UC Berkeley

In close relationships, laughter plays an important role in attachment maintenance, communication, and emotion regulation. We know from previous research that laughter, particularly in response to watching humorous film clips, is associated with increased positive emotion (Ruch, 1995), increased cardiovascular and electrodermal arousal, including heart rate, respiration rate, and skin conductance (Marci, Moran, et al. 2004), and decreased arterial stiffness--indicated by longer pulse transmission times (Vlachopoulos, Xaplanteris, et al. 2009). We do not know, however, much about the time course of these changes, how these changes persist following laughs, and whether these changes will also be found in more naturalistic and more emotionally varied settings (i.e., middle-age and older couple conversations about marital conflict). It is also unclear whether previous research findings associating laughter with emotional and physiological changes in arousal are dependent on the kinds of laughs involved. Previous research has tended to pool all laughs into a single category; however, recent research has demonstrated compelling evidence that laughter is a highly complex and diverse phenomenon (e.g., Smoski & Bachorowski, 2003; Keltner & Bonanno, 1997)

In the present study, laughter was investigated using a previously collected dataset (Levenson & Carstensen, 1993) that included a sample of 156 middle-aged (40-50 yrs, N=82) and older (60-70 yrs, N=74) married couples who engaged in 15-minute videotaped discussions of conflict. Physiological arousal (heart rate inter-beat interval, skin conductance, finger temperature, finger pulse amplitude, finger pulse transit time, ear pulse transit time, and general somatic activity) was measured continuously for both spouses throughout each discussion. Also, in the original study, couples returned to the laboratory within one week following the conflict discussion to watch a videotape of themselves while using a simple rating dial (1-extremely negative to 9-extremely positive) to continuously indicate how they had been feeling throughout the original discussion. The videotapes, physiological arousal data, self-reported emotion data, as well as demographic and questionnaire data (two measures of marital satisfaction) collected during the previous study were used in the present study. A team of trained raters coded the videotapes for the different kinds of laughs investigated. Physiological arousal data and self-reported emotion data were first averaged on a second-by-second basis and then, for each laugh, into three epochs: (a) 10-seconds before the laugh, (b) during the laugh, and (c) 10-seconds following the laugh.

Three aims were pursued in this study, (Aim #1) to determine how self-reported emotion and physiological arousal change during laughs, (Aim #2) to determine the impact of different kinds of laughs (Antiphonal, Duchenne, and Voiced) on emotional experience and physiological arousal, and (Aim #3) to determine individual differences in the use of laughter based on sex, age, and marital satisfaction.

Analyses for Aim #1 revealed: (a) laughter was associated with self-reported emotion becoming more positive during and following laughs, (b) laughter was associated with physiological arousal increases (Inter-beat Interval, Skin Conductance, and Somatic Activity) and decreases (Finger Pulse Transit Time and Ear Pulse Transit Time) during laughs. Analyses for Aim #2 revealed: (c) self-reported emotion became more positive during and following Antiphonal, Duchenne, and Voiced laughs compared to non-Antiphonal, non-Duchenne, and non-Voiced laughs, respectively, (d) Antiphonal, Duchenne, and Voiced laughs were also found to have greater physiological arousal (somatic activity and inter-beat interval) during laughs than non-Antiphonal, non-Duchenne, and non-Voiced laughs, respectively, and (e) Antiphonal laughs were found to have greater skin conductance arousal during laughs than non-Antiphonal laughs. Analysis for Aim #3 revealed: (f) middle-aged couples laughed more than older couples; and (g) satisfied couples laughed more than unsatisfied couples with middle-aged satisfied couples primarily contributing to these differences, (h) no differences in the use of laughter were found between husbands and wives, (i) older couples used proportionately more Duchenne and Voiced laughs than middle-aged couples; however, (j) middle-aged couples used proportionately more Antiphonal laughs than older couples, (k) satisfied couples used proportionately more Duchenne and Voiced laughs than unsatisfied couples, and (l) no differences between satisfied and unsatisfied couples were found in the use of Antiphonal laughter. The implications of these findings for laughter, aging, and marital research were discussed.