"...has to do with the pleasure and effectiveness of use." Behavioural design is probably more often referred to as usability, but the two terms essentially refer to the practical and functional aspects of a product or anything usable we are capable of using in our environment. Behavioral design (we shall use this term in place of usability from now on) is interested in, for example, how users carry out their activities, how quickly and accurately they can achieve their aims and objectives, how many errors the users make when carrying out certain tasks, and how well the product accommodates both skilled and inexperienced users.