Human uses of mammals that "one is well advised to study the behaviour rather than attempting to get at any underlying emotion". Charles Darwin however had accepted the idea of emotion in animals, writing his 1872 book "The Expression of the Emotions in Man and Animals" on the subject. Darwin believed that mammals had social, mental and moral lives. In "The Descent of Man" (1871), he wrote: "There is no fundamental difference between man and the higher mammals in their mental faculties." Biologists remained wary of the idea, even for the great apes, but this led to serious difficulties, as Donald O. Hebb explained
Invasion of the Body Snatchers Invasion of the Body Snatchers Invasion of the Body Snatchers is a 1956 American science fiction horror film produced by Walter Wanger, directed by Don Siegel, that stars Kevin McCarthy and Dana Wynter. The black-and-white film, shot in Superscope, was partially done in a film noir style. Daniel Mainwaring adapted the screenplay from Jack Finney's 1954 science fiction novel "The Body Snatchers". The film was released by Allied Artists Pictures as a double feature with the British science fiction film "The Atomic Man" (and in some areas with "Indestructible Man".) The film's storyline concerns an extraterrestrial invasion that begins in