According to Barbara and Philip Newman infants (birth to two years old) experience the psychsocial crisis of Trust vs Mistrust. A psychosocial crisis is a predictable life tension during a certain stage in life. Psychosical in this sense draws to the point that the crisis is due to societal and cultural influences as well as psychological. Crisis in this sense refers to a normal stressor instead of an extraordinary event.
It is a crisis, in that an infant will either develop trust like attributes or will develop attributes of mistrust. It is amazing that it is at this young age that this is when trust is first developed.