Diane F. Halpern

LEFT-HANDEDNESS : A MARKER FOR DECREASED SURVIVAL FITNESS

Life span studies have shown that the population percentage of left-handers diminishes steadily, so that they are drastically underrepresented in the oldest age groups. Data are reviewed that indicate that this population trend is due to the reduced longevity of left-handers. Some of the elevated risk for sinistrals is apparently due to environmental factors that elevate their accident susceptibility. Further evidence suggests that left-handedness may be a marker for birth stress related neuropathy, developmental delays and irregularities, and deficiencies in the immune system due to the intrauterine hormonal environment. Some statistical and physiological factors that may cause left-handedness to be selectively associated with earlier mortality are also presented.

The Smarter Sex: A Critical Review of Sex Differences in Intelligence

Although there are no sex differences in general intelligence, reliable differences are found on some tests of cognitive abilities. Many of the tasks that assess the ability to manipulate visual images in working memory show an advantage for males, whereas many of the tasks that require retrieval from long-term memory and the acquisition and use of verbal information show a female advantage. Large effects favoring males are also found on advanced tests of mathematical achievement, especially with highly select samples. Males are also overrepresented in some types of mental retardation. Effects sizes are variable and often large. These differences are generally found cross-culturally and across the life span. The nature–nurture dichotomy is rejected as an interpretive framework. In light of recent findings that environmental variables alter the biological underpinnings of intelligence and individuals actively participate in creating their environments, we prefer a psychobiosocial model for understanding sex differences in intelligence.

A process-oriented model of cognitive sex differences

Abstract Previous researchers have concluded that males perform better, on average, than females on visual-spatial tasks and quantitative tasks, while females show superior performance on verbal tasks. However, this tri-partite abilities rubric cannot account for the many cognitive tasks that do not conform to this pattern and the wide variety of tasks that are subsumed under each category heading. Males perform more accurately and quickly on some verbal tasks (e.g., verbal analogies), females perform more accurately and quickly on some quantitative tasks (e.g., arithmetic), and many visual-spatial tasks show no sex differences. In order to explain these anomalies, Halpern (1992), suggested that a more useful model for understanding cognitive sex differences would be organized according to the underlying cognitive processes. A process-oriented model based on what people do when they perform a cognitive task was investigated. We concluded that categorizing sex differences according to the underlying cognitive processes and utilizing recent advances in cognitive theory and measurement, allows us to explain anomalies in the research literature and provides a more meaningful approach to investigating individual differences in cognition.

Analogies as an aid to understanding and memory

The purpose of this study was to investigate the effect of domain distance on the comprehension of and memory for scientific passages. A near and far domain analogy were selected for each of three scientific passages

Sex differences in visuospatial working memory: components of cognitive processing.

Numerous studies have shown that sex differences in visuospatial tasks vary in size and direction depending on the nature of the task, with large differences favoring males on tasks that require transformations in visuospatial working memory. The cognitive processes underlying these differences were investigated using laboratory tasks developed by Dror and Kosslyn (1994). Four cognitive components of visuospatial working memory were assessed—image generation, maintenance, scanning, and transformation—in an attempt to identify the components that would show differential effects for females and males. The image generation task required retrieval of shape information from long-term memory, generation of a visual image in working memory, and utilization of the information about the shape in a decision task. The image maintenance task required only the latter two processes. The information processing demands required by scanning and rotation tasks came from the need to transform the visual image so that it could be used in decision making. Males responded more quickly on all four tasks (ds between .63 and .77), with no between-sex differences in accuracy. We concluded that speed of processing is central to understanding sex differences in visuospatial working memory. We discuss implications of these findings for performance on real-world visuospatial tasks.

Assessing Student Outcomes for Psychology Majors.

Numerous state legislatures, accrediting agencies, and public interest groups now require postsecondary institutions to produce evidence that they are providing a quality education for their students. One quality indicator is a measure of the “value added” to the cognitive development of students by the educational program. This approach emphasizes the educational gains made by students in each academic major and from the general education portion of their degree. Psychology departments are often expected to take the lead in assessing educational outcomes because learning assessments are a natural outgrowth of several fields of concentration in psychology–human learning, adult development, psychometrics, and program evaluation. When outcomes are used to improve psychology curricula or departmental policies, they become a powerful tool for improving teaching and learning.

Changing data, changing minds: What the data on cognitive sex differences tell us and what we hear

Abstract There is a widespread belief among the general public that females and males differ in many ways. Although the usual preference for environmentally-based explanations of these differences is, in part, a reaction against group-based prejudices, there is no justification for stereotypes or prejudices based on the finding that some areas of cognition show sex differences. New types of data are accumulating at a rapid rate that would logically require revised conclusions about the origins of cognitive sex differences. Despite large quantities of rapidly changing data, the willingness to embrace new sorts of judgments has been slow to follow. Sociocultural influences and personal tendencies to maintain a consistent belief system are identified as possible reasons why there is considerable disgreement in this area of research. Finally, practical applications for those concerned with the full development of human potential are offered.

Chapter 18 Laterality and Longevity: Is Left-Handedness Associated with a Younger Age at Death?

Publisher Summary The argument that sinistrality is associated with reduced longevity comes from a series of life-span and population surveys of handedness. Such studies have produced the surprising result that regardless of the index used to measure handedness, with increasing age, the number of lefthanders diminishes markedly. Several genetic models have been proposed to explain sinistrality as an inherited trait. Simple single gene theories in which sinistrality is viewed as a recessive trait that is transmitted much like blue eyes or blonde hair cannot account for the fact that a majority of the children of two left-handed parents are right-handed. A more complex two-gene model was proposed by Levy and Nagylaki. According to these authors, laterality is determined by the joint action of two genes—one that determines which cerebral hemisphere is dominant for speech and the other that determines whether motor control will be dominant in the contralateral or ipsilateral hemisphere. A third genetic model known as the “right shift” theory was proposed by Annett. Annett has hypothesized that the normal development of language in the left hemisphere and right-side motor control is genetically programmed. When this genotype is absent, right or left dominance for speech and motor control is equally likely. When genetic theories cannot be used to describe a phenomenon, psychologists typically look for environmental explanations such as pressures imposed on young children to use one hand or the other.

Age differences in response time to verbal and symbolic traffic signs

It is well established that verbal skills are maintained at a high level into old age while visuo-spatial skills begin to decline at an earlier age. it was hypothesized that the elderly would therefore respond more quickly to verbal traffic signs than to symbolic ones. In a test of this hypothesis, response times (RTs) to symbolic and verbal traffic signs were obtained from subjects in two age groups (19-29 and 65-77 years). While the elderly responded more slowly than the young subjects, they were an average of .2 seconds quicker in response to verbal traffic signs than symbolic ones. There were no differences in RT for symbolic and verbal signs for the young subjects. It is clear that the impact of traffic signs changes on the elderly deserves more attention than it is currently being given.

The influence of sex-role stereotypes on prose recall

The influence of sex-role stereotypes on memory was investigated. High-school students read a short story about a protagonist named either Linda or David. Results indicated that when the sex of the protagonist was the same as their own, the students answered significantly more questions about the story correctly than in the cross-sex conditions. A qualitative analysis of the kinds of errors and inferences made revealed that female subjects tended to rely on sex-role stereotypes when answering factual questions about a male protagonist, and male subjects tended to rely on sex-role stereotypes when answering inference questions about a female protagonist. These results provide partial support for the notion that individuals are more predisposed to view members of the opposite sex stereotypically and are more likely to alter their memories in accordance with these stereotypes than they are when answering questions about members of their same sex.