tag:blogger.com,1999:blog-9048879464910781933.post8831467777684576887..comments2020-05-27T11:13:04.120-07:00Comments on Talking Brains: What is the extent of motor influence on speech perception?Greg Hickokhttp://www.blogger.com/profile/16656473495682901613noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-9048879464910781933.post-83876359172826958712015-02-17T14:06:14.892-08:002015-02-17T14:06:14.892-08:00The emphasis on this paper on &quot;causality&quot...The emphasis on this paper on &quot;causality&quot; is interesting. The word is used 15 times in the paper. But I&#39;m not sure how much it really means.<br /><br />Suppose the experiment were identical accept that instead of TMS applied to lip and tongue motor cortex, puffs of air were directed at the lip or tongue and the same effects were obtained. Could we then claim a causal role for the lip and tongue in speech perception. Sure! Why not? The causal effect is clear as day. It would still not necessarily hold that the lip and tongue are critical for speech perception. The same holds for TMS to lip and tongue areas.<br /><br />A second thing that occurred to me with this study. Suppose in another block of trials the authors had presented the words in noise-degraded handwritten text with the same lip/tongue critical pair manipulation. Would the same effects obtain? And if so, what would that mean? <br />Support for the motor theory of handwriting perception? <br /><br />Lastly, although with minimal data (only 22 trials per subject) this is hard, but it would be nice to see more sophisticated RT analyses applied to these data, for example, Ratcliff-style diffusion model analysis could potentially clarify to what extent these effects are decision biases versus increase in sensitivity (or &quot;drift rate&quot;).<br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br />Brad Buchsbaumhttps://www.blogger.com/profile/10757537675625801119noreply@blogger.com