Predicting adolescent eating and activity behaviors: the role of social norms and personal agency.

Guided by the theory of planned behavior, this 2-week longitudinal study examined health behaviors in a sample of 279 adolescents. Social norms and perceived behavioral control (PBC) were tested as predictors of self-reported intentions and behaviors in 2 domains, eating and physical activity. Differentiating, as opposed to aggregating, parent and peer norms provided unique information. For PBC, the authors distinguished global causality beliefs from self-related agency beliefs and intraself (effort, ability) from extraself (parents, teachers) means. Intraself agency beliefs strongly predicted healthy intentions, whereas intraself causality beliefs had a negative influence. Patterns differed somewhat across behaviors and gender. Results highlight theoretical issues and provide potential targets for research on health promotion programs for youth.     

Spectral content as a cue to perceived auditory distance.

Changes in the spectral content of wide-band auditory stimuli have been repeatedly implicated as a possible cue to the distance of a sound source. Few of the previous studies of this factor, however, have considered whether the cue provided by spectral content serves as an absolute or a relative cue. That is, can differences in spectral content indicate systematic differences in distance even on their first presentation to a listener, or must the listener be able to compare sounds with one another in order to perceive some change in their distances? An attempt to answer this question and simultaneously to evaluate the possibly confounding influence of changes in the sound level and/or the loudness of the stimuli are described in this paper. The results indicate that a decrease in high-frequency content (as might physically be produced by passage through a greater amount of air) can lead to increases in perceived auditory distance, but only when compared with similar sounds having a somewhat different high-frequency content, ie spectral information can serve as a relative cue for auditory distance, independent of changes in overall sound level.