Encyclopedia of Psychology and Law

evidence. When, however, the identification of the

suspect is not made with extremely high confidence,

and is perhaps made in a ponderous manner, it should

signal real doubts about whether the suspect is the cul-

prit and act as a reminder to investigators that they

should strongly consider alternative hypotheses about

the culprit’s identity. In contrast, investigators should

not attempt to interpret the likely accuracy of wit-

nesses’ rejections of a lineup based on the associated

confidence levels. Although lineup rejections have

diagnostic value with respect to the guilt or innocence

of the suspects, the witnesses’ confidence levels do not

assist in that diagnosis.

Encouragingly consistent with these conclusions

that are based on experimental simulations are some

analyses of findings from real criminal cases. In this

archival work, when there was strong incriminating

(nonidentification) evidence against a suspect (which

admittedly does not prove that the suspect was the

culprit), very confident witness identifications much

more strongly pointed to the police suspect than to the

innocent lineup foils.

Barriers to the Use of

the Calibration Approach

Application of the calibration approach to the study of

the CA relation in eyewitness identification has

clearly been valuable. Unfortunately, there is one

major obstacle to the more widespread application of

the approach. As the published work shows, use of

this approach in the eyewitness identification context

requires extremely large sample sizes. The typical

eyewitness identification task simulates the real-world

investigation: The witness observes a crime, views a

lineup, and either makes a positive identification or

rejects the lineup. In other words, only one data point

is provided by each participant witness. However, sta-

ble calibration curves and statistics (for choosers or

nonchoosers) require approximately 200 to 300 data

points for each experimental condition examined.

Thus, the existing published studies with an identifi-

cation paradigm are characterized by sample sizes

considerably in excess of what many laboratories find

practical to achieve. In contrast, an old-new face

recognition paradigm allows for a large number of

repeated measures and, in turn, derivation of calibra-

tion statistics for each participant. One consequence

of this sample size problem is that future research into

how calibration varies over forensically relevant con-

ditions is likely to proceed quite slowly.

Confidence Malleability

The issue of social influences on identification confi-

dence and the malleability of confidence have already

been mentioned—and these issues are also discussed

specifically elsewhere. Some further discussion of

these issues is required here, however, to round out the

discussion of identification confidence.

As has been indicated, the empirical evidence

shows that witness confidence judgments are informa-

tive about the likely accuracy of positive identification

decisions if they are solicited at the time of the identi-

fication. But from the time of the identification

through to the end of a trial, witnesses may have a

variety of further interactions with the police, other

witnesses, and lawyers, culminating often in a court-

room appearance. Although none of these interactions

can have any bearing on the accuracy of the decision

that was indicated at the identification test, they do

have the potential to influence significantly any subse-

quent expression of confidence in that decision. This

may mean, for example, that any confidence judgment

expressed in the courtroom may be quite different

from the one that was made at the time of the actual

identification test. In turn, whereas confidence at the

time of the identification decision may be informa-

tive about identification accuracy, these subsequent

expressions of confidence may not be.

Some of the key variables that have been shown to

influence postidentification judgments of confidence

include confirming and disconfirming feedback about

the accuracy of the identification provided, for exam-

ple, by a lineup administrator or another witness. This

feedback may be in the form of explicit verbal feed-

back from one of these sources or may involve more

subtle verbal or nonverbal cues. Regardless of when

and how the feedback is delivered, its impact will be to

make a witness appear more credible or believable if it

is confirming feedback and thus inflates confidence or

less credible if it disconfirms and deflates confidence.

In other words, cues that can affect confidence judg-

ments but not the underlying judgmental accuracy can

render a witness more or less believable to jurors.

Thus, a witness who falsely identifies an innocent

police suspect may not be particularly confident at the

time of making an identification but may be exception-

ally confident at some later stage in a courtroom. It is

for these reasons that eyewitness researchers have

strongly endorsed the collection of any assessments of

confidence at the time of the identification—for it is

then that the confidence judgments are maximally

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