Speed Modulation in Swimming Frogs

Swimming movements of 7 European green frogs (Rana esculenta) were studied, starting from the detailed analysis of the speed and timing of the propulsive, glide, and recovery phases of their intermittent swimming behavior. First, the authors identified the spatiotemporal factors used by the frogs to modulate their swimming behavior. None of the gait variables correlated strongly with average swimming speed, and no significant correlations were found between variables belonging to different phases. There did not seem to be an obvious control strategy. Instantaneous speeds at the transition of the different phases all increased significantly with average speed, however. The strong correlation between maximal speed at the end of propulsion and the speed averaged over a cycle might reflect the dominance of the propulsive phase in the determination of the overall swimming speed. The modulation of swimming speed thus seemed largely comparable with the regulation of jumping distance. That finding was confirmed in a mathematical model, in which the positive correlations between both glide and recovery speeds, on the one hand, and average speed, on the other, were shown to be only mathematical consequences of the strong impact of the propulsive phase on overall swimming performance. That finding suggests that the correlations did not result from an active control strategy.     

Age and Sex Differences in the Cooperative and Noncooperative Behavior of Pairs of American Children

Game playing behavior of same and mixed sex pairs of 5-, 8-, and 11-year-old American children was compared, using a game in which cooperative behavior maximized reward. Pairs of 8- and 11-year-old children were relatively more cooperative and attained significantly more Joint Reward Goals than 5-year-old pairs. Older pairs were not maximally cooperative, however, in terms of all the dependent measures; in adjusting for initial differences on practice trials, 5-year-olds and 8-year-olds took less time than the 11-year-olds, and 11-year-old pairs of boys took significantly more time than all other pairs. In addition, cooperative behavior increased across trials, especially for the 11-year-old children.     

Intuitive Heuristics Linking Perfectionism, Control, and Beliefs Regarding Body Shape in Eating Disorders

A number of correlational studies have established a clear association between perfectionism, control and beliefs regarding body shape in eating disorders (EDs). The aim of this study is to test the effectiveness of the above- mentioned associations in exploring the presence of intuitive heuristics. Intuitive heuristics can be conceived as as mental shortcuts, cognitive processes that are highly susceptible to irrational biases. Forty one non clinical female controls and 27 in-patient females with an ED diagnosis participated in an experimental task that tested whether participants would show an intuitive rather than a logically based link between perfectionism in different domains (study, work, hygiene) and a thin body shape. In the healthy female participants the occurrence of proposed link was noted in the hygiene domain only, while ED participants showed this intuitive association in all the domains explored: study, work, and hygiene. The study confirms in clinical ED sample a wider employment of heuristics associating perfectionism and thinness that is based on purely intuitive irrational reasoning.     

Discrimination and production of English vowels by bilingual speakers of Spanish and English

The goal of this study was to examine whether listeners bilingual in Spanish and English would have difficulty in the discrimination of English vowel contrasts. An additional goal was to estimate the correlation between their discrimination and production of these vowels. Participants (40 bilingual Spanish- and English-speaking and 40 native monolingual English-speaking college students, 23-36 years of age) participated (M age = 25.3 yr., Mdn = 25.0). The discrimination and production of English vowels in real and novel words by adult participants bilingual in Spanish and English were examined and their discrimination was compared with that of 40 native monolingual English-speaking participants. Stimuli were presented within triads in an ABX paradigm. Novel words were chosen to represent new words when learning a new language and to provide a more valid test of discrimination. Bilingual participants' productions of vowels were judged by two independent listeners to estimate the correlation between discrimination and production. Discrimination accuracy was significantly greater for native English-speaking participants than for bilingual participants for vowel contrasts and novel words. Significant errors also appeared in the bilingual participants' productions of certain vowels. Earlier age of acquisition, absence of communication problems, and greater percentage of time devoted to communication contributed to greater accuracy in discrimination and production.     

