Observer effect

People’s tendency to (unconsciously) distort or influence situations or events and make them fit with their preconceptions, having unintended effects on the situation or event, for example, a clinician may give more care and attention to a patient receiving a new, experimental treatment which the clinician believes will be a better, more effective treatment option – and because this greater care and attention might itself produce a noticeable degree of improvement in the patient’s well-being or recovery – make the new treatment look more effective than it actually is. People and animals learn to behave in particular ways by responding to subtle cues unintentionally given by others.

Observer bias

People’s tendency to (unconsciously) distort how they see what is happening in situations or events – we often see what we expect to see. This has been demonstrated many times by direct experiment, for example, in one experiment clinicians were shown a film of a younger man talking with an older man about his feelings and experiences. Some of the subjects were told that the young man was a ‘patient’, the others were informed that he was a ‘job applicant’. Later the viewers were asked for their impressions of what they thought the young man was like. All subjects watched the same film. Each group of judges had distinctly different reactions, depending upon what they thought they were seeing. Those who saw the ‘job applicant’ described the target as “attractive, candid, innovative, and realistic”, while those who believed him to be a ‘patient’ saw the man as a “tight, defensive person” who seemed “frightened of his own aggressive impulses”. The judges’ ideas about patients and job applicants biased their observations of the target’s behaviour.

(see also: schema, expectations, expectancy, placebo, double-blind, experimenter bias, belief bias, myside bias)

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