How does the peak-end rule smell? Tracing hedonic experience with odours

Area of Science:

• Psychology
• Neuroscience
• Sensory Science

Background:

• The peak-end rule suggests memory for events is based on peak intensity and final moments, neglecting duration.
• This rule was primarily studied for negative experiences, leaving its applicability to positive experiences unclear.
• Previous research lacked direct comparisons using similar stimuli for positive and negative affective events.

Purpose of the Study:

• To investigate the applicability of the peak-end rule to both positive and negative affective experiences.
• To conduct a rigorous comparison of the peak-end rule across different emotional valences using controlled stimuli.
• To determine if the rule holds for short-duration positive and negative sensory experiences.

Main Methods:

• Two experiments were conducted with 48 participants each.
• Participants evaluated continuous odour sequences delivered via an olfactometer.
• Stimuli varied in valence (positive/negative), duration (36s/72s), and temporal trajectory (increasing, decreasing, U-shaped, inverse U-shaped).

Main Results:

• Evidence supports the peak-end rule for both positive and negative affective experiences.
• Intense negative experiences were overweighted in sequences containing mixed pleasant and unpleasant episodes.
• The temporal trajectory of the experience had minimal impact on retrospective evaluations.

Conclusions:

• The peak-end rule is a robust predictor of memory for both positive and negative affective events.
• Emotional intensity and final moments significantly influence retrospective evaluations, regardless of experience duration.
• Future research should explore the nuances of mixed valence experiences and trajectory effects.