Mapping the differential impact of spontaneous and conversational laughter on brain and mind: an fMRI study in autism

Spontaneous and conversational laughter are important socio-emotional communicative signals. Neuroimaging findings suggest that non-autistic people engage in mentalizing to understand the meaning behind conversational laughter. Autistic people may thus face specific challenges in processing conversational laughter, due to their mentalizing difficulties. Using fMRI, we explored neural differences during implicit processing of these two types of laughter. Autistic and non-autistic adults passively listened to funny words, followed by spontaneous laughter, conversational laughter, or noise-vocoded vocalizations. Behaviourally, words plus spontaneous laughter were rated as funnier than words plus conversational laughter, and the groups did not differ. However, neuroimaging results showed that non-autistic adults exhibited greater medial prefrontal cortex activation while listening to words plus conversational laughter, than words plus genuine laughter, while autistic adults showed no difference in medial prefrontal cortex activity between these two laughter types. Our findings suggest a crucial role for the medial prefrontal cortex in understanding socio-emotionally ambiguous laughter via mentalizing. Our study also highlights the possibility that autistic people may face challenges in understanding the essence of the laughter we frequently encounter in everyday life, especially in processing conversational laughter that carries complex meaning and social ambiguity, potentially leading to social vulnerability. Therefore, we advocate for clearer communication with autistic people.

Evolution of laughter from play

In this hypothesis, I discuss how laughter from physical play could have evolved to being induced via visual or even verbal stimuli, and serves as a signal to highlight incongruity that could potentially pose a threat to survival. I suggest how laughter's induction could have negated the need for physical contact in play, evolving from its use in tickling, to tickle-misses, and to taunting, and I discuss how the application of deep learning neural networks trained on images of spectra of a variety of laughter types from a variety of individuals or even species, could be used to determine such evolutionary pathways via the use of latent space exploration.

Stress management strategies for NP practice

ABSTRACT

Knowledge of stress management strategies is helpful to NPs in clinical practice, as they frequently encounter patients or patients' family members who require assistance in managing acute stress. Patients or patients' family members may experience a high level of stress due to health factors such as pain, life-changing diagnoses, treatment options viewed as undesirable, and/or poor medical prognoses. In addition, healthcare visits, hospitalization, diagnostic tests, surgical procedures, and other treatments can cause stress for some patients. NPs should therefore be well informed about stress management strategies to be able to effectively educate and provide compassionate care for their patients. This article reviews four strategies designed to assist patients and/or their family members in reducing stress to allow for a more positive experience during a healthcare visit or hospitalization.

Association between laughter, frailty, and depression in rheumatoid arthritis patients

OBJECTIVE

This study aimed to determine whether there are associations between laughter, disease activity, frailty, and depression in rheumatoid arthritis (RA) patients.

METHODS

A total of 240 patients were included in this prospective cohort study on frailty in RA patients between March 2021 and June 2022. Patients were divided into the following four groups according to the frequency of laughter: "almost every day," "1-5 days per week," "1-3 days per month," and "never or almost never." Patient characteristics were compared among the four groups by analysis of variance. Factors associated with laughter were identified by multivariable logistic analysis.

RESULTS

The mean 28-joint Disease Activity Score using CRP was 1.91, with 70.7% of patients in remission and 12.6% in low disease activity. For the "almost every day" (42.5% of patients), "1-5 days per week" (40.0%), "1-3 days per month" (11.3%), and "never or almost never" (6.3%) groups, scores of the Kihon Checklist (KCL) for assessing frailty status were 3.5, 4.6, 7.3, and 8.1 (p < .001), respectively, and scores of the Beck Depression Inventory (BDI-II) were 8.4, 10.7, 15.1, and 16.5 (p < .001), respectively. Multivariable analysis revealed that KCL (OR: 0.81, 95% CI: 0.73-0.90) and BDI-II (OR: 0.91, 95% CI: 0.86-0.95) scores were independently associated with the frequency of laughter.

CONCLUSION

Frailty and depression were associated with laughter in RA patients with controlled disease activity. Interventions aimed at not only disease activity control but also frailty prevention may lead to a life filled with laughter.

Understanding mixed emotions in organized helping through emotionography

Introduction

Emotionography studies emotion: (a) as it occurs naturally in display, reception, attribution, and avowal; (b) within and across diverse stretches of interaction and varied institutional contexts; (c) grounded purposefully in the perspectives of the interactants as those perspectives are displayed in real-time through unfolding talk; (d) using materials that are recorded and transcribed in sufficient precision to capture the granularity consequential for the interactants. We overview contemporary research on "mixed emotion" highlighting theoretical and methodological issues and explore the potential of emotionography as a generative alternative.

Methods

The analysis will use contemporary conversation analysis and discursive psychology to illuminate the workings of organized helping using a collection of recordings from a child protection helpline all of which include laughter alongside crying.

Results

Analysis shows, on the one hand, how crying and upset display the caller's stance on the trouble being reported, and mark its action-relevant severity; on the other, how laughter manages ongoing parallel issues such as advice resistance. We show that the "mixture" is public and pragmatic, displaying different concerns and stances, and dealing with different issues; all is in the service of action.

Discussion

When analyzing the specifics of interaction, the concept of "mixed emotion" loses clarity, and it is more accurate to observe competing pragmatic endeavors being pursued in an intricately coordinated fashion. These practices would not be captured by conventional emotion measurement tools such as scales, vignettes, or retrospective interviews. Broader implications for theories of emotion and methods of emotion research are discussed.

Play and tickling responses map to the lateral columns of the rat periaqueductal gray

The persistence of play after decortication points to a subcortical mechanism of play control. We found that global blockade of the rat periaqueductal gray with either muscimol or lidocaine interfered with ticklishness and play. We recorded vocalizations and neural activity from the periaqueductal gray of young, playful rats during interspecific touch, play, and tickling. Rats vocalized weakly to touch and more strongly to play and tickling. Periaqueductal gray units showed diverse but strong modulation to tickling and play. Hierarchical clustering based on neuronal responses to play and tickling revealed functional clusters mapping to different periaqueductal gray columns. Specifically, we observed play-neutral/tickling-inhibited and tickling/play-neutral units in dorsolateral and dorsomedial periaqueductal gray columns. In contrast, strongly play/tickling-excited units mapped to the lateral columns and were suppressed by anxiogenic conditions. Optogenetic inactivation of lateral periaqueductal columns disrupted ticklishness and play. We conclude that the lateral periaqueductal gray columns are decisive for play and laughter.

Humor, hypnosis and kids

Bertrand Russell, philosopher and Nobel prize winner said "Laughter is the most inexpensive and most effective wonder drug. Laughter is a universal medicine." Humor as medicine may be just what the doctor ordered to keep us emotionally, mentally and physically fit. Children are not only wonderful hypnotic subjects, they love laughter and silliness. The therapeutic effectiveness of hypnotherapy with children and adolescents can be enhanced when humor is incorporated into the session. Laughter is fun and free and can be used to strengthen rapport and the therapeutic alliance between the clinician and the child. The neuro-psychological development in children necessary for the appreciation and development of humor will be discussed along with how and why humor and hypnosis can be combined to increase therapeutic effectiveness.

