If an adult always finds it hard to trust people in close friendships and doesn't like to share their deep feelings, what kind of early childhood way of connecting with others likely caused this?

The adult's pattern of finding it hard to trust people in close friendships and not liking to share deep feelings likely originated from an early childhood experience that fostered an avoidant attachment style. An attachment style describes the distinct way individuals relate to others in close relationships, a pattern formed in early childhood based on interactions with primary caregivers. In the development of avoidant attachment, primary caregivers were consistently unresponsive, unavailable,....