Abstract:

This study explored possible confounding effects of echoic memory on estimates of attentional capacity by attempting to estimate capacity while controlling the effect of echoic memory. Detection of a target stimulus and identification of its carrier stream was investigated as a function of variation in number of concurrent non-overlapping auditory streams (1 to 4) and of condition of echoic memory involvement (available or eliminated via articulatory suppression). Error rates were found to increase non-linearly as a function of number of streams, but with a different point of discontinuity - indicative of a processing limitation - under different conditions of memory involvement, a higher capacity (3 as opposed to 2 streams) being achieved with echoic memory contribution. Detection response latencies also increased as a function of number of streams, but the increases were linear. Echoic memory also significantly reduced the response latency. These findings, which implicate echoic memory as a contributory factor in estimates of auditory attention, may help to resolve discrepancies in previous research and have implications for modeling auditory attentional processes.