Personality

Regardless of which approach to personality is adopted, the most widely used method of measurement is self-report. (Other methods include life ratings, observer ratings, and objective tests). Most self-report personality instruments typically use questions or items. Usually these items have been subjected to psychometric analyses, and have been shown to have adequate reliability and validity. Self-report instruments for measuring various personality characteristics abound, although some are used more widely than others.

Some have criticized the reliance on self-report measures by those who study personality and personality development. Such critics argue that more objective means are necessary for the accurate assessment of personality. The chief alternative to self-report is other-report. This broad category includes reports or ratings by peers, spouses, friends, siblings, or trained observers. In other-reports, a subjective judgment is still rendered, but it is deemed more objective in some ways than self-reports, which can be biased by a person's unwillingness to admit faults or weaknesses. Spouse reports or friend reports also are subject to such biases, which makes observer reports attractive to many researchers. Observer reports are usually obtained by associates of the researcher who have been trained to evaluate particular behaviors or actions of the subjects under study, and to code them according to a predetermined scheme. Often, observer reports make use of videotaped behaviors.

Although most personality researchers use self- or other-reports of various kinds, an increasing number are making use of physiological, neurological, and other biological measurements. Assessments of heart rate, blood pressure, neurochemicals (dopamine, epinephrine), and immune system biomarkers (interleukin-1, interleukin-6) are being used by personality researchers with increasing frequency. Neuroimaging techniques have been utilized in a small number of studies of personality. Use of these measurement techniques is not surprising, given the evidence that many aspects of personality have a biological or genetic basis.