Impact of Evening Light Exposures with Different Solid Angles on Circadian Melatonin Rhythms, Alertness, and Visual Comfort in an Automotive Setting.

Future automotive interior lighting might have the potential to go beyond decorative purposes by influencing alertness, circadian physiology, and sleep. As the available space in the interior of an automobile for lighting applications is limited, understanding the impact of various luminous surface sizes on non-image-forming effects is fundamental in this field. In a laboratory study using a within-subject design, 18 participants were exposed to two bright light conditions with different solid angles and one dim light condition in a balanced, randomized order during the course of the evening. Our results demonstrate that both light conditions significantly increased subjective alertness and reduced salivary melatonin concentration but not cognitive performance compared to dim light. The solid angle of light exposure at constant corneal illuminance only affected visual comfort. While subjective alertness can be increased and melatonin can be attenuated with rather small luminaires, larger solid angles should be considered if visual comfort is a priority.

Recovery from accumulated strain: the role of daily mood and opportunity costs during a vacation.

OBJECTIVE: Recovery from strains accumulated over longer periods of time is essential for health and well-being. Most people take vacations to ensure that they achieve a state of recovery that will allow them to prevent a state of enduring exhaustion. Extending a recent motivational model of recovery, we examined recovery processes during a vacation. DESIGN: In the current daily diary study, 147 university students reported their daily recovery, mood, opportunity costs, and subjective time perception over 21 consecutive days (2342 observations) during the summer break. RESULTS: Multilevel analyses showed that students reported higher recovery on days when they were in a better mood and perceived lower opportunity costs than usual. These results held after controlling for the passage of time and well-established covariates of recovery (i.e., psychological detachment, relaxation, mastery, and control). CONCLUSION: Supporting the motivational model of recovery, positive mood, the absence of opportunity costs and, to a lesser degree, the perception of time passing quickly contribute to daily recovery during a vacation. Thus, recovery is not simply the result of elapsed time but also depends on the kinds of experiences people have on a given vacation day.

More or less energy with age? A motivational life-span perspective on subjective energy, exhaustion, and opportunity costs.

Two studies investigated subjective conceptualizations of energy for goal pursuit across adulthood. Study 1 (N = 276, 20-92 years of age) explored age-related differences in the (a) endorsement of a limited versus nonlimited account of energy for goal pursuit, (b) amount of energy available for physically, mentally, socially, and emotionally demanding activities, and (c) extent to which spending energy on a demanding activity inhibits or facilitates energy expenditure for subsequent activities, both within and across functional domains. Study 2 (N = 147, 18-86 years of age) experimentally induced energy loss through a 20-min physical exercise and examined age-related differences in the increase of subjective exhaustion and opportunity costs as a motivational cue for goal disengagement. With increasing age, adults more strongly endorsed a nonlimited account of energy and perceived having more energy available for personally relevant social activities. However, older adults also reported higher negative cross-domain energy spillover after physical exertion. Multilevel growth curve models further revealed that, compared with younger adults, older adults reported a steeper initial increase in exhaustion and opportunity costs during physical exercise, but converged with the younger age groups again at the close of the exercise session. The discussion centers around the importance of selectivity in older adulthood and motivational accounts of effort and exhaustion. (PsycInfo Database Record (c) 2020 APA, all rights reserved).