[A case of behavioral variant frontotemporal dementia presenting with frequent laughter during conversations]

We describe a case of behavioral variant frontotemporal dementia (bvFTD) presenting with frequent laughter during conversations. A 72-year-old male patient visited our hospital because of aspontaneity and abnormal behaviors. His medical history revealed epilepsy attacks approximately five years prior, which improved following administration of antiepileptic drugs. At the age of 67 years, the patient began exhibiting aspontaneity and abnormal behaviors, such as leaving a teahouse without paying for his coffee. Neurological examinations indicated moderate dementia and bradykinesia while walking. The patient frequently laughed during conversations with his wife and doctor, creating the impression that he was euphoric. His laughter was neither explosive nor obsessive, and did not involve loss of consciousness or seizures. MRI of the head revealed symmetrical atrophy of the bilateral frontal lobes. SPECT demonstrated decreased cerebral blood flow in the bilateral frontal lobes, particularly in the outer and inner frontal convexities. Based on the patient's clinical history and imaging results, a diagnosis of bvFTD was established. Our literature review identified only one research paper discussing the frequency of laughter in frontotemporal dementia, which suggested that patients with bvFTD laugh less often. However, several reports indicated that patients with FTD exhibit euphoric behaviors more frequently compared to those with other forms of dementia. We hypothesize that euphoric patients with bvFTD may laugh more frequently during conversations, reflecting disorders of emotional expression and a loss of empathy.

The Levels of Auditory Processing during Emotional Perception in Children with Autism

BACKGROUND

The perception of basic emotional sounds, such as crying and laughter is associated with effective interpersonal communication. Difficulties with the perception and analysis of sounds that complicate understanding emotions at an early development age may contribute to communication deficits.

METHODS

This study focused on auditory nonverbal emotional perception including emotional vocalizations with opposite valences (crying and laughter) and neutral sound (phoneme "Pᴂ"). We conducted event-related potential analysis and compared peak alpha frequencies (PAFs) for different conditions in children with autism spectrum disorder (ASD) and typically developing (TD) children aged 4 to 6 years old (N = 25 for each group).

RESULTS

Children with ASD had a higher amplitude of P100 and lower amplitude of N200 for all types of sounds and higher P270 in response to neutral phoneme. During the perception of emotional sounds, children with ASD demonstrated a single P270 electroencephalography (EEG) component instead of a P200-P300 complex specific to TD children. However, the most significant differences were associated with a response to emotional valences of stimuli. The EEG differences between crying and laughter were expressed as a lower amplitude of N400 and higher PAF for crying compared to laughter and were found only in TD children.

CONCLUSIONS

Children with ASD have shown not just abnormal acoustical perception but altered emotional analysis of affective sounds as well.

Subjective Happiness, Frequency of Laughter, and Hypertension: A Cross-Sectional Study Based on the Japan Gerontological Evaluation Study (JAGES)

In recent years, positive psychological factors, such as subjective happiness and laughter, have been reported to be associated with cardiovascular disease. In this study, we examined the relationship of hypertension with subjective happiness and frequency of laughter using the data from the Japan Gerontological Evaluation Study (JAGES). Of the 138,294 respondents, 26,368 responded to a version of the self-administered questionnaire that included a question about the frequency of laughter in the JAGES 2013. In total, 22,503 (10,571 men and 11,932 women) were included in the analysis after excluding those with missing responses regarding a history of hypertension, frequency of laughter, and subjective happiness. The prevalence of hypertension in this study was 10,364 (46.1%). Multivariate logistic regression analysis showed that age, female sex, obesity, infrequent chewing, former and current drinker, seeing three to five friends, and the absence of hobbies were positively associated with hypertension. However, infrequent laughter/high level of subjective happiness, frequent laughter/high level of subjective happiness, being underweight, and current smoker were negatively associated with hypertension. As per the findings of this study, it was determined that subjective happiness was negatively associated with hypertension. Therefore, this study suggests that having more opportunities to feel happiness may be important in preventing hypertension.

Cultural Differences in How People Deal with Ridicule and Laughter: Differential Item Functioning between the Taiwanese Chinese and Canadian English Versions of the PhoPhiKat-45

The PhoPhiKat-45 measures three dispositions toward ridicule and laughter, including gelotophobia (i.e., the fear of being laughed at), gelotophilia (i.e., the joy of being laughed at), and katagelasticism (i.e., the joy of laughing at others). Despite numerous cultural adaptations, there is a paucity of cross-cultural studies investigating measurement invariance of this measure. Undergraduate students from a Canadian university (N = 1467; 71.4% females) and 14 universities in Taiwan (N = 1274; 64.6% females) completed the English and Chinese PhoPhiKat-45 measures, respectively. Item response theory and differential item functioning analyses demonstrated that most items were well-distributed across the latent continuum. Five of 45 items were flagged for DIF, but all values had negligible effect sizes (McFadden's pseudo R² < 0.13). The Canadian sample was further subdivided into subsamples who identified as European White born in Canada (n = 567) and Chinese born in China, Hong Kong, or Taiwan (n = 180). In the subgroup analyses, no evidence of DIF was found. Findings support the utility of this measure across these languages and samples.

Laughter yoga as an enjoyable therapeutic approach for glycemic control in individuals with type 2 diabetes: A randomized controlled trial

BACKGROUND

Laughter has been reported to have various health benefits. However, data on the long-term effects of laughter interventions on diabetes are limited. This study aimed to investigate whether laughter yoga can improve glycemic control among individuals with type 2 diabetes.

METHODS

In a single-center, randomized controlled trial, 42 participants with type 2 diabetes were randomly assigned to either the intervention or the control group. The intervention consisted of a 12-week laughter yoga program. Hemoglobin A1c (HbA1c), body weight, waist circumference, psychological factors, and sleep duration were evaluated at baseline and week 12.

RESULTS

Intention-to-treat analysis showed that participants in the laughter yoga group experienced significant improvements in HbA1c levels (between-group difference: -0.31%; 95% CI -0.54, -0.09) and positive affect scores (between-group difference: 0.62 points; 95% CI 0.003, 1.23). Sleep duration tended to increase in the laughter yoga group with a between-group difference of 0.4 hours (95% CI -0.05, 0.86; P = 0.080). The mean attendance rate for laughter yoga program was high (92.9%).

CONCLUSIONS

A 12-week laughter yoga program is feasible for individuals with type 2 diabetes and improves glycemic control. These findings suggest that having fun could be a self-care intervention. Further studies with larger numbers of participants are warranted to better evaluate the effects of laughter yoga.

CLINICAL TRIAL REGISTRATION

http://www.chinadrugtrials.org.cn, identifier UMIN000047164.

