Figure 2

Adaptation to Mechanical and Delay conditions with catch trials of the opposite condition. (A) Results of group 1 where participants manipulated the cursor under the Delay condition and experienced unexpected Mechanical catch trials. Squares are the average root mean square error (RMSE) for all participants, and error bars are 95% confidence intervals. (B) The same notation as in (A) for the results of group 2 where participants manipulated the Mechanical cursor and experienced Delay catch trials. (C–F) Tracking errors as predicted by the simulations. Two internal representations were used for these simulations, one which estimates a mechanical system linking hand and cursor position (C,D), and a second system which estimates the time delay between hand and cursor (E,F). The two systems were used to control a delayed cursor (trials indicated by red squares) or to control the mass in a mechanical setup representing the cursor (trials indicated by blue squares). Squares represent the average root mean square error (RMSE) between cursor and the tracking target positions. Simulations using the mechanical system based representation best capture the trends exhibited by participants in (A,B).