Evidence accumulation is biased by motivation: A computational account

Area of Science:

• Cognitive Psychology
• Decision Science
• Neuroscience

Background:

• Making accurate judgments requires gathering sufficient information.
• Deciding when to stop collecting evidence is a critical cognitive process.
• Beliefs can be influenced by the motivation to reach a desired conclusion.

Purpose of the Study:

• To investigate how the desire for a specific belief affects information gathering and judgment.
• To determine if individuals require less evidence to support a preferred belief.
• To explore the underlying mechanisms of belief-biased evidence accumulation.

Main Methods:

• Participants engaged in a sequential sampling task with incentives for accuracy.
• A drift-diffusion model was used to analyze evidence accumulation processes.
• Valence-dependent and independent models were compared to explain behavioral biases.

Main Results:

• Participants showed a bias towards believing they were in a desirable state.
• Less evidence was needed to conclude a desirable state, leading to earlier stopping.
• A drift-diffusion model incorporating valence-dependent response and process biases best explained the data.

Conclusions:

• Motivation to hold a desired belief reduces the required amount of supporting evidence.
• Valence-dependent biases in evidence accumulation significantly impact decision-making.
• Integrating valence into cognitive models enhances the explanation and prediction of behavior.