Pupil Dilation Reflects Emotional Arousal Via Poetic Language

We investigated pupillary responses to the world's shortest fixed verses, Japanese haiku as aesthetic poetry (AP) and senryu as comic poetry (CP), in comparison with non-poetry control stimuli (NP) comprised of slogans that had the same rhythm patterns. Native Japanese speakers without literary training listened to these stimuli while we recorded their pupil diameters. We found that participants' pupils were significantly dilated for CP compared to NP in an early time window. While AP also evoked larger dilations than NP, the latency for AP-related pupil dilation was relatively long. Thus, lay people experience quick and intense arousal in response to funny and humorous words, while aesthetic properties of words may also elicit intense but slower changes in listeners' arousal levels, presumably because they evoke more implicit and subtle emotional effects. This study is the first to provide evidence that poetic language elicits human pupillary dilation. A better understanding of the cognitive and neural substrates for the sensitive awareness of pleasures expressed via poetic language will provide insights for improving mental and physical health. Hence, pupillometry can act as a useful convenient measurement to delineate the sympathetic activation of emotional contexts via language.

When laughter arrests speech: fMRI-based evidence

Who has not experienced that sensation of losing the power of speech owing to an involuntary bout of laughter? An investigation of this phenomenon affords an insight into the neuronal processes that underlie laughter. In our functional magnetic resonance imaging study, participants were made to laugh by tickling in a first condition; in a second one they were requested to produce vocal utterances under the provocation of laughter by tickling. This investigation reveals increased neuronal activity in the sensorimotor cortex, the anterior cingulate gyrus, the insula, the nucleus accumbens, the hypothalamus and the periaqueductal grey for both conditions, thereby replicating the results of previous studies on ticklish laughter. However, further analysis indicates the activity in the emotion-associated regions to be lower when tickling is accompanied by voluntary vocalization. Here, a typical pattern of activation is identified, including the primary sensory cortex, a ventral area of the anterior insula and the ventral tegmental field, to which belongs to the nucleus ambiguus, namely, the common effector organ for voluntary and involuntary vocalizations. During the conflictual voluntary-vocalization versus laughter experience, the laughter-triggering network appears to rely heavily on a sensory and a deep interoceptive analysis, as well as on motor effectors in the brainstem.

This article is part of the theme issue ‘Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience’.

Laughter and culture

Like most human non-verbal vocalizations, laughter is produced by speakers of all languages, across all known societies. But despite this obvious fact (or perhaps because of it), there is little comparative research examining the structural and functional similarity of laughter across speakers from different cultures. Here, we describe existing research examining (i) the perception of laughter across disparate cultures, (ii) conversation analysis examining how laughter manifests itself during discourse across different languages, and (iii) computational methods developed for automatically detecting laughter in spoken language databases. Together, these three areas of investigation provide clues regarding universals and cultural variations in laughter production and perception, and offer methodological tools that can be useful for future large-scale cross-cultural studies. We conclude by providing suggestions for areas of research and predictions of what we should expect to discover. Overall, we highlight how important questions regarding human vocal communication across cultures can be addressed through the examination of spontaneous and volitional laughter.

This article is part of the theme issue ‘Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience’.

The different shades of laughter: when do we laugh and when do we mimic other's laughter?

Laughter is an ambiguous phenomenon in response to both positive and negative events and a social signal that coordinates social interactions. We assessed (i) who laughs and why, and (ii) if the type of laughter and whether the observer approves of it impact on facial mimicry as a proxy for shared laughter. For this, 329 participants watched funny, schadenfreude and disgusting scenes and then saw individuals who purportedly reacted to each scene while participants' facial expressions were recorded and analysed. Participants laughed more in response to funny than in response to schadenfreude scenes and least in response to disgust scenes, and laughter within each scene could be explained both by situational perceptions of the scenes as well as by individual differences. Furthermore, others' laughter in response to funny scenes was perceived as more appropriate, elicited more closeness and more laughter mimicry than others' laughter in response to schadenfreude and especially in response to disgust scenes. Appropriateness and closeness as well as individual differences could explain laughter mimicry within each scene. This is in line with the notion that laughter is not per se an affiliative signal and that different types of laughter have distinct social implications. This article is part of the theme issue 'Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience'.

Robert Provine: the critical human importance of laughter, connections and contagion

Robert Provine made several critically important contributions to science, and in this paper, we will elaborate some of his research into laughter and behavioural contagion. To do this, we will employ Provine's observational methods and use a recorded example of naturalistic laughter to frame our discussion of Provine's work. The laughter is from a cricket commentary broadcast by the British Broadcasting Corporation in 1991, in which Jonathan Agnew and Brian Johnston attempted to summarize that day's play, at one point becoming overwhelmed by laughter. We will use this laughter to demonstrate some of Provine's key points about laughter and contagious behaviour, and we will finish with some observations about the importance and implications of the differences between humans and other mammals in their use of contagious laughter.

This article is part of the theme issue ‘Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience’.

Laughter, play faces and mimicry in animals: evolution and social functions

Human laughter and laugh faces show similarities in morphology and function with animal playful expressions. To better understand primordial uses and effects of human laughter and laugh faces, it is important to examine these positive expressions in animals from both homologous and analogous systems. Phylogenetic research on hominids provided empirical evidence on shared ancestry across these emotional expressions, including human laughter and laugh faces. In addition, playful expressions of animals, in general, arguably have a key role in the development of social cognitive skills, a role that may help explain their polyphyletic history. The present work examines the evolution and function of playful expressions in primates and other animals. As part of this effort, we also coded for muscle activations of six carnivore taxa with regard to their open-mouth faces of play; our findings provide evidence that these carnivore expressions are homologues of primate open-mouth faces of play. Furthermore, our work discusses how the expressions of animal play may communicate positive emotions to conspecifics and how the motor resonance of these expressions increases affiliation and bonding between the subjects, resembling in a number of ways the important social-emotional effects that laughter and laugh faces have in humans. This article is part of the theme issue 'Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience'.

Mu-opioid receptor system modulates responses to vocal bonding and distress signals in humans

Laughter is a contagious prosocial signal that conveys bonding motivation; adult crying conversely communicates desire for social proximity by signalling distress. Endogenous mu-opioid receptors (MORs) modulate sociability in humans and non-human primates. In this combined PET-fMRI study (n = 17), we tested whether central MOR tone is associated with regional brain responses to social signals of laughter and crying. MOR availability was measured with positron emission tomography (PET) using the high-affinity agonist radioligand [11C]carfentanil. Haemodynamic responses to social laughter and crying vocalizations were measured using functional magnetic resonance imaging (fMRI). Social laughter evoked activation in the auditory cortex, insula, cingulate cortex, amygdala, primary and secondary somatosensory cortex, and primary and secondary motor cortex; crying sounds led to more restricted activation in the auditory cortex and nearby areas. MOR availability was negatively correlated with the haemodynamic responses to social laughter in the primary and secondary somatosensory cortex, primary and secondary motor cortex, posterior insula, posterior cingulate cortex, precuneus, cuneus, temporal gyri and lingual gyrus. For crying-evoked activations, MOR availability was negatively correlated with medial and lateral prefrontal haemodynamic responses. Altogether our findings highlight the role of the MOR system in modulating acute brain responses to both positive and negative social signals. This article is part of the theme issue 'Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience'.

