On theoretical and realizable ideal conditions in psychophysics: Magnitude and category scales and their relation

By spacing 10 stimuli (white noise) between 40 and 110 dB according to two criteria [equal response ambiguity (ERA) and equal discriminability (ED)], an attempt was made to construct an “ideal” case for magnitude estimation and category rating. The “ideal” case is defined by linear and constant Weber functions (SDs as a function of scale values) for the two scales, respectively. Altogether, three group and two individual magnitude and category rating experiments were run with these two spacings. It was found that the ERA spacing approximated the ideal case well for both Weber functions and the ED spacing only for the Weber function of the category scale. The general psychophysical differential equation that relates scale values and Weber functions for the two scales allowed good prediction of the category scales from the magnitude scales and the Weber functions. The data suggested a distinction between phenotypic (empirical) and genotypic Weber functions, analogous to “real” and “ideal” cases in physics.     

Conditioning of a free operant in Octupus cyaneus Gray

Operant conditioning was studied in six specimens of Octopus cyaneus Gray. An “arm-out-of-water” operant, in which the octopus inserted an arm up a feeding-tube breaking the water surface, proved susceptible to reinforcement schedules. An apparatus was developed that provided automated reinforcement and recording. Performance was studied under continuous reinforcement, fixed-ratio and variable-ratio schedules, and extinction conditions.     

Memory colors in afterimages: A bicentennial demonstration

Six observers adjusted a colorimeter to match afterimages that resembled either a red, white, and blue American flag or a simple striped pattern. They matched the afterimages of stripes in a flag pattern as redder than afterimages of the same stripes in a simple striped pattern. The results suggest that the apparent color of an afterimage depends on memory color.     

Mental Health and Incarcerated Youth. II: Service Utilization

The incarceration of mentally ill youth is a serious problem not receiving the same attention as in adults. In this study, we examine the level of prior service utilization in incarcerated youth versus youth receiving community mental health services. We randomly recruited youth from middle South Carolina served by a local community mental health center (CMHC; n = 60), hospitalized in the state adolescent inpatient program (n = 50), and incarcerated in the S.C. Dept. of Juvenile Justice facilities (n = 75). We used a Services History to evaluate episodes of prior utilization of mental health, social service, educational, residential, and volunteer services, as well as the DISC-PC 2.3 to evaluate DSM-III-R diagnoses and symptoms and the CBCL and YSR to evaluate behavioral symptomatology. Incarcerated, hospitalized, and CMHC youth utilized similar levels of educational services and social services. Incarcerated youth had a significantly lower lifetime utilization of outpatient and acute mental health services and significantly higher utilization of out-of-home residential services than the other groups. These services utilization variables, along with gender and age, significantly distinguish incarcerated youth from the clinical groups, with clinical variables not serving to significantly distinguish them. Our results indicate the need to develop programs to prevent the entry of mentally ill/emotionally disturbed youth into the juvenile justice system. Youth who are at risk for incarcenation may benefit from intensive mental health services to prevent out-of-home placement and later incarceration.     

Presurgery distress and specific response expectancies predict postsurgery outcomes in surgery patients confronting breast cancer.

Prior to scheduled surgery, patients frequently experience particularly high levels of distress and expect a variety of postsurgery symptoms. Surgery patients who confront breast cancer are no exception. It has been suggested that such presurgery distress and response expectancies are predictive of postsurgery outcomes. To test the contribution of presurgery distress and expectancies to common postsurgery symptom outcomes (pain, nausea, fatigue, and discomfort), 63 female patients undergoing breast cancer surgery were recruited to a prospective study. Results indicated that presurgery distress uniquely contributed to patients' postsurgery nausea, fatigue, and discomfort; specific expectancies uniquely contributed to pain intensity, pain unpleasantness, and fatigue (ps < .05). Consistent with expectancy theory, associations between response expectancies and postsurgery outcomes were not due to presurgery distress.     

ON OUTLINING THE SHAPE OF DEPICTION

In this paper, I discuss the account of depiction proposed by Robert Hopkins in his book Picture, Image and Experience. I first briefly summarise Hopkins's account, according to which we experience depictions as resembling their objects in respect of outline shape. I then ask whether Hopkins's account can perform the explanatory tasks required of an adequate account of depiction. I argue that there are at least two reasons for which Hopkins's account of depiction is inadequate. Firstly, the notion of outline shape, as Hopkins presents it, is inconsistent. Moreover, I argue that, while a consistent construal of outline shape is possible, Hopkins's account becomes indistinguishable from previous accounts of depiction under any such construal. Second, I argue that, however it is construed, the notion of outline shape is unable to explain one of the central features which Hopkins himself insists any successful account of depiction must explain.     

Behavioral and genetic characterization of habituation using Caenorhabditis elegans

This review surveys the literature that investigates the behavioral characterization and cellular and molecular mechanisms of habituation using the model organism Caenorhabditis elegans. In 1990, C. elegans was first observed to show habituation to a non-localized mechanical tap. The parameters that govern this behavioral plasticity in C. elegans were subsequently characterized, which lead to the important hypothesis that habituation is mediated by multiple mechanisms. Many tools are available to C. elegans researchers that allow for relatively easy genetic manipulation. This has lead to a number of recent genetic studies that have begun to identify key genes and molecules that play a role in the mechanisms of habituation. Some of these genes include a vesicular glutamate transporter, a glutamate receptor subunit, a dopamine receptor and downstream intracellular signaling molecules, such as G proteins and kinases. Some of these genes only affect certain parameters of habituation, but not others supporting the hypothesis that multiple mechanisms mediate habituation. The field of research has also led to the dissection of different phases of memory (short-term vs. long-term memory for habituation), which are triggered by different training paradigms. The differences in mechanism between these various forms of memory are also beginning to be revealed.     

Intelligence in childhood and risk of psychological distress in adulthood: The 1958 National Child Development Survey and the 1970 British Cohort Study

Lower cognitive ability is a risk factor for some forms of severe psychiatric disorder, but it is unclear whether it influences risk of psychological distress due to anxiety or the milder forms of depression. The participants in the present study were members of two British birth national birth cohorts, the 1958 National Child Development Survey (n = 6369) and the 1970 British Cohort Study (n = 6074). We examined the association between general cognitive ability (intelligence) measured at age 10 (1970 cohort) and 11 years (1958 cohort) and high levels of psychological distress at age 30 (1970 cohort) or 33 years (1958 cohort), defined as a score of 7 or more on the Malaise Inventory. In both cohorts, participants with higher intelligence in childhood had a reduced risk of psychological distress. In sex-adjusted analyses, a standard deviation (15 points) increase in IQ score was associated with a 39% reduction in psychological distress in the 1958 cohort and a 23% reduction in the 1970 cohort [odds ratios (95% confidence intervals) were 0.61 (0.56, 0.68) and 0.77 (0.72, 0.83), respectively]. These associations were only slightly attenuated by further adjustment for potential confounding factors in childhood, including birth weight, parental social class, material circumstances, parental death, separation or divorce, and behaviour problems, and for potential mediating factors in adulthood, educational attainment and current social class. Intelligence in childhood is a risk factor for psychological distress due to anxiety and the milder forms of depression in young adults. Understanding the mechanisms underlying this association may help inform methods of prevention.