Blindness influences emotional authenticity perception in voices: Behavioral and ERP evidence

The ability to distinguish spontaneous from volitional emotional expressions is an important social skill. How do blind individuals perceive emotional authenticity? Unlike sighted individuals, they cannot rely on facial and body language cues, relying instead on vocal cues alone. Here, we combined behavioral and ERP measures to investigate authenticity perception in laughter and crying in individuals with early- or late-blindness onset. Early-blind, late-blind, and sighted control participants (n = 17 per group, N = 51) completed authenticity and emotion discrimination tasks while EEG data were recorded. The stimuli consisted of laughs and cries that were either spontaneous or volitional. The ERP analysis focused on the N1, P2, and late positive potential (LPP). Behaviorally, early-blind participants showed intact authenticity perception, but late-blind participants performed worse than controls. There were no group differences in the emotion discrimination task. In brain responses, all groups were sensitive to laughter authenticity at the P2 stage, and to crying authenticity at the early LPP stage. Nevertheless, only early-blind participants were sensitive to crying authenticity at the N1 and middle LPP stages, and to laughter authenticity at the early LPP stage. Furthermore, early-blind and sighted participants were more sensitive than late-blind ones to crying authenticity at the P2 and late LPP stages. Altogether, these findings suggest that early blindness relates to facilitated brain processing of authenticity in voices, both at early sensory and late cognitive-evaluative stages. Late-onset blindness, in contrast, relates to decreased sensitivity to authenticity at behavioral and brain levels.

Mini-review: Wild laughs: Ontogenesis and phylogenesis of humour

This mini-review discusses the existing evidence on various forms of humour and humour-like behaviour in non-human animals, combining ontogenetic and phylogenetic perspectives. The first section describes humour-like behaviours, from the simplest to the most complex form (from laughing, tickling, joking, and chasing to ToM humour). In the second section, we propose the SPeCies (Social, Physiological, and Cognitive) Perspective, which frames the various types of humour based on Social motivation, Physiological state, and Cognitive skills. Finally, in the third section, we discuss future directions for further development.

'Should we laugh?' Acoustic features of (in)voluntary laughters in spontaneous conversations

Laughter is one of the most common non-verbal features; however, contrary to the previous assumptions, it may also act as signals of bonding, affection, emotional regulation agreement or empathy (Scott et al. Trends Cogn Sci 18:618-620, 2014). Although previous research agrees that laughter does not form a uniform group in many respects, different types of laughter have been defined differently by individual research. Due to the various definitions of laughter, as well as their different methodologies, the results of the previous examinations were often contradictory. The analysed laughs were often recorded in controlled, artificial situations; however, less is known about laughs from social conversations. Thus, the aim of the present study is to examine the acoustic realisation, as well as the automatic classification of laughter that appear in human interactions according to whether listeners consider them to be voluntary or involuntary. The study consists of three parts using a multi-method approach. Firstly, in the perception task, participants had to decide whether the given laughter seemed to be rather involuntary or voluntary. In the second part of the experiment, those sound samples of laughter were analysed that were considered to be voluntary or involuntary by at least 66.6% of listeners. In the third part, all the sound samples were grouped into the two categories by an automatic classifier. The results showed that listeners were able to distinguish laughter extracted from spontaneous conversation into two different types, as well as the distinction was possible on the basis of the automatic classification. In addition, there were significant differences in acoustic parameters between the two groups of laughter. The results of the research showed that, although the distinction between voluntary and involuntary laughter categories appears based on the analysis of everyday, spontaneous conversations in terms of the perception and acoustic features, there is often an overlap in the acoustic features of voluntary and involuntary laughter. The results will enrich our previous knowledge of laughter and help to describe and explore the diversity of non-verbal vocalisations.

Laughter and lies: Unraveling the intricacies of humor and deception

Deception and humor are ubiquitous in interpersonal interactions and intricately interrelated. In this article, we review and integrate prior research on humor and deception and propose a theoretical model - the Interpersonal Humor Deception Model (IHDM) - to understand the interpersonal effects of humor on deception. We argue that humor can both promote and curtail the use of deception, as well as influence the detection of deception and responses to detected deception (retraction, retaliation, and the restoration of trust). The specific effects of humor depend on whether it is successful or unsuccessful. In all, our article provides a theoretical framework to guide research on humor and deception and offers important insights into the costs and benefits of humor in negotiations, organizations, and everyday life.

Maternal depressive symptoms and affective responses to infant crying and laughing

Depressive symptoms are common in the postpartum period and can affect mother-infant interaction. To better understand the role of depressive symptoms in the mother-infant interchange, this study examined whether maternal depressive symptoms are associated with self-reported, physiological, and facial expressive responses to infant crying and laughing sounds. A nonclinical sample was used, consisting of 101 mothers (Age M = 30.88 years, 33% scored 7 or higher on the Edinburgh Postnatal Depression Scale) with a young child. Mothers were exposed to standard infant crying and laughing sounds. Affect, perception of crying and laughing, intended caregiving responses, skin conductance level reactivity, and facial expressive responses to infant crying and laughing were measured. Higher levels of depressive symptoms were associated with more self-reported negative affect in general and a more negative perception of infant crying. Depressive symptoms were not associated with intended caregiving responses and physiological responses to infant crying. Infant laughing increased self-reported positive affect and happy facial expressions in mothers with all levels of depressive symptoms. Higher levels of depressive symptoms were associated with higher sad facial expressivity in general. Depressive symptoms were not related to positive perception of infant laughing, intended caregiving responses, and physiological responses to infant laughing. The findings suggest that mothers who score high on depressive symptoms send subtle facial cues showing sadness, which may overshadow happy facial expressions during infant laughing and may affect mother-infant interaction. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Real-time magnetic resonance imaging reveals distinct vocal tract configurations during spontaneous and volitional laughter

