Measuring caregiver-child proximity in daily life: Feasibility and acceptability of the TotTag wearable sensor.

Physical proximity between caregivers and infants facilitates early social, emotional, and cognitive development, yet most research relies on brief laboratory observations that fail to capture how proximity unfolds across daily life. To address this gap, we developed the TotTag, an infrastructure-free wearable system that provides moment-to-moment measurement of distance between multiple wearers. The current study assessed the feasibility and acceptability of deploying the TotTag with infants (M = 12.19, SD = 0.50 months) and their family members, including siblings and up to two caregivers, in their everyday environments. Families were instructed to use the devices daily for seven consecutive days and to complete brief morning and evening surveys. Most participants held a bachelor's degree or higher, and on average families had two children in the household. Feasibility was evaluated across procedural, technical, and adherence domains. Acceptability reflected caregivers' perceptions of ease of use, comfort, privacy protection, perceived scientific benefit, integration into routines, and overall satisfaction. Procedural feasibility was rated highly, and families were able to implement the protocol as intended, with strong adherence to daily surveys and successful generation of interpretable proximity data. Caregivers reported high acceptability overall, particularly with respect to perceived scientific benefit, ease of use, and satisfaction. Open-ended participant feedback described the TotTag as straightforward and easy to integrate into routines but identified challenges related to wearability, remembering devices after baths or swimming, and confirming charging status. Results indicate that multi-day, multi-wearer proximity sensing can be implemented feasibly and acceptably in families, supporting its use in future naturalistic studies of families.