A dimensional summation account of polymorphous category learning

This is the author accepted manuscript. The final version is available from Springer via the DOI in this record.Data and code availaibility: The data and code for all analyses for all experiments are available at the OSF addresses given in each Results section. The stimuli are available at the same locations.Polymorphous concepts are hard to learn, and this is perhaps surprising because they, like many natural concepts, have an overall similarity structure. However, the dimensional summation hypothesis (Milton & Wills, 2004) predicts this difficulty. It also makes a number of other predictions about polymorphous concept formation, which are tested here. In Experiment 1 we confirm the theory’s prediction that polymorphous concept formation should be facilitated by deterministic pretraining on the constituent features of the stimulus. This facilitation is relative to an equivalent amount of training on the polymorphous concept itself. In Experiments 2–4, the dimensional summation account of this single feature pretraining effect is contrasted with some other accounts, including a more general strategic account (Experiment 2), seriality of training and stimulus decomposition accounts (Experiment 3), and the role of errors (Experiment 4). The dimensional summation hypothesis provides the best account of these data. In Experiment 5, a further prediction is confirmed — the single feature pretraining effect is eliminated by a concurrent counting task. The current experiments suggest the hypothesis that natural concepts might be acquired by the deliberate serial summation of evidence. This idea has testable implications for classroom learning.Biotechnology and Biological Sciences Research Council (BBSRC

Significance of background activity and positive sharp waves in neonatal electroencephalogram as prognostic of cerebral palsy Valor do ritmo de base e da onda aguda positiva no eletrencefalograma neonatal como prognóstico da paralisia cerebral

OBJECTIVE: To study the significance of electroencephalographic background activity and positive sharp waves in neonatal electroencephalogram as prognostic of cerebral palsy. METHOD: We studied prospectively and sequentially 73 newborns who had severe neonatal complications (neonatal anoxia, seizures, respiratory distress, sepsis, and meningitis). Nineteen newborns were excluded and 54 children formed the object of our study and were followed for 2 years. We analyzed gestational age, conceptional age, electroencephalographic background activity and positive sharp waves, which were correlated with cerebral palsy. RESULTS: There were no statistically significant correlation between gestational age and conceptional age and cerebral palsy; the electroencephalographic background activity was correlated with cerebral palsy as well as the positive sharp waves. CONCLUSION: Children with electroencephalographic background activity markedly abnormal and accompanied by positive sharp waves were associated with a worse prognosis.<br>OBJETIVO: Estudar o valor do ritmo de base e das ondas agudas positivas no eletrencefalograma neonatal como prognóstico da paralisia cerebral. MÉTODO: Nós estudamos, prospectiva e sequencialmente, 73 recém-nascidos que apresentaram complicações neonatais graves (anoxia neonatal, crises convulsivas, desconforto respiratório, septicemia e meningite). Dezenove recém-nascidos foram excluídos e 54 crianças formaram o objeto do nosso estudo e foram seguidas por 2 anos. Nós analisamos a idade gestacional, a idade corrigida, o ritmo de base e as ondas agudas positivas, que foram correlacionadas com a paralisia cerebral. RESULTADOS: Não houve correlação estatisticamente significante entre as idades gestacional e corrigida com a paralisia cerebral; o ritmo de base foi correlacionado com a paralisia cerebral, tanto quanto as ondas agudas positivas. CONCLUSÃO: Crianças com o eletrencefalograma com o ritmo de base marcadamente anormal e ondas agudas positivas estão associadas com pior prognóstico neurológico