A substantial body of acoustic and behavioural evidence points to the existence of two broad categories of laughter in humans: spontaneous laughter that is emotionally genuine and somewhat involuntary, and volitional laughter that is produced on demand. In this study, we tested the hypothesis that these are also physiologically distinct vocalizations, by measuring and comparing them using real-time magnetic resonance imaging (rtMRI) of the vocal tract. Following Ruch and Ekman (Ruch and Ekman 2001 In Emotions, qualia, and consciousness (ed. A Kaszniak), pp. 426-443), we further predicted that spontaneous laughter should be relatively less speech-like (i.e. less articulate) than volitional laughter. We collected rtMRI data from five adult human participants during spontaneous laughter, volitional laughter and spoken vowels. We report distinguishable vocal tract shapes during the vocalic portions of these three vocalization types, where volitional laughs were intermediate between spontaneous laughs and vowels. Inspection of local features within the vocal tract across the different vocalization types offers some additional support for Ruch and Ekman's predictions. We discuss our findings in light of a dual pathway hypothesis for the neural control of human volitional and spontaneous vocal behaviours, identifying tongue shape and velum lowering as potential biomarkers of spontaneous laughter to be investigated in future research. This article is part of the theme issue 'Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience'.

The naturalistic approach to laughter in humans and other animals: towards a unified theory

This opinion piece aims to tackle the biological, psychological, neural and cultural underpinnings of laughter from a naturalistic and evolutionary perspective. A naturalistic account of laughter requires the revaluation of two dogmas of a longstanding philosophical tradition, that is, the quintessential link between laughter and humour, and the uniquely human nature of this behaviour. In the spirit of Provine's and Panksepp's seminal studies, who firstly argued against the anti-naturalistic dogmas, here we review compelling evidence that (i) laughter is first and foremost a social behaviour aimed at regulating social relationships, easing social tensions and establishing social bonds, and that (ii) homologue and homoplasic behaviours of laughter exist in primates and rodents, who also share with humans the same underpinning neural circuitry. We make a case for the hypothesis that the contagiousness of laughter and its pervasive social infectiousness in everyday social interactions is mediated by a specific mirror mechanism. Finally, we argue that a naturalistic account of laughter should not be intended as an outright rejection of classic theories; rather, in the last part of the piece we argue that our perspective is potentially able to integrate previous viewpoints-including classic philosophical theories-ultimately providing a unified evolutionary explanation of 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'.

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'.

The web of laughter: frontal and limbic projections of the anterior cingulate cortex revealed by cortico-cortical evoked potential from sites eliciting laughter

According to an evolutionist approach, laughter is a multifaceted behaviour affecting social, emotional, motor and speech functions. Albeit previous studies have suggested that high-frequency electrical stimulation (HF-ES) of the pregenual anterior cingulate cortex (pACC) may induce bursts of laughter-suggesting a crucial contribution of this region to the cortical control of this behaviour-the complex nature of laughter implies that outward connections from the pACC may reach and affect a complex network of frontal and limbic regions. Here, we studied the effective connectivity of the pACC by analysing the cortico-cortical evoked potentials elicited by single-pulse electrical stimulation of pACC sites whose HF-ES elicited laughter in 12 patients. Once these regions were identified, we studied their clinical response to HF-ES, to reveal the specific functional target of pACC representation of laughter. Results reveal that the neural representation of laughter in the pACC interacts with several frontal and limbic regions, including cingulate, orbitofrontal, medial prefrontal and anterior insular regions-involved in interoception, emotion, social reward and motor behaviour. These results offer neuroscientific support to the evolutionist approach to laughter, providing a possible mechanistic explanation of the interplay between this behaviour and emotion regulation, speech production and social interactions. This article is part of the theme issue 'Cracking the laugh code: laughter through the lens of biology, psychology and neuroscience'.

Investigating form and content of emotional and non-emotional laughing

As cold actions (i.e. actions devoid of an emotional content), also emotions are expressed with different vitality forms. For example, when an individual experiences a positive emotion, such as laughing as expression of happiness, this emotion can be conveyed to others by different intensities of face expressions and body postures. In the present study, we investigated whether the observation of emotions, expressed with different vitality forms, activates the same neural structures as those involved in cold action vitality forms processing. To this purpose, we carried out a functional magnetic resonance imaging study in which participants were tested in 2 conditions: emotional and non-emotional laughing both conveying different vitality forms. There are 3 main results. First, the observation of emotional and non-emotional laughing conveying different vitality forms activates the insula. Second, the observation of emotional laughing activates a series of subcortical structures known to be related to emotions. Furthermore, a region of interest analysis carried out in these structures reveals a significant modulation of the blood-oxygen-leveldependent (BOLD) signal during the processing of different vitality forms exclusively in the right amygdala, right anterior thalamus/hypothalamus, and periaqueductal gray. Third, in a subsequent electromyography study, we found a correlation between the zygomatic muscles activity and BOLD signal in the right amygdala only.

