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  • Writer's pictureJamie Lee

Understanding early signs of autism: Identifying red flags in infants and toddlers.

Updated: May 17, 2023

Autism Spectrum Disorder is a neurological and developmental condition associated with problems in social interaction, behaviours, and the way they learn. Understanding and recognizing the early signs of autism is paramount, as it can help prevent any disruptions that may affect a child’s later-stage development. Some children may develop ASD symptoms within the first 12 months, while in other kids, symptoms may only appear when they are 24 months of age or even later. Many parents are unaware that these symptoms are telltale signs of ASD until they realise their children are not achieving the developmental milestones and skills at a typical age.


Infants with ASD may exhibit subtle disruptions in social interest, attention, communication, and temperament. There are few detectable early signs of developmental differences to look out for which are commonly the absence of a skill or ability that usually develops by a certain age.

Lack of eye contact / Joint attention

Typically, by two months old, infants can locate faces and make eye contact with other people but researchers have found that babies who develop ASD make less eye contact when they are approximately two months old. Declining eye contact may be the earliest indicator of ASD.

Joint attention refers to the focus on an item and the ability to share a common focus on something (e.g., people, objects or area). Joint attention is essential for interacting with others but children with autism may have difficulties with joint attention, which they are unable to interact while having their attention on the person or the object.

Not responding to their names

Infants do show awareness of their names at 6 months old but infants with autism do not respond to names even when they are at 9 months of age. A pattern of non-responsive behavior towards their names when being called rather than a single occurrence, is a sign to look out for.

Delayed in their speech development

Babbling develops around 6 to 7 months of age while infants with ASD demonstrate significantly lower canonical babbling. Diagnosed infants display notably fewer total vocalizations. They may have trouble developing language skills and understanding things that are being said (e.g., instructions).

Limited facial expressions

Babies should be able to smile uninhibitedly or let others know whenever they are experiencing certain emotions. At 6 months, a baby should recognize others’ emotions and respond accordingly. The lack of facial expression in infants may be an early sign of autism. They may not understand and respond to facial expressions appropriately (e.g., smile and cry).

Restricted or Repetitive behaviors or interest

Some common repetitive behaviours that one may observe in an infant with ASD include clapping/flapping their hands, banging their head against the wall, or rocking their body. These behaviours help them feel better as it has a soothing effect on them or it is their way of expressing their emotions.


Identifying the early signs of autism during their early years can be tricky as many of these signs are common in all young children but are seen more often in children with autism. If the kids do not match the expected developmental milestones, we might want to be aware of it and look out for possible signs to identify them early.

Social Interaction/Speech

We are likely to observe toddlers with ASD to have minimal social engagement such as the use of very few or no gestures (e.g., not waving goodbye). They would not join other children in play or conversations and have a lack of eye contact. There is also an absence of speech or the failure to use ‘I’, ‘me’, and ‘you’ pronouns. The child may also have unusual speech patterns, and persistent repetition of words, phrases, or sounds (echolalia). Most of the time, they are likely to avoid social interaction and prefer to be alone. Toddlers with ASD have limitations in the types of play activities, particularly imaginative play and they might have difficulties understanding or following simple instructions (e.g., sit or open).

Repetitive behaviours

Lining up toys or objects (e.g., lining up toy cars or legos), getting upset when the sequence is changed, echolalia (repeating words or phrases), and always playing in a certain way every time is categorized as repetitive behaviours. Just like infants with ASD, toddlers show symptoms of flapping of hands, rocking the body, spinning in circles, or clapping. They might focus on certain parts of an object intently (e.g., wheels or colours) and ignore other things.

Lack of Attention

Kids who fall into the spectrum show no attention when their names are being called or turn their heads to locate any sounds in the room. They appear not to have any response to loud sounds as well. However, sometimes certain noises are exceptionally stressful to some children with ASD (e.g., busy public places or construction sites).

Rigidities and Restrictive Behaviour

The child may resist any changes in their usual routines and or the environment (e.g., a change of routine in school). They are often against solid food or may reject a variety of foods in their diet (e.g., leafy vegetables, carrots or rice). Toilet training would be a challenge as ASD kids may have sensory sensitivities and they struggle to regulate their emotions to these sensory inputs (e.g., the sound of flushing or the sensation of a cold toilet seat).

Early identification would benefit the child in getting the appropriate treatment to prevent disruptions that may influence their later development stage. Symptoms can be easily missed or mistaken, especially in younger children. Therefore, it is vital to understand the early signs of autism and take appropriate steps to help your child.

Written by Jamie Lee

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