Memory scanning of described images and undescribed images: Hemispheric differences

Seamon (1972) has found that reaction times (RTs) to memory probes do not increase with memory set size (M) for words encoded in mental images in a memory scanning task. Rothstein and Atkinson (1975) have failed to replicate Seamon’s results. Experiment 1 investigated this discrepancy by manipulating one methodological difference (whether images were or were not described) between the two investigations. Results revealed that described images produced typical linear increases in RT with M. Undescribed images, however, revealed no change in RT with M for positive probes (i.e., the word presented was contained in the current memory set). Experiment 2 manipulated to which visual field probes were presented (RVF — right visual field; LVF = left visual field). Results showed that the imagery group showed no relation between RT and M for probes presented to the LVF, but a linear relation for probes presentedto the RVF. Described-image and repetition groups revealed a linear relation between RT and M no matter which visual field received the probe.