Tendency to laugh is a stable trait: findings from a round-robin conversation study

People often laugh during conversation. Who is more responsible for the laughter, the person laughing or their partner for eliciting it? We used a round-robin design where participants (N = 66) engaged in 10 different conversations with 10 same-gender strangers and counted the instances of laughter for each person in each conversation. After each conversation, participants rated their perceived similarity with their partner and how much they enjoyed the conversation. More than half the variability in the amount a person laughed was attributable to the person laughing-some people tend to laugh more than others. By contrast, less than 5% of the variability was attributable to the laugher's partner. We also found that the more a person laughed, the more their partners felt similar to them. Counterintuitively, laughter negatively predicted conversation enjoyment. These findings suggest that, in conversations between strangers, laughter may not be a straightforward signal of amusement, but rather a social tool. We did not find any personality predictors of how much a person laughs or elicits laughter. In summary, how much a person laughs in conversation appears to be a stable trait associated with being relatable, and is not necessarily reflective of enjoyment. This article is part of the theme issue 'Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience'.

The Association between Laughter and Functional Dyspepsia in a Young Japanese Population

The potential health benefits of laughter are recognized in relation to several chronic diseases. However, no study has yet investigated the association between laughter and functional dyspepsia (FD). The purpose of this study was to investigate this issue in a young Japanese population.

METHODS

This study was conducted on 8923 Japanese university students. Information on the frequency of laughter and types of laughter-inducing situations, digestive symptoms (Rome III criteria) were obtained through a self-administered, web-based questionnaire.

RESULTS

The percentage of respondents who laughed out loud almost every day was 64.3%. On the other hand, 1.8% of the subjects reported that they rarely laughed. No association was found between the total frequency of laughter and FD. Laughing while talking with family and friends almost every day was significantly inversely associated with FD (adjusted odds ratio (OR): 0.47 (95% confidence interval (CI): 0.28-0.81); p for trend was 0.003). On the other hand, laughing while watching TV or videos and laughing while looking at comics or magazines independently showed a positive correlation with FD (TV or videos: adjusted OR, 1-5 times a week: 1.74 (95% CI: 1.16-2.60); comics or magazines: adjusted OR, 1-5 times a week: 1.78 (95% CI: 1.08-2.81)).

CONCLUSION

In this young Japanese population, no association between laughter frequency and FD was observed although laughing while talking with friends and family was independently and inversely associated with FD.

Occasions for laughter and dementia risk: Findings from a six-year cohort study

AIM

Currently, there is little evidence on the relationship between laughter and the risk of dementia, and since laughter is mainly a social behavior, we aimed to examine the association between various occasions for laughter and the risk of dementia in Japanese older adults.

METHODS

We draw upon 6-year follow-up data from the Japan Gerontological Evaluation Study, including 12 165 independent older adults aged 65 years or over. Occasions for laughter were assessed using a questionnaire, while dementia was diagnosed using the standardized dementia scale of the long-term care insurance system in Japan. Cox proportional hazards models were estimated, yielding hazard ratios and 95% confidence intervals (CIs).

RESULTS

The multivariable hazard ratio of dementia incidence for all participants in the groups for high versus low variety of occasions for laughter was 0.84 (95% CI: 0.72-0.98, P for trend <0.001). A greater variety of occasions for laughter was associated with a lower risk of dementia 0.78 (95% CI: 0.63-0.96, P for trend <0.001) among women, but was less pronounced for men, with significant associations only for the medium group. Laughing during conversations with friends, communicating with children or grandchildren, and listening to the radio were primarily associated with decreased risk.

CONCLUSION

A greater variety of laughter occasions in individual and social settings was associated with a reduced risk of dementia. Geriatr Gerontol Int 2022; 22: 392-398.

"It's Hard, but We Could Kind of Laugh About It": Exploring the Role of Humor in Brain Cancer Caregiving

Research exploring the benefits of humor for caregivers is limited and, to date, no qualitative studies have explored the role of humor in brain cancer caregiving. To address this gap, we analyzed transcripts from twenty-one in-depth telephone interviews conducted with brain cancer caregivers from a strengths perspective. Thematic analysis using Braun and Clarke's method revealed that humor functions as (1) an innate element of the self and relationship, (2) an expression of mutual connection and understanding, (3) a way of managing difficult or awkward moments, (4) a form of avoidance or a welcome distraction, and may be (5) helpful, or unhelpful, depending on where someone is in the brain cancer trajectory. Findings suggest that humor represents an important yet complex individual and family strength for health service providers to identify and build upon.

The origin of smiling, laughing, and crying: The defensive mimic theory

Why do we leak lubricant from the eyes to solicit comfort from others? Why do we bare our teeth and crinkle our faces to express non-aggression? The defensive mimic theory proposes that a broad range of human emotional expressions evolved originally as exaggerated, temporally extended mimics of the fast, defensive reflexes that normally protect the body surface. Defensive reflexes are so important to survival that they cannot be safely suppressed; yet they also broadcast information about an animal's internal state, information that can potentially be exploited by other animals. Once others can observe and exploit an animal's defensive reflexes, it may be advantageous to the animal to run interference by creating mimic defensive actions, thereby manipulating the behaviour of others. Through this interaction over millions of years, many human emotional expressions may have evolved. Here, human social signals including smiling, laughing and crying, are compared component-by-component with the known, well-studied features of primate defensive reflexes. It is suggested that the defensive mimic theory can adequately account for the physical form of not all, but a large range of, human emotional expression.

Perception of group membership from spontaneous and volitional laughter

Laughter is a ubiquitous social signal. Recent work has highlighted distinctions between spontaneous and volitional laughter, which differ in terms of both production mechanisms and perceptual features. Here, we test listeners' ability to infer group identity from volitional and spontaneous laughter, as well as the perceived positivity of these laughs across cultures. Dutch (n = 273) and Japanese (n = 131) participants listened to decontextualized laughter clips and judged (i) whether the laughing person was from their cultural in-group or an out-group; and (ii) whether they thought the laughter was produced spontaneously or volitionally. They also rated the positivity of each laughter clip. Using frequentist and Bayesian analyses, we show that listeners were able to infer group membership from both spontaneous and volitional laughter, and that performance was equivalent for both types of laughter. Spontaneous laughter was rated as more positive than volitional laughter across the two cultures, and in-group laughs were perceived as more positive than out-group laughs by Dutch but not Japanese listeners. Our results demonstrate that both spontaneous and volitional laughter can be used by listeners to infer laughers' cultural group identity. This article is part of the theme issue 'Voice modulation: from origin and mechanism to social impact (Part II)'.

A Study on Instructional Humor: How Much Humor Is Used in Presentations?