Laughter and smiling facial expression modelling for the generation of virtual affective behavior

Laughter and smiling are significant facial expressions used in human to human communication. We present a computational model for the generation of facial expressions associated with laughter and smiling in order to facilitate the synthesis of such facial expressions in virtual characters. In addition, a new method to reproduce these types of laughter is proposed and validated using databases of generic and specific facial smile expressions. In particular, a proprietary database of laugh and smile expressions is also presented. This database lists the different types of classified and generated laughs presented in this work. The generated expressions are validated through a user study with 71 subjects, which concluded that the virtual character expressions built using the presented model are perceptually acceptable in quality and facial expression fidelity. Finally, for generalization purposes, an additional analysis shows that the results are independent of the type of virtual character’s appearance.

Inappropriate Laughter and Behaviours: How, What, and Why? Case of an Adult with Undiagnosed Gelastic Seizure with Hypothalamic Hamartoma

Gelastic seizures (GS) are a rare form of epilepsy characterized by inappropriate, uncontrolled laughter. They are highly associated with abnormal cognitive development and behavioral problems in patients. Research has shown that GS can originate from hypothalamic hamartomas (HH), non- neoplastic masses consisting of gray matter with large and small neurons interspersed with glial nuclei. GS have also been observed in patients with frontal and temporal lobe lesions. The patient in this case report is a 40-year-old man with a past medical history significant for brain tumor, diabetes mellitus, and schizophrenia who presented with a long standing history of sudden, involuntary laughter occurring 2-3 times a week since 8 years old. Since the onset of these laughing spells the patient has displayed gradual cognitive impairment and increasing behavioral problems. Subsequent EEG (21-channel electroencephalogram) showed focal epileptiform activity in the right frontotemporal region and MRI studies revealed a mass arising from the hypothalamus suggestive of a HH. Other conditions should be considered in the differential diagnosis for laughing spells and distinguishing different causes can be challenging. As demonstrated by this case report, in patients with behavioral issues, especially those with inappropriate uncontrolled laughter, gelastic seizures need to be included in the differential diagnosis. Thus, a thorough workup should include neuroimaging with attention to the suprasellar region and EEG. Accurate, early diagnosis and patient education are critical in avoiding excessive and unnecessary treatments. This condition may be pharmacoresistant and is often associated with progressive cognitive and behavioral issues. Studies have shown a surgical treatment approach may be effective.

Thermal Augmented Expression Recognition

Visible facial images provide geometric and appearance patterns of facial expressions and are sensitive to illumination changes. Thermal facial images record facial temperature distribution and are robust to light conditions. Therefore, expression recognition is enhanced by visible and thermal image fusion. In most cases, only visible images are available due to the widespread popularity of visible cameras and the high cost of thermal cameras. Thus, we propose a novel visible expression recognition method by using thermal infrared (IR) data as privileged information, which is only available during training. Specifically, we first learn a deep model for visible images and thermal images. Then we use the learned feature representations to train support vector machine (SVM) classifiers for expression classification. We jointly refine the deep models as well as the SVM classifiers for both thermal images and visible images by imposing the constraint that the outputs of the SVM classifiers from two views are similar. Thermal IR images during training are then exploited to construct better facial representations and expression classifiers from visible images. We extend the proposed thermal augmented expression recognition method for partially unpaired data, acknowledging that visible images and thermal images maybe not be recorded synchronously. Experimental resulton the MAHNOB laughter database demonstrate that the proposed thermal augmented expression recognition method can effectively exploit thermal IR images' supplementary role for visible facial expression recognition during training to obtain better facial representations and a better visible expression classifier. The proposed thermal augmented expression recognition method achieves state-of-the-art expression recognition performance for both paired and unpaired facial images.

I Think We're Alone Now: Solitary Social Behaviors in Adolescents with Autism Spectrum Disorder

Research into emotional responsiveness in Autism Spectrum Disorder (ASD) has yielded mixed findings. Some studies report uniform, flat and emotionless expressions in ASD; others describe highly variable expressions that are as or even more intense than those of typically developing (TD) individuals. Variability in findings is likely due to differences in study design: some studies have examined posed (i.e., not spontaneous expressions) and others have examined spontaneous expressions in social contexts, during which individuals with ASD-by nature of the disorder-are likely to behave differently than their TD peers. To determine whether (and how) spontaneous facial expressions and other emotional responses are different from TD individuals, we video-recorded the spontaneous responses of children and adolescents with and without ASD (between the ages of 10 and 17 years) as they watched emotionally evocative videos in a non-social context. Researchers coded facial expressions for intensity, and noted the presence of laughter and other responsive vocalizations. Adolescents with ASD displayed more intense, frequent and varied spontaneous facial expressions than their TD peers. They also produced significantly more emotional vocalizations, including laughter. Individuals with ASD may display their emotions more frequently and more intensely than TD individuals when they are unencumbered by social pressure. Differences in the interpretation of the social setting and/or understanding of emotional display rules may also contribute to differences in emotional behaviors between groups.

