Signs of autism in an infant include lack of response to cuddling, being picked up or being called by name; lack of eye contact, especially when being fed; and failure to follow objects by sight, according to Helpguide.org. Autistic babies usually do not point or wave goodbye.
Most babies and toddlers with autism do not smile at people who smile at them, do not produce noises to catch a person's attention and do not copy the facial expressions or movements of people, states Helpguide.org. Being unenthusiastic to play with others may also indicate autism in infants.
The early signs of autism often manifest as the lack of normal behaviors instead of the presence of unusual actions, notes Helpguide.org. Autistic infants are generally quiet, docile and independent. Babies who are 12 to 18 months old typically start to show recognizable signs of autism. It is crucial to detect the condition in the earliest time possible to start intensive treatment focusing on rewiring the brain and reversing symptoms.
If a baby does not show happy facial expressions, such as big smiles, by 6 months, a parent should consult a pediatrician immediately, explains Helpguide.org. The absence of interactive sharing of sounds and facial expressions by 9 months of age also requires evaluation by a health care professional.