Alongside language and bipedal locomotion, tool use is a characterizing activity of human beings. Current theories in
the field embrace two contrasting approaches: “manipulation-based” theories, which are anchored in the embodied-cognition view, explain tool use
as deriving from past sensorimotor experiences, whereas “reasoning-based” theories suggest that people reason about object properties to solve
everyday-life problems. Here, we present results from two eye-tracking experiments in which we manipulated the visuoperceptual context (thematically
consistent vs. inconsistent object-tool pairs) and the goal of the task (free observation or looking to recognise). We found that participants
exhibited reversed tools’ visual-exploration patterns, focusing on the tool’s manipulation area under thematically consistent conditions and on
its functional area under thematically inconsistent conditions. Crucially, looking at the tools with the aim of recognising them produced longer
fixations on the tools’ functional areas irrespective of thematic consistency. In addition, tools (but not objects) were recognised faster in the
thematically consistent conditions. These results strongly support reasoning-based theories of tool use, as they indicate that people primarily
process semantic rather than sensorimotor information to interact with the environment in an agent’s consistent-with-goal way. Such a pre-eminence
of semantic processing challenges the mainstream embodied-cognition view of human tool use.
Tool use represents a fundamental facet of the human intrinsic ability to interact with the environment. In two
experiments, presented at the Trieste Symposium on Perception and Cognition, we show how the action readiness prompted by the visuo-perceptual context
may affect object recognition performance.
In the present eye-tracking study, we analysed the visuo-spatial attentional patterns of participants looking at 3D images depicting single tools and object-tool pairs. The object-tool pairs could be thematically consistent, thematically inconsistent or spatially inconsistent. During the first 500 ms of visual exploration, tools were fixated longer on their functional area in all experimental conditions. However, extending the time-window of analysis to 1750 ms, the visual scene was encoded in a faster and more suited-for-action way in the thematically consistent condition (e.g., hammer-nail). Most important, the visual exploration of the thematically consistent pairs focused on the manipulation area of the tool (e.g., the handle of the hammer) more than on its functional area (e.g., the head of the hammer). Finally, when single tools were shown and the entire time-window of analysis was considered (1750 ms), fixation focused on the tool’s manipulation area. These results are discussed within the reasoning-based framework of tool use. They highlight the relative role of the visuo-perceptual context in affordance perception and suggest a novel interpretation of the cognitive mechanisms underlying the processing of tools and object-tool pairs in terms of action reappraisal (i.e., a re-functionalization process when the action possibility is mined by the visuo-perceptual context).Read more...
Introducing Web Gazer: an eye tracking library that uses common webcams to infer the eye-gaze locations in real time. The article contains the slides presented during an university seminary related to Eye Tracking technologies. Read more...