Aging and visual 3-D shape recognition from motion

Two experiments were conducted to evaluate the ability of younger and older adults to recognize 3-D object shape from patterns of optical motion. In Experiment 1, participants were required to identify dotted surfaces that rotated in depth (i.e., surface structure portrayed using the kinetic depth effect). The task difficulty was manipulated by limiting the surface point lifetimes within the stimulus apparent motion sequences. In Experiment 2, the participants identified solid, naturally shaped objects (replicas of bell peppers, Capsicum annuum) that were defined by occlusion boundary contours, patterns of specular highlights, or combined optical patterns containing both boundary contours and specular highlights. Significant and adverse effects of increased age were found in both experiments. Despite the fact that previous research has found that increases in age do not reduce solid shape discrimination, our current results indicated that the same conclusion does not hold for shape identification. We demonstrated that aging results in a reduction in the ability to visually recognize 3-D shape independent of how the 3-D structure is defined (motions of isolated points, deformations of smooth optical fields containing specular highlights, etc.).     

Use of the Personality Assessment Inventory in Assessment of Posttraumatic Stress Disorder in Women

This study investigated the utility of the Personality Assessment Inventory (PAI) for the assessment of posttraumatic stress disorder (PTSD). Participants were 55 community-residing adult women who were administered a comprehensive battery that included the PAI and the Clinician-Administered PTSD Scale (CAPS). Participants were classified as either PTSD or non-PTSD based on the CAPS, and PAI profiles were compared between the two groups. Significant group differences were found for seven PAI clinical scales (Anxiety, Depression, Anxiety-Related Disorders, Somatic Complaints, Paranoia, Borderline Features, and Schizophrenia), one validity scale (Negative Impression), and two treatment scales (Nonsupport and Treatment Rejection). When all PAI scales and component subscales are considered, the largest group differences were found for the physiological subscale of the Depression scale (DEP-P) and the Traumatic Stress subscale of the Anxiety-Related Disorders scale (ARD-T). ARD-T and DEP-P also demonstrated excellent diagnostic utility. Finally, correlations between PAI scales and four CAPS symptom clusters provided additional validity evidence, in particular supporting a distinction between effortful avoidance and numbing. Taken together, these results support the use of the PAI in the assessment of PTSD.This study was the basis of a Masters thesis for Meghan McDevitt-Murphy. Portions of this study were presented at the annual meeting of the Association for Advancement of Behavior Therapy, November 2000.     

Decisions and the evolution of memory: multiple systems, multiple functions

Memory evolved to supply useful, timely information to the organism's decision-making systems. Therefore, decision rules, multiple memory systems, and the search engines that link them should have coevolved to mesh in a coadapted, functionally interlocking way. This adaptationist perspective suggested the scope hypothesis: When a generalization is retrieved from semantic memory, episodic memories that are inconsistent with it should be retrieved in tandem to place boundary conditions on the scope of the generalization. Using a priming paradigm and a decision task involving person memory, the authors tested and confirmed this hypothesis. The results support the view that priming is an evolved adaptation. They further show that dissociations between memory systems are not--and should not be--absolute: Independence exists for some tasks but not others.