The wheels keep turning Reply to Holcombe et al.

In their original paper, Kline et al. [1] explained the wagon-wheel illusion in continuous light (WWIc) [2] in terms of Reichardt motion detectors [3]. We initially questioned this conclusion because such detectors are primarily tuned to velocity rather than temporal frequency [4], whereas the preferred temporal behavior of the WWIc remains constant over a range of spatial frequencies [5,6]. The authors now counter that their case rested on a subcomponent of Reichardt detectors that is velocity tuned, but only in the forward direction, and that the full detector is in fact sensitive to temporal frequency [7].

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