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, or dismissive when the child expressed needs for comfort, closeness, or emotional support. These caregivers often discouraged emotional expression, reacting with discomfort or withdrawal when the child showed vulnerability, distress, or sought reassurance. The child, learning that their emotional needs would not be met and that vulnerability led to dismissal, adapted by suppressing their own emotions and needs for connection. They developed a strategy of becoming overly self-reliant and minimizing the importance of close relationships to protect themselves from perceived rejection or disappointment. This early learning creates an internal working model where others are not reliable sources of comfort and emotional intimacy is seen as threatening. As adults, this translates into difficulty trusting others, as their foundational experiences taught them that people are unreliable for support and that showing vulnerability leads to negative outcomes. They avoid sharing deep feelings as a protective mechanism, maintaining emotional distance to prevent potential hurt or perceived rejection, and prioritizing independence over intimate emotional connection.