This is a piece of coursework I did for one of my modules, Evidence and Enquiry, in Year 1 of uni. We had to design our own experiment and write it up in the style of a research paper. We picked one out of three broad topics - I chose 'Why do some things make us laugh?'. I narrowed down the question based on what I was interested in and wrote the essay from there.
Since first year doesn't count anymore because of the coronavirus I thought I'd put it here because I had a lot of fun writing it. Because it was submitted in January, this piece of coursework was still marked and obtained a First. The formatting is a bit off here but it's meant to emulate the format of an APA journal article, which is why it's split into the different sections. All tables and diagrams that are shown in the following paper were self-made and hence not referenced.
Introduction
“Laughter is the best medicine”. Is this famous saying actually grounded in truth?
Laughter is a social phenomenon (Wallis, 1922). Described as an ‘effective self-care tool to cope with stress’ by Wooten (1996), laughter has been identified as one of the many facets of holism in healthcare globally (MacDonald, 2004). There is a plethora of literature that evidences this; Berk et al. (1989) found that people who laughed had lower levels of cortisol, epinephrine and growth hormone levels, resulting in a decrease in physiological stress response. In tandem, McGhee (1998) reported that such biological responses result in an increase in bodily immune response. This was demonstrated by the laughter group of Berk et al.’s study (1989), indicating the utility of laughter in the realm of healthcare, as well as illuminating the benefits of laughter to physical wellbeing.
Contradictorily, however, White & Winzelberg (1992) found that laughter was less effective than relaxation training in reducing physiological stress despite its evident reduction of psychological stress. Nonetheless, it remains that laughter was able to decrease some aspect of physiological measures of stress albeit not as significantly as it did psychological ones. These differences may additionally be explained by individual differences in personality factors such as one’s sense of humor and their likelihood to use humor as a coping mechanism (White & Winzelberg, 1992).
It is therefore imperative to first elucidate the reasons for which people laugh. Laughter occurs in a plethora of contexts, during exhilaration, trauma, aggression, as well as to express superiority and subvert power structures (Ruch, 1993; Van Hoof, 1972; Darwin, 1972; Arendt, 1969). In this sense, laughter can be seen as a means of releasing excess nervous energy (Freud, 1959), accompanying shifts from negative to positive sentiment while acting as ‘undoers’ of negative emotion (Levenson, 1988). Keltner & Bonanno (1997) postulate that laughter facilitates adaptive responses to stress by “increasing the psychological distance from distress and enhancing social relations”.
Experiencing pleasure or enjoyment, however, are not necessarily linked to the expression of smiles (Fernández-Dols & Ruiz-Belda, 1995). The facial feedback hypothesis states that feedback from facial muscles to the brain can modulate affective emotional experience (Tourangeau & Ellsworth, 1979). Zajonc et al. (1998) found that holding a pencil between your teeth uses the same facial orbicularis oculi muscle as a real smile, creating a Duchenne smile (Duchenne, 1862). When asked to watch cartoons, participants in the experimental group who held the pencil between their teeth found them funnier than those in the control condition who did not. They established that the use of facial muscles triggered a physiological response and the release of dopamine, then resulting in the reduction of psychological stress and an increase in happiness. This is a demonstration of the James-Lange theory of emotion, which defines emotional experiences as a consequence of physiological reactions to objects or events.
Similarly, Duchenne laughter shares a single form or structure: sudden unexpected changes in events that occur in social context (Gervais & Wilson, 2005). All elicitors of Duchenne laughter have similar structures; these stimuli access a single ‘laugh generator’ despite being perceived through different modalities (Darwin 1872; Provine, 1996). It is worth noting, however, that Duchenne laughter correlates with different inter and intrapersonal positive responses than Duchenne smiles. Duchenne laughter is linked to feelings of wellbeing and heightened affect, potentially due to a release of endorphins (Dunbar et al., 2011). Laughter follows the reduction of anger and the distancing of oneself from distressing events, while a smile results in the ‘reduction of fear and distress’ (Keltner & Bonanno, 1997). Laughing therefore shifts psychological affect from negative to positive, reducing the distress induced by the former and producing a positive re-interpretation of the source of distress. This relief of stress is thus likely to improve psychological functions and reduce its negative impacts upon well-being. Danzer, Dale & Klions (1990) found that listening to a comedian, following the Velten Mood Induction Procedure (Buchwald et al., 1968), increased participants’ smiling and reduced their self-reported depression ratings in comparison to a control group. This indicates that humor is likely to improve psychological functioning during stressful periods, emphasising that laughter results in a dissociation from the negative impacts of stressful events.
