The Expression of the Emotions in Man and Animals Robert Grant's Lamarckist philosophy) ridiculed Bell's theological explanations, pointing instead to the striking similarities of human and animal biology. The meeting then ended in uproar. Forty-five years later, Darwin revisits these arguments and recruits Duchenne's (1862) unmasking of the facial mechanisms, shifting the argument from philosophical speculation to scientific discourse. Darwin's response to Bell's natural theology is discussed by Lucy Hartley (2001). In the composition of the book, Darwin drew on worldwide responses to his questionnaire (circulated in the early months of 1867) concerning emotional expression in different ethnic groups; on anthropological memories from his time on ; on conversations
Emotion in animals could be used to include all the animal kingdom as well as some plants. The second approach, mechanistic, requires an examination of the mechanisms that drive emotions and search for similarities in animals. The mechanistic approach is utilized extensively by Paul, Harding and Mendl. Recognizing the difficulty in studying emotion in non-verbal animals, Paul et al. demonstrate possible ways to better examine this. Observing the mechanisms that function in human emotion expression, Paul et al. suggest that concentration on similar mechanisms in animals can provide clear insights into the animal experience. They noted that in humans, cognitive biases vary according