Effect of an initiating action on the up-right/down-left advantage for vertically arrayed stimuli and horizontally arrayed responses

When up and down stimuli are mapped to left and right keypresses or "left" and "right" vocalizations in a 2-choice reaction task, performance is often better with the up-right/down-left mapping than with the opposite mapping. This study investigated whether performance is influenced by the type of i nitiating action. In all, 4 experiments showed the up-right/down-left advan tage to be reduced when the participant's initiating action was a left resp onse compared with when it was a right response. This reduction occurred wh en the initiating action and response were both keypresses, both were spoke n location names, and one was a spoken location name and the other a keypre ss. The results are consistent with the view that the up-right/down-left ad vantage is due to asymmetry in coding the alternatives on each dimension, a nd a distinction between categorical and coordinate spatial codes seems to provide the best explanation of the advantage.