VISUAL SELECTION MEDIATED BY LOCATION - SELECTING SUCCESSIVE VISUAL OBJECTS

In these experiments, each stimulus consists of a series of frames, ea ch containing a target digit of one color and a distracter digit of an other color. The task is to name the highest digit of the target color . Subjects make fewer errors when successive targets appear at the sam e location than when they appear at different locations, apparently be cause they select target objects by using a mechanism that is based on location. When successive targets appear at the same location, there is no need to ''move'' the selection mechanism to a new location, leav ing more time to identify the stimuli. These experiments show that loc ation-based selection is used even though selection by color would be more direct. They also demonstrate a method of measuring location-base d selection that can be applied to a variety of visual tasks. Further experiments reveal that although location-based selection is used to i dentify a digit in the presence of a digit distracter, it is not used to identify a digit in the presence of a letter distracter, suggesting that this selection mechanism is not used in this situation to preven t interference among the basic features making up letters and digits, but to inhibit responses associated with the distracters.