A series of investigations are summarized from a personality research program that have relevance for mental state estimation. Of particular concern are those personality variables that are believed to have either a biological or perceptual basis and their relationship to human task performance and psychophysiology. These variables are among the most robust personality measures and include such dimensions as extraversion-introversion, sensation seeking, and impulsiveness. These dimensions also have the most distinct link to performance and psychophysiology. Through the course of many of these investigations two issues have emerged repeatedly: these personality dimensions appear to mediate mental state, and mental state appears to influence measures of performance or psychophysiology

Gilliland, Kirby

English

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N88-2 394
BRAINSTEM RESPONSE AND STATE-TRAIT VARIABLES
Kirby Gilliland *
Department of Psychology
University of Oklahoma
Norman, Oklahoma
INTRODUCTION
The purpose of this paper is to summarize a series of investigations
from our personality research program that have relevance for mental state
estimation. For several years, we have been conducting research at the
interface between the areas of personality, human performance, and
psychophysiology. Of particular concern have been those personality
variables that are believed to have either a biological or perceptual basis and
their relationship to human task performance and psychophysiology. These
variables are among the most robust personality measures and include such
dimensions as extraversion-introversion, sensation seeking, and impulsiveness.
These dimensions also have the most distinct link to performance and
psychophysiology. Through the course of many of these investigations two
issues have emerged repeatedly: a) these personality dimensions appear to
mediate mental state, and b) mental state appears to influence measures of
performance or psychophysiology.
This paper will provide a selective review of some of those studies that
have highlighted these issues. Of particular concern will be those studies
that offer specific insight into these issues or possible mechanisms for
exploring them.
SOME FUNDAMENTAL DISTINCTIONS
To better understand the influence of personality variables or mental
states it is important to understand the distinction between trait and state
variables. Both are theoretical in nature, and both are believed to influence
behavior. Traditionally, personality tra/t variables have been viewed as
relatively permanent internal dispositions. That is, traits are evidenced
regularly, are internal in origin, and are enduring in their nature. States, on
the other hand, have been viewed as characteristics that are irregular and
short-lived, and are usually viewed as responses to external social or
environmental factors (ref. 1). While this distinction-is generally accepted, it
has not had universal support (ref. 1,2,3,4,5). 1 .
\
z The presentation of this paper was supported in part by N.T.I.,
Incorporated, Dayton, Ohio. .... ......
1 Allen and Potkay (ref. 2) have suggested that the distinction between traits
and states is arbitrary. They argue that rather than being two
separate types of dimensions, traits and states are simply ends on a
continuum. Further, (ref. 3) they argue that the delineation of trait or
state measures is unnecessary and that researchers should simply
"...adopt a more neutral, operational approach to predicting behavior."
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https://ntrs.nasa.gov/search.jsp?R=19880014010 2020-03-20T06:18:55+00:00Z
It is also important to establish the relationship between traditional
personality states and more general mental states. Personality states have
typically referred to characteristics that have parallel trait measures, for
example, state and trait anxiety and state and trait arousal. The term mental
states refers to a much broader range of tnental phenomena including such
states as confusion, disorientation, boredom, and even fatigue. In this sense,
personality states could be viewed as a subgroup of the broader category of
mental states. Therefore, much of our research has been an exploration of a
special category of mental states and its relationship to performance and
psychophysiology. The remainder of this paper will concentrate on one state-
trait dimension, that of arousal.
TRAIT-STATE MEASURES OF AROUSAL, PERFORMANCE, AND PSYCHOPHYS]OLOGY
Recent interest in the biological bases of personality has centered on a
group of personality dimensions that are believed to share the common
underlying dimension of arousal. The most intensely researched arousal-based
dimension, extraversion-introversion (ref. 6), is believed to be the result of
differential ascending reticular activating system (ARAS) arousal. It is
believed that introverts have higher ARAS arousal levels as compared to
extraverts and seek to restrict environmental stimulation in order to maintain
a more comfortable overall level of arousal. Conversely, extraverts have a
lower ARAS arousal level and seek higher levels of environmental stimulation
to provide a more comfortable overall level of neural activity. The
extraversion-introversion dimension and construct of arousal have been so
closely linked they have often been viewed as synonymous. In fact, it is not
unusual to find extraversion-introversion scales being used as a trait arousal
measurement instrument, or as a method to "manipulate" arousal.
