Prefrontal cortex and the mediation of proactive interference in working memory

Mediating proactive interference (PI), the deleterious effect of antecedent information on current memory representations, is believed to be a key function of prefrontal cortex (PFC). Item-specific PI results when an invalid probe matches a memorandum from the preceding trial; item-nonspecific PI is produced by the accumulation of no-longer-relevant items from previous trials. We tested the hypothesis that these two types of PI are mediated by common PFC-based processes with an fMRI study of a delayed-recognition task designed to produce both types of PI. Our results indicated that the fMRI correlates of both effects were restricted both to Brodmann’s area 45 in the left hemisphere and to the memory probe epoch of the trial. These results suggest that a unification of the literatures and approaches that have independently studied these phenomena might offer a fruitful new perspective from which to study the relations between working memory, executive control, and the PFC.     

Productive activity and the prevention of behavior problems

This study used data from the National Institute of Child Health and Human Development Study of Early Child Care to examine relations between parenting, self-control, and externalizing behavior among 1st graders. Of special concern was the relation between opportunities for productive activity and behavior problems and whether the relation was mediated by self-control. Evidence in favor of the hypothesis was observed for both mother-reported and teacher-reported externalizing behavior even with substantial controls on the models examined. Self-control also mediated relations for maternal harshness and maternal sensitivity. Somewhat surprisingly, the direct effect of maternal sensitivity on mother-reported externalizing behaviors was positive.     

Schematic influences on category learning and recognition memory

The results from 3 category learning experiments suggest that items are better remembered when they violate a salient knowledge structure such as a rule. The more salient the knowledge structure, the stronger the memory for deviant items. The effect of learning errors on subsequent recognition appears to be mediated through the imposed knowledge structure. The recognition advantage for deviant items extends to unsupervised learning situations. Exemplar-based and hypothesis-testing models cannot account for these results. The authors propose a clustering account in which deviant items are better remembered because they are differentiated from clusters that capture regularities. The function of clusters is akin to that of schemas. Their results and analyses expose connections among research in category learning, schemas, stereotypes, and analogy.     

Team learning: collectively connecting the dots

This article tests the degree to which personal and situational variables impact the acquisition of knowledge and skill within interactive project teams. On the basis of the literature regarding attentional capacity, constructive controversy, and truth-supported wins, the authors examined the effects of cognitive ability, workload distribution, Agreeableness, Openness to Experience, and structure on team learning. Results from 109 four-person project teams working on an interdependent command and control simulator indicated that teams learned more when composed of individuals who were high in cognitive ability and when the workload was distributed evenly. Conversely, team learning was negatively affected when teams were composed of individuals who were high in Agreeableness. Finally, teams using a paired structure learned more than teams structured either functionally or divisionally. Theoretical and practical implications are discussed, as well as possible limitations and directions for future research.     

Context in verbal short-term memory

We tested the hypothesis that stimulus-related contextual information that is incidental to task demands-an episodic code-is automatically, obligatorily encoded and stored as a part of short-term memory (STM) representations. Four experiments employed a running span task to investigate the effects of manipulating two types of contextual information: stimulus grouping and color. Three experiments established that grouping context effects are sensitive neither to volitional control nor to task difficulty and that they generalize across testing procedures (yes/no recognition and immediate serial recall). A fourth experiment demonstrated an effect of manipulating the congruity of the color of stimuli between study and test. These demonstrations of the robustness and generality of context effects in STM are consistent with the predictions of the episodic coding model of STM.     

Generativity-Stagnation: A Five-Category Model

The main task of generativity–stagnation, Erik Erikson's seventh stage of normative psychosocial development, is to establish and guide the next generation through one's acts of care. Five statuses, or prototypic styles of resolving the issues of this stage, determined using a new, semistructured interview measure, are defined using combinations of (1) an individual's level of involvement, or active concern for the growth of the self and others; and (2) an individual's inclusivity, or scope of caregiving concern. Construct validation efforts sought concurrent validity using two different scale measures of generativity, and discrimination between status profiles using the NEO Personality Inventory and Loevinger's Sentence Completion Test of ego development. Results generally support the new status model and point to areas of conceptual convergence and divergence between this approach and other generativity measures.     

Leibniz on Intension,Extension, and the Representation of Syllogistic Inference

New light is shed on Leibniz’s commitment to the metaphysical priority of the intensional interpretation of logic by considering the arithmetical and graphical representations of syllogistic inference that Leibniz studied. Crucial to understanding this connection is the idea that concepts can be intensionally represented in terms of properties of geometric extension, though significantly not the simple geometric property of part-whole inclusion. I go on to provide an explanation for how Leibniz could maintain the metaphysical priority of the intensional interpretation while holding that logically the intensional and the extensional stand in strictly inverse relation to each other. This revised version was published online in June 2006 with corrections to the Cover Date.     

Reading Cultural Studies of Medicine

This article introduces cultural studies of medicine to medical humanities readers. Rather than offer extended definitions of cultural studies of medicine or provide a detailed history of the domain, I have organized this introduction around a close reading and review of three recently published texts in the field. These three texts, dealing respectively with “cyborg” technology, AIDS, and the medical “management” of sexual identity problems, represent excellent examples of the opportunities and possibilities of applying cultural studies approaches to medical topics. After working through these texts (and the semiotic “theories” which animate them), I devote my conclusion to a broader consideration of the role of cultural studies of medicine for both medical practice and medical humanities scholarship.     

MUST FIGURE-GROUND ORGANIZATION PRECEDE OBJECT RECOGNITION?

The assumption that figure-ground segmentation must precede object or shape recognition has been central to theories of visual perception We showed that assumption to be incorrect in an experiment in which observers reported the first perceived figure–ground organization of briefly exposed stimuli depicting two regions sharing a figure–ground border We manipulated the symmetry of the two regions and their orientation-dependent denotivity (roughly, their meaningfulness), and measured how each of these variables influenced figure–ground reports when the stimuli were exposed for 14, 28, 57, 86, or 100 ms, and followed immediately by a mask Influences on figure–ground organization from both symmetry and orientation-dependent object recognition processes were found, both were observed first in the 28-ms condition Object recognition inputs did not dominate symmetry inputs We suggest that object recognition processes may operate simultaneously on both sides of edges detected before figure–ground relationships are determined