Laughter down-regulates negative emotional arousal amongst friends

Introduction

Laughter is an inherently social behaviour which is prevalent in interactions as wide ranging as tickling and conversations (Gervais and Wilson 2005; Provine 2001). Laughter is not automatic, rather highly modulated by social factors. Humorous material, for example, is rated more amusing when participants believe others have also found it amusing (Wimer & Beins, 2008).

Within interactions, laughter regulates mood and coordinates the behaviour of laughter through a group (Spoor and Kelly 2004; Deacon 1997; Provine 1992). Affect and laughter are induced in a listener both through the directly arousing acoustic properties of laughter, and indirectly as a conditioned positive affective social experiences (Owren and Bachorowski 2003). Laughter shows an in-group function: the act of laughing increases positive affect which further enhances the perceived pleasure of social interactions, promoting affiliative and cooperative behaviour (Owren and Bachorowski 2003; Martin 2007; Smoski and Bachorowski 2003). Participants laughed and smiled more, laughed longer, and rated humorous material more favourably when they heard in-group laughter as opposed to out-group laughter or no laughter at all (Platow et al. 2005).

The “undo” hypothesis theorises that positive emotions, including laughter and smiling, function to mitigate negative arousal that arises from stressful events (Levenson 1988). Cardiovascular arousal, including increased heart rate and blood pressure associated with a fearful film, dissipated more quickly when followed by happy films as compared to sad or neutral films (Fredrickson and Levenson 1998). Music-induced positive emotions preceded by the viewing of unpleasant pictures restored baseline cardiovascular and respiratory levels faster than did white noise (Sokhadze 2007).

The aim of the present study was to combine these two separate explorations of laughter and address the use of laughter to regulate negative emotional affective states amongst people known to each other. The study investigated whether more laughter and positive emotional expressions were produced by participants in familiar than unfamiliar company, in the context of transition from negative arousal to a more positive affect. Music was used to induce an affective state (positive or negative) or a non-affective state using non-arousing music as a control group. The music presentations were followed by presentation of infectious laughter. The hypothesis was that laughter produced in response to infectious laughter would be greatest following fearful affect, and would show sensitivity to social context, being greatest in familiar compared to unfamiliar company.

Methods

Results

Participant demographic details and group compositions are above. Mean age, gender, and familiarity of participants, did not significantly differ between the three experimental groups. No participants recognised the musical part of the excerpts presented. Self-reported emotions were consistent with intended mood induced in each of the three conditions; negative and arousing emotions in the fearful aroused condition, positive emotions in the happy condition, mostly relaxing, though also some reports of positive and negative emotions in the control condition. Some participants reported that the laughter made them feel uncomfortable. Facial expressions of participants were generally reliably categorized on the mirth scale by observers. Observers expressed particular difficultly when trying to classify faces of participants who appeared to be stopping themselves laugh, where participants were seen to flare nostrils, bite lips, raise eyebrows and fidget or display other behaviours not enlisted in the mirth scale.

Peak mirth

The peak mirth scores of familiar and unfamiliar participants did not significantly differ, F(1, 84) = 1.73, p < .05, and there was no significant effect of mood-induced, F(2, 84) = 1.59 p > .05. There was a significant interaction between the affect and familiarity, F(2, 84) = 4.68, p = .01 (Figure 1). Post-hoc comparisons revealed that familiar participants had significantly greater peak mirth scores (M = 3.27, SD = 1.34) than unfamiliar participants (M = 1.97, SD = 1.46) in the fearful affect condition (Figure 1). The size of this effect is 1.05.

Figure 1. Line graph showing the peak mirth scores of familiar (green solid line) and unfamiliar (green dotted line) participants, and the time familiar (solid lines) and unfamiliar (dotted lines) participants spent in full smiles (blue) and half smiles (red) in the different experimental conditions.

Error bars represent the standard error of the mean. There is a significant interaction in all three dependent variables where familiar participants have higher peak mirth ratings, longer time spent smiling (full and half smiles) than unfamiliar participants in the fearful affect condition. Time spent laughing is not shown as results for this dependent variable were not significant.

Discussion

The present study asked whether laughter produced in the context of negative emotions was modulated by social context. The main finding was a significant affect-familiarity interaction in three of the four dependent variables. In the fearful affect condition participants familiar to the experimenter had significantly greater peak mirth scores, spent longer smiling (half and fully) in response to the infectious laughter than participants unfamiliar to the experimenter. Familiar participants also laughed for longer than unfamiliar participants in the fearful affect condition, but the familiarity-affect interaction was not significant. This is perhaps because fewer participants laughed overall in this condition, making the interaction underpowered.

This experiment was designed to combine previous work showing that laughter is both sensitive to social group and can regulate affective states within interactions. Laughter is greater amongst members of a group (Smoski and Bachorowski 2003) and is increased when participants hear in-group laughter (Platow et al. 2005) or when further affiliation with one’s experimental partner is desired (Grammer and Eibl-Eibesfeldt 1990). Additionally, positive affect, including smiles and laughter, down-regulate negative arousal arising from stressful events. This has been demonstrated in stressful events ranging from a forced speech task (Fredrickson et al. 2000), a fearful film (Fredrickson and Levenson 1998), viewing unpleasant pictures (Sokhadze 2007). The findings presented here uniquely demonstrate that mirthful expression following a transition from negative to positive arousal is greater when in company of in- compared to out-group, members.

