negative association with the time youngsters spent watching television during the 10th grade: that is, as hours of work increased, time spent watching television decreased. If watching television—which entails relatively little challenge, low demand, and usually little educational benefit—is the activity mainly sacrificed by employment, it could account for the null findings regarding the effects of working on the time youngsters spend doing homework (Mortimer and Johnson, 1998; Mortimer et al., 1996; Schoenhals et al., 1997).
However, Bachman and Schulenberg (1993) report that hours of sleep significantly decline as seniors' hours of work increase. The investigators also report that those working longer hours are less likely to eat breakfast. They are also less likely to exercise vigorously if they work up to 25 hours per week, after which exercising increases. Carskadon and colleagues have similarly found a reduction in sleep and increased daytime sleepiness among high school students who work; the effects increase as the numbers of hours worked increase (Carskadon, 1990; Carskadon et al., 1989).
Because the quality of adult work has been found to have substantial consequences for adult psychological functioning (Baker and Green, 1991; Kohn et al., 1983; Mortimer et al., 1986), some researchers have studied whether adolescent psychological functioning is similarly responsive to the quality of work. Young workers may be exposed to job-related stressors, especially if they are required to take on adult responsibilities when their coping skills are not yet adequate (Greenberger, 1988). Moreover, combining school and work may not be easy; adolescents generally perceive it as stressful, and increasingly so, as they progress through high school (Mortimer et al., 1994). This is especially the case for those boys who work nearly continuously, at high levels of intensity, during high school (Mortimer and Johnson, 1998). In an analysis of data from the first year of the National Longitudinal Study on Adolescent Health, Resnick and colleagues (1997) found that working more than 20 hours per week during the school year was associated with emotional distress (defined as physical or emotional symptoms of distress as reported by the young people themselves or by their parents).
There is evidence that the quality of youngsters' work does, in fact, significantly affect their mental health. In the Youth Development Study, opportunities for advancement and compatibility between school and work for boys and good pay for girls promoted a sense of self-efficacy over time (Finch et al., 1991). Boys' sense of