Marking behavior is innate and not learned in the Mongolian gerbil.
(9/508)
We studied whether marking behavior in Mongolian gerbils would be innate or learned behavior. The marking behavior was defined as "animals rubbing their abdominal scent glands on small protruding objects". Between 21 and 90 days of age, Mongolian gerbils, which were kept under such conditions that they would be unable to learn this behavior, were observed at intervals of 5-15 days to find out if there were signs of the behavior or not. Six male and four female Mongolian gerbils were used for observing. Neonate Mongolian gerbils during the age of 3 to 28 days were fostered by ICR mother mice. Weaning Mongolian gerbils were then individually kept away from the others. Marking behavior was observed in 2 out of 6 males at 50 days of age and 2 of 4 females at 60 days and the mean frequency of the marking behavior for 10 min was 3.5 in the males and 5.0 in the females. These results suggest that marking behavior was innate and not learned behavior in Mongolian gerbils. (+info)
Early exposure leads to repeatable preferences for male song in female zebra finches.
(10/508)
This study addressed the question of how early learning processes in females influence later preferences for a male trait. I tested whether exposure to song alone (of a male other than the father) was sufficient for inducing a stable (repeatable) preference in female zebra finches (Taeniopygia guttata) by limiting early exposure to tape tutoring. A group of controls heard no songs before also being tested in adulthood. Repeated tests for preferences for tutor or unfamiliar song were made, interspersed with additional tests involving new songs. Preferences were tested in an operant task where pecking of response keys led to song playback. Most females significantly preferred one of the two songs in a given test. In the first test, the relative preference for the tutor song was significantly higher for the tutored than for the control females. Subsequently, tutored females' preferences for the tutor song remained higher on average, but the two groups did not differ significantly. However, tutored, but not untutored females' preferences were highly repeatable between tests, suggesting that early exposure to song might lead to a consolidation ol choice behaviour, a previously unknown effect of early exposure to song in female songbirds. (+info)
Favourite movie stars, their tobacco use in contemporary movies, and its association with adolescent smoking.
(11/508)
OBJECTIVE: To assess the relation between adolescents' favourite movie stars, the portrayal of tobacco use by those stars in contemporary motion pictures, and adolescent smoking. DESIGN AND SETTING: 632 students (sixth to 12th grade, ages 10-19 years) from five rural New England public schools completed a voluntary, self administered survey in October 1996. The survey assessed tobacco use, other variables associated with adolescent smoking, and favourite movie star. In addition, tobacco use by 43 selected movie stars was measured in films between 1994 and 1996. OUTCOME MEASURES: Students were categorised into an ordinal five point index (tobacco status) based on their smoking behaviour and their smoking susceptibility: non-susceptible never smokers, susceptible never smokers, non-current experimenters, current experimenters, and smokers. We determined the adjusted cumulative odds of having advanced smoking status based on the amount of on-screen tobacco use by their favourite film star. RESULTS: Of the 43 stars, 65% used tobacco at least once, and 42% portrayed smoking as an essential character trait in one or more films. Stars who smoked more than twice in a film were considered smokers. For adolescents whose favourite stars smoked in only one film, the odds of being higher on the smoking index was 0.78 (95% confidence interval (CI) 0.53 to 1.15). For adolescents whose favourite stars smoked in two films, the odds of being higher on the smoking index was 1.5 (95% CI 1.01 to 2.32). For adolescents whose favourite stars smoked in three or more films (Leonardo DiCaprio, Sharon Stone, John Travolta), the odds of being higher on the smoking index was 3.1 (95% CI 1.34 to 7.12). Among never smokers (n = 281), those who chose stars who were smokers in three or more films were much more likely to have favourable attitudes toward smoking (adjusted odds ratio 16.2, 95% CI 2.3 to 112). CONCLUSIONS: Adolescents who choose movie stars who use tobacco on-screen are significantly more likely to have an advanced smoking status and more favourable attitudes toward smoking than adolescents who choose non-smoking stars. This finding supports the proposition that the portrayal of tobacco use in contemporary motion pictures, particularly by stars who are admired by adolescents, contributes to adolescent smoking. (+info)
Dynamics of the vocal imitation process: how a zebra finch learns its song.
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Song imitation in birds provides good material for studying the basic biology of vocal learning. Techniques were developed for inducing the rapid onset of song imitation in young zebra finches and for tracking trajectories of vocal change over a 7-week period until a match to a model song was achieved. Exposure to a model song induced the prompt generation of repeated structured sounds (prototypes) followed by a slow transition from repetitive to serial delivery of syllables. Tracking this transition revealed two phenomena: (i) Imitations of dissimilar sounds can emerge from successive renditions of the same prototype, and (ii) developmental trajectories for some sounds followed paths of increasing acoustic mismatch until an abrupt correction occurred by period doubling. These dynamics are likely to reflect underlying neural and articulatory constraints on the production and imitation of sounds. (+info)
Is suicide contagious? A study of the relation between exposure to the suicidal behavior of others and nearly lethal suicide attempts.
