The Nature of Contagious Yawning

Report title: Contagious yawning Introduction Yawning in general Yawning is a common act in all humans from birth and is one of the best examples of a fixed action pattern; once a yawn begins it becomes unstoppable. It also occurs in the same way each time. Several theories have been proposed to explain its existence in everyday life. There has been no definitive way of explaining why yawning occurs. Communication, physiology and arousal will be discussed. Firstly, communication is proposed as a primary reason for yawning, by Guggisberg, Mathis, Herrmann & Hess (2007). They attribute yawning to vigilance and suggest that unconscious communication occurs to synchronise a group and show vigilance. Baenninger (1987) also suggest that yawning helps to maintain attention levels and it may have evolved to promote vigilance and further suggest that it could communicate drowsiness or illness to a group. Another theory suggests a physiological link, whereby the yawn maintains mental efficiency by regulating the brain temperature through a cooling mechanism (Palagi, Leone, Mancici & Ferarri, 2009). However, a study by Gallup & Gallup jr. (2008) has shown inconclusive results for this theory. Another theory suggests that yawning is due to arousal. Matikainen and Elo (2007) report that yawning increases arousal and helps the individual to waken up. They suggest that it is due to connections between the mouth and the neck which when stretched stimulates the carotid body responsible for oxygen homeostasis. However, research by Guiggisberg et al (2007) found opposing research and their results showed that arousal levels decreased after yawns. It is clear that further research needs to be conducted to find the causes of yawns, and it has been shown that there is possibly more than one answer for this problem. However conclusive evidence for any theory is yet to be found. Contagious yawning Seeing, hearing or even thinking about another person yawning can trigger a yawn, contagious yawns occur in 40-60% of human adults but its primary reason and function is still unknown. Some advancement nevertheless, has been made to explain its cause. The advance in research into contagious yawning has come from the discovery of mirror neurons (Arnott, Singhal & Goodale, 2009). These are cells which are located in the posterior inferior frontal gyrus (pIGF) and are active when an individual sees another perform and action. They activate in the same was as they do when an individual performs the task themselves. It is proposed that mirror neurons enable individuals to understand others experiences and emotional states. This research therefore suggests that seeing or hearing a yawn activates this area of the brain and so initiates a yawning action. It has also been proposed that as mirror neurons help to understand emotional states, it is closely linked with empathy. This means that contagious yawning could be linked to empathy too. Contagious yawning and empathy This study has been conducted to assess the relationship between contagious yawning and empathy. Previous research highlights a strong relationship. Arnott et al (2009) investigated empathy and auditory contagious yawning and their results show a positive correlation between the two with more yawns elicited by those who scored higher on the empathy scale given. The relationship was modest but still significant below . 05. Also Periol & Monaca (2006) point out that contagious yawning doesn’t occur in species that cant recognise themselves in the mirror, nor can infants under two, suggesting that sense of self is required which is a key element to understanding others. Other research has shown that those with autistic spectrum disorder, and schizophrenia are unable to yawn contagiously as much as controls and that this is due to lack of empathy (Haker & Rossler, 2008). The premise of this study is to add to current research by expanding on Arnott et al’s research, by using visual stimuli. This study will test further the relationship between empathy and contagious yawning as this seems to be the area with most evidence. If the pilot data suggests a trend consistent with the current data then it will suggest further research and a full study should be conducted, however if the results gained show little evidence for a relationship then it will be suggested that other areas of contagious yawning should be looked into in more depth to find its possible cause. Hypotheses 1a) Contagious yawning is elicited from visual stimuli a) Higher amounts of contagious yawning will be present in those with higher levels of empathy. Null hypotheses 1b) Visual stimuli does not elicit contagious yawning 2b) There is no difference in amount of contagious yawning and level of empathy. Method 30 Stirling University students took part. This experiment was a between participants design. Independent variable is number of yawns produced in each condition. Dependant variable is empathy score The experiment consisted of two parts. To begin, each participant was required to complete the interpersonal reactivity index questionnaire to determine empathy levels. From this the participants were classified as empathetic or non empathetic and form the