Interference in immediate spatial memory: shifts of spatial attention or central-executive involvement?

Interference in serial spatial memory was investigated in six experiments. Experiment 1 replicated Experiment 2 by Smyth and Scholey (1994) in showing that listening to tones that originated from different directions interfered with spatial memory. Experiment 2 showed, however, that the effect of mere listening was not observed when this was the only interference condition experienced by the subject. In Experiment 3, a binary pitch discrimination task performed on spatially separated tones impaired recall performance to the same extent as did left-right decisions. The same disrupting effect was also observed when the tones were presented from the same direction in the pitch discrimination task (Experiment 4) as well as in a binary loudness discrimination task (Experiment 5). Finally, repeating heard words did not interfere, whereas pitch discrimination performed on these same words disrupted recall (Experiment 6). It is argued that the disrupting effects reflect not a specifically spatial interference, but a central executive involvement in the rehearsal process in serial spatial memory.