Visual object memory and memory-guided saccades rely on shared mental representations

We investigated the organisation of working memory processes by examining how a secondary memory task interferes with the accuracy of memory-guided saccades. A target was flashed at a random location, followed by a Kanji character. Subjects had to remember the location of the target and the Kanji character, and then they had to make a saccade towards the remembered target location. A second Kanji character was displayed and the subject had to decide if it was same or different. The performance of seven non-Kanji reader's were compared with six fluent Kanji readers in the task. Memorisation of Kanji characters was found to interfere with the accuracy of memory-guided saccades made by non-Kanji, but not by Kanji readers. These findings directly contradict accounts of working memory function which propose that spatial and visual object memory are functionally discrete.