Explicitly modeling the effects of aging on response time

Research into the effects of aging on response time has focused on Brinley plots. Brinley plots are constructed by plotting mean response times for older subjects against those for young subjects for a set of experimental conditions. The typical result is a straight line with a slope greater than 1 and a negative intercept. This linear function has been interpreted as showing that aging leads to a general slowing of cognitive processes. In this article, we show that the slope of the Brinley plot is actually a measure of the relative standard deviations of older versus young subjects’ response times; it is not a measure of general slowing. We examine current models of the effects of aging on mean response time and show how they might be reinterpreted. We also show how a more comprehensive model, Ratcliff’s diffusion model (1978), can account for Brinley plot regularities and, at the same time, provide an account of accuracy rates, the shapes of response time distributions, and the relative speeds of error and correct response times, aspects of the data about which models designed to account for Brinley plots are mute. We conclude by endorsing a research approach that applies explicit models to response time data in aging in order to use the parameters of the model to interpret the effects of aging.     

What people believe about memory

Two representative samples of adult Norwegians (n=2000) were asked a set of general and specific questions regarding their beliefs and opinions about human memory. The results indicate that on many questions, such as time of the earliest memories, inhibiting effects of collaboration, and memory for dramatic versus ordinary events, the views of the general public concurred with current research findings, and people in general had realistic views about their own memory performance. On other questions, such as the reliability of olfactory as compared with visual and auditory memory, the memory of small children in comparison with that of adults, the likelihood of repression of adult traumatic memories, and on more general questions such as the possibility of training memory and the capacity limitations of long-term memory, a large proportion of the participants expressed views that are less supported by scientific evidence. Implications of these findings are briefly discussed.     

Context sensitivity in children's reasoning about ability across the elementary school years

Children's sensitivity to context when making inferences about ability was investigated. In three studies, elementary school children (ages 5 to 10, total N = 332) were asked to reason about the relation between academic ability and the speed with which characters completed puzzle tasks. Participants were primed to interpret the characters' task completion rates with reference to either (1) the character's perceptions of the difficulty of the task, or (2) the character's level of effort on the task. Children who were primed to consider the perceived difficulty of the task were more likely to view ability as a static quality, a pattern of reasoning that included a tendency to associate task completion rates with ability, and to agree that not all individuals are capable of achieving high levels of success. These results provide evidence that even early elementary school children are sensitive to subtle contextual cues when making inferences about ability, and are consistent with the possibility that children make use of implicit cues available to them in their social environment to derive meaning from achievement situations.     

Individual differences in emotional memory: adult attachment and long-term memory for child sexual abuse

In the present study, attachment-related differences in long-term memory for a highly emotional life event, child sexual abuse (CSA), were investigated. Participants were 102 documented CSA victims whose cases were referred for prosecution approximately 14 years earlier. Consistent with the proposal that avoidant individuals defensively regulate the processing of potentially distressing information (Bowlby, 1980), attachment avoidance was negatively associated with memory for particularly severe CSA incidents. This finding was not mediated by the extent to which participants reported talking about the abuse after it occurred, although post abuse discussion did enhance long-term memory. In addition, accuracy was positively associated with maternal support following the abuse and extent of CSA-related legal involvement. Attachment anxiety was unrelated to memory accuracy, regardless of abuse severity. Implications of the findings for theories of avoidant defensive strategies and emotional memory are discussed.     

Timely Completion of Class Requirements: Effects of Student and Faculty Gender

Male and female students have displayed different reactions to the gender of their faculty. This research was designed to explore whether biases exist early in the school term. Students unfavorable attitudes toward instructors were measured by the extent to which they delayed completing a course requirement: participation in a subject pool. Students scheduled a date upon which to participate in a research study. Discrepancies between their scheduled and their actual participation dates reveal that male students delayed their requirement (a) more when their instructors were female than when they were male, and (b) more than female students when the instructors were female. Supporting data suggest that the delayed completion time reflects lower evaluations of female faculty. Discussion focuses on implications in academic settings.     

Mothers and Models of Disability

Based on a qualitative anthropological study of American mothers of infants and young children newly diagnosed with disability, this essay examines how mothers understand their children and define disability in relation to publicly available discourses of disability and identity. In seeking to improve their children's opportunities in mainstream society, mothers appear to comply with the medical model. But over time and in the process of providing meaning to their experience, mothers retool models, drawing both on the social and minority group models' rejection of a problem-based definition of disability as inherently caused by impairment and on their own intimate engagement with impairment as an embodied experience.     

Children's evaluation of sources of information about traits

Children's assessment of the value of different sources of information about psychological traits was investigated among 6- to 7-year-olds and 10- to 11-year-olds across 5 studies (N = 330). Older children were more likely than younger children to reject self-report as a source of information about the highly evaluative traits smart and honest, but no such age-related difference was seen for the less evaluative comparison traits outgoing and nervous. A similar pattern of age-related differences was seen when children were asked to identify which of 4 sources of information--self-report, teacher report, peer report, or direct observation--would be most useful for obtaining information about the evaluative and comparison traits. The age-related increase in skepticism about self-report as a source of information for evaluative traits was associated with an increased appreciation of the role that social desirability plays in self-presentational processes.     

Relationships among compulsive hoarding, trauma, and attention-deficit/hyperactivity disorder

The current study investigated aspects of post-traumatic stress disorder and attention deficit/ hyperactivity disorder (ADHD) among hoarders. Compared to a sample of 36 controls, hoarders (n=26) reported a significantly greater number of different types of trauma, more frequent traumatic experiences, more symptoms of inattention, hyperactivity, and greater comfort derived from possessions. These findings are consistent with previous reports of extensive comorbidity associated with hoarding behaviors, and may reflect the potential usefulness of assessing PTSD and ADHD symptoms at the outset of hoarding treatments, as well as considering alternative pharmacological interventions.     

Analysis of group differences in processing speed: Where are the models of processing?

Recently, Myerson, Adams, Hale, and Jenkins (2003) replied to arguments advanced by Ratcliff, Spieler, and McKoon (2000) about interpretations of Brinley functions. Myerson et al. (2003) focused on methodological and terminological issues, arguing that (1) Brinley functions are not quantile-quantile (QQ) plots of distributions of mean reaction times (RTs) across conditions; that the fact that the slope of a Brinley function is the ratio of the standard deviations of the two distributions of means has no implications for the use of slope as a measure of processing speed; that the ratio of slopes of RT functions for older and young subjects plotted against independent variables equals the Brinley function slope; and that speed-accuracy criterion effects do not account for slowing with age. We reply by showing that Brinley functions are plots of quantiles against quantiles; that the slope is best estimated by the ratio of standard deviations because there is variability in the distributions of mean RTs for both older and young subjects; that the interpretation of equality of the slopes Brinley functions and plots of RTs against independent variables in terms of processing speed is model dependent; and that speed-accuracy effects in some, but not all, experiments are solely responsible for Brinley slopes greater than 1. We conclude by reiterating the point that was not addressed in Myerson et al. (2003), that the goal of research should be modelbased accounts of processing that deal with correct and error RT distributions and accuracy.