AbstractA report by Deubel that adaptation to scanning saccade (S‐sacc) transfers to both memory‐guided saccade (M‐sacc) and visually‐guided internally‐initiated saccade (VI‐sacc) and a report by the authors that adaptation transfer does not occur between M‐sacc and VI‐sacc on previous experimental results seem at first sight to indicate a contradiction. Thus, the properties of S‐sacc are clarified here from the points of view of the main sequence characteristics and adaptation transfer. The results show that S‐sacc and M‐sacc have wholly different main sequence characteristics while S‐sacc and VI‐sacc have almost identical main sequence characteristics. In addition, main sequence characteristic similar to those of M‐sacc was not observed in any stage of S‐sacc adaptation. On the other hand, the results of experiments that study the degree of transfer of adaptation to S‐sacc or M‐sacc onto another saccade show that adaptation transfers occur asymmetrically but complete transfers do not occur. In addition, when adaptations are induced simultaneously to S‐sacc and M‐sacc, such that the gain increases to one and decreases to another, selective adaptations occur. These results show that S‐sacc and M‐sacc are saccades that have significant asymmetrical crosstalk. © 2001 Scripta Technica, Syst Comp Jpn, 32(11): 70–79, 2001