Personality Assessment

Assessment of personality can be accomplished from three domains: subjective experience, behavior, and physiology. Traditional means for assessing
personality have included objective and projective paper-and-pencil or interview
measurements that tap the domain of subjective experience. Behavioral
assessment techniques such as direct observation of behavior, selfmonitoring
(having the individual record occurrences of his or her own
behavior), self-report questionnaires, role-play scenarios, and behavioral
avoidance tests (systematic, controlled determination of how close an individual
can approach a feared object or situation) tap the domains of subjective
experience and objective behavior. These techniques have been used in
clinical settings to aid in the diagnosis and treatment of deviant or abnormal
behavior patterns.

Although psychophysiological measurement of personality has not gained
popular use in clinical settings, it complements the techniques mentioned
above and contributes to understanding the nature and development of psychological
and physical disorders. Just as patterns of responding on traditional
personality tests can indicate the possibility of aberrant behavior, so
too can tests of physiological patterns. Typical measures taken during this
type of assessment include heart rate, blood pressure, muscle tension (measured
via electromyography), brain-wave activity (measured via electroencephalography),
skin temperature, and palmar sweat gland or electrodermal
activity. These measures of physiological activity are sensitive to
“emotional” responses to various stimuli and have been instrumental in clarifying
the nature of certain psychological and physical conditions. One of
the fundamental assumptions of psychophysiology is that the responses of
the body can help reveal the mechanisms underlying human behavior and
personality.

Physiological responsivity can be assessed in a number of different ways.
Two primary methodologies are used in the study of the relations between
personality and physiology. The first method simply looks at resting or baseline
differences of various physiological measures across individuals who either
possess or do not possess the personality characteristic of interest. The
second method also assesses individuals with or without the characteristic of
interest but does this under specific stimulus or situational conditions
rather than during rest. This is often referred to as measuring reactivity to
the stimulus or situational condition. Resting physiological measures are referred
to as tonic activity (activity evident in the absence of any known stimulus
event). It is postulated that tonic activity is relatively enduring and stable
within the individual while at rest, although it can be influenced by external
factors. It is both of interest in its own right and important in determining
the magnitude of response to a stimulus. On the other hand, phasic activity
is a discrete response to a specific stimulus. This type of activity is suspected
to be influenced to a much greater extent by external factors and tends to be
less stable than tonic activity. Both types of activity, tonic and phasic, are important
in the study of personality and physiology.

Standard laboratory procedures are typically employed to investigate tonic activity and phasic responses to environmental stimuli. For example, a
typical assessment incorporating both methodologies might include the following
phases: a five-minute baseline to collect resting physiological measures,
a five-minute presentation of a task or other stimulus suspected to differentiate
individuals in each group based on their physiological response
or change from baseline, and a five-minute recovery to assess the nature and
rate of physiological recovery from the task or stimulus condition. Investigations
focusing on the last phase attempt to understand variations in recovery
as a response pattern in certain individuals. For example, highly anxious individuals
tend to take much longer to recover physiologically from stimulus
presentations that influence heart rate and electrodermal activity than individuals
who report low levels of anxiety.

Studies of physiological habituation—the decline or disappearance of response
to a discrete stimulus—also have been used to investigate personality
differences. Physiological responses to a standard tone, for example, eventually
disappear with repeated presentations of the tone. The rate at which
they disappear varies across individuals; the disappearance generally takes
longer in individuals who tend to be anxious. Thus, individuals who tend to
have anxious traits may be more physiologically responsive, recover from
the response less rapidly, and habituate to repeated stimulation more slowly
than those who tend to be less anxious. Such physiological differences may
be an important characteristic that determines anxious behavior or results
from subjective feelings of anxiousness. 612