two experimental groups (mean was calculated and sample split above and below the mean). After the empathy questionnaire was completed, the experimental phase began which contained two conditions, firstly a yawning condition (test phase) whereby participants were shown a slide show of 15 yawning faces each slide lasting 10seconds. Within the time period the participant was required to focus on each face and rate how many times the face made them feel like yawning or actually yawn. Secondly, participants were given a neutral condition whereby a similar slide show was given but with 15 neutral expressions. This was given as a control for the test phase so that condition effects could be tested for. If a similar frequency of yawn was observed in both phases then the yawns wouldn’t be classed as contagious, and attributed to boredom rather than condition. The two phases were reversed for half the participants for counterbalancing and also to aid understanding of when contagious yawning had occurred- neutral phase was not always last which may have indicated boredom, so results are more reliable. The analysis was in two parts firstly, the frequency of yawning was compared in each condition to determine if visual stimuli induced contagious yawning in the test phase compared to the neutral. Secondly, the analyses compared empathetic participants with non empathetic participants to test if empathy was related to contagious yawning. Examples of stimuli: Neutral phase Yawning phase [pic] [pic] All images contained a full face and expressions were face on to the participant in attempt to maintain validity for each phase. Results | Hypothesis 1 Contagious yawning is elicited from visual stimuli Tests of normality showed that there was significance for yawning and so parametric tests were conducted. Graph 1 shows that there was a higher amount of yawns produced in the yawning condition than the neutral condition and the Wilcoxon test shows there was significantly different result. Z= -2. 722, p. 006 Graph 1 Total amount of yawing produced in each condition [pic] The significant difference found between yawning in the yawn condition and the neutral condition shows that contagious yawning occurred to visual stimuli, and the null hypothesis can be rejected. Therefore further analyses can be conducted into empathy and contagious yawning. Hypothesis 2 Higher amounts of contagious yawning will be present in those with higher levels of empathy. Graph 2 shows the relationship between the amount of yawns produced and empathy scores. Those with high empathy scores (62+) yawned more in the yawning condition compared to those with low empathy scores. However, the graph also shows similar amounts of yawning between empathy groups in the neutral condition. Graph 2 Total amount of yawning produced in each condition, split by empathy score. [pic] Due to small sample size and the data having an abnormal distribution a spearman’s rho test for correlation was conducted. It showed no significant relationship between empathy score and number of yawns produced in each condition, p= . 27 with a correlation of . 259, in neutral condition and p=. 686, with a correlation of . 96 in the yawn condition. Therefore the null hypothesis has to be accepted. Discussion Previous research has suggested that contagious yawning is due to empathy and a higher level of empathy suggests the individual is more likely to contagiously yawn. This study aimed to determine if this was found with visual stimuli in the form of consecutive images of individuals yawning on a screen. The study tested to see if contagious yawning could be induced by images and compared the results to number of yawns produced by images of neural expressions in the same format. The study also aimed to contribute to the existing knowledge on the relationship between empathy and contagious yawning. Due to the small sample size and the test for normality showing that there wasn’t a normal distribution of the data, the statistics performed were limited, and are not generalisable to the overall population. The results show that there was a significant difference between the two conditions and more yawns were produced in the yawning condition compared to the neutral. The study was conducted in a way that yawns produced by boredom could be controlled for. If it was the case that yawns were produced due to boredom then a similar frequency would be observed in both conditions especially as the conditions were counterbalanced. The results were highly significant (p=. 