A SIMULATED COCKTAIL PARTY:
INFLUENCES OF ALCOHOL ON PERCEPTUAL-COGNITIVE MEASURES1
M. W. PERRINE
UNIVERSITY OF VERMONT
The present study is part of a larger project which is concerned with the role
of alcohol in traffic accidents.
A before-after, treatment x subjects design was
used for the immediate purpose of assigning certain behavioral and attitudinal
changes to increasing blood-alcohol concentrations (BÂC) obtained in a controlled
social drinking situation. These results will be related (elsewhere) to selected
psychological-biographical variables and, eventually, to analogous data from
drivers actually involved in major traffic violations and/of serious or fatal
crashes.
Thus, the intermediate goals of the simulated cocktail party consist of
selecting and testing psychological tasks which meet three criteria:
(1) are
related to the information-processing aspects of driving. (2) are readily, but
differentially subject to the influence of alcohol, and (3) differentiate high-risk
and low-risk drivers.
The results of recent pilot work and two previous simulated cocktail parties
indicate that the first two criteria can be met by three performance tasks (dichotic identification, information transmission, and risk taking) which are briefly
reported below as separate experiments.
In addition, data were obtained on
selected biographical variables, personality attributes, and driving-related
attitudes.
Method
Subjects. Eighteen, paid, male volunteers served as Ss.
average undergraduates and were 21 or more years of age.
session and none of his data was analyzed.
All were academically
One S completed only one
Procedure. The three sessions occurred on consecutive days (Thursday afternoon and
evening, Friday 4:30-10:00 pm, and Saturday 9:00-12:00 am).
Since all tasks were
individual, extensive scheduling of Ss was required at all 3 sessions, but espe­
cially at the "party," during which a staggered sequence of the 5 test stations
was maintained with the aid of volunteer female "assistants." Thus, each S was
assigned a female partner who paced his drinking at 15-minute intervals, drank
non-alcoholic punch herself, and escorted him on the 4 highly programmed, 80-minute
cycles of tests.
Every 15 minutes, each S_ received and consumed a pre-determined amount of vodka
punch based on his body weight such that his BAC would steadily increase 30 mg%
every 80-minute cycle to a final level of about 100 mg%. To maximize the simulation
of a normal cocktail party, hors d foeuvres were provided throughout on an ad lib
basis (Ss had been requested not to eat or drink after lunch), appropriate recorded
music was played, and the first floor of a large, old, one-family house was used.
Blood-alcohol concentration. A 10 cc. blood sample was taken every 80 minutes
at the party and once at the post-test.
Laboratory analysis revealed a progressive
increase in BACs across the 4 sample-cycles at the party.
The mean BAC at the
fourth sample was 110 mg%.
Personality and attitude scales. At the pre-test session, Ss completed a
biographical data schedule on which detailed questions about drinking behavior and
drinking experience were asked, as well as rather standard items on background
variables.
In addition, 5 other instruments were administered:
an attitude-towardalcohol scale, Eysenck’s Personality Inventory (EPI), Zuckerman's Multiple Affect
Adjective Check List (MAACL), Brownfain’s Self-evaluation Rating Scale, and semantic
differential (ratings of 20 concepts concerning drinking, driving, drinking-anddriving, death, accidents, risk taking, hostility, etc.)»
At the party, the latter
three scales were given all S s four times, once on each 80-minute cycle.
At the
post-test, all instruments except the EPI and biographical were administered again.
These data are extensive, are not yet completely processed, and will therefore
be reported in detail at a later date.
However, it can be noted now that analyses
of variance indicate significant changes in affect level on the MAACL, namely an
increase in hostility and depression and a decrease in anxiety with higher BACs.
Those Ss with high neurotic scores on the EPI showed especially significant changes
in affect level (MAACL scores).
Experiment I:
Dichotic Identification
Procedure. In order to study auditory information processing under conditions
which met the first 2 criteria stated above, a perceptual conflict was created by
presenting numerical stimuli dichotically.
The competing inputs consisted of 10
pairs of different 2-digit or 3-digit numbers which had been carefully taperecorded on 2 channels at 4-second intervals.
Each pair was then presented simul­
taneously, but separately to each ear by means of earphones.
was instructed to
write down the numbers he heard and, if possible, to maintain the proper laterality
The tape was played through twice at each sitting.
Results. Errors of omission were analyzed across all 6 treatments (pre-test,
alcohol 1 or Al, A2, A3, A4, and post-test) by means of a Friedman two-way analysis
of variance.
The resulting Xr (26.82) was significant beyond the .001 level.
Differences between treatments were then analyzed by means of one-tailed Wilcoxon
paired-replicates tests with the following results:
significantly more errors were
made in pre-test than in Al, A2, A3, and post-test, and more in A4 than in A2, A3,
and post-test (all beyond .01 level).
Conclusion. Evidence was obtained for learning effects and for hypothesized
deterioration in information processing due to high alcohol intake.
Experiment II:
Information Transmission
Procedure. Ten of the 18 Ss were pre-selected and tested in a performance
task developed to simulate the time-sharing, and information-réduction and -trans­
mission aspects of automobile driving.
