Testing perceptual limits of functional units: Are there "automatic" tendencies to associate tools and objects?

Prior work has demonstrated a unique network involving the insula, temporal cortex, and precuneus in evaluating appropriate relationships between tool-object pairings under instruction [20]. However, are there automatic tendencies to evaluate appropriate tool-object pairings? Using electroencephalography (EEG), we emulated our prior work to identify neural mechanisms that, in the absence of task-related consciousness, differentiate functionally matching from mismatching tool-object pairs. This was compared to any activation consistent with this using environmental image pairs. In addition, based on the paradigm we were able to discern any naïve processes that distinguish tools from non-tool environmental images. Results show that without task-related consciousness, the left occipitotemporal gyrus is preferentially active for tools compared to environmental images. Tool-object match and mismatch each versus control images show differences relative to a control image over the left temporal cortex, extending into the insula, yet there was no difference between tool-object match and mismatch. This suggests that there is no clear neural mechanism for continual evaluation of tool matching from mismatching, though there is for broad picture classifications. Taken together with our previous results, this creates a discussion for the role of intention when determining such relationships.