Encyclopedia of Psychology and Law

session, where they will be sober when they complete the

dependent measures. Regardless of the research ques-

tion, for safety purposes, all participants in this type of

research must be relatively sober before they are permit-

ted to leave the research lab. To ensure that participants’

BAC is low enough for them to be excused (usually

0.03% or lower, as set by individual institutional review

boards), a breathalyzer is used. It should be noted that

although a blood-test analysis could also be conducted in

lieu of a breathalyzer, this practice is not normally used

by psychology and law researchers. Also, laboratory

research is limited with regard to the amount of alcohol

that can be safely administered to participants. Although

there may be exceptions depending on the location

(country) of data collection, the research question, and

individual IRBs, generating BACs in the lab greater than

0.08% is rarely permitted.

FFiieelldd SSttuuddiieess

Field studies, on the other hand, do not normally

screen participants for characteristics that would make

them ineligible for lab studies because participants in

field studies are obtained in bars or drinking establish-

ments and have consumed alcohol, presumably on

their own volition, prior to taking part in the research

study. Also, because participants have consumed alco-

hol on their own, obtaining participants with BACs

higher than 0.08% is common. Overall, there are few

differences between field and lab research with regard

to the presentation of stimuli or measuring of depen-

dent variables. One important difference, however,

should be noted. Due to the fact that participants in

field studies are intoxicated at the time when consent

to participate is given, they must be provided with an

opportunity to withdraw their participation at a later

time (i.e., when they are sober).

Intoxicated Eyewitnesses:

Experimental Findings

Researchers have been examining the effects of alco-

hol on eyewitness memory since the early 1990s.

Early experiments examined the effects of alcohol on

memory by comparing groups that were either sober

or intoxicated at the time of encoding and then testing

all participants on a different day when all participants

were sober. The results from these studies suggested

that intoxicated participants were less accurate when

asked to recall the features of a target person and less

accurate about describing the events that took place

during the critical encoding period than were sober

witnesses. However, participants who were intoxicated

during encoding were just as accurate at identifying a

target person in an identification task as witnesses who

had not consumed alcohol. Although these studies were

not specifically testing alcohol myopia theory, the

results are consistent with alcohol myopia theory

predictions.

Later research examined the effects of alcohol intox-

ication at the time of encoding and at the identification

task. Although it is possible to conduct this research by

having participants return to the lab a second time to

become intoxicated again (i.e., context reinstatement),

this body of research administered the dependent vari-

ables (e.g., a showup) relatively soon after the viewing

of the target person and while the participants were still

intoxicated. This research was unique from earlier

studies in that it allowed researchers to study alcohol

myopia theory by manipulating (a) the behavior of the

investigator and (b) the identification procedure. This

research was relevant to real police practice because the

police often encounter intoxicated individuals in the

course of their investigations and there had been no

research on the potential vulnerabilities of intoxicated

witnesses to police practices. The findings of these

studies suggest that intoxicated participants are more

susceptible to minor changes in police procedure, such

as the instructions that are given to a witness prior to

viewing a showup (e.g., “Please be careful when mak-

ing your decision.”) and biased identification proce-

dures (e.g., when the suspect is shown wearing similar

clothes to those worn by the perpetrator). Ultimately,

however, intoxicated witnesses could, under the cir-

cumstances of these research studies, be more accurate

than sober witnesses. In addition, correct identification

decision rates were in the neighborhood of 90%—a

notably high rate even for sober witnesses in eyewit-

ness identification research.

Jennifer E. Dysart

See also Eyewitness Descriptions, Accuracy of; Eyewitness

Memory; Identification Tests, Best Practices in

Further Readings

Dysart, J. E., Lindsay, R. C. L., MacDonald, T. K., & Wicke,

C. (2002). The intoxicated witness: Effects of alcohol on

identification accuracy. Journal of Applied Psychology,

87,170–175.

Read, J. D., Yuille, J. C., & Tollestrup, P. (1992).

Recollections of a robbery: Effects of arousal and alcohol

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