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.     

On the special status of "ego threats".

This article comments on a recent article by Heatherton, Herman, and Polivy (1991) in which they suggest that ego threats are a prerequisite to affectively induced disinhibition of food intake in restrained eaters and current dieters. In contrast, the present review suggests that mood induction procedures that involve no apparent threat (e.g., viewing a frightening film) can also prompt disinhibition in restrained eaters. Thus, any mood induction procedure that does not directly physically threaten the S may disinhibit restrained eaters. It is concluded that recommendations to focus future research on ego threats are premature and may serve to obscure the mechanisms by which changes in affective state influence food intake in dieters.     

Integration of the big five and circumplex approaches to trait structure.

To integrate the 5-dimensional simple-structure and circumplex models of personality, the Abridged Big Five Dimensional Circumplex (AB5C) taxonomy of personality traits was developed, consisting of the 10 circumplexes that can be formed by pitting each of the Big Five factors against one another. The model maps facets of the Big Five dimensions as blends of 2 factors. An application to data consisting of 636 self-ratings and peer ratings on 540 personality trait adjectives yielded 34 well-defined facets out of a possible 45. The AB5C solution is compared with simple-structure and lower dimensional circumplex solutions, and its integrative and corrective potential are discussed, as well as its limitations.     

Defensiveness in response to aid from a sibling.

Defensive reactions to aid in the context of a close relationship were studied. Young adult siblings reported on their self-esteem, the quality of the sibling relationship, relevant demographic variables, and a variety of components of defensiveness to aid. Consistent with theory, the components of defensiveness were interrelated. A large percentage (52%) of the variance in defensiveness was accounted for by conflict between siblings, dominance relative to one's sibling, low global self-esteem, high self-esteem when comparing oneself with one's sibling, and low levels of feelings of entitlement. Siblings were least defensive in reaction to aid from older and female siblings. Corroboration from a subset of benefactor siblings was obtained. The results are discussed in relation to recent thinking about the nature of receiving support in close relationships and recipients' reactions to aid.     

Postural requirements and progression velocity in young walkers

This article describes developmental changes in gait velocity and relates these changes to gait parameters that index postural stability (step width and lateral acceleration) and two components of velocity (cadence and step length). Five children were observed longitudinally over a 2-year period after onset of independent walking. Their range of speed increased threefold in the first 6 months of independent walking and then remained constant. In contrast, step width decreased approximately twofold. Whereas in adults, cadence and step length contribute approximately equally to speed, when infants first begin to walk independently, increase in velocity is due mostly to increased step length. After 5 months of independent walking, the pattern reverses, and increase in velocity is due primarily to increased cadence. The pattern remains constant over the next 18 months. From a developmental point of view, the data lead us to interpret early walking (the first 5 months) as a process of integration of postural constraints into the dynamic necessities of gait movement. A second phase, beginning after 4 to 5 months of independent walking, is considered to be a tuning phase characterized by a more precise adjustment of the gait parameters.     

Recovery of Locomotion in Monkeys With Spinal Cord Lesions

This study reanalyzes kinematically (via film) the pre- and postoperative locomotor behavior of 4 of the 10 monkeys with partial spinal cord lesions (T8) briefly described by Eidelberg, Walden, and Nguyen (1981). The behavior of the remaining 6 monkeys is qualitatively described. The analysis reveals that 5 of the animals initially exhibited unilateral hind limb stepping. Hind and forelimb cycle durations often differed postoperatively; the hind limbs commonly showed increased values, whereas forelimb cycle durations were reduced: ipsilateral interlimb phase values were usually inconsistent. A review of prior studies of primate spinal cord lesions indicates that sparing of the ventrolateral quadrant may not be essential for locomotor recovery (cf. Eidelberg, Walden, & Nguyen, 1981). Furthermore, this review as well as the kinematic analysis indicates that primates with very significant spinal lesions can stilI exhibit locomotor movements. Thus, although the primate's spinal cord seems less able than other mammals' to readily organize locomotor movements (Eidelberg, Walden, & Nguyen, 1981), the total absence of stepping in primates with completely transected cords is unexpected and warrants further research.     

Why do people need self-esteem? Converging evidence that self-esteem serves an anxiety-buffering function.

Three studies were conducted to assess the proposition that self-esteem serves an anxiety-buffering function. In Study 1, it was hypothesized that raising self-esteem would reduce anxiety in response to vivid images of death. In support of this hypothesis, Ss who received positive personality feedback reported less anxiety in response to a video about death than did neutral feedback Ss. In Studies 2 and 3, it was hypothesized that increasing self-esteem would reduce anxiety among individuals anticipating painful shock. Consistent with this hypothesis, both success and positive personality feedback reduced Ss' physiological arousal in response to subsequent threat of shock. Thus, converging evidence of an anxiety-buffering function of self-esteem was obtained.     

Effects of real gender and labeled gender on adults' perceptions of infants.

Three experiments were conducted to discover factors mediating adults' perceptions of male and female infants. In the first experiment, college students were shown 30-s videotapes of four male and four female babies, each of whom was randomly labeled with a male or a female name. Infants labeled as male were perceived as significantly more masculine and stronger than those labeled as female. Discriminant analyses revealed that both rated masculinity and the combination of ratings on male stereotyped traits differentiated infants labeled as male or female. Analyses of real gender revealed that boys were rated as less sensitive and stronger than girls. Discriminant analyses suggested that the combination of less sensitive, more of a problem, more mature, and more playful best differentiated real males from real females. In Experiment 2, the findings of Experiment 1 were confirmed with a sample of mothers of young infants. In Experiment 3 college students' judgments of the sex of the eight babies were correctly predicted from the sensitivity ratings of these babies in Experiment 1. It appears that there is a complex of cues from which adults make judgments of infants' gender and inferences about their characteristics: Boys may appear stronger, more playful, and more of a problem, and girls seem to look more sensitive. Implications for further studies of gender labeling and for sex typing are discussed.     

Effects of Pointing Rate and Availability of Visual Feedback on Visual and Proprioceptive Components of Prism Adaptation

While looking through laterally displacing prisms, subjects pointed 60 times straight ahead of their nose at a rate of one complete movement every 2 or 3 s, with visual feedback available early in the pointing movement or delayed until the end of the movement. Sagittal pointing was paced such that movement speed covaried with pointing rate. Aftereffect measures (obtained after every 10 pointing trials) showed that when the limb became visible early in a pointing movement, proprioceptive adaptation was greater than visual, but when visual feedback was delayed until the end of the movement, the reverse was true. This effect occurred only with the 3-s pointing rate, however. With the 2-s pointing rate, adaptation was predominately proprioceptive in nature, regardless of feedback availability. Independent of the availability of visual feedback, visual adaptation developed more quickly with 3-s pointing, whereas proprioceptive adaptation developed more rapidly with 2-s pointing. These results are discussed in terms of a model of perceptual-motor organization in which the direction of coordinative (guidance) linkage between eye-head (visual) and hand-head (proprioceptive) systems (and consequently the locus of discordance registration and adaptive recalibration) is determined jointly by pointing rate and feedback availability. An additional effect of pointing rate is to determine the rate of discordant inputs. Maximal adaptive recalibration occurs when the input (pointing) rate matches the time constant of the adaptive encoder in the guided system.