The ABCs of categorical perception

Studies of speech perception first revealed a surprising discontinuity in the way in which stimulus values on a physical continuum are perceived. Data which demonstrate the effect in nonspeech modes have challenged the contention that categorical perception is a hallmark of the speech mode, but the psychophysical models that have been proposed have not resolved the issues raised by empirical findings. This study provides data from judgments of four sensory continua, two visual and two tactual-kinesthetic, which show that the adaptation level for a set of stimuli serves as a category boundary whether stimuli on the continuum differ by linear or logarithmic increments. For all sensory continua studied, discrimination of stimuli belonging to different perceptual categories was more accurate than discrimination of stimuli belonging to the same perceptual category. Moreover, shifts in the adaptation level produced shifts in the location of the category boundary. The concept of Adaptation-level Based Categorization (ABC) provides a unified account of judgmental processes in categorical perception without recourse to post hoc constructs such as implicit anchors or external referents.     

The relative contributions of subjective and objective measures of body shape and size to body image and disordered eating in women

This research explored the relative contributions of subjective perceptions of body weight and body shape/proportion, as well as objective measures of body mass index (BMI) and waist-to-hip ratio (WHR) to disordered eating, exercise involvement, and body image. One hundred and fifty-eight female university students completed questionnaires and provided body measurements for this study. Although an interaction between BMI and WHR was found for some measures (i.e., Eating Disorder Examination Questionnaire total and subscale scores), results indicated that BMI was consistently the better objective predictor of disordered eating and body image. Subjective perceptions of body weight and, to a lesser extent, body shape, were found to account for the greatest proportion of variance in the dependent measures (disordered eating, body esteem, and body dissatisfaction). Overall, these results offer more support for sociocultural theories emphasizing the importance of thinness for women, than evolutionary theories emphasizing the role of WHR.     

The relation of lifetime cognitive activity and lifetime access to resources to late-life cognitive function in older African Americans

Research in older Caucasians has demonstrated that cognitive activity is related to cognitive function in late adulthood. Knowledge of this association is limited in older minority populations. We examined the relation of cognitive activity and access to cognitive resources, with cognitive function in a group of 108 older African Americans. We constructed two scales to measure the frequency of cognitive activity and the presence of resources that promote cognitive activity during early and late life. Both measures had high internal consistency and the cognitive activity scale had adequate temporal stability over a 4-week interval. In analyses that controlled for age and education, more frequent lifetime cognitive activity was related to current cognitive function, but lifetime cognitive resources only approached significance. The results suggest that both measures are psychometrically sound in a minority population and that lifetime cognitive activity may contribute to current cognitive function in African Americans.     

Strengthening the validity of population-based suicide rate comparisons: an illustration using U.S. military and civilian data

The objectives of this study were to generate precise estimates of suicide rates in the military while controlling for factors contributing to rate variability such as demographic differences and classification bias, and to develop a simple methodology for the determination of statistically derived thresholds for detecting significant rate changes. Suicide rate estimates were calculated for the military population and each service branch over 11 years, directly standardized to the 2000 U.S. population. Military rates were highly comparable across branches and were approximately 20% lower than the civilian rate. Direct adjustment essentially controlled for the demographic confounds in this sample. Applying the Poisson-based method, we demonstrate that suicide rate fluctuations as large as 20-40% in any year may be attributed to random error.     

Loss aversion is an affective forecasting error

Loss aversion occurs because people expect losses to have greater hedonic impact than gains of equal magnitude. In two studies, people predicted that losses in a gambling task would have greater hedonic impact than would gains of equal magnitude, but when people actually gambled, losses did not have as much of an emotional impact as they predicted. People overestimated the hedonic impact of losses because they underestimated their tendency to rationalize losses and overestimated their tendency to dwell on losses. The asymmetrical impact of losses and gains was thus more a property of affective forecasts than a property of affective experience.     

Cognitive decline in old age: separating retest effects from the effects of growing older

Repeated administration of cognitive tests improves test performance, making it difficult for researchers to gauge the true extent of age-related cognitive decline. The authors examined this issue using data from the Rush Religious Orders Study and linear mixed-effects models. At annual intervals for up to 8 years, more than 800 older Catholic clergy members completed the same set of 19 cognitive tests from which previously established composite measures of cognitive domains were derived. Retest effects on some measures were substantial and continued to accumulate even after 8 annual test readministrations, but effects on other measures were minimal. Across cognitive measures, retest effects were not related to age, sex, or education. Individual differences in retest effects were substantial but not consistent across cognitive measures. The results suggest that retest-based improvement in cognitive test performance can be substantial and persistent.     

Inaccurate self-knowledge formation as a result of automatic behavior

Four studies tested a post-priming misattribution process whereby a primed goal automatically influences people's behavior, but because people are unaware of that influence, they misattribute their behavior to some other internal state. People who were primed with a goal were more likely to choose an activity that was relevant to that goal, but did not recognize that the prime had influenced their choices. Instead, people used more accessible and plausible reasons to explain their behavior. The goals were seeking romantic interaction (Studies 1 and 2), helping (Study 3) and earning money (Study 4). People made choices related to these goals but misattributed the choices to temporary preferences (Studies 1 and 3) and more permanent dispositions (Studies 2 and 4). The misattribution had downstream effects, leading to choice behavior consistent with the erroneous self-knowledge. We suggest that automatic behavior can lead to a confabulated self-knowledge with behavioral consequences.