The effect of mirthfulness upon amount of discordant right-left occipital EEG alpha

A total of 68 subjects participated in two experiments that tested the effect of exposure to comedy upon amount of discordant right-left occipital EEG alpha. Data from both showed less discordant alpha in the laughers and more in the nonlaughers at the end of exposure to a filmed comedy, as contrasted by no such group difference before treatment. Experiment 2 clarified that the production of discordant alpha in the right hemisphere was significant to this group difference, that this effect was specific to comedy treatment (nondiscriminative effects of exposure to a neutral film), and that a reversed group difference in amount of discordant right hemisphere alpha occurred after instructed hypoventilation (nondiscriminative effect of hyperventilation; counterbalanced order of all four treatments). The results were discussed in relation to (a) recent findings on right-left hemisphere characteristics of depressed individuals, (b) the significance of motivational states, (c) a link between cerebral blood flow and EEG indicators of activation, (d) ventilatory effects upon cortical activation, (e) personality differences inherent in tolerance for CO₂-blood concentration, and (f) recent findings on corticothalamic connections.