"All homeothermic animals including humans rigidly regulate their core body temperature through a variety of involuntary thermoregulatory responses, such as shivering and non-shivering thermogenesis, cutaneous vasomotor responses, sweating, piloerection and panting.
Of these, sympathetically (via sympathetic nervous system (SNS)) mediated changes in peripheral skin blood-flow (manifest as a change in peripheral temperature) are the most acutely sensitive to environmental temperature change.
However, changes in peripheral body temperature are additionally linked to changes in emotional state, e.g. hot, clammy hands in anxiety or facial flushing in embarrassment, and can be modulated by mental imagery, hypnotic suggestion and disruption of the sense of body ownership using the rubber hand illusion and illusory self-identification with an avatar.
Together these findings suggest sensitivity of peripheral body temperature to top-down cognitive processes and a complimentary role in social communication.
In addition to bottom-up feed-forward pathways triggered by changes in skin temperature, thermoregulatory responses are also sensitive to top-down influences for example though visual imagery, temperature biofeedback and hypnotic suggestion.”
" The Navajo (Diné) people have a specific tradition around celebrating a baby’s first laugh.
Around three months, they watch the baby closely for that first real giggle. The person who has the good fortune of eliciting that first laugh is then responsible for throwing a party, with the baby playing the role of host. As a baby can’t actually host a party, the relative or friend who coaxed out that first laugh hands out rock salt, candy, and gifts on the baby’s behalf.
The belief behind the tradition is that when a baby is born, she belongs to two worlds: the spirit world and the physical one. Perhaps it was because of the fragility of new life that infants were treated as still “between worlds” for those delicate first few months, until parents heard a sign of joy and wellbeing that reassured them their baby was healthy enough to survive. The first laugh is seen as a sign of the baby’s desire to leave the spirit world and join her earthly family and community."