Does Fixation Interfere with Product Usability?

In operating unfamiliar products users often show fixation to certain action patterns even when it does not lead to any success. In fixation, users keep repeating non-working solutions and stick to an ineffective hypothesis. In this study the factors influencing fixation behaviour are examined. An experiment has been conducted in which three unfamiliar products and two familiar products had to be manipulated. The unfamiliar products were a can-opener, an overhead projector and a radio alarm clock. Subjects were selected from two age groups: 10 design students and 10 people between 45 and 65 years old, both males and females. The results show that fixation can exist on different levels: (1) on the level of the rules applied and (2) on a higher abstraction level dealing with the problem solving-strategy. Both user-related and product-related aspects influence the occurrence of fixation. It is concluded that designers should be aware of the fixation effects caused by interface errors and poor feedback. Designers should also realise that the type of problem (static versus dynamic problem; number of variables; the length of the use-sequence) has an impact on the way users deal with unfamiliar products.