To Move or Not to Move: Development of Fine-Tuning of Object Motion in Haptic Exploration

Recognizing objects through touch is a complex task based on integrating information coming from multiple senses and motor commands guiding the exploratory motions. To gain insight into the development of exploratory strategies in children, in this study, we addressed the question: how does exploration change when the stimulus becomes freely movable rather than fixed? We tested whether the possibility to move the object ushers in a strategic advantage, reducing the time and the number of touches necessary. We analyzed how school-aged children explore iCube, which is a sensorized cube measuring its orientation in space and contacts location. We tasked participants with finding specific cube faces; they could only touch the static cube, move and touch it, or move, touch, and look at it. Visuo-haptic performances were adult-like at seven years of age, whereas haptic exploration was less effective until nine years. The fine-tuning of object movements as a function of task constraints, e.g., the availability of the vision or blind haptic task, increased significantly with age. Shedding light on how different factors shape haptic exploration could help researchers in the pursuit of detecting the occurrence of abnormal exploratory behaviors early on during the development, providing a novel approach to detecting perceptual problems.