Repetition blindness for locations: evidence for automatic spatial coding in an RSVP task

The authors report a new phenomenon called repetition blindness (RB) for locations: When 3 or 4 letters are presented rapidly and sequentially at random locations within a spatial array, experimental participants have difficulty reporting pairs of letters appearing in the same location within 250 ms of each other. This deficit occurs both during report of letter identities and during report of the locations in which the letters appear; it can also be found using a partial report task. During letter report, the deficit is found for 4-location arrays but not for 8-location arrays. In contrast, letter RB is not found during location report even when the letters are always chosen from a set of 4. These results indicate that a small number of locations--but not letters--can be encoded automatically even when they are not explicitly reported. The authors argue that RB for locations results from a difficulty individuating 2 tokens at the same spatial location.