Strategic calibration and spatial alignment: a model from prism adaptation

Two types of adaptive processes involved in prism adaptation have been identified&colon: Slower spatial realignment among the several unique sensorimotor coordinate systems (spatial maps) and faster strategic motor control responses(including skill learning and calibration) to spatial misalignment. One measures the 1st process by assessing the aftereffects of prism exposure, whereas direct effects of the prism during exposure are a measure of the 2nd process. A model is described that relates those adaptive processes and distinguishes between extraordinary alignment and ordinary calibration. A conformal translation algorithm that operates on the hypothesized circuitry is proposed. The authors apply to the model to explain the advantage of visual calibration when the limb is seen in the starting position prior to movement initiation. Implications of the model for the use of prism adaptation as a tool for investigation of motor control and learning are discussed.     

The role of the left hemisphere in motor control of touch: a functional magnetic resonance imaging analysis

Previous research using a simple finger-touching task has shown greater blood oxygenation level dependent (BOLD) activation volume in the motor cortex of the right hemisphere for contralateral finger touching compared to ipsilateral finger touching, but no significant contralateral advantage for the left hemisphere. Such equal involvement of the left hemisphere for both contralateral and ipsilateral finger touching suggests a special role of the left hemisphere for finger touching. In contrast, we found a contralateral advantage in the motor cortex of both hemispheres in a majority of participants (14/16) when consistently activated BOLD volumes were examined. However, participants who did not show a clear contralateral advantage for the left hemisphere did show activation in the left inferior frontal gyrus (IFG; Broca's Area) and in the left insular cortex, which suggests that verbally mediated sequencing of finger movements can account for our less frequent result.     

A test of size-scaling and relative-size hypotheses for the moon illusion

In two experiments participants reproduced the size of the moon in pictorial scenes under two conditions: when the scene element was normally oriented, producing a depth gradient like a floor, or when the scene element was inverted, producing a depth gradient like a ceiling. Target moons were located near to or far from the scene element. Consistent with size constancy scaling, the illusion reversed when the "floor" of a pictorial scene was inverted to represent a "ceiling." Relative size contrast predicted a reduction or increase in the illusion with no change in direction. The relation between pictorial and natural moon illusions is discussed.     

Perfectionism, ego defense styles, and depression: a comparison of self-reports versus informant ratings

The present study examined the associations among perfectionism, defense styles, and depression in an Israeli community sample of young adults. This study involved a comparison of self-reports and informant ratings on all measures. A community sample of 210 pairs of same-sex best friends from Israel completed the Multidimensional Perfectionism Scale, the Defense Styles Questionnaire - 40, and a depression measure. Analyses confirmed that socially prescribed perfectionism is associated with depression, not only in terms of self-reports but also in terms of informant ratings. In addition, informant ratings revealed a link between other-oriented perfectionism and depression. Both self-reports and informant ratings also indicated that socially prescribed perfectionism is associated with immature defense styles and neurotic defense styles. Further simultaneous Structural Equation Modeling (SEM) analyses of self-reports and informant ratings showed that maladaptive defense styles mediate the link between socially prescribed perfectionism and depression. The practical and theoretical implications of these findings are discussed.     

Pronouns in marital interaction

Recent studies in social psychology have found that the frequency of certain words in people's speech and writing is related to psychological aspects of their personal health. We investigated whether counts of "self" and "other" pronouns used by 59 couples engaged in a problem-solving discussion were related to indices of marital health. One spouse in each couple had a diagnosis of obsessive-compulsive disorder or panic disorder with agoraphobia; 50% of the patients and 40% of their spouses reported marital dissatisfaction. Regardless of patients' diagnostic status, spouses who used more second-person pronouns were more negative during interactions, whereas those who used more first-person plural pronouns produced more positive problem solutions, even when negative behavior was statistically controlled. Moreover, use of first-person singular pronouns was positively associated with marital satisfaction. These findings suggest that pronouns used by spouses during conflict-resolution discussions provide insight into the quality of their interactions and marriages.     

Wishful thinking and source monitoring

Memory distortions sometimes serve a purpose: It may be in our interest to misremember some details of an event or to forget others altogether. The present work examines whether a similar phenomenon occurs for source attribution. Given that the source of a memory provides information about the accuracy of its content, people may be biased toward source attributions that are consistent with desired accuracy. In Experiment 1, participants read desirable and undesirable predictions made by sources differing in their a priori reliability and showed a wishful thinking bias--that is, a bias to attribute desirable predictions to the reliable source and undesirable predictions to the unreliable source. Experiment 2 showed that this wishful thinking effect depends on retrieval processes. Experiment 3 showed that under some circumstances, wishes concerning one event can produce systematic source memory errors for others.     

Effects of intrastimulus modality change on audiovisual time-to-arrival judgments

In this research, anticipatory perception of an approaching vehicle was examined. By varying the availability of visual and acoustic media, conditions occurred in which the input to the modalities was repetitively interrupted while the presentation of the approach event continued. In these conditions, the audio and the visual signals were presented either in short and concurrent segments at regular intervals or in alternation (interleaved) at regular intervals. It was found that interrupting the signal within a single modality did not affect performance if the approach information was available in the alternate modality. These results are consistent with a modally flexible detection mechanism for the perception of approaching objects. This modal flexibility may provide some evidence that information is detected using a modality-neutral strategy.     

Manual asymmetries in bimanual reaching: the influence of spatial compatibility and visuospatial attention

The goal of the present investigation was to explore the possible expression of hemispheric-specific processing during the planning and execution of a bimanual reaching task. Participants (N = 9) completed 80 bimanual reaching movements (requiring simultaneous, bilateral production of arm movements) to peripherally presented targets while selectively attending to either their left or right hand. Further, targets were presented in spatially compatible (ipsilateral to the aiming limb) and incompatible (contralateral to the aiming limb) response contexts. It was found that the left hand exhibited temporal superiority over the right hand in the response planning phase of bimanual reaching, indicating a left hand/right hemisphere advantage in the preparation of a bimanual response. During response execution, and consistent with the view that interhemispheric processing time (Barthelemy & Boulinguez, 2002) or biomechanical constraints (Carey, Hargreaves, & Goodale, 1996) generate temporal delays, longer movement times were observed in response to spatially incompatible target positions. However, no hemisphere-specific benefit was demonstrated for response execution. Based on these findings, we propose lateralized processing is present at the time of response planning (i.e., left hand/right hemisphere processing advantage); however, lateralized specialization appears to be annulled during dynamic execution of a bimanual reaching task.     

Subitizing and similarity: Toward a pattern-matching theory of enumeration

Pattern-matching theories of subitizing claim that subjects enumerate displays with small numerosities by retrieving numerical responses associated with similar displays experienced in the past. Such retrieval implies that displays with small numerosities are similar to other displays of the same numerosity and dissimilar to other displays of different numerosities. These hypotheses were tested by having subjects rate the similarities of displays of dot patterns with numerosities in the range of 1-10. One group of subjects rated patterns of the same numerosity. Their ratings were higher for patterns in the subitizing range (numerosities of 1-3) than for patterns beyond the subitizing range (numerosities of 4-10). Another group rated patterns of different numerosities. Their ratings were lower in the subitizing range than beyond the subitizing range. An analysis based on multidimensional scaling suggested that numerosity could be retrieved accurately for displays of 1-3 dots, but not for displays of 4-10 dots.