8. Heuristics and heuristic evaluation


The origin of heuristics

Heuristics, a form of cognitive strategy, have been studied in discplines such as cognitive psychology, social psychology and social cognition. Heuristics are rules of thumb for reasoning, a simplification, or educated guess that reduces or limits the search for solutions in domains that are difficult and poorly understood. Unlike formal structures like algorithms, heuristics do not guarantee optimal, or even feasible, solutions and are often used with no theoretical guarantee.

The use of heuristics is often contrasted with probalistic, statistical, or rationalistic reasoning, according to which people use rationalistic and systematic ways to solve problems and generally seek the optimal results. As suggested by the definition of heuristics, this is not always the case. Herbert Simon, whose primary object of research was problem solving, has shown that we operate within what he calls bounded rationality. He coined the term 'to satisfice', which denotes the situation where people seek solutions or accept choices or judgments that are 'good enough' for their purposes, but could be optimised (Simon 1957; see the encyclopedia entry 'satisfice').

Heuristics in interaction design

The use of the term is widespread in the HCI and interaction design community and has become particularly visible in the HCI or interaction design community because of Jakob Nielsen's 'Heuristic Evaluation' method (Nielsen 1994). In its simplicity, the method involves a few usability literate persons that evaluate a given design (in the case of Nielsen's method, a web page) on the basis of a set of heuristics. They do this by judging the webpage's compliance with the heuristics. An example of such a (usability) heuristic is as follows:

Visibility of system status:
The system should always keep users informed about what is going on, through appropriate feedback within reasonable time.

The advantages of heuristic evaluation is that it is cheap, intuitive (since you are applying a set of predefined rules/heuristics), it hardly requires any planning, and it can be used early in the design process (it does not require a nearly finished user interface). The disadvantage is that there is a focus on problems rather than solutions.

Further reading

A good place to read more about research in heuristics in psychology is Kunda (1999). For further reading on heuristic evaluation, see Nielsen (1994) or simply his website, useit.com

8.2 References

  • Nielsen, Jakob (1994): Heuristic evaluation. In: Nielsen, Jakob, Mack, Robert L. (eds). "Usability Inspection Methods" Wiley .
  • Kunda, Ziva (1999): Social cognition: Making sense of people, MIT Press,
  • Simon, Herbert A. (1957): Models of man - social and rational, John Wiley and Sons,
  • (1985): The Penguin Dictionary of Psychology, Penguin,