DISCOUNTING OF DELAYED REWARDS:

Abstract— In this study, children, young adults, and older adults chose between immediate and delayed hypothetical monetary rewards The amount of the delayed reward was held constant while its delay was varied All three age groups showed delay discounting, that is, the amount of an immediate reward judged to be of equal value to the delayed reward decreased as a function of delay The rate of discounting was highest for children and lowest for older adults, predicting a life-span developmental trend toward increased selfcontrol Discounting of delayed rewards by all three age groups was well described by a single function with agesensitive parameters (all R²s>94) Thus, even though there are quantitative age differences in delay discounting, the existence of an age-invanant form of discount function suggests that the process of choosing between rewards of different amounts and delays is qualitatively similar across the life span     

The impact of lesion laterality on neuropsychological change following posterior pallidotomy: a review of current findings

This paper reviews seven studies evaluating the impact of lesion laterality on the neuropsychological sequelae of posterior pallidotomy for treatment of Parkinson's disease. Left lesions of the internal globus pallidus (GPi) were associated with subtle deficits on measures sensitive to frontal lobe function. The findings of a randomized clinical trial including a patient control group indicated that many of these deficits were transient, resolving by 6 months following surgery. Right GPi lesions were not consistently associated with neuropsychological deficit, except in one study that included a significant proportion of demented patients. It is hypothesized that when neuropsychological decline is present following surgery, this reflects impingement of posterior GPi lesions into proximal regions such as anterior GPi or the external pallidum that participate in cognitive basal ganglia-thalamocortical circuits. The findings from neuroimaging will be important for elucidating the relationship between lesion locus and neuropsychological sequelae.     

Computer models of cognitive processes

Conclusion From the small sample of achievements that I have had time to mention, we can only conclude that automation is here to stay. Nor is there any doubt that more powerful automata will be built. A great many of the higher human abilities will be given to machines. The great rush to automation is sure to stimulate psychologists to learn more about the human symbolic processes being mimicked by the machines. And the computers, which are the ultimate cause of the feverish scramble toward automation, are providing both the framework for describing complex models of behavior and also the means for testing these models. With both the means and the motivation at hand, psychologists are sure to make rapid progress in understanding complex human behavior.Operated with support from the United States Army, Navy, and Air Force.     

Face and mouth inversion effects on visual and audiovisual speech perception

Three experiments examined whether image manipulations known to disrupt face perception also disrupt visual speech perception. Research has shown that an upright face with an inverted mouth looks strikingly grotesque whereas an inverted face and an inverted face containing an upright mouth look relatively normal. The current study examined whether a similar sensitivity to upright facial context plays a role in visual speech perception. Visual and audiovisual syllable identification tasks were tested under 4 presentation conditions: upright face-upright mouth, inverted face-inverted mouth, inverted face-upright mouth, and upright face-inverted mouth. Results revealed that for some visual syllables only the upright face-inverted mouth image disrupted identification. These results suggest that upright facial context can play a role in visual speech perception. A follow-up experiment testing isolated mouths supported this conclusion.     

Similarity and inhibition in long-term memory: evidence for a two-factor theory

Recalling a past experience often requires the suppression of related memories that compete with the retrieval target, causing memory impairment known as retrieval-induced forgetting. Two experiments examined how retrieval-induced forgetting varies with the similarity of the competitor and the target item (target-competitor similarity) and with the similarity between the competitors themselves (competitor-competitor similarity). According to the pattern-suppression model (M. C. Anderson & B. A. Spellman, 1995), high target-competitor similarity should reduce impairment, whereas high competitor-competitor similarity should increase it. Both predictions were supported: Encoding target-competitor similarities not only eliminated retrieval-induced forgetting but also reversed it, whereas encoding competitor-competitor similarities increased impairment. The differing effects of target-competitor and competitor-competitor similarity may resolve conflicting results concerning the effects of similarity on inhibition.     

Positive behavior support and applied behavior analysis

This article reviews the origins and characteristics of the positive behavior support (PBS) movement and examines those features in the context of the field of applied behavior analysis (ABA). We raise a number of concerns about PBS as an approach to delivery of behavioral services and its impact on how ABA is viewed by those in human services. We also consider the features of PBS that have facilitated its broad dissemination and how ABA might benefit from emulating certain practices of the PBS movement.     

Heart rate and ratings of perceived exertion during treadmill and elliptical exercise training

Elliptical exercise has recently increased in popularity. However, little is known regarding heart rate and perceptual responses during this exercise mode even though such information is important with respect to prescribing and regulating exercise intensity. In the current study, heart rate and perceived exertion were compared between treadmill and elliptical exercise. During treadmill exercise (TM(EST)) participants estimated RPE-Overall as well as RPE-Legs and RPE-Chest. Two elliptical sessions followed: (1) RPE estimation during elliptical exercise (EL(EST)): HR (b/ min.) from TM(EST) was achieved during elliptical exercise, with participants estimating RPE-Overall, RPE-Legs, and RPE-Chest. (2) RPE production during elliptical exercise (EL(PROD)): RPE-Overall from TM(EST) was produced during elliptical exercise. There were no significant differences between modes for RPE-Overall (TM(EST): 11.2 +/- 2.2 vs EL(EST): 11.9 +/- 3.2) or RPE-Chest (TM(EST): 11.0 +/- 2.4 vs EL(EST): 11.7+/- 3.2). Mean RPE-Legs was significantly different (TM(EST): 11.2 +/- 2.4 vs EL(EST): 12.5 +/- 3.1). Heart rate was not significantly different between TM(EST) (163 +/- 16.6) and EL(PROD) (159 +/- 20.0). Analysis indicated elliptical exercise is perceived as more intense with respect to leg (RPE-Legs) exertion. Further, RPE-Overall appears effective for regulating heart rate during elliptical exercise.