stimulus

A stimulus (plural: stimuli) refers to any physical or sensory input from the environment that elicits a response or reaction from someone. It can be any sensory information, such as sound, light, touch, taste, or smell, that triggers a biological or behavioural response. Stimuli can range from simple to complex and vary in intensity and duration. They play a crucial role in sensory processing, perception, and learning, providing the necessary information for people to interact with and adapt to their surroundings.

What counts as a stimulus?

A stimulus is any change or event in the environment (internal or external) that an organism can detect and that triggers a response in the nervous system. For humans, stimuli encompass everything we perceive through our senses, including sight, hearing, touch, taste, smell, and internal sensations.

What do stimuli have to do with neurodivergence?

In neurodivergent conditions like autism, ADHD, and sensory processing disorders, the brain often processes stimuli differently than in neurotypical individuals. These differences can include being overly sensitive to certain stimuli (hypersensitivity), under-responsive to others (hyposensitivity), or having difficulty filtering out irrelevant stimuli (habituation).

The brain may struggle with sensory integration—combining information from multiple senses—or may process certain types of stimuli with unusual intensity or focus.

These differences in stimulus processing contribute to many characteristic presentations and experiences of neurodivergent individuals, including sensory seeking or avoidance behaviours, difficulty maintaining attention in stimulating environments, and sensory overwhelm or shutdown in response to excessive stimulation.