Napping promotes inter-session habituation to emotional stimuli

The effects of a daytime nap on inter-session habituation to aversive visual stimuli were investigated. Healthy young adult volunteers viewed repeated presentations of highly negative and emotionally neutral (but equally arousing) International Affective Picture System (IAPS) photographs during two afternoon sessions separated by 2.5h. Half of the photographs were shown at both sessions (Repeated Sets) and half differed between sessions (Novel Sets). For each stimulus presentation, evoked skin conductance response (SCR), heart-rate deceleration (HRD) and corrugator supercilii EMG response (EMG), were computed and range corrected using respective maximum session-1 responses. Following each presentation, subjects rated each photograph on dimensions of pleasantness and arousability. During the inter-session interval, Nap subjects had a 120-min polysomnographically monitored sleep opportunity, whereas Wake subjects watched a non-stimulating video. Nap and Wake subjects did not differ in their subjective ratings of photographs. However, for Repeated-Set photographs, Nap subjects demonstrated greater inter-session habituation in SCR and EMG but a trend toward lesser inter-session habituation in HRD. These group differences were absent for Novel-Set photographs. Group differences across all measures were greater for negative stimuli. Occurrence of SWS during the nap was associated with greater inter-session habituation of EMG whereas occurrence of REM was associated with lesser inter-session habituation of SCR to negative stimuli. Sleep may therefore promote emotional adjustment at the level of somatic responses. Physiological but not subjective inter-session habituation to aversive images was enhanced by a daytime nap.     

Selective information processing and schematic content related to eating behavior

An adaptation of the Stroop color-naming task was used to investigate selective information processing related to eating behavior in 90 undergraduate women. This study differed from previous studies by (a) treating eating behavior as a continuous variable and (b) looking at five separate categories of words including color, neutral, food, body shape, and other emotionally salient words. We did not find a strong pattern of relation between the Stroop task and eating and body image measures. Results suggest that in a nonclinical population, direct methods of accessing cognitions related to eating may be more fruitful than indirect measures.     

Age-related changes in the associations of social network ties with mortality risk

Age-related changes in the associations of social network ties with mortality risk were investigated using data from the Terman Life-Cycle Study (L. M. Terman, 1925; L. M. Terman & M. H. Oden, 1947, 1959). Marital status, number of living children, number of living siblings, and number of group memberships in 1940, 1950, 1960, and 1977 were reported across middle adulthood by 697 men and 544 women, with mortality follow-up as of 1991. Initial analyses confirmed previous work indicating that marital history (men only), number of children (both genders), and organizational memberships (both genders) are predictive of mortality risk. Further analyses compared the associations between these social ties and mortality prior to age 70 and at age 70 and older. Results indicated that for men, experiencing marital dissolution and subsequently remarrying is a stronger predictor of mortality risk prior to age 70 (p = .05), whereas for women, number of children (p < .05) is a stronger predictor of mortality risk after age 70. Implications of these age-related changes in social ties and mortality risk are discussed.