The US-preexposure effect in lithium-induced flavor-aversion conditioning is a consequence of blocking by injection cues

In 2 experiments, rats received flavor-aversion conditioning in which the unconditioned stimulus (US) was an orally consumed solution of lithium chloride (LiCl). The resulting aversion was not attenuated by giving preexposure to injections of LiCl, although such preexposure did attenuate aversions established using injected LiCl as the US (Experiment 1). This outcome suggests that blocking by injection-related cues is responsible for the US-preexposure effect observed in this situation. Experiment 2 confirmed this interpretation by showing that presenting such cues (by giving an injection of saline) at the time that the LiCl was drunk resulted in an attenuation of conditioning in animals preexposed to injections of LiCl. The US-preexposure effect obtained in these experiments can be explained solely in terms of blocking by injection cues, although other mechanisms may contribute to the effect seen in other flavor-aversion paradigms.     

Saccadic output is influenced by limb kinetics during eye-hand coordination

In several recent studies, saccadic eye movements were found to be influenced by concurrent reaching movements. The authors investigated whether that influence originates in limb kinematic or kinetic signals. To dissociate those 2 possibilities, the authors required participants (N = 6) to generate pointing movements with a mass that either resisted or assisted limb motion. With practice, participants were able to generate pointing responses with very similar kinematics but whose kinetics varied in a systematic manner. The results showed that saccadic output was altered by the amount of force required to move the arm, consistent with an influence from limb kinetic signals. Because the interaction occurred before the pointing response began, the authors conclude that a predictive signal related to limb kinetics modulates saccadic output during tasks requiring eye-hand coordination.     

Measuring "negative body image": validation of the Body Image Disturbance Questionnaire in a nonclinical population

Despite numerous measures of facets of the body image construct, no single assessment broadly measures a continuum of body image disturbance. Accordingly, this study developed the Body Image Disturbance Questionnaire (BIDQ), derived from the Body Dysmorphic Disorder Questionnaire. Participants were 220 college women and 75 college men who completed an online survey containing this new assessment and established measures of body image and psychosocial functioning. Results confirmed that the Body Image Disturbance Questionnaire was internally consistent and free of impression-management response bias. For both sexes, the measure converged appropriately with other body image indices (evaluation, affect, investment, and impact), was positively correlated with depression, social anxiety, and eating disturbance. Scores on this assessment also predicted psychosocial functioning above and beyond body dissatisfaction as a predictor. Greater body image disturbance was observed among women than men, among heavier than lighter women, and among White than African American women. Limitations and future research implications are discussed.     

Integrating biological and social processes in relation to early-onset persistent aggression in boys and girls

This study examined the relationship between biological and social risk factors and aggressive behavior patterns in an Australian high-risk sample of 370 adolescents. Perinatal, temperamental, familial, sociodemographic, and behavioral data were collected during interviews completed during pregnancy. immediately postpartum, and when the children were 6 months old and 5, 14, and 15 years old. Youths were given tests of verbal and neuropsychological functioning at the age 5 and age 15 follow-ups. Youths were divided into early-onset persistent aggression, adolescent-onset aggression, and nonaggressive behavior groups. Results revealed that the interaction of biological and social risk factors was significantly related to early-onset persistent aggression. Gender and developmental phase of measurement moderated the relationship between biosocial risks and the outcomes of early-onset persistent aggression and adolescent-onset aggression.     

Directed forgetting of related words: evidence for the inefficient inhibition hypothesis

Fifth-grade children and college students were asked to remember some words and to forget others in an item-cued-directed-forgetting task. Taxonomically related pairs of words and control pairs that were unrelated in meaning were used as stimuli. Children found it more difficult than did adults to ignore forget-cued words that followed associatively related words that were remember-cued. The results provide support for D. F. Bjorklund and K. K. Harnishfeger's (1990) inefficient inhibition hypothesis (i.e., that the efficiency of inhibitory mechanisms improves as children develop). The results also suggest that the inhibition is occurring primarily in the early stages of processing.     

Secure and defensive high self-esteem

Long-standing theories have suggested high self-esteem (SE) can assume qualitatively different forms that are related to defensiveness. The authors explored whether some high-SE individuals are particularly defensive because they harbor negative self-feelings at less conscious levels, indicated by low implicit SE. In Study 1, participants high in explicit SE but low in implicit SE showed the highest levels of narcissism--an indicator of defensiveness. In Studies 2 and 3, the correspondence between implicit and explicit SE predicted defensive behavior (in-group bias in Study 2 and dissonance reduction in Study 3), such that for high explicit-SE participants, those with relatively low implicit SE behaved more defensively. These results are consistent with the idea that high SE can be relatively secure or defensive.     

Tooth color: effects on judgments of attractiveness and age

Tooth whitening has become a very popular procedure. Advertisements for whitening products imply that whiter teeth are more attractive than yellower teeth. We tested this idea empirically by manipulating the tooth color of pictures of male and female targets. Participants' ratings of attractiveness were not influenced by tooth color. Exp. 2 yielded a negative correlation between attractiveness and age ratings: targets judged to be older were rated as less attractive. Unless whiter teeth help in some other way, e.g., improved self-esteem or confidence, it seems that tooth whitening procedures or products are not associated with increased attractiveness to others.     

Perceptual learning in flavor aversion: evidence for learned changes in stimulus effectiveness

Rats were exposed to the compound flavors AX and BX, presented in alternation, and to CX on a separate block of trials. Generalization to BX after aversion conditioning with AX was less than to CX. An equivalent effect was found when the nature of the common element was changed after preexposure but not when the common element was omitted during preexposure, during conditioning and test, or both. Rats conditioned with X alone again showed less aversion to BX than to CX; similarly, rats conditioned with a novel flavor (Y) showed less aversion to BY than to CY. These effects support the proposal that intermixed preexposure to AX and BX enhances the perceptual effectiveness of their unique features, A and B.     

Modeling memory decline in older adults: the importance of preclinical dementia, attrition, and chronological age

This longitudinal study examined memory loss in a sample of 391 initially nondemented older adults. Analyses decomposed observed memory loss into decline associated with preclinical dementia, study attrition, terminal decline, and chronological age. Measuring memory as a function of only chronological age failed to provide an adequate representation of cognitive change. Disease progression accounted for virtually all of the memory loss in the 25% of the sample that developed diagnosable dementia. In the remainder of the sample, both chronological age and study attrition contributed to observed memory loss. These results suggest that much of memory loss in aging adults may be attributable to the progression of preclinical dementia and other nonnormative aging processes that are not captured by chronological age.