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At least 19 recordsLinked to original sources

A study of laughter and dissociation: distinct correlates of laughter and smiling during bereavement.

Laughter facilitates the adaptive response to stress by increasing the psychological distance from distress and by enhancing social relations. To test these hypotheses, the authors related measures of bereaved adults' laughter and smiling 6 months postloss to measures of their (a) subjective emotion and dissociation from distress, (b) social relations, and (c) responses they evoked in others. Duchenne laughter, which involves orbicularis oculi muscle action, related to self-reports of reduced anger and increased enjoyment, the dissociation of distress, better social relations, and positive responses from strangers, whereas non-Duchenne laughter did not. Lending credence to speculations in the ethological literature, Duchenne laughter correlated with different intrapersonal and interpersonal responses than Duchenne smiles. Discussion focuses on the relevance of these findings to theories of positive emotion.

Adaptation, Psychological↗

The evolution and functions of laughter and humor: a synthetic approach.

A number of recent hypotheses have attempted to explain the ultimate evolutionary origins of laughter and humor. However most of these have lacked breadth in their evolutionary frameworks while neglecting the empirical existence of two distinct types of laughter--Duchenne and non-Duchenne--and the implications of this distinction for the evolution of laughter as a signal. Most of these hypotheses have also been proposed in relative isolation of each other and remain disjointed from the relevant empirical literature. Here we attempt to remedy these shortcomings through a synthesis of previous laughter and humor research followed by (i) a reevaluation of this research in light of theory and data from several relevant disciplines, and (ii) the proposal of a synthetic evolutionary framework that takes into account phylogeny and history as well as proximate mechanisms and adaptive significance. We consider laughter to have been a preadaptation that was gradually elaborated and co-opted through both biological and cultural evolution. We hypothesize that Duchenne laughter became fully ritualized in early hominids between 4 and 2 mya as a medium for playful emotional contagion. This mechanism would have coupled the emotions of small hominid groups and promoted resource-building social play during the fleeting periods of safety and satiation that characterized early bipedal life. We further postulate that a generalized class of nonserious social incongruity would have been a reliable indicator of such safe times and thereby came to be a potent distal elicitor of laughter and playful emotion. This class of stimuli had its origins in primate social play and was the foundation for formal human humor. Within this framework, Duchenne laughter and protohumor were well established in the hominid biobehavioral repertoire when more cognitively sophisticated traits evolved in the hominid line between 2 mya and the present. The prior existence of laughter and humor allowed them to be co-opted for numerous novel functions, and it is from this process that non-Duchenne laughter and the "dark side" of laughter emerged. This perspective organizes the diversified forms and functions that characterize laughter and humor today and clarifies when and how laughter and humor evolved during the course of human evolution.

Adaptation, Physiological↗

Energy expenditure of genuine laughter.

OBJECTIVE: To measure energy expenditure (EE) and heart rate (HR) during genuine laughter. DESIGN: Experimental trial of viewing film clips in four cycles either intended to evoke laughter (humorous -10 min) or unlikely to elicit laughter (not humorous -5 min) under strictly controlled conditions of a whole-room indirect calorimeter equipped with audio recording system. PARTICIPANTS: Forty five adult friend dyads in either same-sex male (n=7), same-sex female (n=21) and mix-sex male-female (n=17); age 18-34 years; body mass index 24.7+/-4.9 (range 17.9-41.1). MEASUREMENTS: Energy expenditure in a whole-room indirect calorimeter, HR using Polar HR monitor. Laugh rate, duration and type from digitized audio data using a computerized system and synchronized with HR and EE results. RESULTS: Laughter EE was 0.79+/-1.30 kJ/min (0.19+/-0.31 kcal/min) higher than resting EE (P<0.001, 95% confidence interval=0.75-0.88 kJ/min), ranging from -2.52 to 9.67 kJ/min (-0.60-2.31 kcal/min). Heart rate during laughter segments increased above resting by 2.1+/-3.8 beats/min, ranging from -7.6 to 26.8 beats/min. Laughter EE was correlated with HR (r (s)=0.250, P<0.01). Both laughter EE and HR were positively correlated with laughter duration (r (s)=0.282 and 0.337, both P<0.001) and rate (r(s)=0.256 and 0.298, both P<0.001). CONCLUSION: Genuine voiced laughter causes a 10–20% increase in EE and HR above resting values, which means that 10–15 minutes of laughter per day could increase total EE by 10–40 kJ (2–10 kcal) [corrected].

Adolescent↗

Perceived attributes of health-promoting laughter: a cross-generational comparison.