Despite the quantity of research into the psychological benefits of Duchenne laughter, there have been much fewer that investigate the impact non-Duchenne laughter may have on one’s emotional state. Following the facial feedback hypothesis, we seek to uncover whether non-Duchenne laughter will result in the same changes in stress levels as Duchenne laughter to fill in this gap in literature and elucidate the processes behind which non-Duchenne laughter may similarly impact ones’ psychological wellbeing. We therefore hypothesise that non-Duchenne laughs will have the same psychological impact as Duchenne laughs in stress reduction.
Reason for Experimental Aim
There is a marked difference between the psychological response resulting from either a Duchenne smile or a Duchenne laugh. This paper seeks to investigate whether a similar disparity exists between the effects of Duchenne and non-Duchenne laughter. If it is truly the case that these two forms of laughter have the same effect, there is much potential for this to be exploited as a method to treat psychological conditions. For instance, depression as a result of excessive stress may render one unable to inherently produce genuine laughter whilst in depressive states. If this is the case, inducing non-Duchenne laughter to simulate the same physiological response a Duchenne laugh has may prove to be a useful, accessible means of reducing stress levels to improve or alleviate such depressive states. In turn, this may allow persons with depression to be more proactive in behaviours such as attending therapy and engaging in prosocial interactions to improve their condition and resultantly increase their quality of life.
Explanation for choice of Dependent Variable
In past research into Duchenne laughs, the reduction in stress response was operationally measured through several qualitative procedures involving self-report questionnaires with regards to emotion, narrative interviews, as well as the covert observation of participants’ facial expressions following the experimental stimuli. In these experiments, measurements of behaviour all involve the qualitative measurement of participant’s behaviour. This experiment refrains from confining itself to the qualitative and instead includes quantitative measures such as the measurement of heartrate as an indicator for stress response to supplement the aforementioned. Furthermore, we will apply the Emotion Facial Action Coding System (EMFACS, Ekman & Friesen, 1976, 1978) which codes only emotion-relevant facial muscle movements in order to differentiate between Duchenne and non-Duchenne smiles. The smiles will be distinguished from one another on the basis of the ‘presence of orbicularis oculi activation’, which is visible through the presence of wrinkles in the eye region (Ekman & Friesen, 1982). These movements will be scored on a 5-point scale, where 1 = minimal intensity and 5 = extreme intensity.
Proposed Method
Participants
150 Psychology students from University College London will participate in this study for credits as part of their course. Participants will be unaware of the true experimental aim and instead be told that this experiment was conducted in order to investigate the ways in which different video stimuli may impact one’s emotional state.
Approval will be obtained from UCL’s Ethics Committee and consent acquired from participants prior to conducting this experiment. Participants will be randomly allocated to each condition.
Experimental Design
We will employ a between-subjects design. The independent variable is the type of laughter that will be induced in participants. The dependent variable is the resultant relative decrease in stress response in participants. These variables will be operationalised through the following measures:
Operationalisation of Laughter (Independent Variable)
1. Coding of Facial Behaviour
The EMFACS will be used to code facial expressions of Duchenne and non-Duchenne smiles. In turn, Duchenne and non-Duchenne laughter will be coded when Duchenne and non-Duchenne smiles are accompanied by audible laughter and an open mouth (Keltner, 1995). This will be recorded by through video cameras placed in front of each participant in the experimental condition. This experiment employs a double-blind experimental design, where the researcher coding the facial behaviour of participants will be blind to the investigation’s aims in order to prevent possible experimenter biases. Two researchers who have passed EMFACS reliability tests will code the facial behaviour in order to achieve inter-rater reliability (Keltner & Bonanno, 1997). This will generate an agreement ratio for each participant as scored by both researchers to reduce any potential bias and inaccuracy in coding.
Operationalisation of Stress Response (Dependent Variable)
1. Heart Rate Change
Electrocardiogram sensors will be placed on participants’ wrist and forearms to measure heart rate (Keltner & Bonanno, 1997). These will then be processed by an r-wave detector to generate pulse signals when each waveform occurs.
2. Self-Report Questionnaires
Participants will complete self-report questionnaires that we derived from the PHQ-9 scale (Kroenke & Spitzer, 2002) and the Stress Arousal Checklist (Mackay, 1985) prior to the start and following the completion of the experiment. This questionnaire included inquiries with regards to participant’s current levels of perceived stress.
Table 1: List of Questions in the Self-Report Questionnaire
3. Perceived Stress Scale (PSS)
Participants will also complete a Perceived Stress Scale (Cohen, 1994) both prior to the start and following the completion of the experiment. This experiment used an adapted version of the PSS which was crafted to gauge the degree to which participants appraise their current state as stressful. It was chosen for its simplicity and its generality which ensured that questions were relatively content-unspecific to any possible subpopulation groups present in the participant group. We will reverse responses (e.g., 0 = 4, 1 = 3, 2 = 2, 3 = 1 & 4 = 0, where 0 = never, 2 = sometimes and 4 = very often) to the four positively stated items (numbers 4, 5, 7 & 8) before summing across all items to obtain PSS scores.
