Memory for recent behavior in the pigeon

Variations of the symbolic delayed-matching-to-sample procedure were used to study a pigeon's memory for a small number of pecks. In the first experiment a choice of a left or right sidekey after a delay or retention interval was reinforced if a bird had not pecked at all or had pecked exactly once, before the delay, respectively. In the second experiment a choice of a red or green sidekey, regardless of its position, was reinforced if a bird had not pecked at all or had pecked exactly twice, respectively. In the first experiment a bird could orient toward the correct choice during the delay, whereas it could not in the second experiment. In a third experiment a feature-probing method was used to study a pigeon's memory for a number of pecks in the context of certain other pecks. The results showed that a pigeon can remember a small number of pecks for one-half to one minute or more and that the percent correct is a decreasing function of the log retention interval. When a second number of pecks is different from the first number, memory for the first number lasts only a few seconds. When a second number is the same, memory lasts considerably longer. The more recent number of pecks is remembered better. The results are interpreted in terms of a theory which holds that a reinforcer, in general, may act on a subjects' memory for recent behavior to generate patterns of behavior.     

Intermodal perception of expressive behaviors by human infants

Four experiments demonstrate that infants of 5 and 7 months can detect information that is invariant across the acoustic and optic presentations of a single affective expression. Infants were presented simultaneously with two filmed facial expressions accompanied by a single vocal expression characteristic of one of the facial expressions. The infants increased their looking time to a facial expression when it was sound-specified, as compared to when that filmed expression was projected silently. Even when synchrony relations were disrupted, infants looked proportionately longer to the film that was sound-specified, indicating that some factor other than temporal synchrony guided the infants' looking behavior. When infants viewed the filmed facial expressions either in a normal orientation or upside-down, those infants viewing the facial expressions in the normal orientation looked appropriately, while those viewing the inverted films did not. These findings support the view that infants are sensitive to amodal, potentially meaningful invariant relations in expressive behaviors. These results are discussed in the context of J. J. Gibson's theory of affordances.     

Level I and level II abilities in Asian,white, and black children

All the Asian-American, white, and black children in grades 2 through 6 in a California school district were given a battery of tests including measures of IQ, scholastic achievement, and short-term memory. Factor analysis of the tests yielded two main factors identified as Level I (memory) and Level II (general intelligence) in Jensen's system. The three ethnic groups were compared with one another on uncorrelated Level I and Level II factor scores. At every grade level, bivariate means of the three groups occupy distinctly different quadrants in the factor space. Asians and whites differ on Level I (A < W) but not on Level II. Asians and blacks differ on Level II (A > B) but not on Level I. Whites and blacks differ (W > B) on both Levels I and II, but the white-black difference on Level I is less than one fourth as large as the white-black difference on Level II. A similar pattern of group differences is found for scores on tests of memory and nonverbal IQ. Scholastic achievement shows much smaller correlations with the Level I than with the Level II factor.     

An attempt towards differentiating attentional deficits in traumatic brain injury

Attentional deficits in patients suffering traumatic brain injury (TBI) can occur with minor to severe impact to the brain. Based on reviews of both the cognitive and neurobehavioral literature, the following three concepts of attention are addressed: (a) arousal/alertness, (b) selective attention, and (c) energetic aspects of attention, which include such components as effort, resource allocation, and speed of processing. Within each concept, definitions are proposed, the underlying brain mechanisms are identified, and the specific deficits associated with TBI are explored. This review combines theoretical perspectives and clinical findings with the objective of leading toward a diagnostic differentiation that in turn will benefit treatment planning.     

BOOKS Reviews

William James and the Reinstatement of the Vague. By William Joseph Gavin.
Anti-foundationalism Old and New. Edited by Tom Rockmore and Beth Singer.     

Brief report: Relativism and identity crisis in young adulthood

This study investigated the relationship between epistemological world views and identity formation. Forty college students, aged 17 to 23 years, were presented with a paradigm belief scale (Social Paradigm Belief Inventory; SPBI), an identity status questionnaire, and an indepth interview about a conflict they had recently experienced. It was hypothesized that a relativistic world view would be related to a moratorium identity status because relativistic thought processes involve a questioning of the objectivity of knowledge and authority structures and hence an awareness of the variety of alternative and potentially conflicting roles and choices. Results indicated that relativism was the most common world view used when responding to questions about a personal conflict and that relativistic scores on the SPBI were predictive of the moratorium status. Relativistic scores on the SPBI were also negatively related to identity achievement, as were mechanistic scores. Females experienced moratorium to a greater extent than males but were not more relativistic. Results are discussed in terms of linkages among cognitive development, psychosocial development, gender, and the type of measures used to assess world view status.     

Visual marking of old objects

Watson and Humphreys (1997) presented evidence that selection of new elements can be prioritized by on-line top-down attentional inhibition of old stimuli already in the visual field (visual marking). The experiments on which this evidence was based always presented old elements in green and new elements in blue. Because of this, instead of prioritizing new objects by inhibiting old objects, selection could have been based on color. The present experiment, which does not contain this confound, showed that visual marking is a strong and robust process that enables subjects to visually mark at least 15 old elements even when these elements have the same color as the new elements. The results indicate that preview of the elements is critical—not the fact that those elements contained a common feature.