Adaptation effects and reversible figures: A comment on Horlitz and O’Leary

In a recent article, Horlitz and O’Leary (1993) offer a reinterpretation of the results of several studies over the past 40 years that have employed the prolonged-inspection technique in the investigation of reversible figures. Specifically, they contend that, contrary to the favored interpretation of neural adaptation effects, the results of these studies reveal the combined influence of such topdown processes as attention and perceptual learning as well as such methodological difficulties as unwanted demand characteristics. In this note, we examine their analysis of the literature, their alternative theoretical model, and the supporting conclusions they draw from their two experiments. We argue that there is considerable evidence from a variety of studies for the joint role of bottom-up and top-down processes in reversible figures. Moreover, we propose that Horlitz and O’Leary’s own research, rather than eliminating the possibility of neural-adaptation effects, is best conceptualized as providing additional evidence for the role of higher-order processes in these phenomena.     

A Playroom Observation Procedure to Assess Children with Mental Retardation and ADHD

Forty-two children (ages 6 to 12 years old) with moderate mental retardation to borderline intellectual functioning were studied in a laboratory playroom setting to determine whether children identified as ADHD (attention deficit hyperactivity disorder) or controls differed on activity and attentional measures. Children with ADHD were further divided into ADHD + conduct problems (ADHD + CD) and ADHD-only subgroups (with an ADHD-combined group comprising children of both subgroups). An interval recording system was used to code observations of independent play and a restricted academic task. Results indicated that the ADHD-combined group was significantly more vocal and engaged in a significantly greater number of toy changes than controls during independent play. Significant group differences were also noted during the restricted academic task, with the ADHD-combined and ADHD + CD groups more off-task and engaging in a greater number of toy touches than controls. Discriminant analyses found independent play measures to predict group membership in 70 percent of cases (ADHD-combined vs. controls), but in only 64 percent of cases using measures from the restricted academic task. No significant findings resulted when the ADHD subjects were further divided into two subgroups. Despite some inconsistent findings, such laboratory-based observations may be of value in the diagnosis of ADHD in children with moderate mental retardation to borderline intellectual functioning.     

AUGMENTING SIMPLIFIED HABIT REVERSAL WITH AN AWARENESS ENHANCEMENT DEVICE: PRELIMINARY FINDINGS

The chronic hair pulling of a 36-year-old woman with moderate mental retardation was initially treated with a simplified habit-reversal (SHR) procedure that consisted of awareness training, competing response training, and social support. When SHR did not produce large and sustained reductions in hair pulling, an awareness enhancement device was added, and it reduced hair pulling to near-zero levels in two settings. The results are discussed, and directions for future research with this device are provided.     

The contribution of visual persistence to the perceived duration of brief targets

Two experiments were conducted to examine the role of sensory persistence on tasks of perceived duration employing very brief visual stimuli. Using a standard temporal judgment task, the first experiment replicated both the “size effect” and “empty-filled” illusion reported by previous investigators. However, entirely comparable results were also found with a probematching task, which theoretically assesses the degree of persistence exhibited by a stimulus. The second experiment examined the effect of target luminance on perceived duration. Consistent with a sensory persistence interpretation, judgments of duration increased with increasing luminance. The results from the two experiments were discussed in terms of varying degrees of retinal persistence produced by different stimuli. This view was contrasted with currently dominant interpretations that postulate changes in perceived duration to reflect different information-processing requirements across stimulus conditions.     

The effects of spatial frequency and target type on perceived duration

Two experiments are reported that attempt to demonstrate a critical role played by sensory persistence on a standard perceived-duration task employing brief visual stimuli. Experiment 1 examined the effect on perceived duration of varying the spatial frequency of a target. For both 40- and 70-msec flashes, increased spatial frequency resulted in reduced estimates of perceived duration. These results were contrasted with predictions derived from cognitive processing models of duration perception. In Experiment 2, three typical types of target employed in current research (an outlined circle, a “noise”-filled circle, and a completely filled circle) were shown to differ significantly in their perceived duration and in their sensitivity to increases in physical duration. The results were discussed in terms of variable degrees of retinal persistence produced by the three types of targets. The possible implications for specific discrepancies in the literature and across-study comparisons in general were enumerated.     

