Yawning is often noted in medical seminars and conferences – be they surgical, orthopaedic, gastroenterological, endocrinological or neurological. Yet, this condition receives little coverage by professors in medical schools. On the contrary, most lecturers have an adverse reaction to it – when the overworked medical student opens his mouth to raise the topic, the fierce pathology lecturer dema...

Yawning and its involvement in neurological disorders has become the new scientific conundrum. Cortisol levels are known to rise during stress and fatigue; yawning may occur when we are under stress or tired. However, the link between yawning, fatigue, and cortisol has not been fully understood. Expansion of the Thompson Cortisol Hypothesis proposes that the stress hormone, cortisol, is respons...

The authors tested susceptibility to contagious yawning in 120 children, 1-6 years, to identify the time course of its emergence during development. Results indicated a substantial increase in the frequency of contagious yawning at 4 years. In a second study, the authors examined contagious yawning in 28 children with autism spectrum disorders (ASD), 6-15 years. Children with ASD showed diminis...

Contagious yawning may be a useful measure of social psychological functioning, and thus it is important to evaluate the variables influencing its expression in laboratory settings. Previous research has documented that humans yawn less frequently in crowded environments and when under direct observation, but the impact of social presence on contagious yawning remains unknown. Here we present t...

While yawning is an example of behavioral continuity within mammals, the contagion of yawning, that is yawning after seeing someone else yawning, is only present in humans. We proposed that contagion of yawning is only possible in species showing altogether empathy, TOM and imitation and other perspective-taking capabilities. Preston and de Waal claimed that the PA Model might help explaining a...

The ultimate function of yawning continues to be debated. Here, we examine physiological measurements taken before, during, and after yawns in humans, in an attempt to identify key proximate mechanisms associated with this behavior. In two separate studies we measured changes in heart rate, lung volume, eye closure, skin conductance, ear pulse, respiratory sinus arrhythmia, and respiratory rate...

Cortisol is essential to the regulation of the immune system and yawning is a pathological symptom of multiple sclerosis (MS). Electromyography activity (EMG) in the jaw muscles typically rises when the muscles are moved and with yawning is highly correlated with cortisol levels in healthy people. Saliva samples from 59 participants were collected at the start and after yawning, or at the end o...

Most previous studies suggest diminished susceptibility to contagious yawning in children with autism spectrum disorder (ASD). However, it could be driven by their atypical attention to the face. To test this hypothesis, children with ASD and typically developing (TD) children were shown yawning and control movies. To ensure participants' attention to the face, an eye tracker controlled the ons...

Cortisol is essential to the regulation of the immune system and pathological yawning is a symptom of multiple sclerosis (MS). Electromyography activity (EMG) in the jaw muscles typically rises when the muscles are moved – extended or flexed; and yawning has been shown to be highly correlated with cortisol levels in healthy people as shown in the Thompson Cortisol Hypothesis. It is likely that ...

Orexin-A is a neuropeptide which has been suggested to be involved in sleep and arousal mechanisms. Orexin-A, for example, stimulates arousal when administrated intracerebroventricularly to rats. We attempted to identify specific neural sites of orexin-A and orexin-B action. Orexin-A and orexin-B were microinjected into the medial parvocellular subdivision of the paraventricular nucleus (PVN) i...