Humor is applied in pedagogy to create a positive learning environment. Recent research focuses on the theories, effects, individual differences, and qualitative aspects of humor for instruction. However, there is a lack of studies focusing on quantitative features. Therefore, this research explored the quantitative characteristics of instructional humor in a naturalistic setting and applied techniques from natural language processing (NLP). This paper describes the results of two studies. The first study focused on instructional humor frequency and the placement of humor, while the linguistic features of instructional humor and non-instructional humor were compared in the second study. Two corpora were used in this research: TED Talks and user-submitted jokes from “stupidstuff.org” The results found that educators used humor 12.92 times for popular talks, while less popular talks only had 3.92 times. Humor is also more commonly placed during the first parts of the talk and lessens toward the end. There were also significant differences between the linguistic features of instructional and non-instructional humor in terms of readability scores and sentiment. These results provide a substantial update on quantitative instructional humor research and help educators understand how to use humor in the classroom in terms of quantitative and linguistic features.

Association between Laughter and Lifestyle Diseases after the Great East Japan Earthquake: The Fukushima Health Management Survey

We investigated the association between the frequency of laughter and lifestyle diseases after the Great East Japan Earthquake. We included 41,432 participants aged 30-89 years in the Fukushima Health Management Survey in fiscal year 2012 and 2013. Gender-specific, age-adjusted and multivariable odds ratios of lifestyle diseases were calculated using logistic regressions stratified by evacuation status. Those who laugh every day had significantly lower multivariable odds ratios for hypertension (HT), diabetes mellitus (DM) and heart disease (HD) for men, and HT and dyslipidemia (DL) for women compared to those who do not, especially in male evacuees. The multivariable odds ratios (95% confidence intervals) of HT, DM and HD (non-evacuees vs. evacuees) for men were 1.00 (0.89-1.11) vs. 0.85 (0.74-0.96), 0.90 (0.77-1.05) vs. 0.77 (0.64-0.91) and 0.92 (0.76-1.11) vs. 0.79 (0.63-0.99), and HT and DL for women were 0.90 (0.81-1.00) vs. 0.88 (0.78-0.99) and 0.80 (0.70-0.92) vs. 0.72 (0.62-0.83), respectively. The daily frequency of laughter was associated with a lower prevalence of lifestyle disease, especially in evacuees.

Urinary incontinence during laughter in children: Is it giggle incontinence?

AIM

Giggle incontinence is a distinct entity of childhood daytime urinary incontinence (DUI), where children wet themselves only when they laugh. The prevalence of true giggle incontinence is unknown, with confusion about the diagnosis of urinary incontinence occurring during laughter and true giggle incontinence. The aim of the study is to improve our understanding of urinary incontinence during laughter by comparing those children with children who have DUI at other times, but not with laughter.

METHODS

We conducted a retrospective medical record review of children with DUI who presented to a tertiary continence service from 2017 to 2018, collecting data on age, gender, associated comorbidities, lower urinary tract symptoms, investigations, provisional diagnosis at first visit and initial treatment responses. Differences between those with DUI occurring during laughter and those with DUI at other times, but not with laughter were compared using standard statistical methods.

RESULTS

Of the 277 new patients seen during the study period, 140 (51%) had DUI, and of these, 72 (51%) had DUI occurring during laughter. Children with incontinence occurring during laughter were more likely to have incontinence associated with other activities. One child had giggle incontinence according to the International Children's Continence Society's definition. Four other children were referred specifically for urinary incontinence associated with laughter, with the term giggle incontinence sometimes used by the referring doctor.

CONCLUSION

Children with DUI commonly experience incontinence during laughter, but true giggle incontinence is rare. Correct diagnosis is essential as it directs treatment.

Are you laughing with me or at me? Psychopathic traits and the ability to distinguish between affiliation and dominance laughter cues

OBJECTIVE

Laughter conveys important information that supports social communication and bonding. Research suggests that unique acoustic properties distinguish laughter that promotes affiliation from laughter that conveys dominance, but little is known about potential individual differences in laughter interpretation or contagion based on these specified social functions of laughter. Psychopathy is associated with both affiliative deficits (e.g., lack of empathy and impaired social bonding) and behaviors that assert social dominance (e.g., manipulativeness). Thus, relationships between psychopathic traits and impaired laughter interpretation or contagion could give insight into etiological pathways to psychopathy.

METHOD

In two studies conducted with four independent samples (total N = 770), participants categorized laughter clips that varied in the degree of affiliation or dominance conveyed.

RESULTS

Participants overall drew rich and accurate social inferences from dominant and affiliative laughter and modulated their interest in joining in with laughter based on the type and degree of affiliation and dominance conveyed. However, individuals higher in psychopathic traits failed to distinguish between laughter types and did not modulate their level of engagement based on laughter features.

CONCLUSIONS

The results suggest a potential mechanism that underlies the broader social difficulties associated with psychopathic traits.

Protophones, the precursors to speech, dominate the human infant vocal landscape

Human infant vocalization is viewed as a critical foundation for vocal learning and language. All apes share distress sounds (shrieks and cries) and laughter. Another vocal type, speech-like sounds, common in human infants, is rare but not absent in other apes. These three vocal types form a basis for especially informative cross-species comparisons. To make such comparisons possible we need empirical research documenting the frequency of occurrence of all three. The present work provides a comprehensive portrayal of these three vocal types in the human infant from longitudinal research in various circumstances of recording. Recently, the predominant vocalizations of the human infant have been shown to be speech-like sounds, or 'protophones', including both canonical and non-canonical babbling. The research shows that protophones outnumber cries by a factor of at least five based on data from random-sampling of all-day recordings across the first year. The present work expands on the prior reports, showing the protophones vastly outnumber both cry and laughter in both all-day and laboratory recordings in various circumstances. The data provide new evidence of the predominance of protophones in the infant vocal landscape and illuminate their role in human vocal learning and the origin of language. This article is part of the theme issue 'Vocal learning in animals and humans'.

The ontogeny of human laughter

Human adult laughter is characterized by vocal bursts produced predominantly during exhalation, yet apes laugh while exhaling and inhaling. The current study investigated our hypothesis that laughter of human infants changes from laughter similar to that of apes to increasingly resemble that of human adults over early development. We further hypothesized that the more laughter is produced on the exhale, the more positively it is perceived. To test these predictions, novice (n = 102) and expert (phonetician, n = 15) listeners judged the extent to which human infant laughter (n = 44) was produced during inhalation or exhalation, and the extent to which they found the laughs pleasant and contagious. Support was found for both hypotheses, which were further confirmed in two pre-registered replication studies. Likely through social learning and the anatomical development of the vocal production system, infants' initial ape-like laughter transforms into laughter similar to that of adult humans over the course of ontogeny.

The Complexity and Phylogenetic Continuity of Laughter and Smiles in Hominids

Laughter and smiles are often, but not always, associated with positive affect. These expressions of humans help to promote social relationships as well as the development of cognitive and socio-emotional skills and they may have a positive impact on health and well-being, hereby covering a selection of fitness-relevant benefits. Both laughter and smiles of positive affect also occur early in human development and across cultures, suggesting deep roots in human biology. The present work provides an evolutionary reconstruction of the evolution of human laughter and smiles of positive affect in form and function, based on the principle of maximum parsimony. According to the Complexity and Continuity Hypothesis, human laughter and smiles of positive affect must have evolved within the context of play from ancestral species. Furthermore, ancestral ape laughter and their open-mouth faces must already have been complex in form and function and changed over time via categorically different phylogenetic pathways to become characteristic, effective, and pervasive behaviors of everyday social interactions in humans.