Robust estimation of ability in the Rasch model

Estimating ability parameters in latent trait models in general, and in the Rasch model in particular is almost always hampered by noise in the data. This noise can be caused by guessing, inattention to easy questions, and other factors which are unrelated to ability. In this study several alternative formulations which attempt to deal with these problems without a reparameterization are tested through a Monte Carlo simulation. It was found that although no one of the tested schemes is uniformly superior to all others, a modified jackknife stood out as the best one in general, it was also super efficient (more efficient than the asymptotically optimal estimator) for tests with forty or fewer items. It is proposed that this sort of jackknifing scheme for estimating ability be considered for practical work.This research was funded through a grant from the Law Enforcement Assistance Administration (78-NI-AX-0047) to the Bureau of Social Science Research, Howard Wainer, Principal Investigator. We would like to thank Ronald Mead, Anne Morgan and James Ramsay for kind, generous, and invaluable help at various stages of the project.     

Aerobic conditioning and stress reduction: Participation or conditioning?

The efficiency of an aerobic conditioning program (jogging) is compared to cognitive therapy (stress inoculation) and a waiting list control in modifying self-reported chronic stress. The participants were community residents; 48 were females and 25 were males. Treatment sessions were conducted over a 10-week period with subjects meeting in small groups for 1$\text{1}\text{2}$ hours per week. The State/Trait Inventories, a Tension Thermometer and a submaximal bicycle ergometer test were administered pre, post and follow-up. Repeated measures, multivariate analysis of variance indicated that both treatments were effective in reducing stress compared to the waiting list control and that these changes were maintained at 3-month follow-up. Multivariate analysis indicated that participants with higher initial levels of aerobic fitness did not report less stress, while participants who obtained higher levels of fitness during the conditioning program fared no better in reducing stress than their counterparts who obtained lower levels of aerobic fitness. These findings are of interest because they suggest that the psychosocial components of the fitness program were active ingredients of treatment rathee than the effects of improved cardiovascular functioning.     

Somatic complaints in anxious children

Although stomachaches and headaches are considered characteristic of children with anxiety disorders, there is converging evidence that a broader range of somatic symptoms may be associated with children's expressions of anxiety. The purpose of this study was to determine the prevalence of somatic complaints in anxious children. The results indicated that children with anxiety disorders endorsed the presence of many different somatic complaints, and that contrary to clinical intuition, stomaches and headaches were not among the most commonly reported symptoms. In addition, the anxious children endorsed significantly more somatic complaints when compared to normal controls. Furthermore, the symptom pattern reported by anxious children indicated the presence of both the somatic and cognitive components usually associated with panic attacks, although none of the children met diagnostic criteria for panic disorder. The results are discussed in terms of the contribution of somatic symptoms to the understanding of anxiety disorders in children.     

Do learning-disabled children exhibit peripheral deficits in selective attention? An analysis of eye movements during reading

It has been suggested that deficits in selective attention play a functional role in the learning and behavior problems of children diagnosed as learning- disabled. In the present study, peripheral and central aspects of selective attention were distinguished and peripheral aspects were examined. The attending eye movements during reading of 12 fifth-grade learning-disabled children who read at the third-grade level were compared with 12 fifth-grade children who read at the fifth-grade level (grade placement controls) and 12 third-grade children who read at the third-grade level (reading level controls). The learning-disabled children did not differ from their reading level controls on any of W measures but showed a pattern of eye movements that was generally slower and less smooth than their grade placement controls. While these patterns might be considered to be immature relative to normal readers of the same age, they are not indicative of peripheral deficits in selective attention. Males, however, did exhibit more variability in duration of fixations and made more regressive eye movements than did females.     

Salt taste detection: an R-index approach to signal-detection measurements

The R-index approach to the signal-detection P(A) index of sensitivity was used to measure taste sensitivity to NaCl solutions. The R-index is the predicted probability of the correct choice of a signal, for a given signal-noise pair. For flow-wise and sipwise presentation, R-indices did not fluctuate significantly, provided subjects could not see the stimuli yet to be presented, indicating a lack of systematic sensitivity drift. The simultaneous measurement of more than one signal strength with reference to a common noise stimulus was seen to be a viable and sensitive procedure. Comparison of flow-wise and sipwise presentation of stimuli using R-indices, indicated that the former elicited greater subject sensitivity to NaCl taste.