The ontogeny of serial-order behavior in humans (Homo sapiens): representation of a list

The authors trained 3-, 4-, 7-, and 10-year-old children and adults (Homo sapiens) on a nonverbal serial-order task to respond to 5 items in a specific order. Knowledge of each item's sequential position was then examined using pairwise and triplet tests. Adults and 7- and 10-year-olds performed at high levels on both tests, whereas 3- and 4-year-olds did not. The latency to respond to the first item of a test pair or triplet was linearly related to that item's position in the training series for the 7- and 10-year-olds and adults, but not for the 3- and 4-year-olds. These data suggest that older children and adults, but not younger children, developed a well-integrated internal representation of the serial list.     

Experimental tests of an attitudinal theory of the gender gap in voting

This research examined the hypothesis that gender gaps in voting stem from differences in the extent to which men and women agree with candidates' issue stances. Two initial experiments portraying candidates by their sex and attitudes and a third experiment that also included information about political party produced the predicted attitudinal gender-congeniality effect: Participants of each sex reported greater likelihood, compared with participants of the other sex, of voting for the candidate who endorsed positions typically favored more by their own sex than the other sex. In addition, this gender-congeniality effect was present among Republican and independent participants but absent among Democratic participants because Democratic men as well as women favored candidates who advocated the positions typically favored by women. Interpretation invoked the importance of group interest based on gender as an influence on women's voting.     

Antigravity hills are visual illusions

Antigravity hills, also known as spook hills or magnetic hills, are natural places where cars put into neutral are seen to move uphill on a slightly sloping road, apparently defying the law of gravity. We show that these effects, popularly attributed to gravitational anomalies, are in fact visual illusions. We re-created all the known types of antigravity spots in our laboratory using tabletop models; the number of visible stretches of road, their slant, and the height of the visible horizon were systematically varied in four experiments. We conclude that antigravity-hill effects follow from a misperception of the eye level relative to gravity, caused by the presence of either contextual inclines or a false horizon line.     

Longitudinal trajectories of bicultural identity integration in recently immigrated Hispanic adolescents: Links with mental health and family functioning

This study examined, in a sample of recently immigrated Hispanic adolescents in Miami and Los Angeles, the extent to which bicultural identity integration (BII; involving the ability to synthesise one's heritage and receiving cultural streams and to identify as a member of both cultures) is best understood as a developmental construct that changes over time or as an individual‐difference construct that is largely stable over time. We were also interested in the extent to which these trajectories predicted mental health and family functioning. Recent‐immigrant 9th graders (N = 302) were assessed 6 times from 9th to 12th grade. Latent class growth analyses using the first 5 timepoints identified 2 trajectory classes—one with lower BII scores over time and another with higher BII scores over time. Higher heritage and US identity at baseline predicted membership in the higher BII class. At the 6th study timepoint, lower BII adolescents reported significantly poorer self‐esteem, optimism, prosocial behaviour and family relationships compared with their higher BII counterparts. These findings are discussed in terms of further research on the over‐time trajectory of biculturalism, and on the need to develop interventions to promote BII as a way of facilitating well‐being and positive family functioning.     

Psychiatric chrono‐epidemiology: its relevance for the study of aggression

Chrono‐epidemiology is the study of the distribution of health events according to time. The time intervals taken into account have cyclic patterns and include circadian, weekly, seasonal, and circannual rhythms. In the behavioural field, chrono‐epidemiology can be and has been applied to studies concerning the causes of death (suicide and homicide), clinical events such as admissions to and contacts with mental healthcare services, and the seasonal distribution of crime involving the use of violence. Frequently reported findings include clear circadian and seasonal rhythms present in the phenomenon of suicide (rhythms more evident in the case of violent suicide); seasonal rhythms in the expression of aggression by patients hospitalised for mental illness; and a circannual recurrence of crimes with a violent component. The intrinsic circadian and seasonal rhythms of some neuronal systems, particularly those of serotonin, involved in the control of mood and impulses, are thought to favour the behavioural rhythms observed, although the contribution of socio‐environmental factors, such as the fluctuation of supportive networks according to time, is also acknowledged. By demonstrating non‐casual recurrence of certain behaviour and by exploring the socio‐biological basis of the rhythms beneath these recurrences, chrono‐epidemiology may offer important etiologic and preventive clues to the understanding of the biological and environmental correlates of aggressive behaviour. Aggr. Behav. 28:477–490, 2002. © 2002 Wiley‐Liss, Inc.     

Discrimination learning during the first year: stimulus and positional cues

In four studies, 3-, 6-, and 9-month-old human infants were tested in a discrimination learning task in which visual fixation to a particular stimulus or lateral position was reinforced with an auditory stimulus. In Experiment 1, all age groups exhibited acquisition, extinction, and reinstatement of fixation to the reinforced target or position. Experiment 2 revealed that 3-month-olds retained the positional discrimination but not the stimulus discrimination after a 5-min delay between acquisition and extinction; older infants retained both types of discriminations. In Experiments 3 and 4 we investigated a possible developmental shift in the dominance of positional versus stimulus cues by training infants on displays in which stimulus and position were confounded and then by dissociating the cues on test trials. Results from both experiments indicated positional cue dominance for young infants and stimulus cue dominance for older infants. The findings are discussed in terms of differences in the attentional demands elicited by proprioceptive versus exteroceptive cues.     

Hemispheric predominance assessment of phonology and semantics: a divided visual field experiment

The aim of the present behavioural experiment was to evaluate the most lateralized among two phonological (phoneme vs. rhyme detection) and the most lateralized among two semantic ("living" vs. "edible" categorization) tasks, within the dominant hemisphere for language. The reason of addressing this question was a practical one: to evaluate the degree of the hemispheric lateralization for several language tasks, by using the divided visual presentation of stimuli, and then choose the most lateralized semantic and phonological for mapping language in patients by using fMRI in future studies. During the divided visual field experiment by using words (semantic tasks) and pseudo-words (phonological tasks) as stimuli, thirty-nine right-handed participants were examined. Our results have shown that all tasks were significantly left hemisphere lateralized. Furthermore, the rhyme was significantly more lateralized than phoneme detection and "living" was significantly more lateralized than "edible" categorization. The rhyme decision and "living" categorization will be used in future fMRI studies for assessing hemispheric predominance and cerebral substrate for semantics and phonology in patients. Our results also suggest that the characteristics of stimuli could influence the degree of the hemispheric lateralization (i.e., the emotional charge of stimuli for words and the position of the phoneme to be detected, for pseudo-words).