Abstract
Ten monkeys were trained to choose between pairs of dot patterns or pairs of symbols using in-cage touchscreens. Four juvenile monkeys learned the symbols faster than six adults and achieved a higher facility for symbols, but not for dots. Adult and juvenile reaction times were similar for dots, but juveniles were faster than adults in choosing between symbols.
New symbols were introduced in ascending value order. The adults treated each new symbol as unknown in value and required hundreds of trials to realize its value, whereas the juveniles showed an iterative learning pattern, accurately valuing novel symbols within the first few trials.
Thus the juvenile monkeys learned symbols faster than the adults and achieved more facility with the symbols than the adults. This study extends into the cognitive domain numerous previous studies showing that the brains of young animals are more plastic than adult brains.