Slower Perception Followed by Faster Lexical Decision in Longer Words: A Diffusion Model Analysis

Area of Science:

• Cognitive Psychology
• Psycholinguistics
• Computational Neuroscience

Background:

• The word length effect (WLE) in lexical decision tasks is well-documented for non-words but inconsistent for real words.
• Previous research indicates WLE magnitude varies with orthographic transparency across languages.
• Existing studies report conflicting results, including no effect or even faster reaction times (RTs) for longer real words.

Purpose of the Study:

• To investigate the underlying cognitive processes of the WLE in German-English bilinguals using a diffusion model (DM).
• To compare the explanatory power of DM analysis with a traditional linear regression approach.
• To elucidate how orthographic transparency and stimulus length interact in lexical decision.

Main Methods:

• Employed a diffusion model (DM) analysis to characterize RT-accuracy distributions by parameters reflecting latent sub-processes.
• Utilized a linear regression approach as a comparative method.
• Examined lexical decision performance in German-English bilinguals for words and pseudo-words of varying lengths.

Main Results:

• Linear regression showed decreased RTs with length for pseudo-words but no significant length effect for real words.
• DM analysis revealed that the null effect for real words arises from opposing influences of length on perceptual encoding and evidence accumulation.
• Perceptual encoding time increased with length for both words and pseudo-words; evidence accumulation rate increased with length for real words but decreased for pseudo-words.

Conclusions:

• The diffusion model successfully explains the inconsistent findings on the WLE for real words by dissecting opposing sub-process effects.
• Orthographic transparency appears to influence perceptual encoding, while length effects on evidence accumulation may relate to contextual information.
• These findings provide a more nuanced understanding of word recognition processes and the factors modulating the WLE.