The Expression of the Emotions in Man and Animals is discussed in detail by Lucille Ritvo.John Bowlby makes extensive reference to Darwin's ideas in his presentations of attachment theory. Constitutional (psychosomatic) theories of personality were elaborated by Paul Schilder (1886 - 1940) with his notion of the body image, by the psychiatrist Ernst Kretschmer and in the (now largely discredited) somato-typology of W H Sheldon (1898 - 1977). The biology of the human emotions was further explored by Desmond Morris in his (richly illustrated) popular scientific book "Manwatching".In 2003, the New York Academy of Sciences published "Emotions Inside Out: 130 Years after Darwin's The Expression of the Emotions in
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