Experimental tasks.

Schematic trial timelines showing each combination of task (DM, PPM) and movement gain (“small step”, “big step”). Each trial started with a baseline-fixation period (FIX). Next, a grid-like movement space was presented for 1s, containing a target location in the periphery and a color cue in the center indicating subjects the specific task and gain context in a given trial (CUE). Next the screen was masked for 1s (MASK) and afterwards only the fixation cross remained visible, indicating the delay period (DELAY). When the grid appeared again (MOVE), subjects were required to perform a movement to the remembered pre-cued target location in PPM trials (A & B) or to the newly presented grey target in DM (C & D). Arrows (not visible to the subjects) illustrate the way that the virtual end effector moved after each single press of the button given the specific gain context, performing either a “small step” (A & C) or a “big step” movement (B & D). After a time limit of 3s the movement screen was masked again and the subsequent trial began.