Comparison between positively and negatively reinforced variability and extinction effects

• Grant number: 24/22026-6
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: July 01, 2025
• End date: July 31, 2027
• Field of knowledge: Humanities - Psychology - Experimental Psychology
• Principal Investigator: Maria Helena Leite Hunziker
• Grantee: Sofia Azevêdo de Araújo Vaz Oliveira
• Host Institution: Instituto de Psicologia (IP). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The aim of the research is to compare, in humans, positively and negatively reinforced behavioral variability, as well as the effects of two different extinction procedures. The behavioral unit will consist of a sequence of four mouse-click responses between two operanda displayed on a computer screen. Variability will be characterized by differences among the 16 possible sequences. The same consequent stimulus (points) will be used in both positive reinforcement contingencies (addition) and negative reinforcement contingencies (subtraction). Sixty-four participants will be divided into eight groups (n=8), differing in terms of variation contingency (Lag 1r or Lag 6), reinforcement operation (positive or negative), and extinction procedure (by reinforcement suspension or noncontingent presentation). Each participant will undergo an experimental session consisting of 200 reinforcement trials and 100 extinction trials. In the low-demand groups, the Lag 1r contingency will be applied, while in the high-demand groups, the Lag 6 contingency will be used. Under positive reinforcement, sequences meeting the variability criterion will be reinforced with the addition of five points; under negative reinforcement, they will cancel the loss of five points. In extinction by reinforcement suspension, sequences will not be reinforced regardless of their variability. In extinction by noncontingent reinforcement, the reinforcement will be delivered with the same distribution as in the last 100 reinforcement trials. Intra-subject and intra-group performances will be compared under reinforcement and extinction conditions concerning the U-value, the relative frequency of each sequence, percentage of reinforcement, and operational response rate.