Does spatial information impact immediate verbatim recall of verbal navigation instructions?

The present study addresses the issue of whether spatial information impacts immediate verbatim recall of verbal navigation instructions. Subjects heard messages instructing them to move within a two-dimensional depiction of a three-dimensional space consisting of four stacked grids displayed on a computer screen. They repeated the instructions orally and then followed them manually by clicking with a mouse on the grids. Two groups with identical instructions were compared; they differed only in whether the starting position was indicated before or after the instructions were given and repeated, with no differences in the manual movements to be made. Accuracy on both the oral repetition and manual movement responses was significantly higher when the starting position was indicated before the instructions. The results are consistent with the proposal that there is only a single amodal mental representation, rather than distinct verbal and nonverbal representations, of navigation instructions. The advantage for the before condition was found even for the oral repetition responses, implying that the creation of the amodal representation occurred immediately, while the instructions were being held in working memory. In practical terms, the findings imply that being able to form a mental representation of the movement path while being given verbal navigation instructions should substantially facilitate memory for the instructions and execution of them.