Primates rely strongly on vision and touch to perceive and identify objects in the environment. Thus, visuo-tactile interaction is a crucial ability for survival, but to what extent it promotes object recognition still remains to be clarified. Previous evidence indicates that nonhuman primates use the sense of touch to support vision during foraging and that their perceptual and/or attentional processes in the visual modality are influenced by tactile information. We tested capuchin monkeys (n = 14, Sapajus spp.), highly manipulative New World primates, with a recognition memory task aimed at assessing whether haptic cues enhanced the following visual discrimination of objects. The stimulus set included 12 different rotatable objects, six of which contained food rewards. In the preliminary Exploration phase, capuchins manipulated the objects one at a time to identify which of them contained a reward. Half of the objects were explored in the Sight & Touch condition that allowed the acquisition of both visual and haptic cues during manipulation; the other half were explored in the Sight condition, which prevented the acquisition of haptic cues about the objects. In the following Recognition phase, the objects previously explored individually were presented as pairs, and capuchins had to visually identify the rewarded object within each pair. Objects within a pair differed in size, shape or surface structure. We found that when capuchins had the chance to acquire both visual and haptic cues, they recognised the rewarded objects in significantly fewer trials than when the acquisition of haptic cues was prevented. Overall, our findings demonstrate that gaining haptic cues can affect visual memory for valuable and non-valuable objects, which is a fundamental faculty in primate ecology and evolution. We also evaluated hand movements for manipulating objects and compared these with data from humans.
Touch Supports Visual Recognition of Objects in Capuchin Monkeys (Sapajus spp.)
Truppa Valentina
2020
Abstract
Primates rely strongly on vision and touch to perceive and identify objects in the environment. Thus, visuo-tactile interaction is a crucial ability for survival, but to what extent it promotes object recognition still remains to be clarified. Previous evidence indicates that nonhuman primates use the sense of touch to support vision during foraging and that their perceptual and/or attentional processes in the visual modality are influenced by tactile information. We tested capuchin monkeys (n = 14, Sapajus spp.), highly manipulative New World primates, with a recognition memory task aimed at assessing whether haptic cues enhanced the following visual discrimination of objects. The stimulus set included 12 different rotatable objects, six of which contained food rewards. In the preliminary Exploration phase, capuchins manipulated the objects one at a time to identify which of them contained a reward. Half of the objects were explored in the Sight & Touch condition that allowed the acquisition of both visual and haptic cues during manipulation; the other half were explored in the Sight condition, which prevented the acquisition of haptic cues about the objects. In the following Recognition phase, the objects previously explored individually were presented as pairs, and capuchins had to visually identify the rewarded object within each pair. Objects within a pair differed in size, shape or surface structure. We found that when capuchins had the chance to acquire both visual and haptic cues, they recognised the rewarded objects in significantly fewer trials than when the acquisition of haptic cues was prevented. Overall, our findings demonstrate that gaining haptic cues can affect visual memory for valuable and non-valuable objects, which is a fundamental faculty in primate ecology and evolution. We also evaluated hand movements for manipulating objects and compared these with data from humans.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
