Adaptive memory: survival processing enhances retention

The authors investigated the idea that memory systems might have evolved to help us remember fitness-relevant information--specifically, information relevant to survival. In 4 incidental learning experiments, people were asked to rate common nouns for their survival relevance (e.g., in securing food, water, or protection from predators); in control conditions, the same words were rated for pleasantness, relevance to moving to a foreign land, or personal relevance. In surprise retention tests, participants consistently showed the best memory when words were rated for survival; the survival advantage held across recall, recognition, and for both within-subject and between-subjects designs. These findings suggest that memory systems are "tuned" to remember information that is processed for fitness, perhaps as a result of survival advantages accrued in the past.     

Absolute distance perception to locations off the ground plane

Using vision, humans can accurately judge distances to locations on the ground surface up to distances of at least 20 m. Most theories of depth perception assume that this ability is associated with the fact that we live in a terrestrial world in which locations of interest often appear on the ground and for which feedback about distance is often available from nonvisual sources such as walking. Much less is known about the ability of humans to judge absolute distances to locations other than on or supported by the ground plane beyond a few meters, at which point binocular stereo provides at best limited information about distance scaling. We show that one commonly used action measure for probing absolute distance perception exhibits accurate performance, even for targets located on the ceiling of a large room. We follow this with evidence that distance to ceiling locations is recovered with a mechanism that depends, at least in part, on the angle from the line of sight to the target location and a gravity-based frame of reference.     

Solo status and self-construal: being distinctive influences racial self-construal and performance apprehension in African American women

A preliminary study and main experiment tested the hypothesis that racial solo status (being the only member of one's race in a group) increases racial self-construal among African Americans. The preliminary study showed that African American men and women reported greater collectivist (i.e., group-based) over individualist self-construal under solo compared to nonsolo status, whereas Whites did not. The main experiment showed that the increased collectivism among African American solo women appears to be strongly reflected in racial identity becoming a salient aspect of self-construal. African American participants were also more likely than Whites to perceive that their anticipated performance would be generalized to their race, to feel like representatives of their race, and to show greater performance apprehension (indirectly evidenced by increased self-handicapping) when in racial solo status. The implications of solo status for African Americans in evaluative situations (such as academic testing sessions) are discussed.     

Autobiographical memory: unpleasantness fades faster than pleasantness over time

We examined the effects of retention intervals on the recollection of the emotional content of events. Memory for personal events was tested for three retention intervals: 3 months, 1 year, and 4.5 years. Participants made pleasantness ratings both at the time of recording the event and during testing of the events. Analyses of the data show that judgments of pleasantness or unpleasantness of an event became less extreme as retention interval increased. This effect was larger for unpleasant events than for pleasant events. Subsequent memory ratings of pleasant and unpleasant events showed a modest effect of pleasantness with pleasant events remembered slightly better than unpleasant events. The theoretical implications of these data are discussed. © 1997 John Wiley & Sons, Ltd.     

Patterns of marijuana use and physical health indicators among Canadian youth

We examine how trajectories of marijuana use in Canadian youth (ages 15 to 28) are related to physical health indicators in adolescence and young adulthood. Youth were initially recruited in 2003 (N = 662; 48% male; ages 12 to 18) and followed for six waves. Five trajectories of marijuana use (Abstainers-29%, Occasional users-27%, Decreasers-14%, Increasers-20% and Chronic users-11%) were identified. Chronic users reported more physical symptoms, poorer physical self-concept, less physical activity, poorer eating practices, less sleep, and higher number of sexual partners during adolescence than other classes. Decreasers also reported poorer physical self-concept and poorer eating practices than abstainers. Other trajectory classes showed few significant health problems. Chronic users also reported more acute health problems (i.e. serious injuries, early sexual debut, higher number of sexual partners, greater likelihood of having a STI) in young adulthood than all other classes contributing to costs of healthcare. Youth who engage in early, frequent and continued use of marijuana from adolescence to young adulthood are at-risk of physical health problems in adolescence and young adulthood.     

