Working memory and conditional reasoning

Little is known about the role of working memory in conditional reasoning. This paper reports three experiments that examine the contributions of the visuo-spatial scratch pad (VSSP), the articulatory loop, and the central executive components of Baddeley and Hitch's (1974) model of working memory to conditional reasoning. The first experiment employs a spatial memory task that is presented concurrently with two putative spatial interference tasks (tapping and tracking), articulatory suppression, and a verbal memory load. Only the tracking and memory load impaired performance, suggesting that these tap the VSSP and central executive, respectively. Having established the potency of these interference tasks two further experiments examined the effects of tapping and tracking (Experiment 2) and articulation and memory load (Experiment 3) on a conditional reasoning task. Neither tracking nor tapping affected the number of inferences accepted or response latency. Articulation also failed to affect conditional reasoning but memory load selectively reduced acceptance of modus tollens inferences. These results are discussed in terms of both rule-based and mental models theories of reasoning. While these data cannot discriminate between the two perspectives they provide support for one of the central assumptions in each: that some errors in reasoning are attributable directly to working memory demands. Taken together these experiments suggest that conditional reasoning requires an abstract working memory medium for representation; it does not require either the VSSP or the articulatory loop. It is concluded that the central executive provides the necessary substrate.     

Informational and neural adaptation curves are asynchronous.

Norwich's entropy theory of perception (plus a few additional assumptions) suggests the existence of an "infromational adaptation curves" (change in stimulus equivocation with stimulus duration) for suprathreshold prothetic stimuli that is synchronous with the "neural adaptation curve" (change in firing rate with stimulus duration) observed for sensory neurons. Five experiments are reported in which informational adaptation curves were measured for auditory and visual stimuli by having subjects make absolute identifications of suprathreshold sound or light intenstiies of various durations. Information transmissions for the shortest duration stimuli (1 and 5 msec, respectively, for light and sound) were surprisingly large (small equivocations), indicating that intensity information is acquired very rapidly by the whole organism. The equations of entropy theory were fitted to adaptation data for peripheral sensory neurons (spiral ganglion cells and retinal ganglion cells) and were compared to the informational adaptation curves. It was found that informational adaptation occurred more rapidly than neural adaptation. That is, the two types of adaptation process are asynchronous. However, for both audition and vision, the total amount of information mediated by the adaptation process (channel capacity) was about the same for both types of processes (2.03 bits vs. 2.1 bits per stimulus for sound intensity; 1.3 vs. 2.0 bits per stimulus for light intensity). Faster acquisition could be accomplished in the whole organism through convergent neural circuits that increase sampling rate by pooling the samples taken by individual receptor systems.     

Occupational suitability bias for full-time and part-time employment in sex-typed jobs

The present study examines the effects of employment status (full time, part time), job sex type, and job applicant sex upon judgments of occupational suitability. Sixty-three male and 176 female undergraduate students (ranging in age between 17 and 32 years) read a brief vignette describing either a man or a woman. Subjects then rated the occupational suitability of the person for three male sex-typed jobs (plumber, bus driver, cabinetmaker) and three female sex-typed jobs (secretary, telephone operator, hairdresser). In one condition subjects were explicitly told that these jobs were full time. In a second condition subjects were explicitly told that these jobs were part time. Results indicated a sex-congruency bias for both full time and part time employment. However, there was evidence that sex congruency bias is reduced for part-time employment.The author is grateful to Dr. Julian Barling, Dr. Rudolf Kalin, and Kevin Kelloway for their comments on an earlier draft of this article. The comments provided by the anonymous reviews were also appreciated.     

Analyses of feeding lateralization in the small-eared bushbaby (Otolemur garnettii): a comparison with the ring-tailed lemur (Lemur catta)

Feeding related lateralization was examined in a population of 23 small-eared bushbabies (Otolemur garnettii). The three measures used to determine lateralization were food reaching, holding, and manipulation. Sex and age differences were found, with adult females showing a strong right bias and adult males a left bias. Juvenile males were weakly lateralized and less consistent across measures than adult animals. The use of standard scores to assess lateralization allowed species comparisons to be made. The results of this study were compared with results from a previous study on lateralization in the ring-tailed lemur (Lemur catta). Species comparisons found sex differences to be a stronger factor in lateralization than species differences.     

Novel odors evoke risk assessment and suppress appetitive behaviors in mice

The effects of four novel odors on risk assessment by mice (i. e., flat back approach, stretched attention, immobility) and the suppression of appetitive behaviors were examined in two experiments. When novel odors were presented in a straight runway, subjects spent significantly less time in the odor compartment, relative to controls, when it contained sheep wool, chocolate, or citronella (but not cat fur) odors. Risk assessment behaviors occurred at similar levels among all groups and appetitive behaviors were not suppressed by the novel odors. When odorants were scattered over one half of the subjects' home cage floor in Experiment 2, all novel odors increased the duration of at least on e risk assessment measure and/or suppressed appetitive behaviors (i. e., eating, grooming, rearing). The results clearly reveal that a reasonably wide range of novel odors evoke at least some level of risk assessment which presumably reflects increased fearfulness. The odors of sheep wool and cat fur induced a wider range of such responses than did chocolate or cinnamon suggesting that mammalian odors may be particularly effective stimuli. If so, however, it is clear that predator odors are not uniquely effective in this regard. Experiment 1 also underscores the importance of the testing environment in assessing the behavioral effects of novel odors in mice. © 1993 Wiley-Liss, Inc.     

Immigrant Elders: Are We Missing Them? An Examination of Leisure Participation and Identity Among Immigrant Elders

Limited attention has been directed to the recreation and leisure needs of immigrant elders. This paper examines how involvement in recreation and leisure activities contributes to positive identity solidification and self-efficacy among immigrant elders who may be isolated and marginalized.     

Best Practices for Counseling Clients Experiencing Poverty: A Grounded Theory

Poverty is a pressing sociopolitical issue in the United States and worldwide. Poverty experiences have a significant effect on one’s mental health and overall wellness. Therefore, the ability to effectively serve clients experiencing poverty is critically important to professional counselors. However, there are no empirical models for counseling clients experiencing poverty. The authors present the results of a constructivist grounded theory study in which 21 professional counselors who work with clients experiencing poverty were interviewed to identify best practices for working with this population. Five major best practices are identified: (a) awareness, (b) training, (c) knowledge, (d) skills, and (e) advocacy. Implications for professional counseling are included.     

Sometimes The World is Not Enough: The Pursuit of Explanatory Laws in a Humean World

Abstract: A novel motivation for a Humean projectivist construal of our concept of scientific law is provided. The analysis is partially developed and used to explain intuitions that are problematic for a Humean reductionist construal of lawhood. A possible non-Humean rejoinder is discussed and rejected. In an appendix, further intuitions that are problematic for Humean reductionists are explained projectively.