Typically, studies of extraversion-introversion are cast within an arousal
framework and the results of these studies are also interpreted within the
context of arousal dynamics. It was during these types of investigations that
we began to realize that not only were introverts and extraverts performing
differently, but also they were experiencing quite different mental states. For
example, during a study of simple visual reaction time before, during, and
after noise s,tress (ref. 7), extraverts and introverts not only performed quite
differently but also reported quite different mental states. In this study,
groups of introverts and extraverts performed simple visual reaction time
during three seven-rainute periods. One group of extraverts and one group
of introverts simply performed reaction time throughout the overall 21-minute
period. The remaining group of introverts and the remaining group of
extraverts also performed simple visual reaction time throughout the 21-minute
period. However, during the second seven-minute period, both of these
groups were exposed to 75dB intermittent, cafeteria-type noise.
Figure 1 shows the results from this experiment. It should be noted
that introverts showed an overall faster reaction time as compared to
extraverts. This finding is typically explained within the context of an
arousal model, and such results are viewed as supportive of the arousal-based
nature of the extraversion-introversion trait. Noise exposure caused a similar
degradation in reaction time performance for both extrovert and introvert
groups. What was surprising was that during the post noise period, the last
354
seven-minute period of reaction time, introverts exposed to noise returned to
a level of RT performance not unlike that of introverts not exposed to noise.
Extraverts who were exposed to noise appeared to show continued degradation
in performance over that resulting from noise exposure.
It is possible to construct a number of post hoc explanations for these
results based on arousal theory. What is interesting about this particular
study is that there is a much simpler explanation for these results. Following
the completion of the first seven-minute reaction time period, each subject
filled out a post-test questionnaire. Included in this questionnaire were a
number of questions regarding mental state; for example, subjects were asked
to rate their level of interest, boredom, and frustration. They were also
asked to rate the amount of time they performed the simple visual reaction
time task. In analyzing the results of this post-test questionnaire it was
learned that extraverts were significantly more bored and frustrated with the
task as compared to introverts. In addition, extraverts rated the task as
lasting twice as long as the introverts. Thus, introverts and extraverts
appeared to experience quite different mental states during the performance of
this experiment.
This study, as well as many others, have shown what appear to be
important trait arousal differences between introverts and extraverts. In the
present study this can be seen in the overall faster reaction times of
introverts as compared to extraverts. However, this study also demonstrates
that environmental variables (in this case a lack of stimulation) can
differentially influence the mental states of introverts and extraverts leading
to quite different performance.
In subsequent investigations #,+ (ref. 8)j we attempted to explore
more directly a link between extraversion-introversion and neural activity.
These studies have utilized the brainstem auditory evoked response (BAER), a
sensory evoked response reflecting the activity in the auditory pathway--a
neural pathway that transverses the ARAS. The BAER provides an
exceptionally stable measure of neural functioning in the auditory pathway.
The BAER is derived by averaging the first ten msec of multiple (I000 or
more) auditory pathway evoked potentials, elicited by short-latency click or
tone stimuli. This average evoked potential results in seven vertex-positive
waves believed to reflect sequential neural activity at successively higher
levels of the brains,era auditory pathway (ref. 9, 10). The putative
generators of wave I through wave VII are the acoustic nerve, the cochlear
nuclei, the superior olives_ the lateral lemniscus, the inferior colliculus, the
medial geniculate, and the thalamocortical radiationsp respectively (ref. 11_ 12).
was believed that the stability of this measure and its close neural
approximation to the ARAS made it a viable possibility for exploring
differences between introverts and extraverts.
It
# Andress, I).: Individual Differences in Brains,era Auditory Evoked
Responses. Unpublished Master's thesis, University of Oklahoma, 1981.
+Bullock, W.: A Converging Measures Test of Eysenck's Biologically-based
Theory of Introversion-extraversion. Unpublished doctoral
dissertation, University of Oklahoma, 1984.
