Task requirements influence sensory integration during grasping in humans

The sensorimotor transformations necessary for generating appropriate motor commands depend on both current and previously acquired sensory information. To investigate the relative impact (or weighting) of visual and haptic information about object size during grasping movements, we let normal subjects perform a task in which, unbeknownst to the subjects, the object seen (visual object) and the object grasped (haptic object) were never the same physically. When the haptic object abruptly became larger or smaller than the visual object, subjects in the following trials automatically adapted their maximum grip aperture when reaching for the object. This adaptation was not dependent on conscious processes. We analyzed how visual and haptic information were weighted during the course of sensorimotor adaptation. The adaptation process was quicker and relied more on haptic information when the haptic objects increased in size than when they decreased in size. As such, sensory weighting seemed to be molded to avoid prehension error. We conclude from these results that the impact of a specific source of sensory information on the sensorimotor transformation is regulated to satisfy task requirements.     

The simultaneous acquisition effect: simultaneous task learning inhibits memory for order

Delayed recall of a list of words learned simultaneously with other lists is superior to that of a list of words learned singly. A Brown-Peterson-like task was used to investigate this simultaneous acquisition effect from the perspective of the item-order distinction. It was hypothesized that simultaneous task learning would impede the encoding of order information but promote the encoding of item-specific information relative to single-task learning. The results of the first four experiments strongly supported the hypothesis that simultaneous task learning decreases the encoding of order information but provided no evidence that it facilitated the encoding of item-specific information. Additionally, Experiment 5 showed that the simultaneous acquisition effect did not occur in a mixed-list design, demonstrating an important boundary condition of the effect.     

Learning and production of movement sequences: behavioral, neurophysiological, and modeling perspectives

A wave of recent behavioral studies has generated a new wealth of parametric observations about serial order behavior. What was a trickle of neurophysiological studies has grown to a steady stream of probes of neural sites and mechanisms underlying sequential behavior. Moreover, simulation models of serial behavior generation have begun to open a channel to link cellular dynamics with cognitive and behavioral dynamics. Here we review major results from prominent sequence learning and performance tasks, namely immediate serial recall, typing, 2 x N, discrete sequence production, and serial reaction time. These tasks populate a continuum from higher to lower degrees of internal control of sequential organization and probe important contemporary issues such as the nature of working-memory representations for sequential behavior, and the development and role of chunks in hierarchical control. The main movement classes reviewed are speech and keypressing, both involving small amplitude movements amenable to parametric study. A synopsis of serial order models, vis-a-vis major empirical findings leads to a focus on competitive queuing (CQ) models. Recently, the many behavioral predictive successes of CQ models have been complemented by successful prediction of distinctively patterned electrophysiological recordings. In lateral prefrontal cortex, parallel activation dynamics of multiple neural ensembles strikingly matches the parallel dynamics predicted by CQ theory. An extended CQ simulation model--the N-STREAMS neural network model--exemplifies ongoing attempts to accommodate a broad range of both behavioral and neurobiological data within a CQ-consistent theory.     

Stability in autobiographical memories

A total of 30 undergraduates recalled the same 20 autobiographical memories at two sessions separated by 2 weeks. At each session they dated their memories and rated them on 18 properties commonly studied in autobiographical memory experiments. Individuals showed moderate stability in their ratings on the 18 scales (r approximately .5), with consistency of dating being much higher (r = .96). There was more stability in the individuals' average rating on each scale (r approximately .8), even when the averages were calculated on different memories in the different sessions. The results are consistent with a constructive view of autobiographical memory, in which stable individual differences in cognitive style are important.     

Complementary and supplementary fit: a theoretical and empirical integration

Complementary and supplementary fit represent 2 distinct traditions within the person-environment fit paradigm. However, these traditions have progressed in parallel but separate streams. This article articulates the theoretical underpinnings of the 2 traditions, using psychological need fulfillment and value congruence as prototypes of each tradition. Using a sample of 963 adult employees ranging from laborers to executives, the authors test 3 alternative conceptual models that examine the complementary and supplementary traditions. Results show that an integrative model dominates the other two, such that both traditions simultaneously predict outcomes in different ways.     

The Association Between Current Intergenerational Family Relationships and Sibling Structure

The authors examined the relationship between sibling structure variables (i.e., gender, number of sisters, number of brothers, sibling spacing, number of siblings, and birth order, all men, and all women siblings) and current relationships with parents and spouse/partners. Participants included 519 adults between the ages of 19 and 59 years. Two separate canonical correlations were conducted. The results for men indicated that being a younger man with an all‐male sibling group was related to more intimacy with parents and more intimidation by parents. For women, being an older woman with more brothers and more siblings was related to less intimidation by parents and less intimacy with parents and spouses/partners.     

Speakers gaze at objects while preparing intentionally inaccurate labels for them

When describing scenes, speakers gaze at objects while preparing their names (Z. M. Griffin & K. Bock, 2000). In this study, the authors investigated whether gazes to referents occurred in the absence of a correspondence between visual features and word meaning. Speakers gazed significantly longer at objects before intentionally labeling them inaccurately with the names of similar things (e.g., calling a horse a dog) than when labeling them accurately. This held for grammatical subjects and objects as well as agents and patients. Moreover, the time spent gazing at a referent before labeling it with a novel word or accurate name was similar and decreased as speakers gained experience using the novel word. These results suggest that visual attention in speaking may be directed toward referents in the absence of any association between their visual forms and the words used to talk about them.     

I. Validity of WISC-R factor scores in predicting achievement and attention for four sociocultural groups

The predictive validity of WISC-R factor scores was examined with samples from the four sociocultural groups of Anglo, Black, Chicano, and native American Papago. The Full Scale IQ and Verbal Comprehension (VC) factor scores were significantly better predictors of achievement as measured by teacher ratings and the Metropolitan Achievement Test. The Perceptual Organization and Freedom from Distractibility (FD) factor scores were also significantly related to achievement, but at a lower level than Full Scale and VC. The correlations of the WISC-R and achievement measures were nearly the same for three of the four groups (exception was native American Papago). The relationship of the FD factor score to ratings of attention was statistically significant, but relatively low. Cautions in interpreting FD as a measure of attention were recommended due to overlap of distributions and low proportion of variance in attention accounted for by FD.     

Role of contextual imagery in associative recall

The advantage of interactive over separation imagery in associative recall was markedly diminished when a unique imaginary context was provided for each imaged pair of words. Separation imagery was much more sensitive to contextual redundancy than was interactive imagery. Context was viewed as facilitating organization at encoding as well as affecting cue loading at retrieval. A three-element associative model is described.