Table 2: Perceived Stress Scale (Cohen et al., 1994)
Procedure
We will hold this experiment in a common room in UCL. Prior to the study, participants will answer both a self-report questionnaire with regards to their own perceptions of their current stress levels and a PSS.
Participants were split into three groups, each experiencing only one condition of the experiment, the Duchenne, non-Duchenne or control condition. All participants from each condition took part in this experiment in the same room as the rest of their peers in the same condition. Participants were individually monitored by cameras to record their facial responses while simultaneously having their heartrates monitored.
Non-Duchenne Laughter Condition
Participants went through a series of 10-minute long exercises conducted by a researcher to induce non-Duchenne laughter. Such exercises included participants holding a pencil between their teeth to induce Duchenne smiling while simultaneously being asked to laugh when the researcher gave the instruction.
Duchenne Laughter Condition
A 10-minute long British comedy show was played on a big screen for participants to watch and their respective responses were measured. This video was chosen from a sample of 28 items intended to induce positive affect (Soussignan, 2002). The video was first put through a pilot study to achieve a preliminary rating to ensure that laughter induced in participants would be real and Duchenne.
Control Condition
A 10-minute distraction task was conducted where participants were given crossword puzzles to solve. Participants were asked to complete the puzzles individually. The crossword puzzles were standardised and made simple enough so that participants of all linguistic and academic proficiency would be able to answer them easily without impacting their relative stress levels. Stress levels observed in this condition should remain consistent.
The number of Duchenne and non-Duchenne laughs participants made in each condition were noted down as numbers before being converted to percentages by experimenters to ensure the ease of comparison between the two experimental groups. These responses were recorded alongside each participants’ respective stress responses measured through heartrate monitoring.
At the end of the study, participants will fill in an identical self-report questionnaire with regards to their own perceptions of stress levels after the experiment. They will also complete a PSS identical to the one provided at the start of the experiment to determine stress levels after inducement (or lack) of laughter.
Analysis of Results
We predict that non-Duchenne laughter will result in the same decrease in stress response as Duchenne laughter will. Evidence for this will be obtained by comparing stress levels indicated by self-report, the PSS, EMFACS and the participant’s heartrate levels prior to and following the experiment. The qualitative self-report will be used as a supplement to the numericalised values from the other three forms of assessment of stress levels. The Duchenne laughter condition will be compared to the non-Duchenne laughter condition through the use of an appropriate statistical test in order to derive a p-value to indicate the significance of results.
Conclusion
Strengths
This experiment is advantageous for its holism in judgement criteria for stress levels. The use of qualitative measures in tandem with quantitative ones allows for insight into how participants actually feel. This will allow us to judge whether what a participant feels is congruent with the change in their stress levels. For instance, a participant should describe themselves to experience a decrease in stress when their biological and behavioural response similarly indicate a decrease in stress. The strength of the terminology participants used to describe their experience in the self-report questionnaires should also correlate to the extremity of change in reflected in their stress levels. If and when these measures are incongruent with one another, we will be able to further investigate potential reasons for why this is so; the disparities may be a function of individual differences or other confounding factors that we had not previously considered but are still essential to distinguish.
Potential Limitations
The amalgamated use of a British comedy show in the experimental condition and university students from different races as participants may be limiting due to cultural differences. British humor may be specific to those who are raised in this culture and could have less of a comedic effect, and thus elicit less of a real humor response, in those who may not be as ingrained in British culture. This could have meant that non-British participants inherently laughed less simply due to the fact that they were less able to understand the humor. Yet, they may still feel pressured to give the expected response (i.e. laughter) to the video stimuli as the experiment will take place in a single room with all the participants. This may result in non-British participants in the control condition providing non-Duchenne rather than Duchenne laughter. This would, however, be measured through the EMFACS, which means we would still be able to distinguish Duchenne from non-Duchenne laughter in both experimental groups, thus somewhat alleviating the issue. If this ethnic disparity does prove to be an issue, future attempts to homogenise our sample can be made. Nevertheless, this could allow for the distinction of the differing impact non-Duchenne laughs may have on participants of different races, social status, religions, or other sociocultural, economic, or political phenomena.
Summary
There is a wide range of literature that supports the psychological advantages of laughter in stress reduction, but much less so with regards to non-Duchenne laughter in particular. Hence, the purpose of my experiment is to fill this gap in literature by investigating the difference between Duchenne and non-Duchenne laughter on stress response. These findings will provide insight into the mechanisms of laughter and has important applications regarding the potential use of laughter as a therapy for psychological disorders.
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