Cognitive Design

When we interact with anything – a product, a computer or other people – we burn mental energy. Interaction requires making choices, figuring things out and behavioral self control.  Literally, glucose in the brain’s blood is burned or converted into mental task energy to consciously think, decide, learn and self regulate.   

And we have a limited supply of this type of mental energy. Depleting it can lead to poor cognitive performance.  A recent issue of the Journal of Consumer Psychology, (all articles free online) reviews the latest findings on these effects as they related to buying behaviors.  One key finding:

“The capacity for self-control and intelligent decision making involves a common, limited resource that uses the body’s basic energy supply.  When this resource is depleted, self control fails and decision making is impaired.” 

Interactions also lead to the production of mental energy through stimulating emotions, meaning, metaphors, automatic inferences and the like. These effects can also burn glucose but rather than resulting in depletion or fatigue they give rise to a feeling of energy that can in some circumstances improve performance. This feeling of energy is subjective because it does not generate glucose but it is functional (real outcome) because it can improve performance.  For example, consider the impact of increased confidence, emotional pride or excitement on performance.

Complex interactions can be understood as a series of events that burn or produce mental energy at two levels – the biological level (glucose in the brain’s blood) and the psychological or cognitive level (deciding, learning, emotion, meaning, etc.). This is why it is important in cognitive to design to model user-artifact interaction as the conversion of mental energy.