The past is present: The role of maltreatment history in perceptual, behavioral and autonomic responses to infant emotional signals

In the current study associations between parents' experiences of childhood maltreatment and their perceptual, behavioral and autonomic responses to infant emotional signals were examined in a sample of 160 parents. Experienced maltreatment (both physical and emotional abuse and neglect) was reported by the participants and, in approximately half of the cases, also by their parents. During a standardized infant vocalization paradigm, participants were asked to squeeze a handgrip dynamometer at maximal and at half strength while listening to infant crying and laughter sounds and to rate their perception of the sounds. In addition, their heart rate (HR), pre-ejection period (PEP), and vagal tone (RSA) were measured as indicators of underlying sympathetic and parasympathetic reactivity. Results indicated that participants did not differ in their perceptions of the infant vocalizations signals according to their maltreatment experiences. However, maltreatment experiences were associated with the modulation of behavioral responses. Experiences of neglect during childhood were related to more handgrip force during infant crying and to less handgrip force during infant laughter. Moreover, a history of neglect was associated with a higher HR and a shorter PEP during the entire infant vocalization paradigm, which may indicate chronic cardiovascular arousal. The findings imply that a history of childhood neglect negatively influences parents' capacities to regulate their emotions and behavior, which would be problematic when reacting to children's emotional expressions.

Homeostatic effect of laughter on diabetic cardiovascular complications: The myth turned to fact

AIMS

Laughter has been used for centuries to alleviate pain in morbid conditions. It was not until 1976 that scientists thought about laughter as a form of therapy that can modulate hormonal and immunological parameters that affect the outcome of many serious diseases. Moreover, laughter therapy was shown to be beneficial in type 2 diabetes mellitus (T2DM) by delaying the onset of many diabetic complications. Laughter is also described to influence the cardiovascular and endothelial functions and thus may protect against diabetic cardiovascular complications. In this review, we outline the different biochemical, physiological and immunological mechanisms by which laughter may influence the overall state of wellbeing and enhance disease prognosis. We also focus on the biological link between laughter therapy and diabetic cardiovascular complications as well as the underlying mechanisms involved in T2DM.

METHODS

Reviewing all the essential databases for "laughter" and "type 2 diabetes mellitus".

RESULTS

Although laughter therapy is still poorly investigated, recent studies show that laughter may retard the onset of diabetic complications, enhance cardiovascular functions and rectify homeostatic abnormalities associated with T2DM.

CONCLUSIONS

Laughter therapy is effective in delaying diabetic complications and should be used as an adjuvant therapy.

Social Laughter Triggers Endogenous Opioid Release in Humans

The size of human social networks significantly exceeds the network that can be maintained by social grooming or touching in other primates. It has been proposed that endogenous opioid release after social laughter would provide a neurochemical pathway supporting long-term relationships in humans (Dunbar, 2012), yet this hypothesis currently lacks direct neurophysiological support. We used PET and the μ-opioid-receptor (MOR)-specific ligand [11C]carfentanil to quantify laughter-induced endogenous opioid release in 12 healthy males. Before the social laughter scan, the subjects watched laughter-inducing comedy clips with their close friends for 30 min. Before the baseline scan, subjects spent 30 min alone in the testing room. Social laughter increased pleasurable sensations and triggered endogenous opioid release in thalamus, caudate nucleus, and anterior insula. In addition, baseline MOR availability in the cingulate and orbitofrontal cortices was associated with the rate of social laughter. In a behavioral control experiment, pain threshold-a proxy of endogenous opioidergic activation-was elevated significantly more in both male and female volunteers after watching laughter-inducing comedy versus non-laughter-inducing drama in groups. Modulation of the opioidergic activity by social laughter may be an important neurochemical pathway that supports the formation, reinforcement, and maintenance of human social bonds.SIGNIFICANCE STATEMENT Social contacts are vital to humans. The size of human social networks significantly exceeds the network that can be maintained by social grooming in other primates. Here, we used PET to show that endogenous opioid release after social laughter may provide a neurochemical mechanism supporting long-term relationships in humans. Participants were scanned twice: after a 30 min social laughter session and after spending 30 min alone in the testing room (baseline). Endogenous opioid release was stronger after laughter versus the baseline scan. Opioid receptor density in the frontal cortex predicted social laughter rates. Modulation of the opioidergic activity by social laughter may be an important neurochemical mechanism reinforcing and maintaining social bonds between humans.

Clinical features and postoperative seizure outcome in patients with drug-resistant gelastic seizures without hypothalamic hamartoma

OBJECTIVES

The objective of this study was to describe the clinical characteristics and surgical outcome in patients with gelastic seizures without hypothalamic hamartoma.

METHODS

We retrospectively reviewed all the video-EEG reports over a 5-year period (2007-2011) for the occurrence of the terms "laugh" or "giggle" in the text body. All the patients with at least one documented gelastic seizure at the epilepsy monitoring unit were studied. In patients who underwent epilepsy surgery, seizure outcomes were analyzed.

RESULTS

Sixteen patients (10 females and 6 males) with a mean age of 46.3years were studied. Seven patients had invasive intracranial EEG recordings. Seizure onset zone was in a temporal lobe in four patients and the frontal lobe in one patient. Two patients did not have gelastic seizures during their intracranial EEG monitoring. Nine patients underwent resective epilepsy surgery for their seizures. Six patients (67%) were seizure-free after surgery.

CONCLUSION

In adult patients, gelastic seizures can be seen in patients with focal epilepsy without hypothalamic hamartoma. Nonhypothalamic hamartoma gelastic seizures originating from the temporal lobe can be amenable to surgery.