A small but growing body of empirical data support the popular belief that laughter benefits health. However, there are many varieties of laughter and no reason to assume all varieties should be, or would be, perceived as equally beneficial. The authors examined which types of laughter and which characteristics of laughter people associate with health and whether there are generational differences in this perception. Young adults and older participants rated 12 laughter terms (e.g., chuckle, giggle, belly laugh) on their contribution to health and assessed various aspects of each laughter type on 11 scales. The young adults characterized health-promoting laughter as strong, active, uninhibited, and involving movement; the older participants characterized it as socially appropriate. Both groups associated health-promoting laughter strongly with positive emotion and absence of malice. Implications for placebo effects in laughter interventions are discussed. Differences between humor and laughter and among the proposed mechanisms by which they affect health are clarified.

Affect↗

The elevation of natural killer cell activity induced by laughter in a crossover designed study.

The elevation of natural killer cell activity (NKCA) by laughter was not confirmed due to incomplete methodology of previous studies although positive emotion is believed to be favorable for health. To verify NKCA elevation by laughter in a crossover design, we measured NKCA before and after watching films, presenting 75-min comic film and non-emotional control film at different days to the same 21 healthy male subjects. Electromyogram of left major zygomatic muscle was obtained during the films to quantify the magnitude of laughter as an index of emotional expression. As indices of emotional experience, the self-rated pleasantness of the comic film and mood state before and after film were measured using visual analogue scale and Profiles of Mood State (POMS), respectively. The comic film significantly elevated NKCA (26.5-29.4%, p<0.05), whereas the control film did not (27.1-24.8%, not significant). This is the first study to demonstrate NKCA elevation by laughter in a crossover designed study. To examine the contribution of experiential and expressive aspects of laughter to NKCA elevation, correlation of NKCA elevation with the self-rated pleasantness, mood scores before and after comic film and the magnitude of laughter was statistically tested. We found that NKCA elevation was negatively correlated with the scores of negative mood scales of POMS while NKCA elevation had no significant correlation with self-rated pleasantness and the magnitude of laughter. Further group analysis revealed that high scores of depression and anger-hostility suppressed NKCA elevation by laughter. We also found that NKCA before and after comic film had tendency of correlation with self-rated pleasantness of the comic film while NKCA had no correlation with the magnitude of laughter. These findings suggest that NKCA elevation and NKCA before and after comic film seem to be related with the experiential aspects of laughter rather than with the expressive aspects.

Adolescent↗

The functions and dysfunctions of laughter.

Laughter is not usually included in the curriculum of medical schools, therefore it is often neglected by physicians. Laughter is a reflex located in the reticular system of the hindbrain. Rich connections explain its complexity. Laughter appears very early in life and each individual has a very characteristic and stable laughing style. Laughter and speech differentiate human beings from the animal kingdom. Laughter is a unique communication media, common to all human societies speaking different languages. Laughter has a mood elevating and relaxing effect. Laughter dysfunction consists of inappropriate response to the meaning or to the stimulus intensity. In the present study, laughter's dysfunction and disorders are presented. The purpose of this study was to extricate laughter from the diffuse obscurity of information into a new area of interest for scientific research.

Brain Diseases↗

Sharing humour and laughter in autism and Down's syndrome.

Everyday humour and laughter can tell us about children's ability to engage with and understand others. A group of 19 pre-school children with autism and 16 pre-school children with Down's syndrome, matched on non-verbal mental age, participated in a cross-sectional study. Parental reports revealed no group differences in overall frequencies of laughter or laughter at tickling, peekaboo or slapstick. However, in the autism group, reported laughter was rare in response to events such as funny faces or socially inappropriate acts, but was common in strange or inexplicable situations. Reported responses to others' laughter also differed: children with autism rarely attempted to join in others' laughter and rarely attempted to re-elicit it through acts of clowning or teasing. Analysis of videotaped interactions also showed no group differences in frequencies of child or adult laughter. However, the children with autism showed higher frequencies of unshared laughter in interactive situations and lower frequencies of attention or smiles in response to others' laughter. Humour is an affective and cultural phenomenon involving the sharing of affect, attention and convention; children with autism show problems in some simple affective and mutual as well as joint attentional and cultural aspects of humorous engagement.

Adult↗

Laughter therapy modulates the parameters of renin-angiotensin system in patients with type 2 diabetes.

