Confusable gratings selectively elicit orientation-contingent colour aftereffects

Induction of orientation-selective colour aftereffects (the McCollough effect) was studied with groups of young children who differed in their ability to discriminate an oblique grating from its mirror-image under recognition conditions. If the McCollough effect is generated through associative learning, children who failed to learn simple identifying responses to oblique lines as a function of the direction in which the lines point should also fail to associate colour lablels selectively to these same stimuli. Instead, the ease with which the McCollough effect was induced by alternate exposure to left-oblique lines in green light and right-oblique lines in red light was independent of the ability of the young child to discriminate direction of line under recognition conditions.     

Self-directedness: A Process Approach to Cognition

Standard approaches to cognition emphasise structures (representations and rules) much more than processes, in part because this appears to be necessary to capture the normative features of cognition. However the resultant models are inflexible and face the problem of computational intractability. I argue that the ability of real world cognition to cope with complexity results from deep and subtle coupling between cognitive and non-cognitive processes. In order to capture this, theories of cognition must shift from a structural rule-defined conception of cognition to a thoroughgoing embedded process approach.     

No pain, no gain: Perceptions of calorie expenditures of exercise and daily activities

Reduction in physical activity is considered a major contributor to weight problems. Increasingly, people are expending less energy in household chores but joining fitness clubs. Do people perceive ordinary daily activities to expend less energy than exercise activities using similar amounts of calories? In the present study college students were asked to evaluate the calorie expenditure of 30 physical activities (i.e., exercises and household tasks). The household tasks were matched (in terms of caloric expenditure) to at least one exercise activity. When participants rated both exercise and daily activities, it appears that they focused on rate of caloric expenditure rather than type of activity (i.e., household task or exercise). In Study 2, college students evaluated the energy expenditure of light/leisure, moderate, and intense exercise. This emphasis concerning the benefit of intense physical activity was observed once again. College students appear to have assimilated the belief that intense physical activity expends more energy than longer sessions of lower intensity physical activity using similar amounts of calories. Perhaps one reason why people are not physically active is that they believe physical activities must be intense to be of benefit. At the same time they are automatizing household chores and, thus, become less active overall.     

Genetic studies of stuttering in a founder population

Genome-wide linkage and association analyses were conducted to identify genetic determinants of stuttering in a founder population in which 48 individuals affected with stuttering are connected in a single 232-person genealogy. A novel approach was devised to account for all necessary relationships to enable multipoint linkage analysis. Regions with nominal evidence for linkage were found on chromosomes 3 (P=0.013, 208.8 centiMorgans (cM)), 13 (P=0.012, 52.6 cM), and 15 (P=0.02, 100 cM). Regions with nominal evidence for association with stuttering that overlapped with a linkage signal are located on chromosomes 3 (P=0.0047, 195 cM), 9 (P=0.0067, 46.5 cM), and 13 (P=0.0055, 52.6 cM). We also conducted the first meta-analysis for stuttering using results from linkage studies in the Hutterites and The Illinois International Genetics of Stuttering Project and identified regions with nominal evidence for linkage on chromosomes 2 (P=0.013, 180-195 cM) and 5 (P=0.0051, 105-120 cM; P=0.015, 120-135 cM). None of the linkage signals detected in the Hutterite sample alone, or in the meta-analysis, meet genome-wide criteria for significance, although some of the stronger signals overlap linkage mapping signals previously reported for other speech and language disorders. EDUCATIONAL OBJECTIVES: After reading this article, the reader will be able to: (1) summarize information about the background of common disorders and methodology of genetic studies; (2) evaluate the role of genetics in stuttering; (3) discuss the value of using founder populations in genetic studies; (4) articulate the importance of combining several studies in a meta-analysis; (5) discuss the overlap of genetic signals identified in stuttering with other speech and language disorders.     

Genetic Influence Helps Explain Variation in Human Fertility: Evidence From Recent Behavioral and Molecular Genetic Studies

To search for genetic influence on human fertility differentials appears inconsistent with past empirical research and prior interpretations of Fisher's fundamental theorem of natural selection. We discuss Fisher's theorem and give reasons why genetic influences may indeed account for individual differences in human fertility. We review recent empirical studies showing genetic influence on variance in fertility outcomes and precursors to fertility. Further, some of the genetic variance underlying fertility outcomes overlaps with that underlying fertility precursors. Findings from different cultures, different times, different levels of data, and both behavioral and molecular genetic designs lead to the same conclusion: Fertility differentials are genetically influenced, and at least part of the influence derives from behavioral precursors that are under volitional control, which are themselves genetically mediated.     

SEX DIFFERENCES IN CONFORMITY: STATUS AND GENDER ROLE INTERPRETATIONS

The experiment examines status and gender role explanations of the tendency for women to conform more than men in group pressure settings. Subjects believed they were assigned to groups containing two males and two females in addition to themselves and received these other group members' opinions, which were represented as deviating from the opinions that subjects had given earlier. Subjects then gave their opinions with the other group members either having or not having surveillance over these opinions. In addition, subjects were required to form impressions of each other's likability or expertise. The findings indicate that subjects' sex and age affected the extent of their conformity. Among older (19 years and older) subjects, females conformed more with surveillance than without it, whereas surveillance did not affect males' conformity. Among younger (under 19 years) subjects, surveillance had no effects. Analysis of sex differences revealed that older females were significantly more conforming than older males when under surveillance as well as when subjects formed impressions of one another's likability. Among younger subjects, there were no sex differences. These findings are discussed in terms of the theories that (a) both sex and age function as status characteristics and (b) gender roles determine conformity.