006) showing that yawns can be attributed to contagious yawning and not boredom, therefore the null hypothesis could be rejected and the hypothesis that yawning stimuli induces contagious yawning can be accepted. This contributes to the body of research on contagious yawning especially as Arnott et al (2009) has already shown contagious yawning can be elicited to auditory stimuli. This study, compared empathy scores with frequency of yawns in each condition to determine a relationship between the two as proposed by Haker & Rossler (2008), as well as in the study by Arnott et al. This study used the interpersonal reactivity index questionnaire to determine levels of empathy and the mean score was calculated in order to form two experimental groups of high and low empathy. This was only to test for a trend and is understood that due to the abnormal distribution of scores in the data, any results cannot be generalised, as the two experimental groups for empathy are not normally distributed. The results shown in graph 2, clearly show no difference between frequency of yawns and level of empathy especially in the neutral condition where the frequency of yawns for each empathy group are virtually the same. A slight difference is seen in the yawning condition and at a glance looks to suggest that higher empathy scores result in more yawns produced however with a closer look at the frequencies, it is clear that there is only a difference of one or two yawns and the statistical analysis shows no significant difference between empathy and yawns in both conditions. However it should be noted that the correlation conducted cannot be relied on too heavily due to the small sample size and so it can still be concluded that the graph shows a possible trend that for high empathy individuals, contagious yawning is more common. Especially as the graph shows a difference in similarity of empathy group based on condition (neutral shows no difference at all whereas yawn condition shows slight difference) Even though significance is not met and for this study the null hypothesis has to be accepted, the nature of the data and tests performed show that the results are not conclusive and trends can still be relied upon. There are however many limitations to this study. Clearly, with the study being a pilot for future research, the sample size was low and so generalisable results could not be hoped for however methodological improvements could be made to make trends found more reliable. Firstly, only one measure of empathy was used and so empathy scores were only based on specific answers to questions. Arnott et al used several in their study giving a better indication of empathy however due to the small scale of the study and limitations on resources meant only one could be found. The power point slides contained many faces and it was difficult to find yawning faces which looked like yawns and not open mouthed expressions, conveying a yawn through an image was much more complex than anticipated. Another point to consider was the nature of how the study was portrayed, the emphasis on yawning was placed from the beginning and so as one participant remarked he knew it was about yawning so he was thinking about it a lot in the first condition so even thought he was looking at neutral faces, he yawned as he was thinking about it. This shows how contagious yawning can be and how our results can be skewed. For further research, better conditions must be met and participants told of the premise of the study after two conditions had been undertaken. The self report table given to the participants during the study whereby they noted how many times they yawned or felt like yawning may need to include other contagious acts like laughing, to avoid yawns being induced by thinking. This would mean that further studies into contagious yawning would require more expressions to test the participant and so they don’t constantly think about how much they are yawning. Either that or possibly use a camera to record yawns so the participants focus is consistently on the stimuli. Conclusion The results show that visual stimuli can induce contagious yawning and so can aid further research when creating a method of testing yawning. The results obtained from empathy and contagious yawning although in significant, still suggest a trend and so could be further studied if more participant were used and a better methodology was introduced. The pilot study has shown the possibility of a link between contagious yawning and empathy and so needs to be further investigated. Bibliography Arnott, S. R. , Singhal, A. , Goodale, M. A. (2009), An investigation of auditory contagious yawning, Cognitive, Affective & Behavioural Neuroscience 9 (3) 335-342 Baenninger, R. (1987). Some comparative aspects of yawning in Betta splendens, Homo sapiens, Panthera leo, and Papio sphinx. Journal of Comparative Psychology, 101, 349-354. Gallup, A. C. , Gallup, G. G, Jr (2008) Yawning and thermoregulation. Physiology and Behaviour 95 10-16. Guggisberg, A. G. ,Mathis, J. , Herrmann, U. S. , Hess, C. W (2007). The functional relationship between yawning and vigilance. Behavioural brain research  179 (1) 159-66. Haker, H. & Rossler, W. (2009) Empathy in schizophrenia: impaired resonance. European Archive of Psychiatry and Clinical Neuroscience, 259, 352-361. Palagi, E. , Leone, A. , Mancini, G. , Ferrari, P. F. , (2009). Contagious yawning in gelada baboons as a possible expression of empathy. Proceedings of the National Academy of Sciences of the United States of America, 106 (46) 19262-7. Perriol, M. P. & Monaca, C. (2006) One person yawning sets off everyone else. Journal of Neurological Neurosurgical Psychiatry. 77) 3 3 Matikainen, J. , Elo, H (2008). Does yawning increase arousal through mechanical stimulation of the carotid body? Medical Hypotheses 70 488–492 | | |[pic] | | | | | Top of Form ———————– Condition Mean number of yawns Mean number of yawns