Testing the role of response repetition in spatial priming in visual search

In common “attention” tasks, which require stimulus-identity processing prior to the formation of a speeded key-press response, spatial priming effects depend on response repetition. Typically, the repetition of a stimulus location is advantageous when the prior response repeats, but disadvantageous or inconsequential when the prior response changes. This link between responding and space makes it difficult to draw inferences about attentional bias from two-choice key-press tasks. Instead, the findings are accounted for by episodic retrieval theories, which argue that the response associated with a prior stimulus location is retrieved when a later stimulus occupies its space. This retrieval operation is advantageous if the prior response is needed but not otherwise, which explains typical patterns. This perspective motivated us to evaluate whether spatial priming effects in the visual-search literature depend critically on response repetition. To assess this, we reevaluated a series of experiments recently published by Tower-Richardi, Leber, and Golomb (Attention, Perception, & Psychophysics, 78(1), 114–132, 2016). Their goal was to determine the reference frame of spatial priming across visual search displays. Reassessment reveals that spatial priming was strongly dependent on response repetition when spatiotopic, retinotopic, and object-centered reference frames were perfectly confounded. However, when eye movements were made to dissociate the spatiotopic and object-centered reference frame from the retinotopic reference frame, spatial priming was positive and unaffected by response repetition. The findings demonstrate that at least two distinct processes factor into spatial priming across visual searches, which occur at different levels of representation.     

Impulsive choice and pre‐exposure to delays: iv. effects of delay‐ and immediacy‐exposure training relative to maturational changes in impulsivity

Impulsive choice describes preference for smaller, sooner rewards over larger, later rewards. Excessive delay discounting (i.e., rapid devaluation of delayed rewards) underlies some impulsive choices, and is observed in many maladaptive behaviors (e.g., substance abuse, gambling). Interventions designed to reduce delay discounting may provide therapeutic gains. One such intervention provides rats with extended training with delayed reinforcers. When compared to a group given extended training with immediate reinforcers, delay‐exposed rats make significantly fewer impulsive choices. To what extent is this difference due to delay‐exposure training shifting preference toward self‐control or immediacy‐exposure training (the putative control group) shifting preference toward impulsivity? The current study compared the effects of delay‐ and immediacy‐exposure training to a no‐training control group and evaluated within‐subject changes in impulsive choice across 51 male Wistar rats. Delay‐exposed rats made significantly fewer impulsive choices than immediacy‐exposed and control rats. Between‐group differences in impulsive choice were not observed in the latter two groups. While delay‐exposed rats showed large, significant pre‐ to posttraining reductions in impulsive choice, immediacy‐exposed and control rats showed small reductions in impulsive choice. These results suggest that extended training with delayed reinforcers reduces impulsive choice, and that extended training with immediate reinforcers does not increase impulsive choice.     

Recurrence of Posttraumatic Stress Disorder in Late Life: A Cognitive Aging Perspective

Clinical experience with older adults shows that many will experience PTSD symptoms in older adulthood because of trauma exposure early in life. Some of these patients struggled with PTSD in the distant past and remained symptomfree for decades only to have a recurrence of PTSD in late life. This paper outlines a cognitive aging explanation for the recurrence of PTSD. It is proposed that the age-related decreases in attention make the intrusion of trauma-related memories more likely. The increase in intrusive memories, combined with age-related decreases in working memory, explicit memory, and prospective memory, increases the subjective distress associated with the memories and results in a recurrence of PTSD.