AbstractEIBL-EIBESFELDT (1961) and THORPE (1963) have suggested that nest-building in various species is reinforced by stimuli associated with the acquisition of a finished nest. HINDE & STEVENSON (1969, 1970) have proposed, by contrast, that individual nest building activities may persist and act as reinforcers regardless of whether or not they lead to nest formation. Evidence for these views is discussed. Five experiments designed to test HINDE and STEVENSON'S view arc described. In Experiments I and 2, naive female mice were given access to hoppers of paper strips for 14 days. Carrying of strips into the nest box declined rapidly to zero as the nests reached completion, but gathering of strips from the hoppers continued at the original level. It is concluded that carrying and subsequent events associated with nest acquisition are not necessary for the initiation and maintenance of gathering. In Experiments 3 and 4, access to paper strips was made contingent upon performance of an arbitrary operant (key pressing). The majority of subjects continued to key press and gather paper after the cessation of carrying, but at a reduced level. Furthermore, key pressing to gather only occurred if the operant-reinforcer distance was very small. It is concluded that gathering per se is less reinforcing than gathering plus carrying and building. In Experiment 5, amount of gathering per reinforcement was varied by using different widths of paper. Number of reinforcements per session was positively related to paper width, providing further evidence that gathering is reinforcing. It is concluded that gathering is at least to some extent autonomously controlled, and that it is a weak positive reinforcer. However the results also suggest that other reinforcing events are present at a later stage in the nest building sequence. Some theories concerning the causation of selfsustaining activities, and their implications for unitary drive theories, are discussed.
Inadvertent Reinforcement in Oral Myofunctional Therapy