Chunking mechanisms in human learning

Pioneering work in the 1940s and 1950s suggested that the concept of 'chunking' might be important in many processes of perception, learning and cognition in humans and animals. We summarize here the major sources of evidence for chunking mechanisms, and consider how such mechanisms have been implemented in computational models of the learning process. We distinguish two forms of chunking: the first deliberate, under strategic control, and goal-oriented; the second automatic, continuous, and linked to perceptual processes. Recent work with discrimination-network computational models of long- and short-term memory (EPAM/CHREST) has produced a diverse range of applications of perceptual chunking. We focus on recent successes in verbal learning, expert memory, language acquisition and learning multiple representations, to illustrate the implementation and use of chunking mechanisms within contemporary models of human learning.     

An event-related potential evaluation of involuntary attentional shifts in young and older adults

Involuntary shifts in attention to irrelevant stimuli were studied in elderly and young volunteers during a dichotic-listening task. Event-related potentials and behavioral measures were recorded. Volunteers heard pairs of tones presented with 2 different stimulus onset asynchronies (SOAs). To-be-ignored tones were presented to the left ear, followed by to-be-attended tones to the right ear. Left-ear tones were a frequent standard (700 Hz) and an infrequent small (650 Hz) and large (500 Hz) deviant. Right-ear tones (1500 Hz) were presented with 2 equiprobable intensities. Volunteers responded to the lower intensity stimulus. Behavioral performance was impaired at the short SOA when to-be-ignored large deviants preceded to-be-attended targets, but more so for the elderly volunteers. Large deviants also elicited the mismatch negativity (MMN) and P3a for both age groups. It was concluded that the more impaired behavioral performance observed for the elderly was due to greater sensitivity to output from the MMN system by a frontal lobe system responsible for the maintenance of attentional focus.     

Attributional Style and Personality as Predictors of Happiness and Mental Health

This paper contains two studies which set out to examine to what extent attributional style (internal, stable, global) and personality traits predicted happiness and psychiatric symptoms in a normal, non-clinical, population of young people in their early twenties. Two hundred and three participants completed five questionnaires: the Attributional Style Questionnaire (ASQ) (version one & version two), Eysenck Personality Questionnaire, Oxford Happiness Inventory, and Langner 22-Item Measure. Sample 1 (n = 120) completed ASQ version one (in both positive and negative situations) and sample 2 (n = 83) completed ASQ version two (in expanded negative situations). Regressional analysis showed that ASQ (in both versions) was the significant predictor of happiness and mental health accounting for 20% to 38% of variances. The ASQ was significantly associated with extraversion and neuroticism. Further, with happiness and mental health as dependent variables and attributional style, personality traits, and demographic variables as independent variables respectively, extraversion and attributional stability (in positive situations) were the significant predictors of happiness accounting for 59% of the total variance whilst neuroticism and psychoticism were the significant predictors of mental health accounting for 53% of the total variance. The results indicated that optimistic attributional style in positive situations was a stronger predictor of self-reported happiness than mental health and pessimistic attributional style in negative situations was a predictor of both happiness and mental health. Extraverts tended to have optimistic explanatory style for positive outcomes whereas neurotics tended to have pessimistic explanatory style for negative outcomes.     

When is a cause the "same"? Coherent generalization across contexts

Two competing psychological approaches to causal learning make different predictions regarding what aspect of perceived causality is generalized across contexts. Two experiments tested these predictions. In one experiment, the task required a judgment regarding the existence of a simple causal relation; in the other, the task required a judgment regarding the existence of an interaction between a candidate cause and unobserved background causes. The task materials did not mention assessments of causal strength. Results indicate that causal power (Cartwright, 1989; Cheng, 1997) is the mental construct that people carry from one context to another.     

制度反腐:问题、依据与原则

本文以党的十七大精神为指导,运用马克思主义的立场、观点和方法,立足我国当前实际,对目前反腐制度存在的不足、制度反腐的可能与应当遵循的原则进行了深入探讨.