FI SCHEDULES AND PERSISTENCE AT GAMBLING IN THE U.K. BETTING OFFICE

This study reports on the direct observations of customers in two U.K. betting offices gambling on horse and dog races. These observations revealed that bets were more frequently placed in the last minutes just prior to the start (the OFF), and that this was caused by high-frequency gamblers (customers who had eight or more bets in a session) consistently placing their bets in the last two minutes prior to the OFF. Low-frequency gamblers (three or fewer bets/session) avoided this time period placing their bets earlier, or after the OFF, i.e., on a later race. It was argued that the betting behavior of the “gamblers” could not be explained either in terms of “skillful betting” or solely in terms of variable ratio schedules but was more adequately accounted for in terms of an interval schedule. It was further suggested that time-based schedules might be of heuristic value in generally understanding persistence at gambling while losing.     

The Gordon Diagnostic System and WISC-III Freedom from Distractibility Index: validity in identifying clinic-referred children with and without ADHD

Gordon Diagnostic System and WISC-III scores for clinic-referred 6- to 16-yr.-olds (184 with ADHD Combined Type and 46 without ADHD) were analyzed to evaluate the combination of scores and cutpoints that maximized diagnostic accuracy. Using an "ADHD cutpoint" of IQ minus the GDS Composite score > or = 13, 87.8% of the children were correctly identified as having or not having ADHD. IQ minus Freedom from Distractibility > 0 yielded 73.5% accuracy. When the two meaures were combined to create new criteria (IQ minus GDS Composite > or = 13 or IQ minus Freedom from Distractibility > or = 11), diagnostic accuracy increased to 90.9% and negative predictive power improved substantially. Diagnostic agreement between the Gordon Diagnostic System and Freedom from Distractibility was 70%, suggesting that the two tests measure both similar and unique traits.     

Test of the definition of learning disability based on the difference between IQ and achievement

A learning disability is commonly defined as a discrepancy between IQ and achievement. This has been criticized for identifying too many children as having a learning disability who have high IQs and average academic achievement. Such overidentification as actually occurred was assessed in 473 referred children (8-16 years, M= 10, SD=2) with normal intelligence. Learning disability was defined as a significant discrepancy (p<.05) between predicted and obtained achievement in reading, mathematics, or written expression on the Wechsler Individual Achievement Test. Predicted achievement was based on the child's WISC-III Full Scale IQ. Overidentification was considered to occur when a child scored at or above age level in reading, mathematics, and writing but still had a significant discrepancy between predicted and obtained achievement by virtue of a high IQ. Learning disability was diagnosed in 312 (66%) of the children. There was no overidentification because all children had one or more WIAT scores below the normative level for their age, i.e., < 100. Further, only 7% of the children were identified with a learning disability based on a WIAT score in the 90s. These children had a mean IQ of 123 and were rated by their teachers and parents as having learning problems.     

Eliciting and maintaining ruminative thought: the role of social-evaluative threat

This study tested whether a performance stressor characterized by social-evaluative threat (SET) elicits more rumination than a stressor without this explicit evaluative component and whether this difference persists minutes, hours, and days later. The mediating role of shame-related cognition and emotion (SRCE) was also examined. During a laboratory visit, 144 undergraduates (50% female) were randomly assigned to complete a speech stressor in a social-evaluative threat condition (SET; n = 86), in which an audience was present, or a nonexplicit social-evaluative threat condition (ne-SET; n = 58), in which they were alone in a room. Participants completed measures of stressor-related rumination 10 and 40 min posttask, later that night, and upon returning to the laboratory 3-5 days later. SRCE and other emotions experienced during the stressor (fear, anger, and sadness) were assessed immediately posttask. As hypothesized, the SET speech stressor elicited more rumination than the ne-SET speech stressor, and these differences persisted for 3-5 days. SRCE-but not other specific negative emotions or general emotional arousal-mediated the effect of stressor context on rumination. Stressors characterized by SET may be likely candidates for eliciting and maintaining ruminative thought immediately and also days later, potentially by eliciting shame-related emotions and cognitions.     

Prenatal stress affects the developmental trajectory of the rat amygdala

The amygdala plays a critical role in generating the emotion of fear, and alterations in amygdala fear processing are thought to underlie the acquisition and maintenance of anxiety disorders. The prenatally stressed (PS) rat displays hormonal, behavioral and brain anatomical similarities to anxious humans and is useful to study the neurobiological underpinnings of pathological anxiety. We studied PS and control male rats at postnatal days 7 (P7), P25, P45 and P60. Using unbiased stereological analyses we examined the volumes, anterior-posterior lengths and total numbers of neurons and glia of the basolateral (BL), central (Ce) and lateral (La) amygdalar nuclei. We found prenatal stress-associated differences in the developmental trajectories of each nucleus. These were apparent in some measures as early as P7, most extensive at P25 and resolved by P45, at least as seen by Nissl staining. These changes were not a result of differential brain growth. This early divergence in developmental trajectories seen here may be the harbinger of PS rat amygdalas that ultimately function very differently in adulthood.     

Clinical validity and interpretation of the Gordon Diagnostic System in ADHD assessments.

Gordon Diagnostic System (GDS) data were analyzed for 165 referred children with ADHD combined type and 46 referred children without ADHD, 6-16 years of age. Results showed significant differences between children with and without ADHD on the GDS standard scores and the IQ-GDS differences scores. Using a GDS composite standard score of 13 points or more below IQ to classify children as having ADHD resulted in the highest diagnostic accuracy (86%), with positive predictive power equal to 91%, and negative predictive power 67%. Results for the GDS compared favorably with those reported for other continuous performance tests. The findings lend support to the GDS as a clinically useful component of an ADHD evaluation.