Diffusing the bilingual lexicon: Task-based and lexical components of language switch costs.

Area of Science:

• Cognitive Psychology
• Psycholinguistics
• Neuroscience

Background:

• Bilingual speakers exhibit a response time (RT) cost when transitioning between languages.
• This phenomenon is debated, with theories suggesting either a shared bilingual lexicon or domain-general cognitive costs.
• Understanding the source of these costs is crucial for models of bilingual language processing.

Purpose of the Study:

• To investigate the underlying cognitive mechanisms responsible for language switch costs in bilinguals.
• To differentiate between accounts related to lexical organization and general cognitive processing.
• To analyze response time distributions using a diffusion model to pinpoint specific processing stages.

Main Methods:

• Utilized the Ratcliff (1978) diffusion model to analyze response time distributions.
• Employed generalized lexical decision (GLD) tasks with Spanish-English bilingual participants.
• Conducted two experiments, one examining direct language switches and another investigating the anticipation of switches.

Main Results:

• Language switches were found to decrease the rate of evidence accumulation (drift rate).
• Switching languages also increased the time for cognitive processes preceding decision-making (non-decision time).
• Anticipating language switches did not alter these observed effects.

Conclusions:

• Language switch costs arise from a combination of factors affecting both lexical access and task-specific decision processes.
• The findings support a multi-component model of bilingual language control.
• This research provides empirical evidence for the locus of language switch costs within specific cognitive operations.