Reactions to response-contingent stimulation in early infancy.

When a stimulus consistently follows an individual's reponse, the situation is set for instrumental learning. If the stimulus is rewarding and the individual is capable of learning, the response should become more frequent. Thus, the traditional learning analysis would ask whether the response is affected by the situation (e.g., does the re sponse become more frequent, stronger, etc.). In this paper, we shall ask this standard learning question in an analysis of the effectiveness of a special learning situation which was arranged for young infants. As a consequence of an unexpected reaction to this learning situation, however, we shall also consider the question of whether for the hu man infant the response-contingent stimulus is affected by its occur rence in early instrumental learning situations. In the concluding portion of this paper we will propose that the stimulus very likely is affected in that it appears to acquire the functional meaning of a "social stimulus" for the human infant. The data we will discuss are from a short-term longitudinal study conducted at the Institute of Human Development. The study involved presenting two weeks of a special contingency experience to infants between their eighth and tenth weeks of life. Some previous research suggested that the human infant, under natural conditions, might be undergoing a deprivation of opportunity to engage in and adapt to contingency experiences. The combination of his short memory and the long recovery periods of his naturally effective motor responses could prohibit his becoming aware of otherwise manageable contin gencies in his world. Prohibiting the exercise of the available capacity for processing contingency information could deprive the infant of a formative intellective experience. It has been hypothesized that this "natural deprivation period" might exist for much of the first three months of life (Watson, 1966a, 1967).