The brain serves many functions, a complete description of which are beyond the scope of this website. For understanding product interaction, the following are most significant

• Perceiving involves processing to convert low-level senses, such as light, shade and colour into high-level perceptions such as objects, faces, and an overall understanding of the environment
• Working memory describes the temporary storage used to process and rearrange all information with reference to perceptions of the current environment and long-term stored memories
• Long-term memory describes the processes through which information encountered repeatedly in working memory can be learnt, stored indefinitely, and retrieved
• Attention can consciously direct the focus of working memory towards specific things in the environment, and affects awareness of the environment by filtering out non-attended things; yet salient or intrusive events can also "grab" attention unconsciously
• Visual thinking is the ability to perceive and think about visual objects and spatial relationships in two and three dimensions
• Verbal thinking refers to the conversion of speech, words and symbols into language, and the use of language to store and categorise memories as linked episodes

Acting involves processing to convert general intentions and movements into specific actions, in the form of sequenced instructions to muscles