Intersibling agreement for Goldberg's big five adjective markers

Area of Science:

• Psychology
• Social Psychology
• Personality Psychology

Background:

• Sibling relationships offer a unique context for studying personality agreement.
• Previous research has explored interrater reliability in personality assessments, often using peer or spousal ratings.
• Understanding agreement within sibling dyads is crucial for validating personality measures and exploring familial influences on self-perception.

Purpose of the Study:

• To investigate intersibling agreement on personality traits using Goldberg's Big Five adjective markers.
• To examine self-enhancement biases in self-ratings compared to sibling ratings.
• To determine if the quality of the sibling relationship moderates personality agreement.

Main Methods:

• A sample of 240 college students provided self-ratings and sibling ratings on Goldberg's 100 unipolar Big Five adjective markers.
• Self-enhancement was assessed by comparing self-ratings to sibling ratings across the five personality factors.
• Sibling relationship quality was measured to explore its moderating effects on agreement.

Main Results:

• Participants exhibited self-enhancement, rating themselves more favorably on Agreeableness, Conscientiousness, and Culture/Intellect.
• Self-ratings on Neuroticism were higher than sibling ratings, indicating a potential self-protection bias.
• Moderate intersibling agreement (mean r = .41) was found, comparable to peer rating studies.
• Relationship quality moderated rank-order agreement but not mean agreement.

Conclusions:

• Sibling agreement on personality traits is moderate and subject to self-enhancement biases, particularly for positive traits.
• Self-perception differs between individuals and their siblings, with notable discrepancies in Neuroticism ratings.
• The sibling relationship quality plays a role in how personality traits are perceived comparatively, affecting rank-order agreement.