Encyclopedia of Psychology and Law

system variables—those variables the justice system

can control. Many system variables have been impli-

cated in confidence inflation. This influence has been

demonstrated across three different categories of con-

fidence reports: current confidence in the identifica-

tion decision (e.g., How confident are you in the

accuracy of your identification right now?), retrospec-

tive confidence in the identification decision (e.g.,

How confident were you when you made your identi-

fication?), and reports about details of the witnessed

event (e.g., What kind of disguise was the culprit

wearing?). As described below, the malleability of

confidence in each of these three categories can be

attributed to system variables.

Confidence in Reports of Crime Details

Although confidence malleability is most prominently

studied in relation to identification accuracy, some

researchers have focused on its malleability in the con-

text of crime detail recollections. In one investigation,

eyewitnesses questioned over the course of 5 weeks

reported significantly elevated confidence levels at the

end of that period, without any corresponding increase

in the accuracy of their reports. The same elevation

occurred when eyewitnesses were questioned over the

course of 5 days. In addition, a manipulation as simple

as the context in which a confidence report is given can

influence the magnitude of an eyewitness’s certainty.

Witnesses who give reports about crime details in pub-

lic provide significantly lower confidence ratings than

do those witnesses who give reports privately, even

though the accuracy in both groups is equivalent. The

number of times a witness is interviewed and the con-

text of the interview are both variables under the con-

trol of the investigating officers to a certain extent.

Current Confidence in

Identification Accuracy

In many crimes, many people witness the same event.

Some of the crimes for which innocent people were

wrongfully convicted include up to five individuals all

identifying the same person. In one of the most elabo-

rate empirical examinations of the effect of cowit-

nesses, witnesses saw a live staged crime in pairs.

Witnesses were then separated for the identification

attempt and confidence report. Finally, witnesses were

randomly assigned to learn one of four types of infor-

mation about their cowitness’s decision. Those who

learned that their cowitness identified the same person

they did or identified an implausible other reported the

highest levels of confidence. Those who learned that

their cowitness either identified someone else or did

not make an identification all had confidence levels

that were significantly lower than witnesses in a con-

trol (no cowitness information) condition. Information

from a cowitness can also alter confidence in reports of

crime details. In one study, witnesses’ confidence in

whether an accomplice was present at the scene of a

crime changed depending on their partner’s report of

whether that accomplice was present. The justice sys-

tem has limited control of whether cowitnesses speak

to one another. At the very least, cowitnesses should be

separated until each has provided an identification

decision, complete report of crime details, and indi-

cated the confidence in each judgment.

Cowitnesses are not the only source of contamina-

tion for current confidence reports. Photospread

administrators have long been targeted as a potential

source of influence in eyewitnesses’ decisions. Initially,

concerns centered on the ability of a photospread

administrator to affect an eyewitness’s choices; research

does suggest this is a worthy concern. Recently, how-

ever, concerns have expanded to include the problem

of administrators influencing an eyewitness’s confi-

dence. In one demonstration of this problem, eyewit-

nesses attempted identifications in two conditions. In

one condition, the photospread administrator knew

who the suspect was. In the other condition, the photo-

spread administrator did not know who the suspect

was. Eyewitnesses who made identifications under the

first condition reported higher confidence in their

accuracy than did eyewitnesses who made identifica-

tions in the second condition. The influence inherent in

this situation is easily solved by ensuring that the per-

son administering a set of photos to an eyewitness does

not know who the suspect it; the system can control

whether this safeguard is adopted.

Retrospective Confidence

in Identification Accuracy

Malleability in retrospective confidence reports is per-

haps the most problematic of the three categories, in

part because this category is specifically highlighted

by the U.S. Supreme Court for use in determining

accuracy. The Court indicates that the relevant confi-

dence report is from the “confrontation,” suggesting

that they recognized the possibility for confidence to

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