The effect of laughter therapy on the plasma levels of renin, angiotensinogen, and prorenin was investigated in patients with type 2 diabetes. In the diabetic patients, the mean plasma renin concentrations were 24.6+/-12.1 ng/ml/h in the first observation (at the beginning of laughter therapy), 8.2+/-3.4 ng/ml/h in the second observation (three months after the beginning of laughter therapy) and 7.7+/-1.7 ng/ml/h in the third observation (six months after the beginning of laughter therapy). The mean plasma angiotensinogen concentrations in the 1st, 2nd and 3rd observations were 0.19+/-0.08, 0.47+/-0.12, 0.42+/-0.14 microg/ml, respectively. The mean plasma prorenin concentrations in the 1st, 2nd and 3rd observations during the laughter therapy were 195.1+/-66.2, 193.4+/-88.2 and 170.7+/-52.5 pg/ml, respectively. Plasma renin concentrations were significantly decreased (p<0.05) by the therapy. Subnormal concentrations of plasma angiotensinogen were found in the 1st observation and increased significantly (p<0.05) to the normal range after the therapy. Plasma prorenin concentration only slightly changed during the laughter therapy. Other biochemical parameters remained unchanged during the laughter therapy. These results indicated that a long-term laughter therapy changed the plasma components of renin-angiotensin system in patients with diabetes. Thus, laughter therapy can be used as non-pharmacological treatment for the prevention of diabetic microvascular complications.

Angiotensinogen↗

Is motor inhibition during laughter due to emotional or respiratory influences?

We compared the effects of laughter and several respiratory movements on spinal motor excitability to unravel their respective influences. We measured H-reflexes in 13 healthy volunteers during 10 different tasks (including laughter, simulated laughter, and various respiratory movements). We compared the percentage that remained of the initial H-reflex during each task with that during a neutral task. H-reflex percentage differed between the neutral task (79.4 +/- 16.1%), true laughter (43.7 +/- 17.9%), and simulated laughter (66.6 +/- 24.3%), and between the two latter tasks. Coughing also resulted in H-reflex suppression, but not as deeply as true laughter. During the other respiratory maneuvers, the H-reflex increased compared to the neutral task. Our finding that true laughter evoked more H-reflex depression than simulated laughter suggests that mirth on its own depresses the H-reflex. This mechanism may also be involved in the pathophysiology of cataplexy, the main symptom of narcolepsy.

Adolescent↗

Mirth, laughter and gelastic seizures.

Little is known about what pathways subserve mirth and its expression laughter. We present three patients with gelastic seizures and laughter elicited by electrical stimulation of the cortex who provide some insight into the mechanisms of laughter and its emotional concomitants. The first patient had seizures manifested by laughter without a subjective feeling of mirth. Magnetic resonance imaging showed a cavernous haemangioma in the left superior mesial frontal region. Ictal subdural electrode recording showed the seizure onset to be in the left anterior cingulate gyrus. Removal of the lesion and of the seizure focus rendered the patient virtually seizure free over 16 months of follow-up. The other two patients had complex partial seizures of temporal lobe origin. Electrical stimulation of the fusiform gyrus and parahippocampal gyrus produced bursts of laughter accompanied by a feeling of mirth. These cases reveal a high likelihood of cingulate and basal temporal cortex contribution to laughter and mirth in humans, and suggest the possibility that the anterior cingulate region is involved in the motor act of laughter, while the basal temporal cortex is involved in processing of laughter's emotional content in man.

Adult↗

Effects of laughter and relaxation on discomfort thresholds.

Two experiments were conducted to test the proposal that laughter is a pain antagonist. In Experiment I, thresholds for pressure-induced discomfort of 20 male and 20 female subjects were measured after each subject listened to a 20-min-long laughter-inducing, relaxation-inducing, or dull-narrative audio tape or no tape. Discomfort thresholds were higher for subjects in the laughter- and the relaxation-inducing conditions. In Experiment II, 40 female subjects were matched for pressure-induced discomfort thresholds. Their discomfort thresholds were measured after they listened to a laughter-inducing, interesting narrative, or uninteresting narrative audio tape, completed a multiplication task, or experienced no intervention. Discomfort thresholds increased for subjects in the laughter-inducing condition. Laughter, and not simply distraction, reduces discomfort sensitivity, suggesting that laughter has potential as an intervention strategy for the reduction of clinical discomfort.

Adult↗

The integration of laughter and speech in vocal communication: a dynamic systems perspective.

