Response Preparation and the Simon Effect: Experimental and Model-Based Analyses

Area of Science:

• Cognitive Psychology
• Human Factors
• Neuroscience

Background:

• The Simon effect demonstrates how stimulus-response compatibility influences reaction times.
• Previous research has explored various factors contributing to the Simon effect, including attention and response preparation.

Purpose of the Study:

• To investigate the underlying mechanisms of the Simon effect, specifically the modulation by response frequency.
• To differentiate between three competing hypotheses: biased response preparation, attentional facilitation, and trial frequency effects.

Main Methods:

• Conducted three experiments manipulating response frequency and cue validity.
• Utilized a model-based analysis with extensions of the Leaky, Competing Accumulator (LCA) model.
• Assessed the dynamics of the Simon effect using delta plots.

Main Results:

• The Simon effect was significantly modulated by relative response frequency.
• The effect was independent of the physical distance between hands and the monitor.
• Valid response cues almost completely eliminated the Simon effect.
• Model simulations supported biased response preparation as the main factor, though dynamics were less accurately predicted without incorporating shielding.

Conclusions:

• Biased response preparation plays a primary role in the Simon effect modulation by response frequency.
• Response preparation may involve shielding against distraction in addition to anticipatory activation.
• The specific type of congruency effect and stimulus timing influence frequency-based modulations.