Quantitative Laughter Detection, Measurement, and Classification-A Critical Survey

The study of human nonverbal social behaviors has taken a more quantitative and computational approach in recent years due to the development of smart interfaces and virtual agents or robots able to interact socially. One of the most interesting nonverbal social behaviors, producing a characteristic vocal signal, is laughing. Laughter is produced in several different situations: in response to external physical, cognitive, or emotional stimuli; to negotiate social interactions; and also, pathologically, as a consequence of neural damage. For this reason, laughter has attracted researchers from many disciplines. A consequence of this multidisciplinarity is the absence of a holistic vision of this complex behavior: the methods of analysis and classification of laughter, as well as the terminology used, are heterogeneous; the findings sometimes contradictory and poorly documented. This survey aims at collecting and presenting objective measurement methods and results from a variety of different studies in different fields, to contribute to build a unified model and taxonomy of laughter. This could be successfully used for advances in several fields, from artificial intelligence and human-robot interaction to medicine and psychiatry.

Humors Effect on Short-term Memory in Healthy and Diabetic Older Adults

CONTEXT

With aging, the detrimental effects of stress can impair a person's ability to learn and sustain memory. Humor and its associated mirthful laughter can reduce stress by decreasing the hormone cortisol. Chronic release of cortisol can damage hippocampal neurons, leading to impairment of learning and memory. Objectives • The study intended to examine the effect of watching a humor video on short-term memory in older adults. Design • The research team designed a randomized, controlled trial.

SETTING

The study took place at Loma Linda University in Loma Linda, CA, USA.

PARTICIPANTS

The study included 30 participants: 20 normal, healthy, older adults-11 males and 9 females-and 10 older adults with type 2 diabetes mellitus (T2DM)-6 males and 4 females.

INTERVENTION

The study included 2 intervention groups of older adults who viewed humorous videos, a healthy group (humor group), aged 69.9 ± 3.7 y, and the diabetic group, aged 67.1 ± 3.8 y. Each participant selected 1 of 2 humorous videos that were 20 min in length, either a Red Skeleton comedy or a montage of America's Funniest Home Videos. The control group, aged 68.7 ± 5.5 y, did not watch a humor video and sat in quiescence.

OUTCOME MEASURES

A standardized, neuropsychological, memory-assessment tool, the Rey Auditory Verbal Learning Test (RAVLT), was used to assess the following abilities: (1) learning, (2) recall, and (3) visual recognition. The testing occurred twice, once before (RAVLT1) and once after (RAVLT2) the humorous video for the humor and diabetic groups, and once before (RAVLT1) and once after (RAVLT2) the period of quiescence for the control group. At 5 time points, measurements of salivary cortisol were also obtained. The Kruskal-Wallis test was used to measure significance of the data based on the 3 groups.

RESULTS

In the humor, diabetic, and control groups, (1) learning ability improved by 38.5%, 33.4%, and 24.0%, respectively (P = .025); (2) delayed recall improved by 43.6%, 48.1%, and 20.3%, respectively (P = .064); and (3) visual recognition increased by 12.6%, 16.7%, and 8.3%, respectively (P = .321). For levels of salivary cortisol, the research team found significant and borderline decreases for the humor group between baseline and (1) post-RAVLT1 (P = .047), (2) postvideo (P = .046), and (3) post-RAVLT2 (P = .062). The diabetic group showed significant decreases between baseline and (1) post-RAVLT1 (P = .047), (2) postvideo (P = .025), and (3) post-RAVLT2 (P = .034). The study found no significant changes for the control group.

CONCLUSION

The research findings supported potential clinical and rehabilitative benefits for humor that can be applied to whole-person wellness programs for older adults. The cognitive components-learning ability and delayed recall-become more challenging as individuals age and are essential to older adults for providing a high quality of life: mind, body, and spirit. Because older adults can experience age-related memory deficits, complementary, enjoyable, and beneficial humor therapies should be implemented for them.

Humor as a reward mechanism: event-related potentials in the healthy and diseased brain

Humor processing involves distinct processing stages including incongruity detection, emotional response, and engagement of mesolimbic reward regions. Dysfunctional reward processing and clinical symptoms in response to humor have been previously described in both hypocretin deficient narcolepsy-cataplexy (NC) and in idiopathic Parkinson disease (PD). For NC patients, humor is the strongest trigger for cataplexy, a transient loss of muscle tone, whereas dopamine-deficient PD-patients show blunted emotional responses to humor. To better understand the role of reward system and the various contributions of hypocretinergic and dopaminergic mechanisms to different stages of humor processing we examined the electrophysiological response to humorous and neutral pictures when given as reward feedback in PD, NC and healthy controls. Humor compared to neutral feedback demonstrated modulation of early ERP amplitudes likely corresponding to visual processing stages, with no group differences. At 270 ms post-feedback, conditions showed topographical and amplitudinal differences for frontal and left posterior electrodes, in that humor feedback was absent in PD patients but increased in NC patients. We suggest that this effect relates to a relatively early affective response, reminiscent of increased amygdala response reported in NC patients. Later ERP differences, corresponding to the late positive potential, revealed a lack of sustained activation in PD, likely due to altered dopamine regulation in reward structures in these patients. This research provides new insights into the temporal dynamics and underlying mechanisms of humor detection and appreciation in health and disease.

The effect of humor on short-term memory in older adults: a new component for whole-person wellness

CONTEXT

For older adults, the damaging effects of aging and stress can impair the ability to learn and sustain memory. Humor, with its associated mirthful laughter, can reduce stress and cortisol, a stress hormone. Chronic release of cortisol can damage hippocampus neurons, leading to impairment of learning and memory.

OBJECTIVES

The primary goal of this study was to determine whether watching a humorous video had an effect on short-term memory in an older population.

DESIGN

The research team designed a randomized, controlled trial.

SETTING

The study took place at Loma Linda University in Loma Linda, California.

