Premium
PIGEONS' CHOICES BETWEEN FIXED‐RATIO AND GEOMETRICALLY ESCALATING SCHEDULES
Author(s) -
Neuman Paul,
Ahearn William H.,
Hineline Philip N.
Publication year - 1997
Publication title -
journal of the experimental analysis of behavior
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.75
H-Index - 61
eISSN - 1938-3711
pISSN - 0022-5002
DOI - 10.1901/jeab.1997.68-357
Subject(s) - reinforcement , schedule , generality , computation , arithmetic , statistics , psychology , series (stratigraphy) , mathematics , computer science , social psychology , algorithm , paleontology , psychotherapist , biology , operating system
When pigeons choose between situations that provide access to food reinforcers after a delay, choice is better predicted by computations based upon sums‐of‐reciprocals distances from the point of choice to each of the next three or four reinforcers in series than by computations of optimality based upon mean rates of reinforcement. The present experiments were designed to examine the generality of this finding. Pigeons were exposed to concurrent‐chains schedules in which one brief initial link led to a fixed‐ratio schedule (either 15, 30, or 60, depending on the condition), and the other link led to a geometrically increasing progressive‐ratio schedule whose rate of escalation was systematically varied across conditions. Each combination of fixed‐ratio size and escalation rate of the progressive schedule was assessed at two different levels of deprivation (75% and 80% of free‐feeding weights). Computations based upon the sums‐of‐reciprocals principle, treating ratio schedule sizes as proportional to delays, predicted and described the pigeons' median switch points better than those based on arithmetic means. Neither the distance to the next reinforcer (as implied by some molecular analyses) nor molar optimization (as described by arithmetic means) were as successful at accounting for patterns of choice in these situations. Hence, it appears that the birds' choices were most influenced by the relative proximity of a choice to several reinforcers in a series of reinforcers, with each of the less proximal reinforcers having relatively less influence over the current choice.