Encyclopedia of Psychology and Law

then even the most eminent (most highly qualified)

practitioner of that asserted expertise still would not

be permitted to testify as an expert. In fact, courts are

likely to find that the issues of qualifications, reliabil-

ity, and fit are inextricably intertwined and, in prac-

tice, cannot easily be disentangled. Qualifications are

relative, being more or less useful depending on the

expert’s familiarity with the subject that fits, or is rel-

evant to, the matter to be decided by the trier of fact.

Qualifications, therefore, cannot be evaluated in the

abstract. At some point, certainly, the question of

qualifications becomes a matter of weight rather than

admissibility. But just as with Rule 702 validity

assessments, the judge’s gatekeeping obligations

should extend not merely to qualifications in the

abstract but qualifications to testify about the subject

that is relevant to the issues in dispute.

David L. Faigman

See also Expert Psychological Testimony; Expert

Psychological Testimony, Admissibility Standards; Expert

Psychological Testimony, Forms of

Further Readings

Berger, M. (2002). The Supreme Court’s trilogy on the

admissibility of expert testimony. In Federal Judicial

Center (Ed.),Scientific evidence reference manual(2nd ed.,

pp. 9–38). Washington, DC: Federal Judicial Center.

Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579

(1993).

Faigman, D. L., Kaye, D. H., Saks, M. J., Sanders, J., &

Cheng, E. K. (2007). Modern scientific evidence: The law

and science of expert testimony(2nd ed.). St. Paul, MN:

West/Thompson.

Giannelli, P. C. (2004). Expert qualifications: Who are these

guys? Criminal Justice, 19,70–71.

Murphy, C. P. (1994). Experts, liars, and guns for hire: A

different perspective on the qualifications of technical

expert witnesses. Indiana Law Journal, 69,637–657.

EXPOSURETIME AND

EYEWITNESSMEMORY

When assessing the potential of an eyewitness, among

the first things an investigator has to decide is whether

or not the witness had an opportunity to observe what

took place for a sufficient time. The decision is likely

to be influenced by a witness’s assessment of the

length and quality of exposure to a perpetrator’s face.

A longer exposure can increase the ease with which

details come to mind at the time of remembering and

increase the likelihood that witnesses will correctly

recognize a face from an identification lineup and

provide a more detailed description. However, an

extended exposure could make the witness more con-

fident in their identification ability even when they are

wrong. It has been recommended that investigators

should not rely too heavily on witness confidence as an

indicator of accuracy.

There are two points to bear in mind when exam-

ining the relationship between eyewitness memory

and exposure duration. First, eyewitnesses are not

very good at making estimates of the duration of a

given event, and witnesses may overestimate the

length of exposure to a face. Second, a longer expo-

sure to a face can make a witness more confident in

their ability to make an identification, although there

are numerous other factors that could inflate (or

deflate) a witness’s confidence.

When witnesses are asked whether or not they could

identify someone seen earlier, they will rely on various

sources of information when making a judgment about

the strength of their memory. One source of information

that could influence their decision is “availability” or the

ease with which information can be brought to mind. A

longer exposure is associated with an increase in avail-

ability, and this can have interesting consequences for

the accuracy of an eyewitness’s identification.

Don Read was the first to examine the use of the

availability heuristic in an eyewitness identification

setting. He found that participants who interacted with

store clerks for a longer duration (4–15 minutes as

compared with 30–60 seconds) made a higher number

of correct choices from lineups in which the culprit

was present. However, it was found that the false iden-

tification rate in the target-absent lineups were inflated

if the store clerks received additional information

(cues) about the target. The latter finding fits with the

hypothesis that availability of additional cues can

sometimes lead a witness to believe that they have a

stronger memory for the target, and in a target-absent

lineup this can have potentially serious consequences.

The question of why an increase in exposure would

lead witnesses to overestimate their ability to make an

accurate identification from a lineup was explored

by researchers at Aberdeen University using “mock”

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