PARTICIPANTS

The research team recruited 20 normal, healthy, older adults, 11 males and 9 females.

INTERVENTION

The humor group (n = 10, mean = 69.3 ± 3.7 y) self-selected 1 of 2 humorous videos--a Red Skelton comedy or a montage of America's Funniest Home Videos--and watched it for 20 min. A control group (n = 10, mean = 68.7 ± 5.5 y) sat calmly for 20 min and were not allowed to read, sleep, or talk on a cell phone.

OUTCOME MEASURES

The Rey Auditory Verbal Learning Test was used to assess short-term memory--learning ability, delayed recall, and visual recognition. Salivary cortisol levels were measured at predetermined times.

RESULTS

Learning ability improved by 38.5% and 24.0% in the humor and control groups, respectively (P = .014). Delayed recall improved by 43.6% and 20.3% in the humor and control groups, respectively (P =.029). Within the humor group, delayed recall (43.6%) was significant compared with learning ability (38.5%) (P = .002). At 3 predetermined time points, significant decreases in salivary cortisol were observed in the humor group (P = .047, P = .046, and P = .062, respectively).

CONCLUSION

The study's findings suggest that humor can have clinical benefits and rehabilitative implications and can be implemented in programs that support whole-person wellness for older adults. Learning ability and delayed recall are important to these individuals for a better quality of life--considering mind, body, spirit, social, and economic aspects. Older adults may have age-associated memory deficiencies. However, medical practitioners now can offer positive, enjoyable, and beneficial humor therapies to improve these deficiencies.

Laughter and MIRTH (Methodical Investigation of Risibility, Therapeutic and Harmful): narrative synthesis

OBJECTIVE

To review the beneficial and harmful effects of laughter.

DESIGN

Narrative synthesis.

DATA SOURCES AND REVIEW METHODS

We searched Medline (1946 to June 2013) and Embase (1974 to June 2013) for reports of benefits or harms from laughter in humans, and counted the number of papers in each category.

RESULTS

Benefits of laughter include reduced anger, anxiety, depression, and stress; reduced tension (psychological and cardiovascular); increased pain threshold; reduced risk of myocardial infarction (presumably requiring hearty laughter); improved lung function; increased energy expenditure; and reduced blood glucose concentration. However, laughter is no joke-dangers include syncope, cardiac and oesophageal rupture, and protrusion of abdominal hernias (from side splitting laughter or laughing fit to burst), asthma attacks, interlobular emphysema, cataplexy, headaches, jaw dislocation, and stress incontinence (from laughing like a drain). Infectious laughter can disseminate real infection, which is potentially preventable by laughing up your sleeve. As a side effect of our search for side effects, we also list pathological causes of laughter, among them epilepsy (gelastic seizures), cerebral tumours, Angelman's syndrome, strokes, multiple sclerosis, and amyotrophic lateral sclerosis or motor neuron disease.

CONCLUSIONS

Laughter is not purely beneficial. The harms it can cause are immediate and dose related, the risks being highest for Homeric (uncontrollable) laughter. The benefit-harm balance is probably favourable. It remains to be seen whether sick jokes make you ill or jokes in bad taste cause dysgeusia, and whether our views on comedians stand up to further scrutiny.

Laugh yourself to sleep: memory consolidation for humorous information

There is extensive evidence that emotional information is better remembered than neutral information across long delays, especially if the delay interval contains an opportunity for sleep. However, as prior studies have focused on memory for negative stimuli, it is unclear whether positive memories benefit from time and sleep as well. To investigate the consolidation of positive memories, the current study examined differences in memory for humorous and non-humorous cartoons. While prior evidence demonstrates that humorous information is preferentially remembered relative to non-humorous information over brief delays, it is unknown whether this benefit lasts across longer delay intervals or whether sleep is important for lasting humor memories to form. Thus, we tested memory for 27 cartoons across 12-h delay periods containing either sleep or wakefulness. Results indicate that humor's enhancing effect on recall memory is robust across a 12-h delay and that a period of sleep facilitates this effect over wakefulness when cartoons are novel to participants and ranked based on subjective emotional ratings. Further, in accordance with previous studies that reveal diminished emotional reactivity to stimuli following sleep, in a supplemental experiment, we found that sleep reduced subjective ratings of humor, arousal, and positivity of humorous cartoons. These findings provide preliminary evidence that sleep's impact on negative emotional memory consolidation and emotional reactivity can be extended to positive stimuli as well.

Decoding humor experiences from brain activity of people viewing comedy movies

Humans naturally have a sense of humor. Experiencing humor not only encourages social interactions, but also produces positive physiological effects on the human body, such as lowering blood pressure. Recent neuro-imaging studies have shown evidence for distinct mental state changes at work in people experiencing humor. However, the temporal characteristics of these changes remain elusive. In this paper, we objectively measured humor-related mental states from single-trial functional magnetic resonance imaging (fMRI) data obtained while subjects viewed comedy TV programs. Measured fMRI data were labeled on the basis of the lag before or after the viewer’s perception of humor (humor onset) determined by the viewer-reported humor experiences during the fMRI scans. We trained multiple binary classifiers, or decoders, to distinguish between fMRI data obtained at each lag from ones obtained during a neutral state in which subjects were not experiencing humor. As a result, in the right dorsolateral prefrontal cortex and the right temporal area, the decoders showed significant classification accuracies even at two seconds ahead of the humor onsets. Furthermore, given a time series of fMRI data obtained during movie viewing, we found that the decoders with significant performance were also able to predict the upcoming humor events on a volume-by-volume basis. Taking into account the hemodynamic delay, our results suggest that the upcoming humor events are encoded in specific brain areas up to about five seconds before the awareness of experiencing humor. Our results provide evidence that there exists a mental state lasting for a few seconds before actual humor perception, as if a viewer is expecting the future humorous events.

