The effects of memory load on the time course of inhibition of return

Inhibition of return (IOR) refers to a processing disadvantage at a recently attended location. It is generally agreed that when elicited in a cue-target task, IOR will not be apparent until attention is disengaged from the originally cued location and returned to a neutral state. Here we test the hypothesis that when such disengagement is dependent on endogenous control, a secondary task that taxes working memory capacity should delay the appearance of IOR. Participants were given a six-item verbal working memory load prior to the peripheral cue in a cue-target detection task. Consistent with the hypothesis, the appearance of IOR was delayed on trials for which participants had to hold information in working memory. Converging evidence was derived from a second experiment in which the time course of IOR’s appearance, when we added a central cue to exogenously remove attention from the peripheral cue, was unaffected by the memory load.     

Spatial updating relies on an egocentric representation of space: Effects of the number of objects

Models of spatial updating attempt to explain how representations of spatial relationships between the actor and objects in the environment change as the actor moves. In allocentric models, object locations are encoded in an external reference frame, and only the actor’s position and orientation in that reference frame need to be updated. Thus, spatial updating should be independent of the number of objects in the environment (set size). In egocentric updating models, object locations are encoded relative to the actor, so the location of each object relative to the actor must be updated as the actor moves. Thus, spatial updating efficiency should depend on set size. We examined which model better accounts for human spatial updating by having people reconstruct the locations of varying numbers of virtual objects either from the original study position or from a changed viewing position. In consistency with the egocentric updating model, object localization following a viewpoint change was affected by the number of objects in the environment.     

The adrenergic receptor α-2A gene (ADRA2A) and neuropsychological executive functions as putative endophenotypes for childhood ADHD

There is resurgent interest in the psychiatric literature in endophenotypes, variables thought to more strongly reflect the effects of candidate genes than do manifest disorders. In a sample of 176 children with attention deficit hyperactivity disorder (ADHD) and 52 of their siblings, we examined the validity of several putative endophenotypes for ADHD that represent commonly used clinical measures of multiple cognitive/neuropsychological domains of executive functions (EFs). We review their distributional normality, their relations to ADHD symptoms in probands and unaffected siblings relative to nonADHD controls, and their correlation in siblings. We also tested the EF measures’ associations with the ADRA2A gene and whether they mediated or moderated the associations between ADHD and ADRA2A. Several EF measures showed association with ADRA2A, as well as moderation, but not mediation, of its association with ADHD. Implications of the results for evaluating the validity and utility of putative endophenotype measures and for finding candidate gene effects on ADHD are discussed.     

Moving farther but faster: an exception to Fitts's law

Fitts's law holds that movement time (MT) increases with longer distances. Here we report a violation of this law: When the target appears in a structured, linear display with placeholders indicating the possible target locations, MT to the most distant target is not longer than MT to the second most distant target, but rather tends to be shorter. Furthermore, the presence of placeholders attenuates the range effect that occurs in the absence of placeholders. These findings suggest that Fitts's law may be limited to egocentric visuomotor action, and that the visual control of hand movements may use allocentric, in addition to egocentric, spatial information.     

Growing older does not always mean moving slower: examining aging and the saccadic motor system

Although humans typically move more slowly as they age, one exception may be the saccadic motor system. To fully determine whether the execution of saccades is affected by age, the authors examined detailed kinematics of vertical and horizontal saccades across a range of saccadic amplitudes (4 degrees, 8 degrees, and 12 degrees). Ten younger and 20 older adults participated in each experiment. Whereas in the 1st experiment, the authors assessed volitionally generated saccades, in the 2nd experiment, they evaluated reflexively generated saccades. The results of those experiments showed that the saccadic motor system is relatively impervious to the effects of aging; in fact, the differences between vertical and horizontal saccades were more evident than were differences between saccades produced by younger and older adults. The authors discuss possible reasons for that relative resistance to aging.     

Trait and social processes in the link between social support and affect: an experimental, laboratory investigation

This study investigated the extent to which the link between perceived social support and affect reflected support recipients' trait perceived support as well as three distinct social processes: the objective supportiveness of providers, the unique relationships among recipients and providers that were stable over occasions, as well as the unique relationships that varied across occasions. Ten recipients interacted with each of the same four providers on five separate occasions, for a total of 200 interactions. Recipients and independent observers rated recipient affect and provider support. Greater perceived support was related to greater positive affect for recipients' trait perceived support, as well as for relationships that were stable over occasions and relationships that varied across occasions. No social support effects were found for negative affect. Perceived similarity was a consistent predictor of recipients' support perceptions. Implications for social support models and interventions were discussed.     

Stressors, quality of the child-caregiver relationship, and children's mental health problems after parental death: the mediating role of self-system beliefs

Investigated whether three self-system beliefs, fear of abandonment, coping efficacy, and self-esteem, mediated the relations of stressors and caregiver-child relationship quality with concurrent and prospective internalizing and externalizing problems in a sample of children who had experienced parental death in the previous 2.5 years. The cross-sectional sample consisted of 340 children ages 7-16 and their surviving parent/current caregiver; the longitudinal analyses employed a subset of this sample that consisted of 100 children and their parents/caregivers who were assessed at three time points. A multirater, multimethod measure of caregiver-child relationship quality and a multirater measure of children's mental health problems were used. The cross-sectional model supported a mediational relation for fear of abandonment, coping efficacy, and self-esteem. The three-wave longitudinal model showed that fear of abandonment at Time 2 mediated the relation between stressors at Time 1 and internalizing and externalizing problems at Time 3. Implications of these findings for understanding the development of mental health problems in parentally bereaved children and designing interventions for this at-risk group are discussed.     

Stressors, Quality of the Child–Caregiver Relationship, and Children's Mental Health Problems After Parental Death: The Mediating Role of Self-System Beliefs

Investigated whether three self-system beliefs, fear of abandonment, coping efficacy, and self-esteem, mediated the relations of stressors and caregiver–child relationship quality with concurrent and prospective internalizing and externalizing problems in a sample of children who had experienced parental death in the previous 2.5 years. The cross-sectional sample consisted of 340 children ages 7–16 and their surviving parent/current caregiver; the longitudinal analyses employed a subset of this sample that consisted of 100 children and their parents/caregivers who were assessed at three time points. A multirater, multimethod measure of caregiver–child relationship quality and a multirater measure of children's mental health problems were used. The cross-sectional model supported a mediational relation for fear of abandonment, coping efficacy, and self-esteem. The three-wave longitudinal model showed that fear of abandonment at Time 2 mediated the relation between stressors at Time 1 and internalizing and externalizing problems at Time 3. Implications of these findings for understanding the development of mental health problems in parentally bereaved children and designing interventions for this at-risk group are discussed.