Stroop and Garner effects in comparative judgment of numerals: The role of attention.

In 7 experiments, participants selected the larger member of pairs of digits that differed in numerical magnitude as well as in physical size. Selective attention to the relevant dimension (number or size) was gauged by Garner and Stroop interference, both of which varied considerably as a function of the number and relative discriminability of values along the constituent dimensions. When the to-be-ignored dimension was more discriminable, sizable Garner and Stroop effects affected performance on the relevant dimension. When it was less discriminable, Garner and Stroop effects were considerably smaller regardless of whether the relevant dimension was numerical or physical size. The sensitivity of Stroop interference to manipulations of discriminability is accounted for by the allocation of attention to the constituent dimensions. The demonstrated malleability of the Stroop effect is incompatible with claims of strong automaticity in numerical processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparative judgment of numerosity and numerical magnitude: Attention preempts automaticity.

It is commonly believed that humans are unable to ignore the meanings of numerical symbols, even when these meanings are irrelevant to the task at hand. In 5 experiments, the authors tested the notion of automatic activation of numerical magnitude by asking participants to compare, while timed, pairs of numerical arrays on either numerosity or numerical value. Garner and Stroop effects were used to gauge the degree of interactive processing. The results showed that both effects were sensitive to the discriminability of values along the constituent dimensions, to the number of stimulus values used, and to practice and motivation. Notably, Stroop and Garner effects were eliminated under several conditions. These findings are incompatible with claims of obligatory activation of meaning in numerical processing, and they cast doubt on theories positing automatic processing of semantic information for alphanumerical symbols. (PsycINFO Database Record (c) 2011 APA, all rights reserved)