Subgroup analysis of sex difference on the Vandenberg-Kuse mental rotation test

A large sex difference has been elicited on the Vandenberg-Kuse mental rotation test. Prior research emphasizes the biological root of this sex difference. In recent experiments we confirmed this viewpoint. A large sample was administered the test, and the distributions of scores for men and women (N = 138; 68 men and 70 women: ages 19 to 23 years). The mean scores were used as cut-off points to group the men and the women in different subgroups (Low/Women, High/Women, Low/Men, High/Men). There were large differences among all subgroups, reinforcing Kimura's testosterone hypothesis for sex differences in spatial ability.     

Another evaluation of touch and helping behavior

Although positive effect of touch on compliance has been widely reported, new evaluation was made with an unusual request. 80 male bus drivers were solicited by a male or a female confederate to take the bus despite having too little money for the fare. Bus drivers were briefly touched by the confederate during solicitation. Analysis showed that bus drivers who were touched accepted the request more favorably but only when made by a female.     

On discontinuities in motor learning: a longitudinal study of complex skill acquisition on a ski-simulator

The qualitative behavioral reorganizations that occurred during the acquisition of a complex motor skill were examined. Five novice participants practiced for 39 sessions of ten 1-min trials on a modified version of the ski-simulator. Analyses focused on the motion of the apparatus platform, modeled as a self-sustained oscillator. At the beginning of the experiment, all participants adopted a behavior that could be modeled with a highly nonlinear stiffness function and a Rayleigh damping function. The behavior in the final part of the experiment was captured by a qualitatively different model, with a linear stiffness function and a van der Pol damping behavior. The transition from the initial to the final model was gradual and was marked in most cases by an abrupt increase of oscillation frequency. During the transition stage, the 2 damping behaviors seemed alternately exploited within each trial. The results are discussed in the framework of the dynamical systems approach to motor coordination and learning, considering motor skill acquisition as a phase transition.     

Predictable postural perturbation in premotor and motor components of reaction time

The aim of the present experiment was to study the central control of posture and movement coordination. Subjects' task was voluntarily to raise their arms in response to a visual signal, this movement generating an unloading in which the weight of the load (0 gm, 1500 gm, 3000 gm, or 4500 gm) was known in advance. Thus, subjects could predict the postural perturbation generated by the unloading. Analysis showed an effect of the unloading conditions: in the 0-gm and 1500-gm conditions, reaction time (RT) was longer than in the 3000-gm and 4500-gm conditions. This decrease in RT was exclusively due to a reduction of the premotor time, confirming the posturokinetic coordination in the programming processes. The implications of the decrease in premotor time with the increase of the perturbation for the posture/movement coordination strategies are also discussed.     

Development of a Spanish version of the Participation Motivation Inventory for young competitive swimmers

The present study examined the validity of a Spanish version of the Participation Motivation Inventory, modified for swimming by Gould, Feltz, and Weiss in 1985, and investigated whether young swimmers differing in sex and age vary in their objectives for participation. Swimmers (204 boys and 224 girls, ranging in age from 8 to 22 years) were administered the inventory. Factor analysis with varimax rotation identified seven factors fairly consistent with previous research. Differences were found across age and sex. Females placed greater emphasis than males on Friendship and Fun and indicated lower importance rating to Status. Younger children (8-10 years) rated Fun/Friendship, Competition/Skills, Significant Others, and Status significantly higher in importance than did the other age groups.     

Individual differences in children's performance during an emotional Stroop task: a behavioral and electrophysiological study

Two studies using the emotional Stroop with 11-year-old children were completed. In Study 1, children were assigned to either the "interference group" or the "facilitation group" based on their performance on the task. The interference group was slower to respond to emotion words (positive and negative) versus control words. The facilitation group was faster to respond to the emotion words. The groups were then compared on a set of cognitive, emotional, and social measures collected at ages 4, 7, and 11. The interference group showed greater signs of emotional and social, but not cognitive, maladjustment across time. Study 2 replicated the findings of Study 1. In addition, event-related potentials (ERPs) were collected in Study 2. The ERP data replicated earlier traditional Stroop studies. In addition, positive and negative words showed differences in processing across components. In particular, negative words appeared to tax attentional and processing resources more than positive words.     

Stimulus control of predatory behavior by the Iberian wall lizard (Podarcis hispanica, Sauria, Lacertidae): effects of familiarity with prey

The authors examine the relative roles of vision and chemoreception and the influence of previous experience with prey on the predatory behavior of Iberian wall lizards (Podarcis hispanica). Experiment 1 compared the responses to visual, chemical, and a combination of visual and chemical cues of a familiar prey by 2 groups of lizards that had been kept in captivity for either 3 months or 21 days. Experiment 2 assessed the responses of lizards kept in the laboratory for more than 3 months to a novel prey species. The results reveal that feeding on a prey species affects the lizards' responses to chemical stimuli from that prey. The response to chemical cues of a novel prey requires a 1st-feeding experience with that prey. Lizards that have been fed the same prey species for several months cease responding to the chemical stimuli of that particular prey.     

Phenomenal characteristics of cryptomnesia

Qualitative characteristics of cryptomnesia, or unintentional plagiarism were investigated. In Experiment 1 we compared accurate and inaccurate source attributions in terms of their level of confidence using instructions that did not require a fixed number of responses. Confidence was lower for plagiarised responses than for correct responses. Nevertheless, participants provided high ratings of certainty for a large proportion of their plagiarised responses. In Experiment 2 the phenomenological differences between plagiarised recall and veridical recall were compared by using an adaptation of the memory characteristics questionnaire (Johnson, Foley, Suengas, & Raye, 1988). Correct responses were associated with more experiential detail than plagiarised responses. However, a considerable number of plagiarised responses were accompanied by a confident memory of at least one qualitative characteristic. Results are discussed in terms of the source monitoring framework developed by Johnson, Hashtroudi, and Lindsay (1993).     

The time-based word length effect and stimulus set specificity

The word length effect is the finding that short items are remembered better than long items on immediate serial recall tests. The time-based word length effect refers to this finding when the lists comprise items that vary only in pronunciation time. Three experiments compared recall of three different sets of disyllabic words that differed systematically only in spoken duration. One set showed a word length effect, one set showed no effect of word length, and the third showed a reverse word length effect, with long words recalled better than short. A new fourth set of words was created, and it also failed to yield a time-based word length effect. Because all four experiments used the same methodology and varied only the stimulus sets, it is argued that the time-based word length effect is not robust and as such poses problems for models based on the phonological loop.