Testing the associations between dispositions toward ridicule and being laughed at and romantic jealousy in couples: An APIM analysis

OBJECTIVE

How people deal with ridicule and being laughed at plays a role in romantic life. We extend the research on the fear of being laughed at (gelotophobia), joy in being laughed at (gelotophilia), and joy in laughing at others (katagelasticism) by testing their associations with romantic jealousy and its consequences for relationship satisfaction (RS).

METHOD

Our study is based on Actor-Partner Interdependence Model (APIM) analyses of self and partner ratings of the laughter-related dispositions using data from 228 opposite-sex couples. APIM mediation analyses estimated indirect effects of jealousy on the associations between the dispositions and RS.

RESULTS

As expected, gelotophobia-related positively to jealousy in actors, whereas gelotophilia and katagelasticism showed differential relationships. The analysis of partner effects showed that the actual expressions in the dispositions are unrelated to jealousy but perceived expressions account robustly for experiences of jealousy beyond self-ratings. Finally, jealousy had indirect effects on the associations between the dispositions and RS.

CONCLUSION

These findings contribute to our understanding of the role of dealing with ridicule and laughter in romantic life. We embed the findings into the literature, discuss practical implications, and derive future directions to expand the knowledge on gelotophobia, gelotophilia, and katagelasticism in romantic life.

Does Laughter Predict Onset of Functional Disability and Mortality Among Older Japanese Adults? The JAGES Prospective Cohort Study

Background

While laughter is broadly recognized as a good medicine, a potential preventive effect of laughter on disability and death is still being debated. Accordingly, we investigated the association between the frequency of laughter and onset of functional disability and all-cause mortality among the older adults in Japan.

Methods

The data for a 3-year follow-up cohort including 14,233 individuals (50.3% men) aged ≥65 years who could independently perform the activities of daily living and participated in the Japan Gerontological Evaluation Study were analyzed. The participants were classified into four categories according to their frequency of laughter (almost every day, 1–5 days/week, 1–3 days/month, and never or almost never). We estimated the risks of functional disability and all-cause mortality in each category using a Cox proportional hazards model.

Results

During follow-up, 605 (4.3%) individuals developed functional disability, identified by new certification for the requirement of Long-Term Care Insurance, and 659 (4.6%) deaths were noted. After adjusting for the potential confounders, the multivariate-adjusted hazard ratio of functional disability increased with a decrease in the frequency of laughter (P for trend = 0.04). The risk of functional disability was 1.42 times higher for individuals who laughed never or almost never than for those who laughed almost every day. No such association was observed with the risk of all-cause mortality (P for trend = 0.39).

Conclusions

Low frequency of laughter is associated with increased risks of functional disability. Laughter may be an early predictor of functional disability later on in life.

Making Sense of Infants' Differential Responses to Incongruity

Infants show strikingly different reactions to incongruity: looking (Baillargeon, 1998) or smiling (Mireault & Reddy, 2016). The former occurs in response to magical events and the latter to humorous events. We argue that these reactions depend largely on the respective experimental methodologies employed, including the popular Violation of Expectation (VOE) paradigm. Although both types of studies involve infants' reactions to incongruity, their literatures have yet to confront each other and researchers in each domain are drawing strikingly different conclusions regarding infants' understanding of the world. Here, we argue that infants are sensitive to and constrained by several contextual differences in the methodologies employed by incongruity researchers that afford one or the other reaction. We apply De Jaegher & Di Paolo's (2007) Participatory Sense Making framework to further understand what infants are sensitive to in these paradigms. Understanding infants' reactions to incongruity (i.e., VOE) is necessary to clear up claims regarding the sophisticatication of their knowledge of physical and social phenomena. Attention to several simple methodological details is recommended.

Body synchrony in triadic interaction

Humans subtly synchronize body movement during face-to-face conversation. In this context, bodily synchrony has been linked to affiliation and social bonding, task success and comprehension, and potential conflict. Almost all studies of conversational synchrony involve dyads, and relatively less is known about the structure of synchrony in groups larger than two. We conducted an optic flow analysis of body movement in triads engaged in face-to-face conversation, and explored a common measure of synchrony: time-aligned bodily covariation. We correlated this measure of synchrony with a diverse set of covariates related to the outcome of interactions. Triads showed higher maximum cross-correlation relative to a surrogate baseline, and 'meta-synchrony', in that composite dyads in a triad tended to show correlated structure. A windowed analysis also revealed that synchrony varies widely across an interaction. As in prior studies, average synchrony was low but statistically reliable in just a few minutes of interaction. In an exploratory analysis, we investigated the potential function of body synchrony by predicting it from various covariates, such as linguistic style matching, liking, laughter and cooperative play in a behavioural economic game. Exploratory results do not reveal a clear function for synchrony, though colaughter within triads was associated with greater body synchrony, and is consistent with an earlier analysis showing a positive connection between colaughter and cooperation. We end by discussing the importance of expanding and codifying analyses of synchrony and assessing its function.

The importance of humour in oncology: a survey of patients undergoing radiotherapy

Background

Humour has long been considered an important coping tool for patients with cancer, but published quantitative data about its significance are limited. The purpose of our study was to survey patients with cancer undergoing radiotherapy regarding their opinions about the use of humour in their care.

Methods

An anonymous 35-item questionnaire evaluating the patient experience, including the value of humour, was developed by an interdisciplinary team of health care providers (hcps) working within the Radiation Medicine program. This anonymous, voluntary, paper-based survey for self-completion required approximately 10 minutes to finish and was administered during the fall of 2018 and the spring of 2019.

Results

For the 199 patients who completed the survey [108 women, 89 men (2 respondents did not specify)], median age was 68 years. That group represents approximately 30%-35% of the patients on treatment during the study period. Almost all respondents (86%) indicated that, during their visits to the cancer centre, it was "somewhat important" or "very important" for health care providers (hcps) to use appropriate humour, and 61% of respondents indicated using humour "frequently" or "always" when dealing with their individual cancers. Most respondents (79%) said that humour decreased anxiety, and 86% indicated that laughing was considered "somewhat important" or "very important." Approximately 4% of respondents even listed "sense of humour" as being the most important quality that they looked for in their interactions with their hcps.

Conclusions

Cancer patients undergoing radiotherapy clearly view humour as being important for coping and dealing with their disease, and oncology hcps should routinely consider incorporating the use of appropriate humour into the care that they provide.

Scientists as comedians: The effects of humor on perceptions of scientists and scientific messages

Humor has been recommended for scientists looking to conduct communication activities despite relatively little empirical evidence demonstrating its effectiveness. Here, we examine the social environment of a joke through a two-condition experimental design that manipulates the presence or absence of audience laughter. Specifically, we examine how humor experienced from viewing a video clip of a science comedian embedded in an online survey can have downstream effects on whether people view comedy as a valid source of scientific information. We found that respondents who perceived more humor in the video clip (i.e. those in the condition with audience laughter) had more positive views about comedy as a valid source of scientific information. Interestingly, this relationship was mediated by perceived expertise, not likability, of the scientist engaging in comedy.

