Poster #161 - Children’s planning of efficient tool-use in a social context

• In Event: 2-055 - Poster Session 06
  In Poster Session: PS 06 Section - Perceptual, Sensory, Motor

Integrative Statement

When people grasp for objects or tools in order to use them, they usually display the end-state comfort effect (Rosenbaum et al., 1990): they strive to finish the grasping action with a comfortable hand posture even if they have to assume an uncomfortable posture at the beginning. Adults even anticipate another person’s starting comfort when handing over a tool: as an example, when handing over a knife, they present the knife with the handle instead of the blade directed towards the other. The present study investigated, whether children aged between 5 and 7 years, who display a stable rate of end-state comfort grips when acting individually, are able to consider another person’s starting comfort when handing over different tools, and in how far tool identity impacts their grip choices differentially. To this end, 28 children, 14 girls and 14 boys, were engaged in a two-step task. First, in the “Self-condition”, they were required to use each of three tools (bar, brush, hammer), and then were instructed to pass the tools to a collaborator for his use (“Other condition”). Crucially, the tools were presented from different orientations, either with the handle facing towards or away from the child. In order to enable their own or the collaborator’ s comfort, children had to adapt their grip postures flexibly. As an example, when the handle was oriented away from the children, in the Self condition hey had to assume an uncomfortable hand posture at the beginning of the grasp if they planned for end-state comfort. However, in the Other condition, when the handle pointed away from the children, they could pass it to the collaborator without twisting their hands because the handle already pointed in his direction.
In the analysis, children’s rates of comfortable and uncomfortable grip choices for each tool in the Self and Other Conditions were calculated and two different scores were created. The tool-related self-score indicated in how far children planned for their own comfort in the Self condition (regarding each tool orientation), the tool-related Other score indicated how far they considered the collaborator’s comfort in the Other condition. A repeated measures analysis of variance yielded significant effects of condition (self / other), F (1, 27) = 55.07, p <.001, and tool (bar / brush / hammer), F (2, 54) = 9.68, p < .001, and significant interactions among condition and tool, F (2, 54) = 6.16, p = .004, condition and orientation, F (1,27) = 19.29, p <.001, and tool and orientation, F (2, 54) = 4.71, p = .013. When data were analysed in more detail, they indicated that the extent to which own comfort was considered in planning was much higher than the extent to which the collaborator’s comfort was considered. Furthermore, in both conditions, significant effects of tool identity were found, which will be discussed and speak in favor of the assumption that efficient planning is no all-or none phenomenon but context-dependent.

Authors

• Bianca Jovanovic, University of Giessen
  Presenting Author

• Gudrun Schwarzer, Department of Developmental Psychology, Justus-Liebig-University Giessen
  Non-Presenting Author