Psychological, immunological and physiological effects of a Laughing Qigong Program (LQP) on adolescents

OBJECTIVES

One objective of this study was to assess the effects of laughter on the psychological, immunological and physiological systems of the body. Another objective was to introduce the Laughing Qigong Program (LQP), as a method of standardization for simulated laughter interventions.

DESIGN

A randomized, prospective, experimental study of the LQP was conducted in a group of adolescents (n=67) in Taiwan. During study-hall sessions, experimental subjects (n=34) attended the LQP for eight-weeks. Simultaneously, control subjects (n=33) read or did their homework. All subjects were tested before and after the intervention on the following: Rosenberg Self-Esteem scale (RSE), Chinese Humor Scale (CHS) and Face Scale (FS) as psychological markers; saliva cortisol (CS) as an immunological marker; blood pressure (BP), heart rate (HR), and heart rate variability (HRV) as physiological markers of the body's response to stress. Mood states (FS) were measured before/after each LQP session.

RESULTS

Mood states (p=.00) and humor (p=.004; p=.003) improved in the experimental group; no significant changes were found in the controls (p=69; p=60). The immunological marker of stress, cortisol levels, decreased significantly for those who participated in the LQP (p=.001), suggesting lower levels of stress after completion of the program.

CONCLUSIONS

The LQP is a non-pharmacological and cost-effective means to help adolescents mitigate stresses in their everyday life.

Different types of laughter modulate connectivity within distinct parts of the laughter perception network

Laughter is an ancient signal of social communication among humans and non-human primates. Laughter types with complex social functions (e.g., taunt and joy) presumably evolved from the unequivocal and reflex-like social bonding signal of tickling laughter already present in non-human primates. Here, we investigated the modulations of cerebral connectivity associated with different laughter types as well as the effects of attention shifts between implicit and explicit processing of social information conveyed by laughter using functional magnetic resonance imaging (fMRI). Complex social laughter types and tickling laughter were found to modulate connectivity in two distinguishable but partially overlapping parts of the laughter perception network irrespective of task instructions. Connectivity changes, presumably related to the higher acoustic complexity of tickling laughter, occurred between areas in the prefrontal cortex and the auditory association cortex, potentially reflecting higher demands on acoustic analysis associated with increased information load on auditory attention, working memory, evaluation and response selection processes. In contrast, the higher degree of socio-relational information in complex social laughter types was linked to increases of connectivity between auditory association cortices, the right dorsolateral prefrontal cortex and brain areas associated with mentalizing as well as areas in the visual associative cortex. These modulations might reflect automatic analysis of acoustic features, attention direction to informative aspects of the laughter signal and the retention of those in working memory during evaluation processes. These processes may be associated with visual imagery supporting the formation of inferences on the intentions of our social counterparts. Here, the right dorsolateral precentral cortex appears as a network node potentially linking the functions of auditory and visual associative sensory cortices with those of the mentalizing-associated anterior mediofrontal cortex during the decoding of social information in laughter.

Laughing rats are optimistic

Emotions can bias human decisions- for example depressed or anxious people tend to make pessimistic judgements while those in positive affective states are often more optimistic. Several studies have reported that affect contingent judgement biases can also be produced in animals. The animals, however, cannot self-report; therefore, the valence of their emotions, to date, could only be assumed. Here we present the results of an experiment where the affect-contingent judgement bias has been produced by objectively measured positive emotions. We trained rats in operant Skinner boxes to press one lever in response to one tone to receive a food reward and to press another lever in response to a different tone to avoid punishment by electric foot shock. After attaining a stable level of discrimination performance, the animals were subjected to either handling or playful, experimenter-administered manual stimulation – tickling. This procedure has been confirmed to induce a positive affective state in rats, and the 50-kHz ultrasonic vocalisations (rat laughter) emitted by animals in response to tickling have been postulated to index positive emotions akin to human joy. During the tickling and handling sessions, the numbers of emitted high-frequency 50-kHz calls were scored. Immediately after tickling or handling, the animals were tested for their responses to a tone of intermediate frequency, and the pattern of their responses to this ambiguous cue was taken as an indicator of the animals' optimism. Our findings indicate that tickling induced positive emotions which are directly indexed in rats by laughter, can make animals more optimistic. We demonstrate for the first time a link between the directly measured positive affective state and decision making under uncertainty in an animal model. We also introduce innovative tandem-approach for studying emotional-cognitive interplay in animals, which may be of great value for understanding the emotional-cognitive changes associated with mood disorders.

Hypochondria as withdrawal and comedy as cure in Dr. Willibald's Der Hypochondrist (1824)

Balthasar von Ammann's comedy Der Hypochondrist, published in 1824 under the pseudonym Dr. Willibald, foregrounds the social, sexual, and political implications of hypochondria. The play engages with early nineteenth-century medical and popular conceptions of hypochondria to co-opt potentially subversive elements and to promote a specific social, sexual, and political agenda. The text promotes literature — specifically comedic drama — as a cure for hypochondria. Hypochondria functions as a code for withdrawal. The hypochondriac withdraws medically from healthy society, gaining exceptional status. He withdraws sexually from society by remaining a bachelor, possibly engaged in non-normative sexual behaviour. Furthermore, the politically disenfranchised protagonist voices his political frustrations via a coded medical metaphor. The hypochondriac poses a threefold challenge to the social, sexual, and political order, and the play engages with contemporary conceptions of the disease to provide the solution: comedy. The text, presented as a cure for hypochondria, replaces the coded questioning of the social order via hypochondria with the less threatening code of heraldry. A comedy-within-the-comedy uses the hypochondriac's love of heraldry to cure him, resulting in the elimination of his medical problems and exceptional status, in the purification of his bachelorhood from non-normative elements, and in the pre-emption of political frustrations.

