead and blink-eliciting stimuli on blink modulation. Acoustic, visual, or tactile lead stimuli were followed by an acoustic (Experiment 1) or an electrotactile (Experiment 2) blink-eliciting stimulus at lead intervals of -30, 0, 30, 60, 120, 240, 360, and 4,500 msec. The inhibition of blink magnitude at the short (60- to 360-msec) lead intervals and the facilitation of blink magnitude at the long (4,500-msec) lead interval observed for each lead stimulus modality was relatively unaffected by the blink-eliciting stimulus modality. The facilitation of blink magnitude at the very short (-30- to 30-msec) lead intervals was dependent on the combination of the lead and the blink-eliciting stimulus modalities. Modality specific and nonspecific processes operate at different levels of perceptual processing.     

Overwriting of phonemic features in serial recall

We tested two explanations of the phonological similarity effect in verbal short-term memory: The confusion hypothesis assumes that serial positions of similar items are confused. The overwriting hypothesis states that similar items share feature representations, which are overwritten. Participants memorised a phonologically dissimilar list of CVC-trigrams (Experiment 1) or words (Experiment 2 and 3) for serial recall. In the retention interval they read aloud other items. The material of the distractor task jointly overlapped one item of the memory list. The recall of this item was impaired, and the effect was not based on intrusions from the distractor task alone. The results provide evidence for feature overwriting as one potential mechanism contributing to the phonological similarity effect.     

Deficits of anticipatory grip force control after damage to peripheral and central sensorimotor systems

Healthy subjects adjust their grip force economically to the weight of a hand-held object. In addition, inertial loads, which arise from arm movements with the grasped object, are anticipated by parallel grip force modulations. Internal forward models have been proposed to predict the consequences of voluntary movements. Anesthesia of the fingers impairs grip force economy but the feedforward character of the grip force/load coupling is preserved. To further analyze the role of sensory input for internal forward models and to characterize the consequences of central nervous system damage for anticipatory grip force control, we measured grip force behavior in neurological patients. We tested a group of stroke patients with varying degrees of impaired fine motor control and sensory loss, a single patient with complete and permanent differentation from all tactile and proprioceptive input, and a group of patients with amyotrophic lateral sclerosis (ALS) that exclusively impairs the motor system without affecting sensory modalities. Increased grip forces were a common finding in all patients. Sensory deficits were a strong but not the only predictor of impaired grip force economy. The feedforward mode of grip force control was typically preserved in the stroke patients despite their central sensory deficits, but was severely disturbed in the patient with peripheral sensory deafferentation and in a minority of stroke patients. Moderate deficits of feedforward control were also obvious in ALS patients. Thus, the function of the internal forward model and the precision of grip force production may depend on a complex anatomical and functional network of sensory and motor structures and their interaction in time and space.     

Contextualist Approaches to Epistemology: Problems and Prospects

In this paper we survey some main arguments for and against epistemological contextualism. We distinguish and discuss various kinds of contextualism, such as attributer contextualism (the most influential version of which is semantic, conversational, or radical contextualism); indexicalism; proto-contextualism; Wittgensteinian contextualism; subject, inferential, or issue contextualism; epistemic contextualism; and virtue contextualism. Starting with a sketch of Dretskes Relevant Alternatives Theory and Nozicks Tracking Account of Knowledge, we reconstruct the history of various forms of contextualism and the ways contextualists try to handle some notorious epistemological quandaries, especially skepticism and the lottery paradox. Then we outline the most important problems that contextualist theories face, and give overviews of their criticisms and defenses as developed in this issue.     

Effects of slow-release caffeine and a nap on driving simulator performance after partial sleep deprivation

A driving simulator was used to evaluate the effectiveness of a 30-min. nap and 300-mg slow-release caffeine as countermeasures to drivers' sleepiness induced by partial sleep deprivation. 12 participants were allowed 45 hr. time in bed at the laboratory. Driving performance then was measured twice--at 9 a.m. and at 1 p.m.--by a 45-min. driving task on a simulator. Subjective sleepiness/alertness and mood were assessed four times on the Stanford Sleepiness Scale and the Profile of Mood States. Driving performance was assessed as Lane Drifting, Speed Deviation, and Accident Liability. A 30-min. nap opportunity and 300 mg of slow-release caffeine both were successful in counteracting drivers' sleepiness. The remedial effect of slow-release caffeine lasted longer than that of the nap, that is, it was also effective in the afternoon session. This suggests that slow-release caffeine represents a valuable countermeasure that, in the case of partial sleep deprivation, is preferred to a nap when sleepiness has to be counteracted for a longer time.     

Coherence Theory of Knowledge: a Gradational Account

A satisfactory theory of knowledge in which the shortcomings of a pure externalist account are avoided and in which the Gettier problem is solved should consist in a combination of externalist and internalist components. The internalist component should guarantee that the epistemic subject has cognitive access to the justifying grounds of her belief. And the externalist component should guarantee that the justification of her belief does not depend on any false statement. Keith Lehrer's coherence theory of knowledge as undefeated justification is an example of such an internalist-externalist analysis of knowledge. But nevertheless, Lehrer's account leads to unintended results. Therefore, it is argued that a satisfactory coherence theory of knowledge must also be based on a gradual notion of systematic coherence.     

A CLASSIFICATION SCHEME OF SOCIAL CONDITIONS OF REINFORCEMENT WITHIN GROUP OPERANT SYSTEMS1

Many different reinforcement contingencies are found in group operant systems, such as token economies and point systems. Some systems use group contingencies in which the reinforcement of any one participant may depend on the behavior of some other group member. Other programs are individual, in that participants earn reinforcers dependent only on their own behavior. The various possible arrangements of people and their response requirements are labelled “social conditions of reinforcement” in this paper. Previous attempts at classification have failed to categorize the variety of social conditions of reinforcement. In addition, some conditions that may produce behaviorally different effects have not been separated. The present paper classifies the social conditions of reinforcement found in applied programs in a three-dimensional scheme. The efficacy of the three major dimensions—reinforcing agent, recipient response requirement, and group response requirement—is supported by clinical and research data. The reinforcing agent dimension refers to the person(s) who dispenses reinforcers to group members. This major dimension is further subdivided: one or several agents may be either designated or nondesignated. Recipients are the group members who receive reinforcement. This dimension is also subdivided: one or several recipients in a social condition of reinforcement may obtain reinforcers either contingently or noncontingently. The group response requirement is a criterion that must be satisfied before any group participant is eligible for reinforcement. Some systems have no group requirement, and others have a group requirement that must be met by some designated or nondesignated participant(s). Supportive references and examples are given in the explanation of each dimension and subdimension. The behavioral impact of the various categories is emphasized. For all major dimensions, applied implications and research suggestions are discussed. Concluding remarks center on the utility of the present scheme, the classification of operant procedures other than positive reinforcement, and both theoretical and applied issues requiring further study (e.g., the long-term effects of participation in group contingencies).