Emotional arousal when watching drama increases pain threshold and social bonding

Abstract

Fiction, whether in the form of storytelling or plays, has a particular attraction for us: we repeatedly return to it and are willing to invest money and time in doing so. Why this is so is an evolutionary enigma that has been surprisingly underexplored. We hypothesize that emotionally arousing drama, in particular, triggers the same neurobiological mechanism (the endorphin system, reflected in increased pain thresholds) that underpins anthropoid primate and human social bonding. We show that, compared to subjects who watch an emotionally neutral film, subjects who watch an emotionally arousing film have increased pain thresholds and an increased sense of group bonding.

Keywords: emotional arousal; endorphins; pain threshold; social bonding; tragedy.

Figure 1.

Frequency distribution of (a) change in positive affect (after-minus-before composite score) and (b) change in negative affect for the experimental (grey bars) and control (white bars) groups. The dashed vertical line indicates 0 (no change).

Figure 2.

Frequency distribution of (a) change in pain threshold (after-minus-before duration for wall-sit task, in seconds) and (b) change in IOS rating for experimental (grey bars) and control (white bars) participants. The dashed vertical line indicates 0 (no change).

Figure 3.

Marginal means for (a) pain threshold and (b) IOS before and after watching the experimental film (Stuart: A Life Backwards) (solid line) or the control films (dashed line).

Figure 4.

Change in IOS ratings (after-minus-before) plotted against change in pain threshold (after-minus-before duration of wall-sit task, in seconds) for participants in the experimental condition. Five data points more than 3 s.d. of their respective means are excluded. The vertical line indicates no change in pain threshold. The dashed line indicates the separate linear relationships between the two variables below and above Δpain = 0.

Figure 5.

Goodness of fit (indexed by regression F-value) for change in IOS regressed on change in pain threshold for data points below (open symbols) and above (solid symbols) a sliding cut-off in pain threshold change for the distribution in figure 4. All values above the horizontal line are statistically significant (p < 0.05).

Figure 6.

Best-fit model identified by path analysis of the causal relationships between changes in pain threshold and IOS (bondedness) and changes in positive and negative affect. Separate models were tested for the experimental and control conditions. Five subjects in the experimental (Stuart) condition and two subjects in the control condition had individual datapoints that were more than 3 s.d. from their respective means, and these individuals were excluded from the analyses. Six increasingly complex models (incorporating the effects indicated by the dashed doubled-headed arrows in different combinations) were compared by maximum likelihood, but the model indicated by the solid arrows provided the best, as well as the most parsimonious, fit. The numbers against the solid arrows are the standardized partial regression coefficients, β, for this best-fit model; the values without brackets are those for the experimental film (Stuart) (with the first value being for all data and the second that for Δpain > 0 only), while those in square brackets are the equivalent values for the control condition films. All coefficients except that for pain threshold → IOS in the control condition are significant.

Figure 7.

k-means cluster analysis of absolute change in pain threshold for the experimental condition suggests an optimal division into three clusters: those who did not respond to the film at all (negative change: white bars), those who responded somewhat (low positive change: grey bars) and those who responded a lot (high positive change: black bars).