Laughter in infant-directed speech was examined in 13 mother-infant pairs to investigate the possible co-occurrence of speech and laughter. Contrary to previous findings in adult-adult social interaction, all mothers produced speech simultaneously with laughter in up to 50% of laughs. In most of these speech-laughs the onset of laugh and speech was simultaneous. Laughter occurred on both function and content words and was more likely to occur on approximately 2 words and on utterances that were statements rather than questions or exclamations. Laughter and speech are different outcomes produced from a reorganization of the same vocal/anatomical parameters. A 3rd outcome is possible in the form of speech-laughs utilizing features from both laughter and speech. In speech-laughs, the duration of the vocalization was more likely to increase, and the changes in the utterance were likely to include 1 or more of the features of vowel elongation, syllabic pulsation, breathiness, and pitch change. These findings and individual variations in the resulting vocal output are discussed from a dynamic systems perspective. It is argued that neither speech nor laughter is dominant when both are combined, but that this is a more complex vocal outcome produced with idiosyncratic flexibility within stable temporal and physiological constraints.

Communication↗

Laughter among deaf signers.

The placement of laughter in the speech of hearing individuals is not random but "punctuates" speech, occurring during pauses and at phrase boundaries where punctuation would be placed in a transcript of a conversation. For speakers, language is dominant in the competition for the vocal tract since laughter seldom interrupts spoken phrases. For users of American Sign Language, however, laughter and language do not compete in the same way for a single output channel. This study investigated whether laughter occurs simultaneously with signing, or punctuates signing, as it does speech, in 11 signed conversations (with two to five participants) that had at least one instance of audible, vocal laughter. Laughter occurred 2.7 times more often during pauses and at phrase boundaries than simultaneously with a signed utterance. Thus, the production of laughter involves higher order cognitive or linguistic processes rather than the low-level regulation of motor processes competing for a single vocal channel. In an examination of other variables, the social dynamics of deaf and hearing people were similar, with "speakers" (those signing) laughing more than their audiences and females laughing more than males.

Adolescent↗

Pathological laughter as a symptom of midbrain infarction.

Pathological laughter is an uncommon symptom usually caused by bilateral, diffuse cerebral lesions. It has rarely been reported in association with isolated cerebral lesions. Midbrain involvement causing pathological laughter is extremely unusual. We describe three patients who developed pathological laughter after midbrain and pontine-midbrain infarction. In two patients a small infarction in the left paramedian midbrain was detected, whereas the third one sustained a massive bilateral pontine infarction extending to the midbrain. Laughter heralded stroke by one day in one patient and occurred as a delayed phenomenon three months after stroke in another. Pathological laughter ceased within a few days in two patients and was still present at a two year follow-up in the patient with delayed-onset laughter. Pathological laughter can herald midbrain infarction or follow stroke either shortly after onset of symptoms or as a delayed phenomenon. Furthermore, small unilateral midbrain infarctions can cause this rare complication.

Brain Stem Infarctions↗

Dynamic-acoustic variation causes differences in evaluations of laughter.

Exposure to laughter has striking effects on human listeners and may facilitate positive emotional and behavioural responses. The acoustic signal pattern of laughter vocalisations is particularly suitable to elicit these reactions. However, little is known about factors that lead to differences in reactions of listeners. The acoustic quality of laughter, the social context, and the disposition of the listener are possible variables in differences in evaluation. We conducted experiments using playback techniques in which human laughter elicited in a natural setting was evaluated by listeners (N=90). Listeners evaluated several phrases of laughter produced by different laughing targets. We investigated the role of the characteristics of voice, dynamic-acoustic characteristics, and order of playback sequence on the evaluation of laughter. The dynamic-acoustic characteristics of laughter significantly affected evaluations by listeners, whereas voice and the playback order did not. An acoustic analysis allowed us to identify acoustic parameters that contribute to such differences in evaluation.

Adult↗

Sharing laughter: the humour of pre-school children with Down syndrome.

Humour and laughter have often been portrayed as fundamentally cultural and social phenomena. They can be used to tell us about children's ability to engage socially and to understand others, but have rarely been explored for this purpose. The present paper summarises the results of a study of simple forms of humour in children with Down syndrome and with autism, two groups which are reported to differ in their sociality and interpersonal understanding. Sixteen children with Down syndrome and 19 children with autism, matched on non-verbal mental age, participated in a cross-sectional study. Parental reports and video-tapes of naturalistic interaction between parents and children were analysed to show that although there were no overall differences in the presence or frequency of child or parent laughter between the two groups, there were differences in what sorts of events were more likely to prompt child laughter, the extent to which child laughter was shared, and how the children responded to others' laughter. The children with Down syndrome were more likely than the children with autism to laugh at funny faces and socially inappropriate acts and less likely to laugh in strange or inexplicable situations, and more likely to laugh at shared events. They also responded to others' laughter with attention or smiles more, and tried to re-elicit it through acts of clowning. Children with Down syndrome are thus active participants in humour and laughter, sharing it at both an emotional and a cultural level.

Child Behavior↗