An "Epidemic" Model of Adolescent Cigarette Smoking

The prevalence of regular smoking increases rapidly during adolescence. We applied modeling methods from the study of epidemic infectious disease to smoking behavior. Our "epidemic" models dealt with the process of transition among four states: nonsmoker (susceptible), trier (exposed), regular smoker (infected), and ex-smoker (recovered). The best fitting model was one in which the transition from nonsmoker to trier was a social contagion process where nonsmokers contacted either triers or regular smokers. All other transitions were treated as constant rate processes in which a constant proportion of eligible individuals made the transition in a given year. The recursive equation model embodying these assumptions was able to predict accurately the proportion of adolescents in each state in Grades 6–11. Our results support a "stage" model of smoking, suggesting that different psychological and physiological processes are involved in the initiation of smoking than in developing a habit of regular smoking. A possible sex difference was found in the non-contact transition between trier and smoker states, with the transition being more probable in females than in males.     

Pause measures during reading and recall in serial list learning

An investigation is reported into pausing and grouping during the serial learning of letter strings, when presented randomly by length and when presented in ascending order. Mean pause times for the reading and recall of longer lists were significantly greater than for lists of shorter span due to extended pausing at specific list positions. In general, reading rhythms were duplicated during recall. Subjects were highly consistent in maintaining their level of pause duration across lists and responded to additions in list length by increasing their number of groups, not by increasing group size. Triadic sequences were the most popular form of spontaneous organization. Pausing measures are discussed as indices of organizational strategies.     

Adult Attachment Styles, the Desire to Have Children, and Working Models of Parenthood

ABSTRACT College students who had yet to marry and begin a family were asked about their desire to have children and their beliefs and expectations about themselves as parents (Study 1) and the characteristics of their prospective children (Study 2). Persons with more avoidant and anxious-ambivalent models of close adult relationships harbored more negative models of parent-hood and parent-child relationships. These findings indicate that working models of parenting and parent-child relationships form well before marriage and the birth of children and that these models are systematically associated with attachment styles in adult relationships. The findings also suggest ways in which insecure attachments between child and parent may be influenced by the caregiver's models of parenting and parent-child relationships.     

Parental Smoking and the “Epidemic” Spread of Cigarette Smoking1

“Epidemic” models of transitions between stages of cigarette smoking describe the spread of smoking behavior through face-to-face encounters. An epidemic model was successfully fitted that allowed epidemic parameters to be conditioned on the smoking status of adolescents' parents. Model comparisons supported the conclusion that the transition from nonsmoker to trier involved social contacts, whereas the transition from trier to regular smoker was best modeled as a constant rate (i.e., did not depend on the population prevalence of smokers). The transition rate from nonsmoker to trier was more rapid in children of smoking parents than in children of nonsmoking parents. Adolescents with and without smoking parents did not differ in the rate of transition from trier to regular smoking.     

Book reviews

Wyer, Robert S., Jr. Cognitive Organization and Change : an Information Processing Approach. Potomac, Maryland: Lawrence Erlbaum Associates. 1974. Pp. 502. £10.50.

Egan, J. P. Signal Detection Theory and ROC Analysis. New York: Academic Press. 1975. Pp. 277. £9.75. ISBN

Aldis, O. Play-Fighting. New York: Academic Press. 1975. Pp. 319. £8.75.

Warburton, D. M. Brain Behaviour and Drugs. London: John Wiley. 1975. Pp. 280. £6.95. ISBN 0471 91991 8.

Grieve, D. W., Miller, D., Mitchelson, D., Paul, J. and Smith, A. J. Techniques for the Analysis of Human Movement. London: Lepus Books. 1975. Pp. 177. £5.50.     

Depression and engagement in a residential home for the elderly

Traditional residential care environments for the elderly have been criticized because of the observed low levels of residents' engagement. Behavioural models of depression suggest an inverse relationship between engagement in pleasant activities and depression. The present study examined the relationship between depression and engagement in the residents of a home for the elderly. Correlational analyses indicated no relationship between level of depression and level of engagement but an association was found between level of depression and engagement in activities subjectively most enjoyed. There was considerable variation in the residents' perception of their behaviour; some residents viewed active engagement negatively whilst clearly enjoying behaviour that is technically disengaged. It is suggested that the results of the study emphasize the importance both of individual differences in behaviour and of covert behaviour. Implications for the engagement concept are discussed. In particular it is suggested that programmes in care environments aimed at increasing engagement in order to enhance the quality of life should focus more on the individual and on his perception of his behaviour.     

Selectivity and immigration in Canada

One perennial policy question in Canada concerns the kind of immigrants Canada should admit. Should it be those with the best prospects of fast economic assimilation in the labour market?. This research note sketches the earnings outcomes of immigrants associated with different admission categories. Specifically, we examine two databases. The Immigration Data Base (IMDB) provides information on admission categories by linking immigration, administrative records with income tax files. The Survey of Labour and Income Dynamics (SLID) is a longitudinal sample that provides a comprehensive profile of immigrants and native-born Canadians. The IMDB and SLID datasets provide valuable information on the economic outcomes of immigrants in quite different ways.     

The rattling sound of rattlesnakes (Crotalus viridis) as a communicative resource for ground squirrels (Spermophilus beecheyi) and burrowing owls (Athene cunicularia)

Animal communication involves very dynamic processes that can generate new uses and functions for established communicative activities. In this article, the authors describe how an aposematic signal, the rattling sound of rattlesnakes (Crotalus viridis), has been exploited by 2 ecological associates of rattlesnakes: (a) California ground squirrels (Spermophilus beecheyi) use incidental acoustic cues in rattling sounds to assess the danger posed by the rattling snake, and (b) burrowing owls (Athene cunicularia) defend themselves against mammalian predators by mimicking the sound of rattling. The remarkable similarity between the burrowing owl's defensive hiss and the rattlesnake's rattling reflects both exaptation and adaptation. Such exploitation of the rattling sound has favored alternations in both the structure and the deployment of rattling by rattlesnakes.