Any interaction with a product or service typically requires an iterative cycle where the user

• Perceives
• Thinks
• Acts

This cycle can occur very rapidly, where the user perceives information from a product through a range of sensory inputs, chooses and executes a particular action, perceives the resulting change, and so on.

The user’s sensory, cognitive, and motor capabilities are used in combination throughout the interaction cycle, with vision and dexterity most often required for perceiving and acting respectively.

The particular environment in which the interaction takes place also significantly influences the user’s capabilities. The Framework section within User capabilities provides more information on the cycle of product interaction.