Aging and visual masking: sensory and attentional factors

Visual tasks can yield quantitatively similar patterns of performance that reflect different underlying mechanisms in younger and older observers. In 3 experiments, we used the visual masking task of J. T. Enns and V. Di Lollo (1997) to examine 2 of these mechanisms: stimulus contrast and attention. Performance appeared to be equivalent for younger and older observers in some circumstances, although manipulation of contrast and attention suggested that older observers may use focal attention to enhance the perceptual clarity of the target. For older observers, impoverished visual representations may more readily be eliminated by manipulation of attention or by the presence of a mask, indicating that both attention and stimulus quality are important influences on performance.     

Central localization of plasticity involved in appetitive conditioning in Lymnaea

Learning to associate a conditioned (CS) and unconditioned stimulus (US) results in changes in the processing of CS information. Here, we address directly the question whether chemical appetitive conditioning of Lymnaea feeding behavior involves changes in the peripheral and/or central processing of the CS by using extracellular recording techniques to monitor neuronal activity at two stages of the sensory processing pathway. Our data show that appetitive conditioning does not affect significantly the overall CS response of afferent nerves connecting chemosensory structures in the lips and tentacles to the central nervous system (CNS). In contrast, neuronal output from the cerebral ganglia, which represent the first central processing stage for chemosensory information, is enhanced significantly in response to the CS after appetitive conditioning. This demonstrates that chemical appetitive conditioning in Lymnaea affects the central, but not the peripheral processing of chemosensory information. It also identifies the cerebral ganglia of Lymnaea as an important site for neuronal plasticity and forms the basis for detailed cellular studies of neuronal plasticity.     

A test of transitive inferences in free-flying honeybees: unsuccessful performance due to memory constraints

We asked whether honeybees, Apis mellifera, could solve a transitive inference problem. Individual free-flying bees were conditioned with four overlapping premise pairs of five visual patterns in a multiple discrimination task (A+ vs. B-, B+ vs. C-, C+ vs. D-, D+ vs. E-, where + and - indicate sucrose reward or absence of it, respectively). They were then tested with the nonadjacent pairs A vs. E and B vs. D. Preference of B to D is consistent with the use of the implicit hierarchy A > B > C > D > E. Equal choice of B and D supports choice based on the associative strength of the stimuli. The bees' choice was determined by their memory constraints: experience with the last premise pair (D+ vs. E-) predominated. In the tests, bees preferred A to E and chose equally B and D. An analysis of the performance in terms of a reward/penalty ratio showed that B had a higher associative strength than D. Thus, bees do not establish transitive inferences but, rather, guide their choices by the joint action of a recency effect and the associative strength of the stimuli. The former supports choice of D, whereas the latter supports choice of B, thus determining equal choice of B and D in the tests.     

Effectiveness Research in the Context of School-Based Mental Health

There are many challenges to transporting evidence-based treatments from laboratories into real-world settings. However, if we hope to make our evidence-based treatments accessible and available to children and usable by community professionals, effectiveness research is imperative. We argue that schools represent an ideal real world setting in which to conduct such research. The goals of this paper are to present the advantages of conducting effectiveness research in the school setting and to encourage clinical researchers to engage in effectiveness research in this location, as there are benefits to children, pre-service professionals, communities, and researchers. We attempt to further advance the literature by discussing the challenges associated with this work and by providing a case example (The Youth Experiencing Success in School [Y.E.S.S.] Program) that demonstrates real world application of our recommendations.     

The role of employee loyalty and formality in voicing discontent

This study extends prior research on voice, loyalty, and postvoice outcomes by examining a variety of methods by which an employee may choose to voice a dispute. The authors argue that more loyal employees may prefer and use less formal methods to voice discontent and that the use of less formal voice methods relates to less job search activity and lower intent to quit. This study also investigated the interrelation between loyalty, voice method, and satisfaction with the attempt to resolve the dispute. Findings from a sample of university staff employees (N = 452) provide support for the hypotheses.     

Flank transparency: the effects of gaps,line spacing,and apparent motion

We analyze the properties of a dynamic color-spreading display created by adding narrow colored flanks to rigidly moving black lines where these lines fall in the interior of a stationary virtual disk. This recently introduced display (Wollschl?ger et al, 2001 Perception 30 1423-1426) induces the perception of a colored transparent disk bounded by strong illusory contours. It provides a link between the classical neon-color-spreading effect and edge-induced color spreading as discussed by Pinna et al (2001 Vision Research 41 2669-2676). We performed three experiments to quantitatively study (i) the enhancing influence of apparent motion; (ii) the degrading effect of small spatial discontinuities (gaps) between lines and flanks; and (iii) the spatial extent of the color spreading. We interpret the results as due to varying degrees of objecthood of the dynamically specified disk: increased objecthood leads to increased surface visibility in both contour and color.     

Attention to faces: a change-blindness study

What strategies does human vision use to attend to faces and their features? How are such strategies altered by 2-D inversion or photographic negation? We report two experiments in which these questions were studied with the flicker task of the change-blindness literature. In experiment 1 we studied detection of configural changes to the eyes or mouth, and found that upright faces receive more efficient attention than inverted faces, and that faces shown with normal contrast receive more efficient attention than faces shown in photographic negative. Moreover, eyes receive greater attention than the mouth. In experiment 2 we studied detection of local changes to the eyes or mouth, and found the same results. It is well known that inversion and negation impair the perception and recognition of faces. The experiments presented here extend previous findings by showing that inversion and negation also impair attention to faces.     

The Minnesota Multiphasic Personality Inventory-2 across the human immunodeficiency virus spectrum

The Minnesota Multiphasic Personality Inventory-2 (MMPI-2) was used to assess individuals' patterns of psychological symptoms across the spectrum of HIV illness. Two hundred and twenty-five participants in the present sample were administered the MMPI-2, 61 were HIV-seronegative controls, 61 were asymptomatic, 36 were symptomatic, and 67 met criteria for AIDS. Symptomatic HIV-seropositive patients scored higher on the Hypochondriasis, Conversion-Hysteria, and Depression Scales. These differences appeared to be largely due to an increase in somatic complaints rather than an increase in other depressive symptoms. Group differences did not appear to be due to HIV-associated neuropsychological dysfunction. Interpretive strategies for the MMPI-2 and treatment considerations are discussed.