Interpersonal synchronization between infants and parents emerges early in life and serves as a critical foundation for the development of cognitive, social, and communicative abilities. Traditionally, researchers have assessed this synchrony using composite scores that capture the overall degree of reciprocal, coordinated interaction within a dyad. While informative, such measures often overlook the nuanced temporal dynamics of these interactions--how they change during an interaction and vary across contexts. Hyperscanning techniques offer a way to examine real-time coordination of brain activity between social partners. However, a key challenge lies in aligning neural signals with behaviorally relevant markers of synchrony. Recent advances in automated movement analysis and time-series alignment methods are beginning to bridge this gap, enabling researchers to quantify and synchronize neural and behavioral data with greater precision. Continued innovation in these integrative approaches will deepen our understanding of early social development and the bidirectional interplay between brain and behavior.