Modeling synergy: How to assess a Type D personality effect

Area of Science:

• Psychology
• Health Psychology
• Personality Research

Background:

• Type D personality, characterized by negative affectivity (NA) and social inhibition (SI), is theorized to synergistically impact health outcomes.
• Existing methods for analyzing Type D personality have faced criticism regarding their validity.

Purpose of the Study:

• To investigate the performance of different methods in detecting Type D personality effects.
• To determine if common methods adequately capture the synergistic effects of NA and SI.

Main Methods:

• A simulation study was conducted to assess method performance (bias, power, false positives).
• Two empirical datasets on Type D personality were reanalyzed.
• Methods evaluated included subgroup analyses and regression modeling with interaction terms.

Main Results:

• Common subgroup methods primarily detected main effects of NA or SI, falsely indicating synergistic Type D effects.
• Subgroup methods failed to detect combined NA and SI effects, leading to false positives.
• Regression analysis modeling continuous NA, SI, and their interaction demonstrated superior performance in detecting Type D effects.

Conclusions:

• A continuous interaction approach is the recommended method for modeling Type D personality effects.
• Subgroup approaches are biased and should not be used to operationalize Type D personality.
• The findings highlight the importance of appropriate statistical methods in personality research.