goose bumps are caused by action of the
Goose bumps The formation of goose bumps in humans under stress is considered to be a vestigial reflex;[2] and its function in other apes is to raise the body's hair, and would have made our human ancestors appear larger to scare off predators or to increase the amount of air trapped in the fur to make it more insulating. The reflex of producing goose bumps is known as piloerection or the pilomotor reflex. It occurs in many mammals besides humans; a prominent example is porcupines, which raise their quills when threatened, or sea otters when they encounter sharks or other predators.
Laughter Laughter is a physical reaction in humans and some other species of primate, consisting typically of rhythmical, often audible contractions of the diaphragm and other parts of the respiratory system. It is a response to certain external or internal stimuli. Laughter can arise from such activities as being tickled,[1] or from humorous stories or thoughts.[2] Most commonly, it is considered a visual expression of a number of positive emotional states, such as joy, mirth, happiness, relief, etc. On some occasions, however, it may be caused by contrary emotional states such as embarrassment, apology, or confusion such as nervous laughter or courtesy laugh. Age, gender, education, language, and culture are all factors[3] as to whether a person will experience laughter in a given situation.