Facial expression the social component of those like shame, pride, jealousy, envy, deference, etc.) and are recognized by people regardless of culture, language, or time. The belief in the evolutionary basis of these kinds of facial expressions can be traced back to Darwin's "The Expression of the Emotions in Man and Animals." Reviews of the universality hypothesis have been both supportive and critical. Work in 2013 by Nelson and Russell and Jack et al. has been especially critical. Ekman's work on facial expressions had its starting point in the work of psychologist Silvan Tomkins. Ekman showed that facial expressions of emotion are
Body language of dogs emotions, or communicating intentions. Understanding the body language of dogs can also aid in optimal obedience training, as observation of body language may reveal when the dog is most motivated and therefore provides a time-frame whereby dogs will learn more readily. In general, accurately assessing the body language of dogs is quite beneficial as it allows humans to react appropriately to emotions and intentions of the dog. Thus, it fosters successful companionship between the dog owner and pet. Alternatively, ignoring the body language of dogs can pose as a threat for not only humans, but for dogs too. Properly assessing