STROOP EFFECT WITH SIZE WORDS

Abstract Background The Stroop effect has been studied mainly with color as the target dimension. Multistage accounts decompose Stroop interference into task, semantic, and response conflict, and Stroop facilitation into semantic and response facilitation. This exploratory study examined whether standard Stroop effects and their components occur when the target dimension is the physical size of written words. Methods In four experiments, Colombian university students who were native Spanish speakers (analyzed samples of 39, 39, 39, and 50 participants) named aloud the size, large or small, of stimuli presented at two letter sizes. Distractors included the size words GRANDE (large) and PEQUEÑO (small), size-related words (Experiment 1), size synonyms and antonyms (e.g., ENORME, DIMINUTO) (Experiment 2), words orthographically and phonologically similar (Experiment 3 and 4) to the response words, and control stimuli (symbol strings, pseudowords, and size-unrelated words). Vocal reaction times were analyzed with generalized linear mixed models (Gamma distribution, log link) and Holm-corrected pairwise comparisons, complemented by delta plots and simulation-based sensitivity analyses. Response types were analyzed with logistic mixed models. Results Standard Stroop interference (24 to 37 ms) and standard Stroop facilitation (20 to 36 ms) were observed in all four experiments, and errors were concentrated on incongruent size words. Interference grew with reaction time, whereas facilitation was present from the fastest responses. Response conflict and response facilitation were significant only in Experiment 1. Semantic conflict, semantic facilitation, and task conflict were not detected; size-unrelated words were not named more slowly than symbol strings. In Experiment 4, size-related words that resembled the correct response in form were named faster than words that resembled the opposite response. Each experiment could detect differences of about 29 to 34 ms with 80% power. Conclusions Naming the physical size of written words produces standard Stroop interference and facilitation. The absence of task conflict and the dominance of form over meaning are exploratory findings that require confirmation, because the experiments were not preregistered.