Modulating peripersonal and extrapersonal reach space via tool use: a comparison between 6- to 12-year-olds and young adults

This study examined age-related characteristics associated with tool use in the perception and modulation of peripersonal and extrapersonal space. Seventy-six (76) children representing age groups 7-, 9-, 11 years and 36 adults were presented with two experiments using an estimation of reach paradigm involving arm and tool conditions and a switch-block of the opposite condition. Experiment 1 tested Arm and Tool (20 cm length) estimation and found a significant effect for Age, Space, and an Age × Space interaction (ps < 0.05). Both children and adults were less accurate in extrapersonal space, indicating an overestimation bias. Interestingly, the adjustment period during the switch-block condition was immediate and similar across age. Experiment 2 was similar to Experiment 1 with the exception of using a 40-cm-length tool. Results also revealed an age effect and a difference in Space (ps < 0.05), however, participants underestimated. Speculatively, participants were less confident when presented with a longer tool, even though the adjustment period with both tool lengths was similar. Considered together, these results hint that: (1) children as young as 6 years of age are capable of being as accurate when estimating reach with a tool as they are with their arm, (2) the adjustment period associated with extending and retracting spaces is immediate rather than gradual, and (3) tool length influences estimations of reach.