Selection of forced- and free-choice by monkeys (Macaca fascicularis)

Using a concurrent-chains procedure, the present study examined reference of monkeys between forced-choice and free-choice with multiple alternative es. The forced-choice was followed by the reinforcer will a probability of .8. The free-choice was between reinforcement alternatives of high probability (p=.8) and low probability (p=.5) in which the monkeys mostly chose the former. The number of keys with each kind of alternative iii the free-choice was manipulated under four conditions. Preference fur free-choice increased with the number of keys fur the preferred alternative. However, the number of keys for the less-preferred alternative had no influence on preference. Effects of the less-preferred alternative on preference were inconsistent with previous studies using pigeons.