Repetition and the SNARC effect with one- and two-digit numbers.

The SNARC (Spatial Numerical Association of Response Codes) effect is the finding that small numbers elicit faster left than right responses and large numbers elicit faster right than left responses. This effect suggests that numbers activate left-right magnitude-laterality codes and that these codes interact with the selection of left-right responses. In the present research, subjects made parity decisions for one-digit numbers (in Experiment 1) and two-digit numbers (in Experiment 2), and we examined the effect of stimulus repetition on the SNARC effect. With single-digit stimuli, responses were faster and the SNARC effect was eliminated when stimuli were identical on successive trials. With two-digit stimuli, responses were faster when the ones digit was repeated, but the SNARC effect was found regardless of whether the digit was repeated or not. We argue that magnitude-laterality codes are activated in the process of accessing number information in memory and that this process can be short circuited if the visual stimulus matches that on the previous trial. Thus, no SNARC effect is found in Experiment 1 when identical stimuli are presented on successive trials. However, this result is not found in Experiment 2 because successive stimuli do not match even if the ones digit is repeated. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Non-volatile one-transistor-cell multiple-valued CAM with a digit-parallel-access scheme and its applications

A new high-density non-volatile multiple-valued content-addressable memory (CAM) is proposed for highly parallel search operations. Multiple-valued stored data correspond to the threshold voltage of a floating-gate MOS transistor, so that the cell circuit can be designed using only a single transistor. Since a single match line in a one-word circuit is used for performing a multi-input wired AND operation, the magnitude comparison result between multi-digit data can be obtained simultaneously. As a result, a one-word magnitude comparison with n digits can be performed by just n steps in spite of a single-transistor cell circuit and single-match-line architecture, which makes the peripheral circuit of a CAM cell array small. Moreover, typical applications clearly demonstrate that the proposed non-volatile CAM is useful as a hardware accelerator for a high-speed comparison.