How dogs navigate to catch frisbees

Using micro-video cameras attached to the heads of 2 dogs, we examined their optical behavior while catching Frisbees. Our findings reveal that dogs use the same viewer-based navigational heuristics previously found with baseball players (i.e., maintaining the target along a linear optical trajectory, LOT, with optical speed constancy). On trials in which the Frisbee dramatically changed direction, the dog maintained an LOT with speed constancy until it apparently could no longer do so and then simply established a new LOT and optical speed until interception. This work demonstrates the use of simple control mechanisms that utilize invariant geometric properties to accomplish interceptive tasks. It confirms a common interception strategy that extends both across species and to complex target trajectories.     

The persistence of underpowered studies in psychological research: causes, consequences, and remedies

Underpowered studies persist in the psychological literature. This article examines reasons for their persistence and the effects on efforts to create a cumulative science. The "curse of multiplicities" plays a central role in the presentation. Most psychologists realize that testing multiple hypotheses in a single study affects the Type I error rate, but corresponding implications for power have largely been ignored. The presence of multiple hypothesis tests leads to 3 different conceptualizations of power. Implications of these 3 conceptualizations are discussed from the perspective of the individual researcher and from the perspective of developing a coherent literature. Supplementing significance tests with effect size measures and confidence intervals is shown to address some but not necessarily all problems associated with multiple testing.     

Asians on the edge: the reciprocity of allied behavior

The discussion of racial and ethnic minority issues has traditionally been a Black-White discussion. As such, American Indians, Latinos, and Asians have been left out of this discussion. Such exclusion does not make scientific sense, as it makes conclusions about race relations less generalizable. It also comes with a cost, as the excluded groups are often asked to give up their respective ethnicities to join the discussion. The present article, discusses some of these scientific and social losses and suggests that prominent African American and White leaders serve as allies for the inclusion of all groups in the discussion of race relations, focusing particularly on the Asian experience. Such allies must come not only from academicians but also from community activists and those in power positions in the media.     

Selective sex differences in declarative memory

Sex invariance of a six-factor, higher order model of declarative memory (two second-order factors: episodic and semantic memory; and four first-order factors: recall, recognition, fluency, and knowledge) was established for 1,796 participants (35-85 years). Metric invariance of first- and second-order factor loadings across sex was demonstrated. At the second-order level, a female advantage was observed for both episodic and semantic memory. At the first-order level, sex differences in episodic memory were apparent for both recall and recognition, whereas the differences in semantic memory were driven by a female superiority in fluency. Additional tests of sex differences in three age groups (35-50, 55-65, and 70-85 years of age) indicated that the female superiority in declarative memory diminished with advancing age. The factor-specific sex differences are discussed in relation to sex differences in hippocampal function.     

Change in cognitive capabilities in the oldest old: the effects of proximity to death in genetically related individuals over a 6-year period

Change in cognitive abilities was assessed over a 6-year period in a sample of monozygotic and same-sex dizygotic twin pairs (N = 507 individuals), aged 80 and older (mean age = 83.3 years: SD = 3.1). who remained nondemented over the course of the study. Latent growth models (LGMs) show that chronological age and time to death are consistent predictors of decline in measures of memory, reasoning, speed, and verbal abilities. Multivariate LGM analysis resulted in weak and often negative correlations among rates of change between individuals within twin pairs, indicating greater differential change within twin pairs than occurs on average across twin pairs. These findings highlight several challenges for estimating genetic sources of variance in the context of compromised health and mortality-related change.     

Predicting abuse in adolescent dating relationships over 1 year: the role of child maltreatment and trauma

Three mediators of the relationship between childhood maltreatment and dating violence perpetration during midadolescence (i.e., trauma-related symptoms, attitudes justifying dating violence, and empathy and self-efficacy in dating relationships) were tested over 1 year with a sample of students from 10 high schools (N = 1,317). Trauma-related symptoms had a significant cross-time effect on predicting incidents of dating violence for both boys and girls. Attitudes and empathy and self-efficacy did not predict dating violence over time, although they were correlated with such behavior at both time points. Child maltreatment is a distal risk factor for adolescent dating violence, and trauma-related symptoms act as a significant mediator of this relationship. The importance of longitudinal methodology that separates correlates from predictors is discussed.     

The native mind: biological categorization and reasoning in development and across cultures

This article describes cross-cultural and developmental research on folk biology: that is, the study of how people conceptualize living kinds. The combination of a conceptual module for biology and cross-cultural comparison brings a new perspective to theories of categorization and reasoning. From the standpoint of cognitive psychology, the authors find that results gathered from standard populations in industrialized societies often fail to generalize to humanity at large. For example, similarity-driven typicality and diversity effects either are not found or pattern differently when one moves beyond undergraduates. From the perspective of folk biology, standard populations may yield misleading results because they represent examples of especially impoverished experience with nature. Certain phenomena are robust across populations, consistent with notions of a core module.     

An integrated theory of the mind

Adaptive control of thought-rational (ACT-R; J. R. Anderson & C. Lebiere, 1998) has evolved into a theory that consists of multiple modules but also explains how these modules are integrated to produce coherent cognition. The perceptual-motor modules, the goal module, and the declarative memory module are presented as examples of specialized systems in ACT-R. These modules are associated with distinct cortical regions. These modules place chunks in buffers where they can be detected by a production system that responds to patterns of information in the buffers. At any point in time, a single production rule is selected to respond to the current pattern. Subsymbolic processes serve to guide the selection of rules to fire as well as the internal operations of some modules. Much of learning involves tuning of these subsymbolic processes. A number of simple and complex empirical examples are described to illustrate how these modules function singly and in concert.     

High school drinking and its consequences

The present study surveyed 930 high school students regarding self-reported alcohol use, their perceptions of parents and peers, and the negative consequences of drinking. Two-fifths of males and one-fifth of females reported frequent problem (binge) drinking. Problem drinkers reported more negative consequences associated with drinking. In addition, problem drinkers reported greater susceptibility to peer pressure, perceived their peers as drinking more, and reported less parental monitoring and more use of alcohol by parents. The results demonstrate the importance of both parent and peer variables in adolescent substance use and highlight the negative consequences of drinking reported by high school students.