Responding by exclusion in temporal discrimination tasks

Responding by exclusion, one of the most robust phenomena in Experimental
Psychology, consists of choosing an undefined comparison stimulus given an undefined
sample, when the comparison stimulus is presented next to other experimentally defined
stimuli. The goal of the present study was to determine whether responding by
exclusion could be obtained using samples that varied along a single dimension. Using a
double temporal bisection task, ten university students learned to choose visual
comparisons (colored circles) based on the duration of a tone. In tests of exclusion,
sample stimuli with new durations were followed by comparison sets that included one
previously trained, defined comparison (colored circle) and one previously untrained,
undefined comparison (geometric shape). Subjects preferred the defined comparisons
following the defined samples and the undefined comparisons following the undefined
samples, the choice pattern typical of responding by exclusion. The use of samples
varying along a single dimension allows us to study the interaction between stimulus
generalization gradients and exclusion in the control of conditional responding.
The first author was supported by a master's degree fellowship by the Ministry of Education (CAPES). Armando Machado was supported by grant PTDC/MHC-PCN/3540/2012 from the Portuguese Foundation for Science and Technology. Camila Domeniconi had a post-doctoral fellowship from the Foundation for Research Support in the State of Sao Paulo (FAPESP, 2009/18479-5). She is currently affiliated with the National Institute of Science and Technology on Behavior, Cognition and Teaching. Grants: FAPESP (08/57705-8) and CNPq (573972/2008-7). She has a research productivity fellowship by the National Council for Scientific and Technological Development (CNPq, 301623/2012-0).