[Neurology of laughter and humour: pathological laughing and crying]

INTRODUCTION

Laughter, which is usually a healthy biological phenomenon, may be also a symptom of several severe brain pathologies.

AIM

To review the neurobiological bases of laughter and humour, as well as those of pathological laughing and crying syndrome.

DEVELOPMENT

At the mesencephalic-pontine junction there is a central coordinator of the nuclei that innervate the muscles involved in laughter (facial expression, respiratory and phonatory). This centre receives connections from three systems: inhibitory (pre-motor and motor cortex), excitatory (temporal cortex, amygdala, hypothalamus) and modulator (cerebellum). Humour is a complex phenomenon with a range of components: the perception of the unexpected incongruence (occipitotemporal area, prefrontal cortex), emotional (reward circuit) and volitional (temporal and frontal cortex). Functional magnetic resonance imaging studies do not reveal a markedly prominent role of the right frontal lobe in processing humour, as had been suggested in the classical studies. The causes of pathological laughing and crying syndrome can be classified in two groups: altered behaviour with unmotivated happiness (Angelman syndrome, schizophrenia, manias, dementia) and interference with the inhibitory/excitatory mechanisms (gelastic epilepsy, fou rire prodromique in strokes, multiple sclerosis, amyotrophic lateral sclerosis, Parkinson's disease and Parkinson-plus, traumatic injuries, tumours). Serotonin and noradrenalin reuptake inhibitors, levodopa, lamotrigine and the association of dextromethorphan/quinidine can be effective in certain cases of pathological laughing and crying.

CONCLUSIONS

As human neurobiological phenomena, laughter and humour also belong to the field of clinical neurology; their processing is affected in a number of different diseases and, in certain cases, effective treatment can be established.

[The Pilgaard-Dahl syndrome: laughter-induced pneumothorax]

In this article we propose the eponym Pilgaard-Dahl syndrome (named after two Danish revue actors). The syndrome consists of laughter-induced pneumothorax in smoking middle-aged men when exposed to hearty humour. The epidemiology and pathophysiology of spontaneous pneumothorax - in particular the Pilgaard-Dahl syndrome - is described. Finally, the occurrence of other detrimental effects of laughter as syncope, extreme bradycardia, asthma bouts, headache, stroke, death, and incontinence are described, as well as initiatives expected to minimise the occurrence of good mood are proposed.

The therapeutic value of laughter in medicine

OBJECTIVE

The aim of this review is to identify, critically evaluate, and summarize the laughter literature across a number of fields related to medicine and health care to assess to what extent laughter health-related benefits are currently supported by empirical evidence.

DATA SOURCES AND STUDY SELECTION

A comprehensive laughter literature search was performed. A thorough search of the gray literature was also undertaken. A list of inclusion and exclusion criteria was identified.

DATA EXTRACTION

It was necessary to distinguish between humor and laughter to assess health-related outcomes elicited by laughter only.

DATA SYNTHESIS

Thematic analysis was applied to summarize laughter health-related outcomes, relationships, and general robustness.

CONCLUSIONS

Laughter has shown physiological, psychological, social, spiritual, and quality-of-life benefits. Adverse effects are very limited, and laughter is practically lacking in contraindications. Therapeutic efficacy of laughter is mainly derived from spontaneous laughter (triggered by external stimuli or positive emotions) and self-induced laughter (triggered by oneself at will), both occurring with or without humor. The brain is not able to distinguish between these types; therefore, it is assumed that similar benefits may be achieved with one or the other. Although there is not enough data to demonstrate that laughter is an all-around healing agent, this review concludes that there exists sufficient evidence to suggest that laughter has some positive, quantifiable effects on certain aspects of health. In this era of evidence-based medicine, it would be appropriate for laughter to be used as a complementary/alternative medicine in the prevention and treatment of illnesses, although further well-designed research is warranted.

Laughter and humor as complementary and alternative medicines for dementia patients

BACKGROUND

The number of dementia patients has increased worldwide, with an estimated 13.7 million dementia patients in the Asia Pacific region alone. This number is expected to increase to 64.6 million by the year 2050.

DISCUSSION

As a result of advances in research, there several pharmacological therapies available for the treatment of dementia patients. However, current treatments do not suppress the disease process and cannot prevent dementia, and it will be some time before these goals are realized. In the meantime, complementary and alternative medicine (CAM) is an important aspect in the treatment of dementia patients to improve their quality of life throughout the long course of the disease. Considering the individuality of dementia patients, applicability of laughter and humor therapy is discussed. Even though there are many things that need to be elucidated regarding the mechanisms underlying the beneficial effects of laughter and humor, both may be good CAM for dementia patients if they are applied carefully and properly.

SUMMARY

In this debate article, the physiological basis and actual application of laughter and humor in the treatment of dementia patients are presented for discussion on the applicability to dementia patients.