Emotion in animals specialised form of Occam's razor used in ethology, in which he stated: Charles Darwin initially planned to include a chapter on emotion in "The Descent of Man" but as his ideas progressed they expanded into a book, "The Expression of the Emotions in Man and Animals". Darwin proposed that emotions are adaptive and serve a communicative and motivational function, and he stated three principles that are useful in understanding emotional expression: First, "The Principle of Serviceable Habits" takes a Lamarckian stance by suggesting that emotional expressions that are useful will be passed on to the offspring. Second, "The Principle of
Body language develop a more personal rapport. Scholars have long debated on whether body language, particularly facial expressions, are universally understood. In Darwin’s (1872) evolutionary theory, he postulated that facial expressions of emotion are inherited. On the other hand, scholars have questioned if culture influences one’s bodily expression of emotions. Broadly, the theories can be categorized into two models: The cultural equivalence model predicts that "individuals should be equally accurate in understanding the emotions of ingroup and outgroup members" (Soto & Levenson, 2009). This model is rooted in Darwin’s (1872) evolutionary theory, where he noted that both humans and animals share similar