The variability of practice hypothesis in motor learning: does it apply to Alzheimer's disease?

Based on Schmidt's (1975) variability of practice hypothesis, this study examined acquisition and transfer of a gross motor skill, namely tossing, in 58 patients with Alzheimer's disease (AD) and 58 healthy older adults under constant, blocked, and random practice conditions. While healthy older adults were able to learn the tossing task equally well under the three practice conditions, only AD patients receiving constant practice showed significant improvements. Tests of intermediate transfer yielded the expected random practice advantage in healthy controls but not AD patients. None of the practice conditions facilitated intermediate transfer in AD patients; however, constant practice did benefit these impaired individuals on tests of near transfer. These results indicate that the variability of practice hypothesis does not extend to AD patients. As motor learning and transfer were clearly a function of constant practice, future attempts to retrain basic activities of daily living in AD patients should emphasize consistency in training.     

Nonhomogeneous resolution of images of natural scenes

The aim of this research is to model and simulate the loss of visual resolution as a function of retinal eccentricity in the perception of natural scenes. The model of visual resolution is based on a space-variant low-pass filter, having a variable convolution kernel according to retinal eccentricity. The parameters of the model are computed from psychophysical measures of visual acuity as a function of retinal eccentricity. The implementation of the model allowed us to generate images of scenes with nonhomogeneous space-variant resolution, simulating the filtering executed by the eye. These scenes are used to test and optimise the model by means of experiments in static vision (through tachistoscopic presentations) and in dynamic vision where the resolution of the scene is computed, in real-time, as a function of the location of gaze.     

Response strategies and the Simon effect

The study investigated whether the Simon effect, and its facilitation and interference components, shows up in reaction time (RT) or in movement time (MT), depending on the response strategy. Experiment 1 replicated a study by Hietanen and Rämä. Subjects had to press one of two lateralised keys in response to one of two stimuli. The stimuli were presented in the center (neutral condition) or to the left or right side (corresponding or non-corresponding conditions). To press the response key, a reaching movement was necessary, and both RT and MT were recorded. One group of subjects showed an RT facilitation effect and an MT interference effect. Another group of subjects showed both MT facilitation and MT interference effects. It was hypothesized that the two groups used different response strategies. In Exps. 2 and 3, the subjects were explicitly instructed to use the two strategies that were hypothesized for Exp. 1. The results showed that whether facilitation and interference manifest themselves in RT or MT depends on the response strategy adopted by the subjects.     

Personality disorders in a Dutch forensic psychiatric sample: convergence of interview and self-report measures

Convergence of PDQ-R- and SIDP-R-derived personality disorder diagnoses was studied in a sample of 85 forensic psychiatric patients. For categorical diagnoses, the mean kappa was .34, but on a dimensional level convergence was somewhat higher. Paranoid, antisocial and borderline personality disorders had prevalence rates around 40%; the other personality disorders occurred with much lower frequency. The PDQ-R yielded more diagnoses, except for antisocial, histrionic, narcissistic, and sadistic personality disorder. Because the latter disorders are among the most prevalent in forensic settings, and because they have important risk and treatment implications, the PDQ-R is not suitable as a screening device in forensic populations. Semistructured interviews that make use of collateral information are recommended for diagnosing personality disorders in forensic subjects.     

The Collaborative Longitudinal Personality Disorders Study: reliability of axis I and II diagnoses

Both the interrater and test-retest-retest reliability of axis I and axis II disorders were assessed using the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) and the Diagnostic Interview for DSM-IV Personality Disorders (DIPD-IV). Fair-good median interrater kappa (.40-.75) were found for all axis II disorders diagnosed five times or more, except antisocial personality disorder (1.0). All of the test-retest kappa for axis II disorders, except for narcissistic personality disorder (1.0) and paranoid personality disorder (.39), were also found to be fair-good. Interrater and test-retest dimensional reliability figures for axis II were generally higher than those for their categorical counterparts; most were in the excellent range (> .75). In terms of axis I, excellent median interrater kappa were found for six of the 10 disorders diagnosed five times or more, whereas fair-good median interrater kappa were found for the other four axis I disorders. In general, test-retest reliability figures for axis I disorders were somewhat lower than the interrater reliability figures. Three test-retest kappa were in the excellent range, six were in the fair-good range, and one (for dysthymia) was in the poor range (.35). Taken together, the results of this study suggest that both axis I and axis II disorders can be diagnosed reliably when using appropriate semistructured interviews. They also suggest that the reliability of axis II disorders is roughly equivalent to that reliability found for most axis I disorders.     

Using Advice and Assessing Its Quality

People received advice from four sources and used it to produce a judgment. They also assessed the quality of advice by estimating the probability that it would be correct. They were better at assessing than at using advice: combinations of advice based on their assessments were superior to their judgments. Order of assessing and using advice, superficial differences between advisors, and using other methods of advice assessment had no significant effects on this superiority of advice assessment over advice use. However, use but not assessment was improved when some advisors exhibited biases opposite to those that people typically show. It appears that using advice imposes a heavier processing load than assessing its quality and that this load can be lightened by including advisors who exhibit unusual behavior. Their salience may help people working under a heavy processing load make appropriate pairings between advisor weights and advice.     

Prosocial foundations of children's academic achievement

The present longitudinal research demonstrates robust contributions of early prosocial behavior to children's developmental trajectories in academic and social domains. Both prosocial and aggressive behaviors in early childhood were tested as predictors of academic achievement and peer relations in adolescence 5 years later. Prosocialness included cooperating, helping, sharing, and consoling, and the measure of antisocial aspects included proneness to verbal and physical aggression. Prosocialness had a strong positive impact on later academic achievement and social preferences, but early aggression had no significant effect on either outcome. The conceptual model accounted for 35% of variance in later academic achievement, and 37% of variance in social preferences. Additional analysis revealed that early academic achievement did not contribute to later academic achievement after controlling for effects of early prosocialness. Possible mediating processes by which prosocialness may affect academic achievement and other socially desirable developmental outcomes are proposed.     

Visual capture of touch: out-of-the-body experiences with rubber gloves

When the apparent visual location of a body part conflicts with its veridical location, vision can dominate proprioception and kinesthesia. In this article, we show that vision can capture tactile localization. Participants discriminated the location of vibrotactile stimuli (upper, at the index finger, vs. lower, at the thumb), while ignoring distractor lights that could independently be upper or lower. Such tactile discriminations were slowed when the distractor light was incongruent with the tactile target (e.g., an upper light during lower touch) rather than congruent, especially when the lights appeared near the stimulated hand. The hands were occluded under a table, with all distractor lights above the table. The effect of the distractor lights increased when rubber hands were placed on the table, 'holding' the distractor lights, but only when the rubber hands were spatially aligned with the participant's own hands. In this aligned situation, participants were more likely to report the illusion of feeling touch at the rubber hands. Such visual capture of touch appears cognitively impenetrable.     

Modality effects and the development of the word length effect in children

Two experiments investigated the development of the word length effect in children aged 4 to 10 years, comparing auditory and visual stimuli. The question addressed was whether word length effects emerged earlier with auditory presentation or visual presentation, or whether they emerged at the same age regardless of presentation modality. Results provided evidence that word length effects emerge earlier with visual than auditory presentation. The implication of our results is that with visual presentation, 4-year-olds engage in some form of verbalization strategy that involves obtaining phonological representations of picture names and mapping them on to articulatory output plans. This strategy is clearly verbal in nature, but is not necessarily characterised as cumulative verbal rehearsal.