Abstract

FERREIRA ARZA, Yolanda  and  WALKER M., J. Daniel. EFFECTS OF INCREASED FIXED RATIO MAGNITUDES ON CONTRAFREELOADING IN LABORATORY MICE. Ajayu [online]. 2009, vol.7, n.2, pp.22-44. ISSN 2077-2161.

In an ever changing environment, animals must adapt their behavior so as to reduce uncertainty, including foraging tendencies. The Information Primacy Model considers animal foraging and exploration as a way to gather not only food but also environmental information. This model explains a behavior called Contrafreeloading (CFL). CFL occurs when animals emit an operant response to obtain a positive reinforcer, while the same reward exists freely and unrestricted. CFL levels have been reported to be inversely related to effort required in an operant task. To study CFL, an experiment was conducted with laboratory mice (mus musculus) as test subjects, where five fixed ratio magnitudes represented different degrees of effort. Results support previous studies that CFL diminishes whilst effort increases. Three of the four test subjects presented a significant decline in responding in FR2 from FR1 (continual reinforcement), a gradual decline from FR2 through FR4, and an eventual absence of responding in FR5. Simultaneously, feeding from the free food source was positively related to effort increase. Additional results indicate a positive correlative tendency between effort and the commencement of the CFL behavior, suggesting the necessity for future research to determine similar tendencies.

Keywords : foraging; contrafreeloading; mice; effort.

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