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This study sought to determine the association between nearly lethal suicide attempts and exposure to the suicidal behavior of parents, relatives, friends, or acquaintances and to accounts of suicide in the media. The authors conducted a population-based case-control study in Houston, Texas, from November 1992 through July 1995. They interviewed 153 victims of attempted suicide aged 13--34 years who had been treated at emergency departments in Houston and a random sample of 513 control subjects. After controlling for potentially confounding variables, the authors found that exposure to the suicidal behavior of a parent (adjusted OR = 1.5; 95% CI: 0.6, 3.6; p = 0.42) or a nonparent relative (adjusted OR = 1.2; 95% CI: 0.7, 2.0; p = 0.55) was not significantly associated with nearly lethal suicide attempts. Both exposure to the suicidal behavior of a friend or acquaintance (adjusted OR = 0.6; 95% CI: 0.4, 1.0; p = 0.05) and exposure to accounts of suicidal behavior in the media (adjusted OR = 0.2; 95% CI: 0.1, 0.3; p = 0.00) were associated with a lower risk of nearly lethal suicide attempts. Exposure to accounts of suicidal behavior in the media and, to a lesser extent, exposure to the suicidal behavior of friends or acquaintances may be protective for nearly lethal suicide attempts, but further research is needed to better understand the mechanisms underlying these findings. (+info)
The cortical motor system.
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The cortical motor system of primates is formed by a mosaic of anatomically and functionally distinct areas. These areas are not only involved in motor functions, but also play a role in functions formerly attributed to higher order associative cortical areas. In the present review, we discuss three types of higher functions carried out by the motor cortical areas: sensory-motor transformations, action understanding, and decision processing regarding action execution. We submit that generating internal representations of actions is central to cortical motor function. External contingencies and motivational factors determine then whether these action representations are transformed into actual actions. (+info)
Effect of seeing tobacco use in films on trying smoking among adolescents: cross sectional study.
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OBJECTIVE: To test the hypothesis that greater exposure to smoking in films is associated with trying smoking among adolescents. DESIGN: Cross sectional survey of 4919 schoolchildren aged 9-15 years, and assessment of occurrence of smoking in 601 films. SETTING: Randomly selected middle schools in Vermont and New Hampshire, USA. MAIN OUTCOME MEASURE: Number of schoolchildren who had ever tried smoking a cigarette. RESULTS: The films contained a median of 5 (interquartile range 1-12) occurrences of smoking. The typical adolescent had seen 17 of 50 films listed. Exposure to smoking in films varied widely: median 91 (49-152) occurrences. The prevalence of ever trying smoking increased with higher categories of exposure: 4.9% among students who saw 0-50 occurrences of smoking, 13.7% for 51-100 occurrences, 22.1% for 101-150, and 31.3% for >150. The association remained significant after adjustment for age; sex; school performance; school; parents' education; smoking by friend, sibling, or parent; and receptivity to tobacco promotions. The adjusted odds ratios of ever trying smoking for students in the higher categories of exposure, compared with students exposed to 0-50 occurrences of smoking in films, were 1.7 (95% confidence interval 1.2 to 2.4), 2.4 (1.7 to 3.4), and 2.7 (2.0 to 3.8). These odds ratios were not substantially affected by adjustment for parenting style or for personality traits of the adolescent. CONCLUSION: In this sample of adolescents there was a strong, direct, and independent association between seeing tobacco use in films and trying cigarettes, a finding that supports the hypothesis that smoking in films has a role in the initiation of smoking in adolescents. (+info)
Developing generalized behavior-modification skills in high-school students working with retarded children.
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Seven high-school trainees each conducted training sessions with two profoundly retarded children. Each trainee was asked to teach one child to follow the instruction "Bring ball" and the other child to follow the instructions "Sit down" and "Come here". During baseline sessions, before the trainees had been instructed in behavior-modification techniques, no trainee successfully taught either child to follow the instructions. After differing numbers of baseline sessions, trainees were exposed to training procedures designed to teach them to teach one child to follow the instruction "Bring ball". The training procedures consisted of videotaped modelling, rehearsal, and corrective feedback and praise. Following the training procedures, four of the seven trainees successfully taught their child the instruction "Bring ball". Further, all trainees were able to teach their other children to follow the instructions "Sit down" and "Come here", even though they had received no modelling, rehearsal, or feedback on how to teach the children to follow these instructions. The ability of the trainees to teach new behaviors to different children indicates the development of generalized skills in behavior modification. (+info)