355
The results of a series of studies of the BAER in introverts and
extraverts#, + (ref. 8, 9) can be summarized in Figure 2. Introverts have
been shown consistently to have wave V latencies that are significantly faster
than those of extraverts. This has been the major and most consistent
finding across the studies performed in our laboratory. This finding suggests
that introverts have greater neural responsivity in the area of the lateral
lemniscus and inferior colliculus. It is interesting to note that this area
corresponds closely to the hypothalmic region that Eysenck views as the seat
of arousal differences between introverts and extraverts. Thus, these studies
seem to support the view that a personality dimension based primarily on
arousal differences can be demonstrated by a physiological measure.
Another avenue in our research has been the exploration of BAER
differences in relation to cognitive workload_ or alternatively the exploration
of state arousal (ref. 13, 14). In one study, BAERs were recorded during a
pretest baseline period, during three (low, moderate, high) workload sessions,
and during a post-test baseline period (ref. 13). The major results of this
study revealed that longer latencies were produced at wave VI for all
workload conditions as compared to the pretest baseline period. The BAER
differences that were observed did not systematically differentiate the
workload conditions represented in this study. Nor did the post-test baseline
return to the pretest baseline level. However, the BAER was shown to be
sensitive to state arousal manipulation when contrasting baseline and workload
conditions.
These findings were replicated in a followup study of the post-test
baseline recovery period (ref. 14). Subject's BAERs were recorded during a
pretest baseline period, during the same three workload conditions, and
during a post-test baseline period just as in the previous experiment. In
addition, BAERs were recorded at five-minute intervals for forty minutes
following the workload trials. Finally, BAERs were recorded during an
additional trial at the high workload level in ABAB design fashion. The
results of this study are illustrated in Figure 3. These data suggest that
wave VI of the BAER is affected by cognitive workload in comparison to prior
resting conditions (just as in the previous study). Wave VI latency does not
fully recover under passive baseline measurement until after approximately 35-
40 minutes. The final BAER under high workload conditions was comparable to
those obtained under the earlier workload trials. Thus, the apparent
covariation of wave VI latency of the BAER with cognitive workload suggests
that this measure may be a responsive index of state arousal, albeit in a
discrete rather than continuous fashion.
The results of these studies of BAER activity in relationship to
extraversion-introversion and cognitive workload suggest an interesting
possibility. One component, wave V latency, appears to differentiate reliably
the construct of arousal as a trait. Wave VI latency has been shown to
differentiate reliably state alterations in arousal. Thus, it is possible that the
BAER may be useful as a method for assessing neural activity related to both
trait and state forms of arousal.
356
SUGGESTIONS FOR IMPROVED TECHNOLOGY
It is unlikely that any single dependent measure will prove sufficient to
capture and portray mental states. More likely complex multivariate
procedures will be needed to more fully explain the relationship between
mental states, human performance, and psychophysiology. Our past research
has suggested candidate behavioral and psychophysiological measures with the
potential for aiding in the exploration of this complex relationship, but
multivariate measurement alone will probably be insufficient to advance our
understanding.
Major new advances in our knowledge of the relationship between mental
state and task performance will probably be made through research
integrating current advances in cognitive science, human factors, individual
differences, and psychophysiology. For example, our laboratory is currently
moving toward procedures that utilize careful laboratory control of
environmental and task variables combined with real time multivariate data
acquisition and analysis to provide a time-series based method for exploring
these types of relationships. This technique will require the recording of
multiple performance measures along with selected psychophysiological and
subjective ratings, and displaying these outputs in real time. Using time-
series based techniques one can then explore the interrelatedness of these
measures and attempt to identify those measures that may be the most
efficient in predicting such critical operator factors as performance efficiency,
resource recruitment ability, and performance failure.
The distinguishing characteristic of this approach is one of modeling the
performance "dynamically" rather than the usual static method associated with
traditional experimental methodology. By using a more dynamic procedure one
can explore not only the effect of some variable during a baseline and
experimental phase (as is common in experimental techniques), but also the
initial reaction, the long-term recruitment or compensation ability, the additive
effects of stressors or drugs, and the rate of decline in performance ability.
These characteristics are sometimes lost in standard experimental formats, but
are often critical elements in defining the capability of human operators.
Through multivariate, time-series-based techniques and the advent of high
speed/capacity, real-time computer technology, we may be able to learn more
about many of the operator variables, such as mental state, that significantly
influence system performance.
l0
REFERENCES
Zuckerman, M.: General and Situation-specific Traits and States: New
Approaches to Assessment of Anxiety and Other Constructs. In M.
