Resolving the theory of planned behaviour's 'expectancy-value muddle' using dimensional salience

Area of Science:

• Health Psychology
• Behavioral Science
• Decision-Making Models

Background:

• The theory of planned behavior is a key model for understanding health decisions.
• Current methods for assessing expectancy-value models in this theory lead to uninterpretable results, known as the 'expectancy-value muddle'.
• Existing solutions for this muddle have practical and conceptual limitations.

Purpose of the Study:

• To identify and evaluate a simple method for resolving the expectancy-value muddle.
• To test the effectiveness of the dimensional salience approach in predicting attitudes and intentions.

Main Methods:

• 309 Australian residents (aged 18-24) rated expectancy and value for 18 beliefs about posthumous organ donation.
• Participants identified their five most salient beliefs using a dimensional salience approach.
• The expectancy-value term was calculated by summing the value ratings of salient beliefs.

Main Results:

• Salient beliefs were rated as more likely to occur than non-salient beliefs.
• The dimensional salience approach successfully predicted attitude (adjusted R² = 0.21).
• This method also predicted intention (adjusted R² = 0.21).

Conclusions:

• The dimensional salience approach offers a practical solution to the expectancy-value muddle.
• This method can be effectively used in applied research settings for health behavior studies.
• The findings support using salient beliefs to represent the expectancy component in expectancy-value models.