As the only comparative psychology graduate student at Clark University, Massachusetts, I was surrounded by graduate students studying human development assured in their belief that humans were distinctly different psychologically from other animals. When imaginative pretense was brought up as one of many “uniquely human” capacities (including language, intentional deception, imitation, and self-recognition), I mentioned the chimpanzee Viki's imaginary pulltoy (Hayes, 1951), to the general response that it was only one example compared to the myriad instances exhibited by children. The intellectually stimulating debates that followed my frequent disagreements led to this book, and fueled my desire to publish three other books, which I initiated prior to this one – Deception: perspectives on human and nonhuman deceit (Mitchell & Thompson, 1986), Self-awareness in animals and humans (Parker, Mitchell & Boccia, 1994), and Anthropomorphism, anecdotes, and animals (Mitchell, Thompson & Miles, 1997). I hope the skills I learned from my talented co-editors – all ardent educators – are evident in my first run as solo editor.

While I was at Clark, Ina Užgiris introduced me to Paul Guillaume's (1926/1971) Imitation in children in her course on “Imitation, internalization, and identification,” and to Piaget's (1947/1972) Psychology of intelligence in her course on “Piaget's theory.” Reading Guillaume and Piaget was a gift, but reading them with Ina's guidance was an extraordinary gift, for which I am grateful.