Zuckerman & C.D. Spielberger (Eds.) Emotions and Anxiety: New
Concepts, Methods, and Applications. Hillsdale, N.J.: Erlbaum, 1976.
2. Zuckerman, M.: The Distinction Between Trait and State Scales is Not
Arbitrary: Comment on Allen and Potkay's "On the Arbitrary Distinction
Between Traits and States". Journal of Personality and Social
Psychology, vol. 44, 1983, 1083-1086.
3. Allen, B. P., & Potkay, C. R.: On the Arbitrary Distinction Between States
and Traits. Journal of Personality and Social Psychology, voL 41, 1981,
916-928.
357
0 Allen, B. P., & Potkay, C. R.: Just as Arbitrary as Ever: Comments on
Zuckerman's Rejoinder. Journal of Personality and Social Psychology,
vol. 44, 1983, 1087-1089.
0 Fridhandler, B.: Conceptual Note on State, Trait, and the State-Trait
Distinction. Journal of Personality and Social Psychology, vol. 50, 1986,
169-174.
. Eysenck, H. J.: The Biological Basis of Personality.
Illinois: Charles C. Thomas, Inc., 1967.
Springfield,
e Gilliland, K., & Bracey, S.: Simple Visual Reaction Time During and After
Noise Stress in Extraverts and Introverts. Paper presented at the
meeting of the Midwestern Psychological Association, St. Louis, Missouri,
1980.
e Bullock, W., Gilliland, K., & Kujawski, A.: Effects of Stimulus Intensity and
Repetition Rate on Brainstem Auditory Evoked Response and Recovery
Rate of Introverts and Extraverts. Paper presented at the meeting of
the Society of Psych.physiological Research, Minneapolis, Minnesota,
1982.
o Bullock, W., Gilliland, K., & Dannels, S.: The Effect of Simple Vigilance
and Caffeine Administration on the Brainstem Auditory Evoked
Response of Introverts and Extraverts. Paper presented at the
meeting of the Midwestern Psychological Association, Chicago, Illinois,
1984.
10. Jewett, D. L., Roman,, M. N., & Williston, J. S.: Human Auditory Evoked
Potentials: Possible Brainstem Components Detected at the Scalp.
Science, vol. 167, 1970, 1517-1518.
11. Jewett, D. L., & Williston, J. S.: Auditory-Evoked Far Fields Averaged from
the Scalp of Humans. Brain, vol. 94, 1971, 681-696.
12. Stockard, J. J. & Rossiter, V. A.: Clinical Pathological Correlates of
Brainstem Auditory Response Abnormalities. Neurology, voL 27, 1977,
316-325.
13. Gilliland, K., Shingledecker, C., Wilson, G., &Peio, K.: Effect of Workload
on the Auditory Evoked Brainstem Response. Proceedings of the Human
Factors Society, vol. 1, 1984, 37-39.
14. Gilliland, K., & Dannels, S.: Recovery Time of the Wave VI Component of
the Auditory Evoked Brainstem Response Following Cognitive Workload.
Paper presented at the meeting of the Southwestern Psychological
Association, Austin, Texas, 1985.
358
Figure h SimplQ Visual Reaction Tim
of ExtrovQrt$ and IntrovQrts
BeF_Q, O_in 9, _d AftQr NoisQ
NEAN 305
REACTION
TINE
(Bec)
275 ! I
2 3
SESSION
I_ Extravert-
[ Noise I
| .--. Extravert- |
! I_'No'r_ I
I _ Introvmt- •
I ,o,. I
l -- Introvert- II
359
Fi 9ure 2: Mean BAER Wave V Latency
for Introverts and
Extroverts
5. 8'
5.7,
5.6,
5. 52
5.71
Latency
(msec) 5. 4.
5
Introverts Extraverts
360
Figure 3: Mean BAERWave VI Latency
for Base] inc. Work]oad.
and RQcovery CondJt Jarts
Latency
(Nec) 7.25..
7. 15
Low NodNigh 5 10 15 20 25 30 35 40 Hi_o
Vorklood \ Recovery Period (mir_ ! Worl_ ad
361


Brainstem response and state-trait variables

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