Predisposing effects of cigarette advertising on children's intentions to smoke when older.

Six hundred and forty Glasgow children, initially aged between 11 and 14 years, were interviewed twice, with approximately one year between interviews. Children whose intentions to smoke when older became more positive between the two interviews tended to be more aware of cigarette advertising at the time of the first interview (compared with children whose intentions to smoke were negative at both interviews). Children whose intentions to smoke became more negative between the interviews tended to be less appreciative of cigarette advertisements at the time of the first interview (compared with children whose intentions to smoke were positive at both interviews). Since both groups differed from their respective contrast groups before their declared intentions changed, these findings support the view that cigarette advertising has predisposing as well as reinforcing effects on children's attitudes and behaviour with respect to smoking.

Social interactions of mice with congenital Toxoplasma infection.

The social interactions of male mice with subclinical congenital Toxoplasma infection towards their uninfected counterparts was assessed using a procedure based on the subdivision of behaviour into element groups. Infection had no effect on behavioural elements not directly associated with interaction. However infection was found to increase companion investigation as well as a number of elements directly associated with aggression. There was a complementary decrease in elements associated with flight behaviour. These findings suggest that congenital infection with Toxoplasma renders mice less cautious towards uninfected conspecifics and increases the tendency of adult male mice towards territorial aggression.

Reinforcing effects of cigarette advertising on under-age smoking.

Interviews were conducted with 848 Glasgow children aged between 11 and 14 years. There were consistent differences between smokers and non-smokers. Smokers tended to be more adept at recalling, recognizing and identifying cigarette advertisements. This suggests they tend to pay more attention to cigarette advertising. Smokers also tended to be generally more appreciative of cigarette advertising. Moreover, this greater awareness and appreciation of cigarette advertising was independent of other important predictors of under-age smoking, such as smoking by peers, siblings and parents. These findings, taken in conjunction with previous research, indicate that cigarette advertising is reinforcing under-age smoking. The smokers showed an enhanced or heightened preference for Kensitas Club, the brand favoured by adults. This is consistent with previous research indicating that promotional devices which help determine and reinforce adult cigarette brand preferences have an even greater effect on under-age smokers.

Alcohol advertising in developing countries.

Alcohol consumption appears to be increasing in some developing countries. Groups who previously did not drink alcohol, such as young people and women, are now increasingly beginning to drink. Recent anecdotal observations by researchers in Lesotho suggest that aggressive advertising may play a part in encouraging drinking among the young. This commentary suggests that surveys of alcohol advertising and youthful drinking in developing countries would be particularly useful in monitoring the influence of alcohol advertising in rapidly expanding markets. Recent studies have described simple measures of awareness and appreciation of alcohol advertising which discriminate between under-age drinkers and non-drinkers. These measures could be readily adapted by researchers responsible for the design of surveys of youthful drinking.

Ten- to sixteen-year-olds' perceptions of advertisements for alcoholic drinks.

Groups of children discussed a number of issues concerning advertising, including advertisements they liked and disliked. The findings suggest that advertisements for alcoholic drinks become increasingly salient and attractive over the years 10 to 14. For example, although 10-year-olds rarely mentioned advertisements for alcoholic drinks when talking about favourite television commercials, the older children tended to do so almost immediately. There were also consistent developmental trends in their descriptions of liked and disliked qualities of advertisements and of the symbolism in commercials for alcoholic drinks. Whereas the 10-year-olds' comments tended to be tied to what is specifically shown in commercials, the older children tended to go beyond this and alluded to much more complex imagery, much in the same way that adults do. For example, the 14- and 16-year-olds tended to see larger and beer commercials as promoting masculinity, sociability and working-class values. These findings indicate that advertising campaigns for alcoholic drinks aimed at older teenagers and young adults present qualities which younger teenagers find attractive. We suggest it is no longer tenable for advertisers to absolve themselves of any responsibility by saying that advertisements for alcoholic drinks are targeted only at adults.

Toxocara canis infection and hyperactivity.

An observational study using video recordings and computer assisted data analysis showed that infection with Toxocara canis larvae had a marked effect on five readily and reliably differentiable categories of murine behaviour. The infection was also associated with an increase in the number of shorter bouts of each behavior. These results indicate that infection with T. canis renders mice hyperactive, and would appear to justify a complete reappraisal of the role of this neurotropic parasite as a cause of behavioural abnormalities such as hyperactivity in children.

Experimental toxocariasis and hyperactivity in mice.

An observational study using videorecordings and computer-assisted data analysis was undertaken in order to investigate the behaviour of mice infected with larvae of Toxocara canis. The findings indicated that the infection had a marked effect on five readily and reliably differentiable categories of murine behaviour. A marked increase in the number of shorter bouts of each of the five behaviours was also associated with the infection. These results support previous findings and further suggest that T. canis infection affects the way in which mice respond to their environment. In particular the infection appears to be associated with hyperactivity in mice. Possible causes of such behavioural abnormalities as well as implications of these findings for clinical studies concerned with relationships between T. canis infection and hyperactivity in children are discussed.

Children's perceptions of advertisements for cigarettes.

