Linking Early Social Vocalizations to Partner Preference Outcomes in Prairie Voles

Pair bonding is a selective and enduring social attachment that can be experimentally assessed in prairie voles using the partner preference test (PPT). While prior research has focused on bonding outcomes, less is known about whether early social interaction patterns predict later affiliative behavior. The present study examined whether ultrasonic vocalizations (USVs) during early male-female interactions predict subsequent partner preference in male prairie voles. Eight vole pairs underwent acoustic interaction testing, followed by a PPT. USVs were analyzed using DeepSqueak to extract call rate, call duration, and frequency-related features. Behavioral measures included in-chamber time, nose sniffing, and aggression, from which partner preference and aggression bias indices were calculated. Results revealed substantial variability in both vocalization and behavioral measures. Call rate was positively associated with in-chamber partner preference (r(6) = .72, p = .046), indicating that higher early vocal engagement predicted stronger later affiliative bias. In contrast, call duration and frequency measures were not significantly related to partner preference, nor were any acoustic features associated with investigatory behavior or aggression. These findings provide partial support for the hypothesis that early vocal behavior predicts later bonding outcomes and suggest that call rate may serve as a simple behavioral marker of social engagement during initial interactions.