The more, the better? Evidence of parallel growth in intergroup contact quantity and quality over time.

Intergroup contact is a central feature of intergroup relations, yet research has largely examined its quantity and quality as separate, static predictors of intergroup attitudes, leaving relatively little known about how these dimensions themselves develop over time. We examine this question in four longitudinal studies across contexts and age groups, each including both majority and minority group members. Study 1 followed White British and Asian British adolescents undergoing a school merger in the UK (N = 660, 3 waves). Study 2 involved Catholic and Protestant youths participating in a peacebuilding program in Northern Ireland (N = 592, 3 waves). Study 3 tracked British and international students transitioning to university (N = 527, 4 waves), and Study 4 followed Catholic and Protestant children in Northern Ireland from the start of their secondary education (N = 3,057, 3 waves). Using latent growth modelling, we tracked how contact quantity and quality changed over time and how these trajectories were linked. Across all studies, we observed significant co-growth with steeper increases in contact frequency corresponding with greater improvements in interaction quality. When positive and negative valence were measured separately (Studies 3-4), growth in contact quantity was associated with increased interaction positivity, while changes in negativity remained minimal and non-significantly related to contact frequency. These findings suggest that intergroup contact is itself a dynamic experience: changes in how frequently people engage in contact are systematically related to changes in how positively they experience that contact.