S_ was required to monitor a display for 1
of 4 possible visual signals while attending to a fixed, paced (problems presented
every 5 seconds), mantal-arithmetic loading task. At the end of monitoring periods
of varying lengths of time (equal to or less than one minute), a visual signal was
presented.
Ss were trained for 15 minutes prior to a 15-minute pre-test.
Three
performance measures were recorded:
number of correct lever responses, response
latency, and the number of correct mental-arithmetic solutions.
Results. The number of correct lever responses per trial did not change across
trials. And, although S>s took longer to complete a response during the highalcohol trials, the total number of correct mental-arithmetic solutions was
essentially the same for all trials.
Mean reaction time to the visual signals decreased from .67 seconds on the pre­
test to .64 on both Al and A2 trials.
On A3 and A4 trials, the mean reaction time:
increased to .70 and .76 respectively.
The lowest mean reaction time of .59 was
obtained on the post-test.
Analyses of variance indicate that the differences
between latency performance on the 6 treatments is statistically significant beyonc
the .001 level (F = 27.04; df = 1,45).
Conclusion. Comparisons between pre- and post-test latencies suggest an appre­
ciable amount of learning occurred during the study, which, in turn, suggests that
the performance-deteriorating effects of alcohol, (although statistically signifi­
cant) are only conservative estimates of what really happened.
The data also show that the effects of large amounts of alcohol are less on
accuracy than they are on the temporal aspects of performance. This finding is
important when one considers that incorrect responses in psychomotor performance
are frequently the result of information overload, and that information overload is
directly related to decreases in available processing time.
Experiment III:
Risk Taking
Procedure. The influence of increasing BAC on risk-taking behavior in a gaming
situation was investigated by comparing the responses of Ss during control and
experimental trials.
It was hypothesized that degree of risk taking changes as a
function of increasing BAC.
It was also hypothesized that response latency is
affected by BAC.
The game, which consisted of 20 rounds, required
to respond by choosing
either RED or GREEN for each round.
The "opponent" also made such a choice (accord­
ing to random 50% schedules.of RED and GREEN), and the payoff was made according
to the combination of both players’ choices.
Two different, but visible payoff
matrices were utilized to decrease the learning effect due to repeated sessions.
Matrix I awarded
4 points to opponent's 2 if both chose GREEN, but vice versa
if opponent chose RED.
If both chose RED, however,
got 0 points to opponent’s
10, but vice versa if opponent chose GREEN.
Matrix II, which modified the pay­
off by reversing the effects of the opponent’s choice, was introduced after the
second session.
was informed that if he obtained more points than his opponent
after 20 rounds, he would receive $0.50.
(Ss were given $0.25 if they tied, but
were not informed of this arrangement in advance so that tying strategies would
not be encouraged.)
For both payoff matrices, degree of risk taking was defined
as the number of RED responses (i.e., an attempt at the largest gain at the risk
of an equally large loss) per game of 20 rounds. The time between the onset of
a ready light, which signaled the beginning of each round, and S_’s choice pro­
vided a measure of response latency.
Results. The first hypothesis was tested by comparing the mean number of
RED responses played.
It was found that the greatest number of REDs (11.00)
were played when Sjb were at their highest BACs.
This mean differed significantly
from those of A2 (X = 9.69, t^ = 2.10, j3< .05) and the post-test (X = 9.23, t_ = 2.14,
< .05).
Some evidence to support the second hypothesis was found, but only in
comparison of the mean response latencies at the highest BAC (1.14 seconds) with
post-test latencies (1.30 seconds, _t = 2.00, £ = .07).
Conclusion. The present findings indicate that increasing BAC is associated
with an increase in degree of risk taking, accompanied by decreased response lat­
ency.
If performance on A4 was a reflection of learning alone, the reversals
which occurred during the post-test game would not be expected.
It would therefore
seem that Ss become more confident as their BACs increase.
Cohen (1960) found
such a relationship among bus drivers who were required to estimate their chances
of success in driving a familiar vehicle through narrow gaps..
Summary
An induced-intoxication experiment was conducted in a small-group context
to study the effects of vodka on performance of tasks related to some of the
information-processing aspects of driving.
A before-after, treatment x subjects
design was used to assign observed behavioral and attitudinal changes to increas­
ing blood-alcohol concentrations (BAC), as determined from both blood and breath
samples.
A female "assistant" escorted each (17) male
on four 80--minute
cycles through 5 tasks, including blood sample, attitude and personality scales,
dichotic identification, information transmission, and risk taking.
At high BACs
(110 mg.%):
(1) significantly fewer correct numbers were written in response to
dichotically presented pairs of conflicting digits; (2) mean response latencies
on the information-transmission task increased significantly; and (3) risky re­
sponses in the gaming situation increased significantly, while response latencies
decreased significantly.
It was concluded that the basic influence of alcohol
manifested in all 3 performance tasks was a deterioration in the quality of in­
formation processing.
This conclusion is consistent with most drinking and driv­
ing data.
Footnote 1
The author wishes to express his sincere appreciation to the following
individuals for their many ideas and Substantive assistance: William Butynski
(dichotic identification), M. Stephen Huntley(information transmission), Ronald
Melzer (risk taking), and Barbara Sisco (attitude and personality scales).
I. 68