Different mechanisms can account for the instruction induced proportion congruency effect.

Area of Science:

• Cognitive psychology
• Neuroscience

Background:

• The congruency effect, where performance worsens on incongruent trials compared to congruent trials in conflict tasks, is a well-established phenomenon.
• This effect is modulated by the proportion of incongruent trials, known as the proportion congruency effect.

Purpose of the Study:

• To investigate if different instructional strategies can induce a proportion congruency effect.
• To examine whether these strategies alter the congruency effect by distinct underlying mechanisms.

Main Methods:

• Participants performed a conflict task under different instructional conditions.
• Instructions included strategic use of invalid trial proportion information or adopting liberal/conservative response thresholds.
• Data were analyzed using diffusion-model analysis.

Main Results:

• All tested strategies significantly altered the congruency effect compared to baseline, primarily impacting error rates.
• Diffusion-model analysis provided partial support for the hypothesis that different instructions induced the proportion congruency effect via distinct mechanisms.

Conclusions:

• Instructional strategies can effectively manipulate the proportion congruency effect in conflict tasks.
• The underlying mechanisms by which these strategies influence cognitive control may differ, as suggested by diffusion-model findings.