From a behavior analytic viewpoint, the human smile is considered to be a conditioned reinforcer because it`s correlated with unconditioned reinforcers like feeding and fondling. However, it`s possible that some aspects of this kind of social stimuli may function as unconditioned reinforcers. Both naturalistic and arbitrary facial expressions have been established as discriminative stimuli for responding or not responding in so called social referencing episodes. The skills might have resulted from the prompt procedures used. A question that still remains to be answered is: How early is it possible to demonstrate with operant methods that the smile has reinforcing functions for infants` behavior? Knowledge about this is considered to be important if, next it is possible to identify the lack of reinforcing function of others`smile. The absence of looking at faces and guidance of behavior by different facial expressions are known as some of the core symptoms in children with autism. The face is an example of a stimulus class that acts dynamically and fluently in natural situations. Conjugate reinforcement may catch some aspects of this dynamic. Here, the first paper is addressing some of the important studies conducted previously on the topic. The second paper reports two experiments with use of conjugate reinforcement: Kicking responses of infants, 2 to 12 months of age, changed the degree of smiling in pictures of their mothers, presented on a monitor, contingent on either amplitude or interresponse times. No result can be used to conclude either way, but the study may raise some ideas for future experiments.

Master i læring i komplekse systemer