Examples of atypical responses to sensory stimuli

Many children and young people with autism perceive sensory input in a different way to individuals without autism. They may be acutely aware of some stimuli while seeming to ignore obvious input in the environment. This can have an impact on learning and engagement in the classroom, leading to observable behaviours, such as distractibility, over attention to detail, anxiety and difficulties in simultaneously processing multiple stimuli (e.g. listening to an instruction whilst already engaged in a task).


In the diagnostic criteria for autism in DSM 5, the American Psychiatric Association describe atypical responses to sensory stimuli as ‘hyper- or hyporeactivity to sensory input’ (APA, 2013).

– Hyperactivity describes an individual who is overresponsive to sensory input, and is therefore trying to attend to much sensory input and has difficulty filtering out irrelevant input.
– Hyporeactivity describes an individual who is underresponsive to sensory input, and is therefore not registering and attending to adequate amounts of sensory input.

This resource will use the terms Overresponsiveness and Underresponsiveness to examine and describe atypical responses to sensory input. Examples of specific difficulties will be provided within the sections on each sensory systems, but some general examples of sensory over- and underresponsiveness are given below.
It is important to remember that these differences in sensory processing should not always be viewed as difficulties, but rather as a different way of seeing and sensing the world. Children and young people with autism may notice input that others are unaware of and can therefore bring a different perspective and an attention to fine detail.

Sensory Overresponsiveness


A student who is overresponsive to sensory input often has difficulty in selecting and attending to important input in the environment, and filtering out background input. In the classroom, this student may be very aware of all noises (e.g. the hum of the computer and data projector, the whispers of other students, pages turning, the motor of the lawnmower outside) and so cannot focus on the teacher’s voice. This student may also be very aware of smells in the room, all the visual stimulation on display boards and the feeling of his/her school uniform, leading to distractibility and frequently leading to feelings of sensory overload and anxiety.

Some common indicators of overresponsiveness are:

• Defensiveness e.g. pushing someone who is standing too close
• Avoidance e.g. running out of the classroom, hiding in a corner of the playground
• Easily upset
• Anxiety
• Distractibility
• Sensory overload, sometimes leading the child to ‘shut down’ and block out all input
• May engage in disruptive behaviours in order to get removed from the situation which is causing sensory overload and distress
• Avoids close physical proximity to others


Many children and young people with autism and who are overresponsive to sensory input engage in repetitive behaviours as a means of blocking out unwanted sensory input. These repetitive behaviours provide predictable and enjoyable input, and the child/young person focuses on this stimuli instead of the overwhelming stimulation around them. Some examples of such repetitive behaviours are:

• Flapping hands of flicking fingers in front of eyes
• Pacing up down room
• Rocking in chair
• Tapping pencil on desk
• Repeating a favourite noise, song or script from a film
• Focusing intently on a preferred object e.g. spinning coin, light switch

Sensory underresponsiveness

A student who is underresponsive to sensory input is not registering adequate amounts of sensory input, and subsequently the brain is not alert enough for interaction, learning and engagement. This student is filtering out too much sensory input, and so needs a higher intensity or a different type of sensory stimulation to increase alertness and engagement. There are often two types of behaviours observed in the underresponsive student:


1. Low registration

The student is not registering adequate sensory input and may present as follows:
• Disengaged and disinterested in activities, especially more passive activities such as sitting at a desk to listen/read/write
• Appears lethargic
• Slow processing of information
• Delayed or no response to questions and instructions
• Becomes more alert and engaged in more active tasks and multisensory activities e.g. P.E., playground, Art, Music.
• Difficulty completing work


2. Sensory seeking

A sensory seeking student may also be underresponsive to sensory input but tries to improve alertness by seeking increased sensory stimulation, e.g.:
• Frequently stands or moves around the classroom instead of sitting
• Swings in chair
• Enjoys fast movement
• Frequently fidgets
• Frequently touching objects and people
• Likes to hold a fidget object
• Sniffs objects and people
• Makes noise in quiet environments e.g. Assembly, independent work time, exam hall
• Enjoys ‘rough and tumble’ play

Additional note on proprioceptive input

The proprioceptive system is located in the muscles and joints, and many children and young people with autism enjoy proprioceptive input. This is because the input is regulating, and so calms the overresponsive student but also increases alertness in the underresponsive student. Many children and young people with autism therefore seek out proprioceptive input. Indicators that a child or young person is seeking proprioceptive input may include:

• Biting or chewing e.g. on sleeve or pencil
• Jumping or stamping
• Enjoys ‘rough and tumble play’, including wrestling and crashing on to floor
• Loves tight hugs from others
• Writes with excessive force on page
• Enjoys ‘heavy work’ activities e.g. moving furniture, lifting P.E. mats, wiping benches, brushing floor
• Likes to wear tighter clothing

For more information, see section on Proprioceptive System.

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