Any situation where a person conducting an experiment on particular subject, where the experimenter unwittingly influences the reactions of their subject, where the subject responds in a way that meets the experimenter’s expectations, perhaps as a result of the use of non-conscious cues is known as ‘experimenter bias’.
The types of cues that could affect a subject’s behaviours are numerous, from the mood of the person conducting the experiment, to any unintentional facial expressions they may pull, or even to the tone of voice used through the duration of the experiment. For this reason it is common practice for experimental studies to avoid experimenter-participant interaction. This is what is commonly known in science as the double-blind method, and the aim of the technique is to eliminate previous knowledge or the experimenter’s own views from affecting the outcome of the experiment.
This phenomenon of influencing behaviours and responses via the use of subconsciously evoked subtle signals is also known as the ‘Clever Hans Effect’. This term was originally coined as a result of the discovery by a German psychologist named Oskar Pfungst who, in the late 1800s, was called in by a group known as ‘The Hans Commission’. They had been charged with the task of investigating the seemingly spectacular acts performed by an Arab Stallion called Hans; the horse was said to be able to perform some basic maths and spelling feats, and at first glance this appeared to be the case. However through conducting a series of controlled tests upon the horse’s abilities, Pfungst found that Hans was reacting to small involuntary reactions from the people posing the questions.
The types of cues that could affect a subject’s behaviours are numerous, from the mood of the person conducting the experiment, to any unintentional facial expressions they may pull, or even to the tone of voice used through the duration of the experiment. For this reason it is common practice for experimental studies to avoid experimenter-participant interaction. This is what is commonly known in science as the double-blind method, and the aim of the technique is to eliminate previous knowledge or the experimenter’s own views from affecting the outcome of the experiment.
This phenomenon of influencing behaviours and responses via the use of subconsciously evoked subtle signals is also known as the ‘Clever Hans Effect’. This term was originally coined as a result of the discovery by a German psychologist named Oskar Pfungst who, in the late 1800s, was called in by a group known as ‘The Hans Commission’. They had been charged with the task of investigating the seemingly spectacular acts performed by an Arab Stallion called Hans; the horse was said to be able to perform some basic maths and spelling feats, and at first glance this appeared to be the case. However through conducting a series of controlled tests upon the horse’s abilities, Pfungst found that Hans was reacting to small involuntary reactions from the people posing the questions.
