Danny traces his phobia to a very early childhood experience in which a dog jumped toward him causing a fear reaction at that time and from that point forward this explanation is pointing to

Cynophobia is the extreme and irrelevant fear of dogs  .Signs of cynophobia include intense and constant fear of encountering dog, almost in all cases the fear being irresistible and unreasonable. Screaming and crying at a sight of dog. Complete avoidance of places where dogs can be found.

Classical conditioning is a learning process that occurs when 2 stimuli are paired together repeatedly. first the first stimuli evokes a natural response by the subject while the second doesn’t. However, after enough pairing together the second becomes conditioned and causes the response to happened just like with Danny.