Groups of children aged between 6 and 16 years discussed a series of advertisements, including those for cigarettes. Clear patterns emerged in their recognition of cigarette brand imagery. For example, in response to an advertisement for holidays which also presents the brand imagery of John Player Special cigarettes, 22% of primary school children and 91% of secondary school children said it advertises cigarettes. There were consistent trends in responses to the symbolism portrayed. Younger children were very much tied to what was specifically shown in the advertisements; older ones tended to perceive more complex imagery. For example, whereas 10-year-olds said people who like the advertisement for Kim cigarettes (which has symbols for drinking) would smoke and drink, some 12-year-olds and most 14- and 16-year-olds saw Kim as feminine, sociable, trendy and sporty. It seems that some 12-year-olds and most 14- and 16-year-olds perceive cigarette advertisements much in the way that young adults do; therefore advertising campaigns targeted at older teenagers and young adults are likely to present qualities which younger teenagers find attractive.

The influence of congenital Toxoplasma infection on the spontaneous running activity of mice.

Home-cage running-wheel activity of mice congenitally infected with Toxoplasma was recorded over 24 days. Infected mice were consistently more active than uninfected controls over the entire testing period. This finding extends previous studies and indicates that such increased activity levels occur not only in novel but also in familiar environments, and suggests that congenital toxoplasmosis tends to render mice "hyperactive'. If such behavioural alterations occur in wild mice, it is likely that infected mouse intermediate hosts would be more susceptible to predation by cats, the definitive hosts of Toxoplasma.

An observational study of young adults' drinking groups--II. Drink purchasing procedures, group pressures and alcohol consumption by companions as predictors of alcohol consumption.

Quantitative observations were made of 200 groups in bars catering for young adults. Most drinkers were members of groups in which round-buying procedures were used. Purchasing procedures were good predictors of alcohol consumption among males, accounting for 15% of the variance in consumption. Males who purchased rounds tended to consume more alcohol than did males who did not purchase drinks for others. Drinkers with companions who consumed large amounts of alcohol tended to consume more alcohol and tended to have higher drinking rates. Considered alone, the average amount consumed by companions accounted for 62% and 48% the variance in alcohol consumption by males and females respectively. Qualitative observations and interviews with 200 patrons are also described. Findings from the interviews indicate that there were considerable pressures on males and females to conform to the 'institution' and to the 'rules' of round-buying. However, the quantitative observations showed that the majority of females did not openly purchase drinks. This suggests that observational procedures can provide useful checks on findings obtained from questioning procedures.

The effect of congenital Toxoplasma infection on mouse activity and relative preference for exposed areas over a series of trials.

Previous studies showed that mice with congenital Toxoplasma infections tend to be much more active and tend to show a smaller relative preference for more exposed and novel areas than do uninfected controls. However, in those studies, mice were exposed to behavioural testing procedures once only. Results described here show that these differences (and differences defaecation) are more than just transitory phenomena observed on a first exposure to a novel area. The differences between infected and uninfected mice were clear during each of five separate trials; moreover, they tended to increase from the first to the fifth trial. The possible implications of these findings for the continuation of the life-cycle of the parasite in the environment are considered.

Experimental toxocariasis in mice and its effect on their behaviour.

When compared to uninfected controls, mice infected with second-stage larvae of Toxocara canis exhibited: (1) impaired motor performance, (2) increased ambulatory activity, (3) a greater relative preference for more exposed areas and (4) a greater overall preference for novel environments. The infected mice also appeared to show less approach-avoidance conflict and seemed less cautious when presented with novel stimuli. These behavioural differences were independent of measures of general health. Possible explanations for the observed behavioural deficits are discussed. Such alterations in behaviour may be implicated in the continuation of the life-cycle of this parasite by making mouse paratenic hosts more liable to capture and subsequent ingestion by canids, the definitive hosts of T. canis.

Toxoplasma infection and response to novelty in mice.

Three groups of mice were infected with Toxoplasma and used for behavioral testing using a Y-maze. One group was infected when adult and two groups congenitally, one of these born to dams infected during gestation, the other to dams chronically infected prior to mating. In an initial habituation period each mouse was exposed to a black arm and stem of the maze, entrance to a white arm being blocked by a transparent door. In a subsequent free-choice trial both arms were black and the mouse was free to explore all parts of the maze. During both periods infected mice were more active than controls. Infected mice engaged in less grooming behavior indicative of less approach-avoidance conflict than controls prior to entry into a choice arm at the beginning of the free-choice trial. Infected mice spent more time in the familiar than in the novel (previously blocked) arm during the free-choice trial; conversely, uninfected mice spent more time in the novel than in the familiar arm. It is suggested that the reported behavioural changes would lead to dissemination of the infection in the environment by ultimately making infected mouse intermediate hosts more susceptible to predation by domestic cats, the definitive hosts of Toxoplasma.

The effect of congenital and adult-acquired Toxoplasma infections on activity and responsiveness to novel stimulation in mice.

Activity and responsiveness to novel stimulation were assessed in three groups of mice infected with Toxoplasma. One group was infected when adult; two groups were infected congenitally, one born to dams infected during gestation, the other to dams chronically infected prior to mating. Each mouse was tested in a box, the floor of which was marked off into 16 equal squares, and its activity was measured over ten minutes by counting the number of times the mouse entered each square. Infected mice were more active. In addition, infected mice showed a smaller relative preference for the more novel central area of the box, especially towards the end of the observation period. These differences were independent of emotionality (as measured by defaecation counts), general health (as measured by subjective health ratings and body weight) and the number of Toxoplasma tissue cysts in specified brain regions. We suggest that differences arise from pathological changes caused by proliferating toxoplasms in the brains of the infected mice; an immunopathological reaction due to the presence of tissue cysts in the brain may also be involved. Other possible factors contributing to observed deficits in behaviour are also discussed. We suggest that such deficits may render Toxoplasma-infected mice more susceptible to predation by the domestic cat, the definitive host of Toxoplasma.