Although it was theorised that the significant interaction in the fearful affect condition was driven by more laughter amongst participants who knew the experimenter, it could be driven by less laughter in participants unknown to the experimenter. Graphical representation data of the dependent variables suggest known participants express more amusement in the fearful condition. However, some participants reported that the laughter made them uncomfortable. Laughter itself is a universal laughter-provoking stimulus (Provine 1992) reported by listeners to induce in them a positive affect (Szameitat et al., 2009). However, it can be heard in a negative way, especially in people who are “gelatophobic” and fear being laughed at (Ruch, Hofmann, and Platt 2015; Ruch et al. 2014). Perhaps the unfamiliar participants, who were blindfolded and in the company of a stranger, were more likely to perceive laughter negatively in the fearful affect condition.

Previous work suggests that laughter is greater amongst members of a group compared to strangers (Smoski and Bachorowski 2003; Platow et al. 2005; Grammer and Eibl-Eibesfeldt 1990). In this experiment, however, time spent fully smiling was the only dependent with a significant effect of familiarity; familiar participants fully smiled more than the unfamiliar participants. Familiar company only increased the duration of half smiles and extent of mirth in the context of negative emotions. Similarly, although laughter has been found to accompany the transition from negative-to-positive affect (Fredrickson et al. 2000; Fredrickson and Levenson 1998; Sokhadze 2007; Sroufe and Wunsch 1972), there was no significant effect of “affect” alone. These results suggest that the strongest stimulus to laugh and express is when participants are amongst familiar company and experience a transition from a fearful to positive affective state. This is a stronger stimulus to laugh that just being in familiar company or just experiencing transition from a negative-to-positive affect.

Humour is involved in the formation, maintenance, and regulation of close interpersonal relationships (Lefcourt 2001; Shiota et al. 2004). Interactions associated with laughter increase feelings of closeness and attraction to ones’ confederate more than do equally enjoyable but non-humorous experiences (Fraley and Aron 2004). Positive emotions and laughter in humorous communications reinforce mutual feelings of affection, strengthen attachment, and contribute to greater relationship satisfaction (Smoski and Bachorowski 2003). Couples in highly satisfied marriages are better able to regulate negatively aroused states during conflictive interactions using positive affect, including laughter, affection and humour, than couples in less satisfied marriages (Gottman and Levenson 1992; Levenson and Gottman 1983; Carstensen, Gottman, and Levenson 1995) and have greater degrees of marital stability six years later (Gottman et al. 1998). Instructions to suppress negative emotions when discussing negative topics disrupted communication, inhibited relationship formation, and increased the blood pressure of the suppressor’s partner (Butler et al. 2003). It follows that laughter, a communicative group-sensitive behaviour, may have functional and evolutionary role in downregulating negative affective states in familiar company to facilitate successful group cohesion and group bonding. There is likewise less functional a role for laughter amongst strangers when faced with stressful situations.

The limitations of this experiment include the use of a blindfold. The involvement of eyes in smiles is important to distinguish between Duchenne (“emotional”) and non-Duchenne (“social”) smiles when coding smiles in social interaction (Ekman, Davidson, and Friesen 1990). It possible that the smiles recorded in this experiment were both “social” and “emotional” smiles. However, since participants were not directly interacting socially with a companion, “social” smiles were thought to be negligible. Participants were positioned in-front of a camera which could make participants feel self-conscious, and thereby inhibit emotional expressions.

Participants were blindfolded to both aid concentration on acoustic stimuli, and to block out the distraction of a camera. The benefits of using a blindfold for these purposes was thought to outweigh the benefit of including the eyes in rating of degrees of mirth. Another difficulty was found when coding faces for amusement in participants who appeared to be withholding laughter, and often used facial muscles other than the mouth. Future studies may benefit from including an additional “withholding laughter” category on mirth coding scales. “Familiarity” was coded categorically as unfamiliar or familiar, but it is recognized that this variable varies continuously. Future experiments could focus on whether the degree of familiarity influences the degree of mitigation from negatively arousing states. A strength of this experimental design was the use naturalistic methodology to evoke laughter, a sensitive emotion notoriously difficult to evoke in experimental situations. The design also included induction of a positive affective state which demonstrated the humorous response was specific to negative arousal as opposed to arousal in general as has been theorized (Berlyne 1972).

One interesting alternative explanation to the findings in this experiment relates to the ‘relief’ hypothesis of laughter (Ramachandran, Blakeslee, and Sacks 1998; Hayworth 1928; Keltner and Bonanno 1997). This hypothesis states that laughter accompanies the elicitation of positive affect, namely relief, following a negative state. The relief hypothesis can also provide unifying framework explaining why the focus of jokes worldwide tends to centre of taboo topics and slapstick (Freud 1989; Kotthoff 2006; Gervais and Wilson 2005). Future experiments will need to tease out these two alternative explanations of laughter.

Conclusion

In summary mirth intensity, smiles (half and full) were greater in known compared to unknown participants following induction of a fearful affect. This positive affect can be used to regulate negative affective states amongst people known to each other. The stimulus to laugh may be highest when in familiar companies and following a negatively arousal situation.