Hierarchical nesting of affordances in a tool use task

In studying the perception of affordances, researchers have typically identified a single affordance anddesigned experiments to evaluate the perception of that affordance. Yet in daily life, multiple affordancesalways exist. One consequence of this is that there may be higher order, means-ends relations betweendifferent affordances. In 4 experiments, we created situations in which lower order, subordinateaffordances could affect the realization of higher order, superordinate affordances, and we asked whetherparticipants were sensitive to these hierarchical, nested relations. Participants wielded tools that varied inlength, mass, and mass distribution. In Experiments 1 and 2, we asked them to evaluate these tools interms of their suitability for executing specific interactions with target objects (striking vs. poking) thatwere positioned at different distances. In Experiments 3 and 4, we asked participants to select rods andmasses and then to assemble them into tools that could be used to execute specific interactions with targetobjects at different distances. The results were compatible with the hypothesis that participants weresimultaneously sensitive to affordances for tool assembly and affordances for tool use. We argue that thenesting of affordances is characteristic of many situations in daily life and that, consequently, sensitivityto hierarchical, means-ends relations among affordances may be an essential characteristic of perceptuallyguided action.