Name: Public defence: Reut Peleg
Start: 2019-03-20
End: 2019-03-20

Thesis title: Response Variability: A dimension of operant behavior?

Trial lecture title: Behavioral variability: its importance in applied settings.

The ordinary opponents are:

First opponent: Professor Armando Machado, University of Minho, Portugal
Second opponent: Professor Thomas Higbee, Utah State University, USA
Leader of the Committee: Associate Professor Torunn Lian, OsloMet

The leader of the public defence is Head of Department Einar Strumse.

The main supervisor is Dr. Neil Martin, Behavior Analyst Certification Board. The co-supervisor is Dr. Per Holth, Institute of Behavior Science, OsloMet.

Thesis abstract

Response variability increases when reinforcement is contingent upon it, can be placed under stimulus control (e.g., Page & Neuringer, 1985), and matches reinforcement rates (e.g., Neuringer, 1992).

These three observations are the basis of what is termed operant variability, suggesting that variability may be directly reinforced.

However, the term operant variability seems to contradict the very definition of reinforcement as an event that follows behaviour and subsequently increases the likelihood of reoccurrence of those responses that preceded it.

Seeks to provide alternative explanations

The question that arises is how can a process that promotes repetition promote variability at the same time? This thesis seeks to provide alternative explanations for the increased variability observed under variability (lag) schedules and includes four studies.

Studies 1 and 2 draw on research in the field of response sequences and suggest that the resistance to change (RTC) of different response positions within a sequence is differentially affected by reinforcement and extinction, as well as by operant and respondent processes.

Study 3 includes an analysis of different procedural parameters that may contribute to the observed variability level. Study 4 compares different measurement procedures and includes a molecular analysis of the data obtained from two subjects responding on a lag reinforcement schedule.

Based on these four studies, it is concluded that a lag schedule of reinforcement organizes responses in an orderly fashion, and together with other variables such as procedural variations and the possible involvement of respondent processes, variability is likely induced.