Are pharmacological interventions clinically useful to treat emotionalism after stroke? A Cochrane Review update summary with commentary

BACKGROUND

Emotionalism, i.e. uncontrolled episodes of crying (or less commonly laughing) post stroke that are not triggered by situations that would have previously provoked such behavior occur in stroke survivors, may persist in some, and can be socially embarrassing.

OBJECTIVE

To evaluate whether pharmacological interventions are beneficial, acceptable, and safe in the treatment of emotionalism post stroke.

METHODS

A Cochrane review by Allida et al. was summarized with comments.

RESULTS

From a total of 7 eligible trials with a total of 239 participants included in the review, five with 213 participants could be used for data extraction. Very low to moderate quality evidence pointed to some beneficial effects of antidepressants in the treatment of emotionalism after stroke.

CONCLUSIONS

The available data suggest that antidepressants may reduce the frequency and severity of crying or laughing episodes in stroke survivors with emotionalism.

Motor and Limbic System Contribution to Emotional Laughter across the Lifespan

Laughter is a universal human behavior generated by the cooperation of different systems toward the construction of an expressive vocal pattern. Given the sensitivity of neuroimaging techniques to movements, the neural mechanisms underlying laughter expression remain unclear. Herein, we characterized the neural correlates of emotional laughter using the onsets and the duration of laughter bursts to inform functional magnetic resonance imaging. Laughter-related blood oxygen level-dependent (BOLD) increases involved both the motor (motor cortex, supplementary motor area, frontal operculum) and the emotional/limbic (anterior cingulate cortex, amygdala, n. accumbens, hippocampus) systems, as well as modulatory circuitries encompassing the basal ganglia, thalamus, and cerebellum. BOLD changes related to the 2 s preceding the laughter outbreak were selectively observed at the temporo-occipital junction and the periaqueductal gray matter, supporting the role of the former in the detection of incongruity and the gating role of the latter in the initiation of spontaneous laughter. Moreover, developmental changes were identified in laughter processing, consisting in a greater engagement of the reward circuitry in younger subjects; conversely, the default mode network appears more activated in older participants. Our findings contribute valuable information about the processing of real-life humorous materials and suggest a close link between laughter-related motor, affective, and cognitive elements, confirming its complex and multi-faceted nature.

Are you laughing at me? Neural correlates of social intent attribution to auditory and visual laughter

Laughter is a multifaceted signal, which can convey social acceptance facilitating social bonding as well as social rejection inflicting social pain. In the current study, we addressed the neural correlates of social intent attribution to auditory or visual laughter within an fMRI study to identify brain areas showing linear increases of activation with social intent ratings. Negative social intent attributions were associated with activation increases within the medial prefrontal cortex/anterior cingulate cortex (mPFC/ACC). Interestingly, negative social intent attributions of auditory laughter were represented more rostral than visual laughter within this area. Our findings corroborate the role of the mPFC/ACC as key node for processing “social pain” with distinct modality‐specific subregions. Other brain areas that showed an increase of activation included bilateral inferior frontal gyrus and right superior/middle temporal gyrus (STG/MTG) for visually presented laughter and bilateral STG for auditory presented laughter with no overlap across modalities. Similarly, positive social intent attributions were linked to hemodynamic responses within the right inferior parietal lobe and right middle frontal gyrus, but there was no overlap of activity for visual and auditory laughter. Our findings demonstrate that social intent attribution to auditory and visual laughter is located in neighboring, but spatially distinct neural structures.

Post-stroke emotionalism: a qualitative investigation

Introduction: Post-stroke emotionalism, outbursts of involuntary crying or laughing, is common after stroke. Little is known about the psychosocial factors associated with this neurological disorder.Aim: To investigate participant's experiences of emotionalism and explore how they managed their symptoms.Methods: A qualitative study that used framework analysis. Participants were recruited across inpatient and outpatient stroke settings. The average time since stroke was 4.3 months.Results: Eighteen semi-structured interviews were conducted. Four themes were identified: (1) Spontaneous and uncontrollable emotional reactions; (2) Incongruence; (3) Social reactions (sub-theme: The stigma of expressed emotions) and (4) Convalescence. Participants with negative experiences described greater disability, avoidance and mood problems. Positive experiences were shaped by a better understanding of the condition, an increased sense of control, social support and optimism. Few participants knew that their emotionalism was caused by stroke. Embarrassment and social withdrawal were commonly reported and had a detrimental effect on participant's mood and quality of life.Conclusions: Earlier recognition of emotionalism in clinical settings is needed as is promoting discussions about emotional reactions after-stroke. This will reduce the likelihood that patients will develop erroneous beliefs about emotionalism and unhelpful coping responses that may lead to adjustment difficulties in the months that follow their stroke.Implications for rehabilitationThe unpredictable and uncontrollable nature of emotionalism can be embarrassing and cause social withdrawal or avoidance.Waiting for emotionalism episodes to pass, distraction, humor or optimism and social support are successful means of managing the condition.Professionals play a key role in raising awareness that emotionalism is a neurological condition and not a clinical mood disorder as this will promote better understanding for patients, their families and those around them.Encouraging patients to talk about their emotional reactions early after stroke will normalize their experiences and may prevent them from developing unhelpful beliefs that could affect their approach to recovery.

Associations of Frequency of Laughter With Risk of All-Cause Mortality and Cardiovascular Disease Incidence in a General Population: Findings From the Yamagata Study

Background

Positive and negative psychological factors are associated with mortality and cardiovascular disease. This study prospectively investigated associations of daily frequency of laughter with mortality and cardiovascular disease in a community-based population.

Methods

This study included 17,152 subjects ≥40 years old who participated in an annual health check in Yamagata Prefecture. Self-reported daily frequency of laughter was grouped into three categories (≥1/week; ≥1/month but <1/week; <1/month). Associations of daily frequency of laughter with increase in all-cause mortality and cardiovascular disease incidence were determined using Cox proportional hazards modeling.

Results

During follow-up (median, 5.4 years), 257 subjects died and 138 subjects experienced cardiovascular events. Kaplan-Meier analysis revealed that all-cause mortality and cardiovascular disease incidence were significantly higher among subjects with a low frequency of laughter (log-rank P < 0.01). Cox proportional hazard model analysis adjusted for age, gender, hypertension, smoking, and alcohol drinking status showed that risk of all-cause mortality was significantly higher in subjects who laughed <1/month than in subjects who laughed ≥1/week (hazard ratio [HR] 1.95; 95% confidence interval [CI], 1.16–3.09). Similarly, risk of cardiovascular events was higher in subjects who laughed ≥1/month but <1/week than in subjects who laughed ≥1/week (HR 1.62; 95% CI, 1.07–2.40).