Early intervention in the family system: A framework and review

A framework for understanding the effect of early intervention on family structure and functioning is presented. The framework uses five sets of variables to characterize families: Their ecology; and the values, roles, personalities, and interactions of family members. Twenty research studies that met criteria of having comparison/control groups, beginning intervention either prenatally or during the first 3 months of infancy, and directing intervention to family functioning are abstracted and examined in detail. Successful and unsuccessful studies are compared as to population and nature of intervention. Two criteria of success are used: (1) The commonly used criterion of any positive change; (2) a more rigorous criterion of change in at least three areas of family functioning, based on the assumption that more pervasive change will have more lasting influence on child development. Application of the first criterion found that 75% of early family focused intervention studies showed a successful outcome. Application of the latter criterion found that 50% showed a successful outcome. Further, there were no significant differences between successful and unsuccessful studies as to target group or type of intervention. The review suggests that early intervention targeted at family functioning is effective and that a more pervasive and sustained effect is likely if the intervention includes at least 11 or more contacts over at least a 3-month period.     

Twelve‐Step Groups,Attributions of Blame for Personal Sadness,Psychological Well‐Being,and the Moderating Role of Gender1

Two studies investigated links among 12‐step group participation, gender, attributions of blame for personal sadness, and psychological well‐being. Study I used a correlational design to examine these links cross‐sectionally among substance abusers who identified alcohol as their primary drug problem. Study 2 used an experimental design to examine prospective links among these variables for substance abusers who were also adult children of alcoholics. Females engaged in more blame than did males, and personal blame was negatively related to psychological well‐being in Studies 1 and 2. Most significantly, 12‐step group participation was associated with lower personal blame among females but not among males across both studies. These results indicate that 12‐step groups can reduce personal blame among females who have substance abuse problems.     

Strategy selection in causal reasoning: when beliefs and covariation collide.

The present study investigated how people combine covariation information (Cheng & Novick, 1990, 1992) with pre-existing beliefs (White, 1989) when evaluating causal hypotheses. Three experiments, using both within- and between-subjects designs, found that the use of covariation information and beliefs interacted, such that the effects of covariation were larger when people assessed hypotheses about believable than about unbelievable causal candidates. In Experiment 2, this interaction was observed when participants made judgments in stages (e.g., first evaluating covariation information about a causal candidate and then evaluating the believability of a candidate), as well as when the information was presented simultaneously. Experiment 3 demonstrated that this pattern was also reflected in participants' metacognitive judgments: Participants indicated that they weighed covariation information more heavily for believable than unbelievable candidates. Finally, Experiments 1 and 2 demonstrated the presence of individual differences in the use of covariation- and belief-based cues. That is, individuals who tended to base their causality judgments primarily on belief were less likely to make use of covariation information and vice versa. The findings were most consistent with White's (1989) causal power theory, which suggests that covariation information is more likely to be considered relevant to believable than unbelievable causes.     

Differences in performance on a reversal learning test and division of labor in honey bee colonies

We studied the association between honey bee (Apis mellifera) division of labor and performance on an olfactory reversal-learning test. Manipulations of colony age structure and flight experience were used to test whether differences in performance are associated with age, current behavioral state, or flight experience. Nurse bees showed significantly faster rates of extinction to a learned odor than did foragers. This difference was associated primarily with differences in behavioral state, rather than age; it was seen when comparing nurses and foragers from typical colonies and normal-age nurses and precocious foragers from single-cohort colonies. Differences in extinction rate were not related to differences in flight experience; there was no difference between foragers and foraging-age bees denied flight experience. These results suggest that changes in learning and memory occur in association with division of labor. We speculate on the possible functional significance of the difference in extinction rate between nurses and foragers. Received: 15 January 2000 / Accepted: 22 August 2000