Information-processing architectures in multidimensional classification: a validation test of the systems factorial technology

A growing methodology, known as the systems factorial technology (SFT), is being developed to diagnose the types of information-processing architectures (serial, parallel, or coactive) and stopping rules (exhaustive or self-terminating) that operate in tasks of multidimensional perception. Whereas most previous applications of SFT have been in domains of simple detection and visual-memory search, this research extends the applications to foundational issues in multidimensional classification. Experiments are conducted in which subjects are required to classify objects into a conjunctive-rule category structure. In one case the stimuli vary along highly separable dimensions, whereas in another case they vary along integral dimensions. For the separable-dimension stimuli, the SFT methodology revealed a serial or parallel architecture with an exhaustive stopping rule. By contrast, for the integral-dimension stimuli, the SFT methodology provided clear evidence of coactivation. The research provides a validation of the SFT in the domain of classification and adds to the list of converging operations for distinguishing between separable-dimension and integral-dimension interactions.     

Stress and intraocular pressure in myopes

Abstract

The aim of the present study was to investigate whether the intraocular pressure (IOP) responses in myopes and normally-sighted controls differ when the subjects are exposed to a short-term achievement related stressor. A second aim was to examine to what extent IOP would decrease through relaxation in myopes as compared with the controls. Nineteen short-sighted and 19 normally-sighted adults were subjected to four conditions: (1) baseline I, (2) arithmetical mental operations under time pressure and noise, (3) baseline II, and (4) relaxation. IOP was assessed before and after each experimental condition. Heart rate was measured, and subjective ratings were obtained regarding the level of stress and relaxation subjects experienced. The stressing achievement situation led to significant increases in IOP and to significantly higher increases in myopes than in controls. Relaxation led to significant decreases of IOP in both groups. Heart rate and subjective ratings did not differ between groups under any condition. The present results point to specific intraocular reaction patterns to stress in myopic persons. The potential impact of this finding for a behavioral approach to shortsightedness is high since IOP is considered one of the main variables in the development of myopia.     

Severity of Children’s ADHD Symptoms and Parenting Stress: A Multiple Mediation Model of Self-Regulation

The goal of the current study was to determine the extent to which the perceived self-regulation deficits across behavioral, cognitive, and emotional domains seen in children with ADHD explain the association between the severity of ADHD symptoms and parenting stress. Participants for this study included 80 children (mean age = 10 years, 9 months) with a DSM-IV diagnosis of ADHD confirmed by a comprehensive clinical diagnostic assessment. Parents reported their own stress levels as well as the severity of their children’s ADHD symptoms, aggression, emotional lability, and executive functioning difficulties. Results indicated that the severity of children’s hyperactivity/impulsivity symptoms but not their inattention related to parenting stress. Multiple mediational analyses indicated that the association between hyperactivity/impulsivity and parenting stress was explained by children’s perceived comorbid aggression levels, emotional lability, and executive functioning difficulties. No significant differences in the strength of the mediators were found. The current study provides initial data showing that the perceived impairments in children’s self-regulation across emotional, cognitive, and behavioral domains are what parents report as stressful, not simply the severity of ADHD symptoms. Due to the cross-sectional nature of this study and shared variance from relying solely on parent report, it will be critical for future research to replicate our findings using longitudinal and multi-informant data such as teacher reports and standardized assessments.     

The activity of the hypothalamo-neurohypophysial system in response to acute stressor exposure: neuroendocrine and electrophysiological observations

The present mini review focuses on stress-induced alterations of the electrical and secretory activity of vasopressin (AVP) and oxytocin (OXT) neurones originating within the supraoptic nucleus (SON) and constituting the hypothalamo-neurohypophysial system (HNS) in the male rat. Previously, it was thought that SON neurones are predominantly activated by osmotic and reproductive stimuli. However, recent findings also suggest a selective activation of AVP and/or OXT neurones in response to specific stressors. Inhibitory amino acids seem to participate at the level of the SON in the control of HNS activity during stress. Taurine, probably of glial origin, selectively inhibits the secretory activity of AVP neurones. In contrast, GABA, probably of neuronal origin, interferes with the release of OXT both from axon terminals into blood and from somata/dendrites into the extracellular fluid of the SON. Depending upon whether a defined stressor triggers taurine and/or GABA release within the SON the secretion of AVP and/or OXT from HNS neurones will be inhibited. These observations shed new light on the neurone-neurone and glial-neurone interactions that ensure an appropriate neuroendocrine stress response.     

MATERNAL SELF‐REPORTED DEPRESSIVE SYMPTOMS AND MATERNAL CORTISOL LEVELS INTERACT TO PREDICT INFANT CORTISOL LEVELS

Three basic findings have emerged from research on maternal depressive symptoms and offspring hypothalamic–pituitary–adrenal functioning: (a) Mothers’ depressive symptoms are positively associated with their offsprings’ cortisol stress response, (b) numerous individual and interpersonal maternal characteristics moderate this association, and (c) maternal and infant cortisol levels are highly correlated. In combination, these findings have suggested that maternal cortisol levels may moderate the relation between maternal depressive symptoms and infant cortisol responsivity; the current study assessed this hypothesis. Participants were 297 mother–infant dyads who were recruited from the community. Maternal depressive symptoms were assessed via self‐report. Dyads participated in two differentially stressful infant challenges when infants were 16 and 17 months old. Mother and infant salivary cortisol was collected before and after challenges. Results indicate that maternal cortisol levels moderated associations between maternal depressive symptoms and infant cortisol levels across both challenges. Infants showed higher cortisol levels if their mothers had both higher depressive symptoms and higher cortisol levels, as compared to infants of mothers with higher depressive symptoms and lower cortisol, and to infants of mothers with lower depressive symptoms and either higher or lower cortisol levels. We discuss findings in relation to environmental and biological factors that may contribute to the intergenerational transmission of depressive symptoms.     

Surveying a blank field with the attentional spotlight

Spatial localization is a unique aspect of selective attention that precedes and facilitates other aspects of sensory processing. A common model of spatial attention is an attentional spotlight that enlarges to fit attentional demands. It is unclear if this attentional spotlight expands to survey a blank field or to scan the spatial environment with a smaller attentional spotlight. Two tachistoscopic experiments with young adults investigated how attention is surveyed in a blank field. Exp. 1 consisted of single letters at two concentric regions and under different conditions of attentional demand. Reaction times were proportionally slower for stimuli occurring in a combination of the two regions located at different distances from the fixation point than for stimuli occurring in each region alone. This finding is not consistent with attentional spread to encompass the entire attentional field. The addition of more stimulus locations within each single region yielded significantly slower reaction times. Together these findings suggest that a small attentional spotlight serially monitors different regions of the visual field when there are anticipated locations to be attended.