Practice Reduces Barnum Effect in Personality Tests

Computerised, or online, psychometric testing, permits an efficient method of personality assessment, however it also poses threats relating to ethics and to the validity (or truth) of your responses. Thus there are both strengths and limitations to computerised delivery of personality tests, and it is valuable for you, the individual test-taker, to consider these when practicing online psychometric tests. The Barnum effect may influence the way your psychometric test responses are evaluated. This effect is also referred to as the Forer effect, after the researcher who first wrote about it in 1949 (Furnham & Schofield, 1987).

The Barnum / Forer effect in psychometric personality tests refers to the tendency of psychometric test-takers to accept global statements which can be applied to anyone, and which are favourable. Forer (1949, as cited in Furnham & Schofield, 1987) argued that a universally valid statement is one that applies to nearly all the population, and therefore although true of the individual, does not reveal anything specific about them. These types of statements are likely to be endorsed by the psychometric test-taker if they make them feel good about them self. Interestingly, the Barnum effect is also found to be the reason people accept horoscopes, considering they comprise statements which are vague and favourable in nature.

Psychometric personality test interpreters, or employee selection panels, may question the validity of your test responses if the Barnum effect is apparent, if you positively endorse these global, favourable statements. Therefore, practicing online psychometric tests can help to lessen the Barnum effect, and thus improve the psychometric test interpreters’ perceived validity, or accuracy, of your personality test responses. A related argument is that practicing online psychometric personality tests reduces the ‘social desirability effect’, your tendency to stretch the truth when partaking in online psychometric tests, in order to make a good impression. The Barnum effect in psychometric test interpretation could be judged as approval-seeking behaviour, insecurity and vulnerable self-esteem of the test-taker. Therefore, practicing online psychometric tests is an important way of increasing your awareness of these types of general, ambiguous statements and thus increasing the likelihood that you will respond in a more truthful manner.  

As Furnham and Schofield (1987) stated, the origins of the Barnum effect in psychometric tests can be traced back to two causes: the suggestibility of the psychometric test-taker, or the inadequacy of the psychometric test. Alternatively, according to other researchers, the endorsement of global, favourable and vague statements in psychometric tests could reflect that these statements actually are perceived by psychometric test-takers as being accurate descriptions of most people, including themselves. Nevertheless, it is important to practice psychometric tests to improve your ability to distinguish between psychometric test items which are broad, vague and favourable in nature (Barnum statements), compared to items which are more valid and specific (genuine statements).  Barnum statements are of little use to test interpreters, in assessing psychometric personality test outcomes, given that the responses will appear not unique to you, the individual test-taker.