Conclusion

Daily frequency of laughter represents an independent risk factor for all-cause mortality and cardiovascular disease in a Japanese general population.

Impact of social relationships on income-laughter relationships among older people: the JAGES cross-sectional study

OBJECTIVES

Laughter has a positive and quantifiable effect on certain aspects of health, and previous studies have suggested that income influences the emotion. However, it is unknown whether social relationship-related factors modify the association between equivalised income and laughter among older people. In the present study, we examined the relationship between equivalised income and the frequency of laughter. In addition, we examined the impact of social relationship-related factors on the association between equivalised income and frequency of laughter using a cross-sectional study design.

DESIGN

Cross-sectional study and binomial regression analysis.

SETTING

We sampled from 30 municipalities in Japan.

PARTICIPANTS

We examined 20 752 non-disabled Japanese individuals aged ≥65 years using data from the Japan Gerontological Evaluation Study.

PRIMARY OUTCOME

Frequency of laughter.

RESULTS

Laughter increased significantly with an increase in equivalent income (p for trend <0.0001). Prevalence ratios (PR) for laughing almost every day were calculated according to quartile equivalised income after adjusting for age, instrumental activities of daily living, depression, frequency of meeting friends, number of social groups and family structure. The results revealed that PRs in Q4 (men; ≥€24 420, women; ≥€21 154) were 1.21 (95% CI 1.13 to 1.30) among men and 1.14 (95% CI 1.08 to 1.20) among women, as compared with Q1 (men; <€12 041, women; <€9518), respectively. After excluding participants with depression, the association remained significant. In addition, we found inadequate social relationships and living alone were associated with a lower frequency of laughter. In comparison with the lowest equivalent income with meeting friends less frequently and living alone, the PRs of the highest equivalent income with meeting friends frequently and living with someone were higher, respectively.

CONCLUSIONS

The results revealed a significant relationship between equivalent income and the frequency of laughter. Social relationships and family structure were also associated with the frequency of laughter.

Social Facilitation of Laughter and Smiles in Preschool Children

Surprisingly little is known about the social dimensions of laughter in preschool children. We studied children's responses to amusing video clips in the presence or absence of peers. The sample consisted of 9 boys and 11 girls aged 31-49 months (M 39.8, SD 4.2) who watched three cartoons under three different conditions: individually, in pairs, or in groups of 6 or 8. The social viewing conditions showed significantly higher numbers of laughs and smiles than the individual viewing condition. On average children laughed eight times as much in company as on their own and smiled almost three times as much. No differences were found between pairs and groups, and no association was found between subjective funniness ratings and group size. This suggests that the presence of even a single social partner can change behavior in response to humorous material. It supports the idea that laughter and smiles are primarily flexible social signals rather than reflexive responses to humor.

Neuroanatomy of Shared Conversational Laughter in Neurodegenerative Disease

Perceiving another person's emotional expression often sparks a corresponding signal in the observer. Shared conversational laughter is a familiar example. Prior studies of shared laughter have made use of task-based functional neuroimaging. While these methods offer insight in a controlled setting, the ecological validity of such controlled tasks has limitations. Here, we investigate the neural correlates of shared laughter in patients with one of a variety of neurodegenerative disease syndromes (N = 75), including Alzheimer's disease (AD), behavioral variant frontotemporal dementia (bvFTD), right and left temporal variants of semantic dementia (rtvFTD, svPPA), nonfluent/agrammatic primary progressive aphasia (nfvPPA), corticobasal syndrome (CBS), and progressive supranuclear palsy (PSP). Patients were recorded in a brief unrehearsed conversation with a partner (e.g., a friend or family member). Laughter was manually labeled, and an automated system was used to assess the timing of that laughter relative to the partner's laughter. The probability of each participant with neurodegenerative disease laughing during or shortly after his or her partners' laughter was compared to differences in brain morphology using voxel-based morphometry, thresholded based on cluster size and a permutation method and including age, sex, magnet strength, disease-specific atrophy and total intracranial volumes as covariates. While no significant correlations were found at the critical T value, at a corrected voxelwise threshold of p < 0.005, a cluster in the left posterior cingulate gyrus demonstrated a trend at p = 0.08 (T = 4.54). Exploratory analysis with a voxelwise threshold of p = 0.001 also suggests involvement of the left precuneus (T = 3.91) and right fusiform gyrus (T = 3.86). The precuneus has been previously implicated in the detection of socially complex laughter, and the fusiform gyrus has a well-described role in the recognition and processing of others' emotional cues. This study is limited by a relatively small sample size given the number of covariates. While further investigation is needed, these results support our understanding of the neural underpinnings of shared conversational laughter.

The Use of Humor in Palliative Care: A Systematic Literature Review

BACKGROUND

Humor has its own place in the context of medicine. Nevertheless, its acceptance by terminal stage patients and health-care professionals has not been studied in depth and is not free from controversy.

OBJECTIVES

To understand the significance, appropriateness, and pertinence of the use of humor in palliative care and to analyze its applicability.

DESIGN

A narrative systematic review was undertaken and included in PROSPERO.

DATA SOURCES

Online searches were carried out on PUBMED, PSYCINFO, EBSCO (CINHAL), EMBASE, SCIELO, SCOPUS, TESEO, WEB of SCIENCE, and COCHRANE between their launch date and December 31, 2015, complemented with manual searches with queries to experts. A total of 156 studies were identified, which were then filtered in pairs by means of an established hierarchy, selecting studies that discussed the use of humor specifically in palliative care from all perspectives and designs, and finally published in Spanish, English, French, or Portuguese. Critical reading of all the selected studies took place, with no exclusions due to quality evaluation.

RESULTS

Thirty-four studies were included. Five main topics were identified: (1) definition of humor, (2) use and functions of humor in palliative care, (3) how to use humor, (4) when not to use humor, and (5) humor before and after the diagnosis of terminal illness.

CONCLUSIONS

Humor plays an unquestionable role in palliative care, but its use needs training and appropriate use.

Auditory to Visual Cross-Modal Adaptation for Emotion: Psychophysical and Neural Correlates

Adaptation is fundamental in sensory processing and has been studied extensively within the same sensory modality. However, little is known about adaptation across sensory modalities, especially in the context of high-level processing, such as the perception of emotion. Previous studies have shown that prolonged exposure to a face exhibiting one emotion, such as happiness, leads to contrastive biases in the perception of subsequently presented faces toward the opposite emotion, such as sadness. Such work has shown the importance of adaptation in calibrating face perception based on prior visual exposure. In the present study, we showed for the first time that emotion-laden sounds, like laughter, adapt the visual perception of emotional faces, that is, subjects more frequently perceived faces as sad after listening to a happy sound. Furthermore, via electroencephalography recordings and event-related potential analysis, we showed that there was a neural correlate underlying the perceptual bias: There was an attenuated response occurring at ∼ 400 ms to happy test faces and a quickened response to sad test faces, after exposure to a happy sound. Our results provide the first direct evidence for a behavioral cross-modal adaptation effect on the perception of facial emotion, and its neural correlate.