As of now, Allison is seen with short hair only. Actress Mia Farrow cut her hair as a reaction on a contract dispute.
In Mia Farrow's memoir WHAT FALLS AWAY, she states that she cut her hair simply because she grew tired of all the attention the press paid to her hair and her appearance. She didn't want to spend time on having her hair styled everyday, preferring to ride her horse in the morning.