Conducts human and animal studies on tolerance, dependence, craving and drug-taking behavior, looking at the contribution of learning and cognition to addictive disorders. Recent studies have looked at learning and biological factors in the development of drug tolerance. Is investigating the measurement of drug craving and examining the role of craving in addiction. Has appeared on national TV and radio. Current projects include the study of expectancies and the anticipation of future behavior in animals, and how animals form concepts despite the absence of language.
Current studies relate to children's reactions to caregiver turnover in day- care settings.
Has published three books and more than 50 research papers in these areas. Specific studies include the role of individual differences such as sex and temperament in mediating the impact of the environment on individuals, and measuring the impact of early temperament influences. Has conducted extensive research on natural nerve cells and their relation to perception. Has applied this knowledge to the design of artificial nervous systems for the treatment of nerve deafness and neural networks. Recent experiments have studied color vision, backward visual masking, visual persistence, light adaptation and brightness coding.