A connectionist account of asymmetric category learning in early infancy

Young infants show unexplained asymmetries in the exclusivity of categories formed on the basis of visually presented stimuli. A connectionist model is described that shows similar exclusivity asymmetries when categorizing the same stimuli presented to infants. The asymmetries can be explained in terms of an associative learning mechanism, distributed internal representations, and the statistics of the feature distributions in the stimuli. The model was used to explore the robustness of this asymmetry. The model predicts that the asymmetry will persist when a category is acquired in the presence of mixed category exemplars. An experiment with 3-4-month-olds showed that asymmetric exclusivity persisted in the presence of mixed-exemplar familiarization, thereby confirming the model's prediction.     

To what extent does typicality boost semantic priming effects between members of their categories?

Atypical items of their semantic category yield more generalisation than their typical members when relearning in connectionist networks (Plaut, D. C. (1996). Relearning after damage in connectionist networks: toward a theory of rehabilitation. Brain and Language, 52(1), 25–82) and in empirical studies (Kiran, S., & Thompson, C. K. (2003). The role of semantic complexity in treatment of naming deficits: Training semantic categories in fluent aphasia by controlling exemplar typicality. Journal of Speech, Language, and Hearing Research, 46(4), 773–787). It seems therefore that atypical words provide more information about the overall structure of the semantic category due to their specific and shared features. In this view, atypical primes could strongly facilitate the processing of targets compared to typical primes, because typical primes contain little information about the variation between members within a category. In contrast, three semantic priming experiments in visual word recognition showed an advantage with the typical context, but not with the atypical one. These findings were observed in a variety of tasks, including lexical decision, categorisation and semantic judgment. Our results do not support the findings about generalisation in relearning and suggest that typicality effects in semantic priming mostly come from the activation of representative features of categories.     

What Are the Effects of a Parent-Implemented Verbal Responsive Intervention on Preschoolers With Externalizing Behavior Problems?

This research was conducted to assess the impact of a parent-based verbal responsive intervention, aiming to enhance parents’ responsiveness and communication strategies, by way of a sample of parents and their preschool-aged children with a clinical level of externalizing behavior problems. Twenty-one parents received the intervention, consisting of eight 1.5-hour sessions. The study tested the hypothesis that the intervention led to an improvement in parenting variables and a decrease in children’s behavior problems, assessed by a multimethod procedure. The results partially confirmed the prediction, as they showed an enhancement of parents’ responsiveness and parent self-efficacy belief, which are promising findings, but no modifications of negative practices. These effects persisted for 4 months after the intervention. Moreover, a decrease in children’s externalizing behavior problems was reported by parents in a questionnaire, but this was not confirmed by an observational paradigm. This last result seems to show that a parent-implemented verbal responsive intervention is necessary for some children with externalizing behavior difficulties but often insufficient, and has to be part of a multidisciplinary treatment approach.     

Effects of linear and angular velocity on 2-, 4-, and 6-month-olds'' visual pursuit behaviors

We report on a study with 12 infants at each of 2, 4, and 6 months of age which examines the effects on infant visual pursuit of varying the target linear velocity (m/s) and the target angular velocity (deg/s) independently. Tracking performance is described in terms of five behaviors which characterize infant performance as a tracking trial unfolds: time to initial capture, duration of initial tracking, duration of initial break in tracking, frequency of interruptions in tracking, and mean duration of all tracking intervals. Interruptions in tracking become more frequent as linear velocity increases but less frequent as angular velocity increases. The mean duration of later tracking intervals is diminished relative to the duration of earlier tracking intervals in 4- and 6-month-olds, but not in the 2-month-olds. Differences in angular velocity may account for the conflicting reports of disruptions in object permanence studies relying on a visual tracking paradigm.     

Links Between Early Personal Characteristics,Longitudinal Profiles of Peer Victimization in School and Victimization in College or at Work

Research on Child and Adolescent Psychopathology - This study used a longitudinal design from age six through age 19 (N?=?1206 (603 girls)) to examine the associations between...