Source preference and ambiguity aversion: models and evidence from behavioral and neuroimaging experiments.

Area of Science:

• Experimental economics
• Neuroeconomics
• Decision Theory

Background:

• Classical economic theory assumes risk and ambiguity are perceived similarly.
• The source preference hypothesis posits that decision-makers may prefer different outcomes from distinct sources of uncertainty, even with identical probabilities.
• Neuroimaging offers a method to test these decision-making models.

Purpose of the Study:

• To investigate the distinction between risk and ambiguity in decision-making.
• To test the source preference hypothesis using brain imaging techniques.
• To differentiate between various decision-making models, including Chew and Sagi's (2008) axiomatization.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed to observe brain activity.
• Subjects made 48 sequential binary choices between even-chance lotteries based on stock price digits (odd/even).
• Participants subsequently rated the familiarity of the stock symbols used.

Main Results:

• Brain regions such as the putamen, medial frontal cortex, and superior temporal gyrus showed increased activation when contrasting familiar versus unfamiliar sources.
• Activation patterns in familiar-unfamiliar contrasts mirrored those found in risk-ambiguity contrasts.
• These findings support the idea that the distinction between risk and ambiguity can be explained by the source preference hypothesis.

Conclusions:

• The study's odd-even design effectively induced identical probabilities, allowing for clear comparisons.
• Results support the Chew-Sagi model and challenge models based on global probabilistic sophistication and multiple priors.
• Findings align with previous research suggesting a single valuation system for risk and ambiguity aversion.