抄録
Humans often activate a mental representation of a number line when performing quantitative tasks. This is illustrated in the spatial numerical association of response codes (SNARC) paradigm in which people report whether a sample number is odd or even. Humans respond more quickly on the left when the number is small and on the right when the number is large. This indicates that responding is facilitated when the response is congruent with the mental number line even though no explicit magnitude processing is required. The capacity to represent space is fundamental and available to many species. To determine whether spatial representations are involved in quantity processing across species, we tested for SNARC phenomena in monkeys. Monkeys matched the color of a sample array that ranged from 1 and 10 dots to color comparison stimuli on the bottom left and right sides of the screen. After being trained to associate small with left responses and large with right responses, monkeys were more accurate in color matching when responding on the left after seeing a small numerosity sample. This effect reversed after monkeys were trained in the opposite spatial association. These results are consistent with a spatial representation of magnitude in monkeys.
