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Great idea, interesting results (with one remaining caveat)

Posted by AndrewDWilson on 06 Jun 2013 at 12:26 GMT

This is a very interesting result, and a nice application of affordance research.

I do see one minor confound lurking. The key result is that the AN group turned as if they were larger, as measured by an average A/S ratio of 1.40 (higher than the typical 1.25-1.3). The typical behaviour includes a 30% error tolerance, which Warren & Whang found was fairly consistent but is not compulsory. One explanation for the result is that AN participants may be correctly perceiving the affordances but because they are swaying more (for example) they are correctly giving themselves a larger error margin.

I didn't see any sway analyses although it seems that the authors have this data as they used it to identify when turning happened. Were there any group differences in sway? If not, your (perfectly sensible) conclusion holds up, otherwise, if AN is associated with increased sway, this might account for the result. An analysis well worth running, I think, as this is worth clarifying rounding out.

No competing interests declared.