Snakes and cats in the flower bed: fast detection is not specific to pictures of fear-relevant animals

The observation that snakes and spiders are found faster among flowers and mushrooms than vice versa and that this search advantage is independent of set size supports the notion that fear-relevant stimuli are processed preferentially in a dedicated fear module. Experiment 1 replicated the faster identification of snakes and spiders but also found a set size effect in a blocked, but not in a mixed-trial, sequence. Experiment 2 failed to find faster identification of snake and spider deviants relative to other animals among flowers and mushrooms and provided evidence for a search advantage for pictures of animals, irrespective of their fear relevance. These findings suggest that results from the present visual search task cannot support the notion of preferential processing of fear relevance.     

Math and science motivation: A longitudinal examination of the links between choices and beliefs

This study addresses the longitudinal associations between youths' out-of-school activities, expectancies-values, and high school course enrollment in the domains of math and science. Data were collected on 227 youth who reported on their activity participation in 5th grade, expectancies-values in 6th and 10th grade, and courses taken throughout high school. Math and science course grades at 5th and 10th grade were gathered through school record data. Results indicated youths' math and science activity participation predicted their expectancies and values, which, in turn, predicted the number of high school courses above the predictive power of grades. Although there were mean-level differences between boys and girls on some of these indicators, relations among indicators did not significantly differ by gender.     

Déjà Vu all over again: re-revisiting the conceptual status of early word learning: comment on Smith and Samuelson (2006)

The authors assert that L. B. Smith and L. Samuelson's (2006) most recent critique of A. E. Booth, S. R. Waxman, and Y. T. Huang's (2005) work missed its mark, deflecting attention from the important theoretical difference between the two sets of authors' positions and focusing instead on imagined differences and minor expositional complaints. The authors' goal in this response is twofold. First, they aim to redirect attention to the 1 clear difference between the 2 theoretical positions regarding word learning, a difference that is focused on the role of conceptual (in conjunction with perceptual) information in word learning. Second, they place L. B. Smith and L. Samuelson's (2006) current critique in the context of previous exchanges.     

Hemispheric processing of inferences: The effects of textual constraint and working memory capacity

In this study, we investigated hemispheric differences in the generation of bridging and predictive inferences. Participants read texts that provided either strong or weak causal constraints for a particular bridging (Experiment 1) or predictive (Experiment 2) inference and performed a lexical decision task to inference-related targets presented to the left or the right hemisphere. Facilitation for strongly constrained bridging and predictive inferences was found in both hemispheres. In contrast, facilitation for weakly constrained inferences was stronger in the right than in the left hemisphere for both bridging and predictive inferences, although for the latter there was some facilitation in the left hemisphere as well. We also considered whether these effects differ as a function of the working memory capacity of the reader. High working memory capacity readers showed greater facilitation for strongly constrained inferences than for weakly constrained inferences in both hemispheres, whereas low working memory capacity readers showed this same pattern in the left hemisphere but showed equal facilitation for strongly and weakly constrained inferences in the right hemisphere. These results suggest that hemispheric processing, textual constraint, and working memory capacity interact to affect how readers generate causal inferences.     

Perspective taking promotes action understanding and learning

People often learn actions by watching others. The authors propose and test the hypothesis that perspective taking promotes encoding a hierarchical representation of an actor's goals and subgoals-a key process for observational learning. Observers segmented videos of an object assembly task into coarse and fine action units. They described what happened in each unit from either the actor's, their own, or another observer's perspective and later performed the assembly task themselves. Participants who described the task from the actor's perspective encoded actions more hierarchically during observation and learned the task better.     

Self-conscious emotions and self-regulation in the promotion of condom use

Two prospective studies examined the self-regulatory role of anticipated negative self-conscious emotions (ANSCE) in the theory of planned behavior. In Study 1, 147 undergraduates reported condom attitudes, perceived norms, self-efficacy, ANSCE (shame and guilt) should they not use condoms, and intentions to use condoms during the coming 6 weeks. At a 6-week follow-up, ANSCE predicted condom use intentions and behavior and partially mediated the effect of attitudes and norms on both. Study 2 experimentally tested the social nature of self-consciousness in ANSCE; 61 female undergraduates read a scenario priming the private-self or social-self or were assigned to a no-scenario control. They reported condom attitudes, perceived control, ANSCE, condom use intentions, and a 6-week follow-up. ANSCE again predicted condom use intentions. A test of moderated mediation indicated that ANSCE influenced condom intentions more in the social-self condition than in the control condition. Implications of these findings are discussed.