Cognitive Psychology: Connecting Mind, Research and Everyday Experience, 3rd Edition

230 • CHAPTER 8 Everyday Memory and Memory Errors

witness’s initially uncertain response turns into an “absolutely

positive” response. In a paper titled “Good, You Identifi ed the

Suspect,” Gary Wells and Amy Bradfi eld (1998) had partici-

pants view a video of an actual crime and then asked them

to identify the perpetrator from a photospread that did not

actually contain a picture of the perpetrator (● Figure 8.21).

All of the participants picked one of the photographs,

and following their choice, witnesses received either con-

fi rming feedback from the experimenter (“Good, you iden-

tifi ed the suspect”), no feedback, or disconfi rming feedback

(“Actually, the suspect was number __”). A short time later,

the participants were asked how confi dent they were about

their identifi cation. The results, shown at the bottom of the

fi gure, indicate that participants who received the confi rm-

ing feedback were more confi dent of their choice.

Wells and Bradfi eld call this increase in confi dence due

to confi rming feedback after making an identifi cation the

post-identifi cation feedback effect. This effect creates a seri-

ous problem in the criminal justice system, because jurors

are strongly infl uenced by how confi dent eyewitnesses are

about their judgments. Thus, faulty eyewitness judgments

can result in picking the wrong person, and the post-

identifi cation feedback effect can increase witnesses’ con-

fi dence that they made the right judgment (Douglass et al.,

2009; Quinlivan et al., 2009; Wells & Quinlivan, 2009).

The Eff ect of Postevent Questioning Wells and

Bradfi eld showed that postevent feedback can strengthen

witnesses’ confi dence in their lineup identifi cation. We will

now describe an experiment by Jason Chan and cowork-

ers (2009) that considers a related question: How does

taking a recall test after witnessing an event and before

being exposed to misleading postevent information infl u-

ence memory for the event? The design of this experiment is shown in ● Figure 8.22.

Participants fi rst viewed a 40-minute episode of the television program 24 , in which

Jack Bauer, played by Kiefer Sutherland, is trying to thwart a terrorist plot. The par-

ticipants were then split into two groups. The test group took a cued recall test about

the video, which contained questions like “What did the terrorist use to knock out

the fl ight attendant?” (correct answers were not provided). The no-test group played

a computer game. Both groups were then given distraction tasks, such as fi lling out a

questionnaire and completing some tests unrelated to the TV program.

●FIGURE 8.22 Design and results of Chan et al.’s (2009) experiment that demonstrated the

reverse testing eff ect. Participants were presented with a distraction task before receiving the

misinformation.

Take cued

recall test Misinformation

Cued

recall test

Play

Tetris

No-test

group

Test group

Misinformation recall testCued

50%

30%

“Yes” response

to incorrect item

View

24

tape

●FIGURE 8.21 Design and results of Wells and Bradfi eld’s

(1998) “Good, You Identifi ed the Suspect” experiment. The type

of feedback from the experimenter infl uenced participants’

confi dence in their identifi cation, with confi rming feedback

resulting in the highest confi dence.

Receive

feedback.

Receive no

feedback.

5.4 4.0 3.5

View video of

crime.

Pick perpetrator

from photospread.

Confidence level rating

Receive

disconfirming

feedback.

Receive

confirming

feedback.

or or

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