Intimate Partners' Political Influence: Longitudinal Evidence for the Mutual Transmission of Party Support between Women and Men.

Cross-sectional research demonstrates that intimate partners generally hold similar political preferences. It is unclear, however, whether intimate partners influence each other's preferences over time. We address this oversight by investigating the transmission of political party support across 1,613 woman-man couples in long-term intimate relationships using 10 annual waves of longitudinal panel data. Actor-partner interdependence random intercepts cross-lagged panel models revealed that within-person increases in an intimate partner's party support predicted within-person increases in the other couple member's party support the following year. These partner effects emerged for six political parties in New Zealand and, with only one exception, did not differ in strength across women and men. Partner effects for self-rated political orientation were not significant. These results suggest that couples mutually reinforce each other's political party support over time, advancing understanding of the interpersonal transmission of political preferences and identifying a dyadic process that may contribute to political polarization.