Primacy and recency effects in rhesus monkeys (Macaca mulatta) using a serial probe recognition task. III. A developmental analysis.

Abstract

In children, the recency effect emerges prior to the primacy effect. To determine whether this dissociation is also seen in nonhuman primates, we evaluated the development of the primacy and recency effect in 3 young adult (35 months) and 4 adolescent (21 months) male rhesus monkeys (Macaca mulatta) using a six-item serial probe recognition (SPR) task. As predicted, the young adult monkeys displayed both effects, while the adolescent monkeys only displayed the recency effect. Not until after 26 months of training on the SPR task did the adolescent monkeys exhibit both the primacy and recency effect. Interference and strategy differences are discussed in terms of the results along with an interpretation of Rudy's (1992) configural association theory of cognitive development. Additional possible explanations for this developmental dissociation include the delayed maturation of the neocortical, hippocampal, and/or cholinergic systems, the latter two having been shown to be important in the expression of the primacy but not the recency effect.