title: The development of functional response units: the role of demarcating stimuli.
abstract: An experiment with rats examined the roles of demarcating stimuli and differential reinforcement probability on the development of functional response units. It examined the development of units in a probabilistic, free-operant situation in which the presence of demarcating stimuli was manipulated. In all conditions, behavior became organized into two-response sequences framed by changes in local reinforcement probability. A tone demarcating the beginning and end of contingent response sequences facilitated the development of functional response units, as in chunking, but the same units developed slowly in the absence of the tone. Complex functional response units developed even though reinforcement contigencies remained constant. These findings demonstrate that models of operant learning must include a mechanism for changing the response unit as a function of reinforcement history. Markov models may seem to be a natural technique for modeling response sequences because of their ability to predict individual responses as a function of reinforcement history; however, no class of Markov chain can incorporate changing response units in their predictions.
authors.affiliation: Department of Psychology, Wofford College, Spartanburg, South Carolina 29303-3663, USA. reidak@wofford.edu
authors.forename: A K
authors.initials: AK
authors.lastname: Reid
authors.forename: C Z
authors.initials: CZ
authors.lastname: Chadwick
authors.forename: M
authors.initials: M
authors.lastname: Dunham
authors.forename: A
authors.initials: A
authors.lastname: Miller
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D007858:Learning; D008390:Markov Chains; D051381:Rats; D012054:Reinforcement, Psychology; D013239:Stereotyped Behavior; D013997:Time Factors