In humans an emotion experience generally involves a set of cognition, attitudes and beliefs about the world, which we use to assess a specific situation and, therefore, influence the way in which this situation is perceived. Each individual experiencing an emotion in a particular way, depending on your previous experiences, learning, character and situation specific. Some of the physiological reactions and behavioral that trigger emotions are innate, while others can be purchased. Charles Darwin noted as animals (particularly in the primates) had an extensive repertoire of emotions, and this way to express those emotions had a social function, because they collaborated in the survival of the species. Therefore, have an Adaptive function. There is no doubt, that for a long time emotions have been considered little important and have always been more relevant to the more rational part of the human being. But the emotions, to be affective States, indicate personal internal States, motivations, desires, needs and even objectives. Anyway, it is difficult to know from the emotion which will be the future of individual conduct, although it may help us to Intuit it.
Indicated us further, that emotions have a few components particular behavioral, that are the way they are displayed externally. Are to some extent controllable, based on family and cultural learning in each group: facial expressions. Actions and gestures. Distance between people. Non-linguistic components of verbal expression (non-verbal communication). Other components of emotions are physiological and involuntary, equal for all: tremor blushing sweating breathing dilation pupillary increased heart rate these components that are at the basis of polygraph or detector of lies. It is assumed that when a person is lying it feels or it cannot control their physiological changes, but there are people that yes could control it with training. On the other hand, it gives us that Wikipedia, emotions are phenomena psychophysiologic representing modes of adaptation to certain environmental stimuli or yourself.