228 • CHAPTER 8 Everyday Memory and Memory Errors
in the “shoot” condition (the gun was fi red;
● Figure 8.19). Apparently, the presence of
a weapon that was fi red distracted attention
from other things that were happening (also
see Tooley et al., 1987).
Another explanation for the narrowing
of attention caused by the weapons focus
effect is that unusual objects attract attention.
This idea is supported by an experiment by
Kerri Pickel (2009), who found that people’s
ability to describe the perpetrator of a staged
crime was affected more by the presence of a
weapon if the perpetrator was female rather
than male. Pickel relates this result to her par-
ticipants’ reporting it would be less likely for
a woman to be carrying a gun than for a man
to be carrying a gun. Whatever mechanism is
responsible for the weapons focus effect (high
arousal or unusualness, or both), the presence
of weapons does attract attention and impair
the ability to describe or identify perpetrators.Errors Due to Familiarity Crimes not only involve a perpetrator and a victim, but
often include innocent bystanders (some of whom, as we will see, may not even be
near the scene of the crime). These bystanders add yet another dimension to the testi-
mony of eyewitnesses because there is a chance that a bystander could be mistakenly
identifi ed as a perpetrator because of familiarity from some other context. A real-life
example of misidentifi cation based on familiarity is the case of Donald Thompson, a
memory researcher who was talking about memory errors on a TV program at exactly
the time that a woman was attacked in her home. The woman, who had been watching
Thompson on the program, subsequently implicated Thompson as the person who had
raped her, based on her memory for his face. Of course, Thompson had a perfect alibi
because he was in the TV studio at the time of the crime (Schacter, 2001).
In another case, a ticket agent at a railway station was robbed and subsequently
identifi ed a sailor as being the robber. Luckily for the sailor, he was able to show that he
was somewhere else at the time of the crime. When asked why he identifi ed the sailor,
the ticket agent said that he looked familiar. The sailor looked familiar not because he
was the robber, but because he lived near the train station and had purchased tickets
from the agent on a number of occasions. This was an example of a source monitoring
error. The ticket agent thought the source of his familiarity with the sailor was seeing
him during the holdup; in reality, the source of his familiarity was seeing him when
he purchased tickets. The sailor had become transformed from a ticket buyer into a
holdup man by the source monitoring error (Ross et al., 1994).
● Figure 8.20a shows the design for a laboratory experiment on familiarity and
eyewitness testimony (Ross et al., 1994). Participants in the experimental group saw a
fi lm of a male teacher reading to students, and participants in the control group saw
a fi lm of a female teacher reading to students. Participants in both groups then saw a
fi lm of the female teacher getting robbed and were asked to pick the robber from a
photospread. The photographs did not include the actual robber, but did include the
male teacher, who resembled the robber. The results indicate that participants in the
experimental group were three times more likely to pick the male teacher than were
participants in the control group (Figure 8.20b). Even when the actual robber’s face
was included in the photospread, 18 percent of participants in the experimental group
picked the teacher, compared to 10 percent in the control group (Figure 8.20c).Errors Due to Suggestion From what we know about the misinformation effect, it is
obvious that a police offi cer asking a witness “Did you see the white car?” could infl u-
ence the witness’s later testimony about what he or she saw. But suggestibility can alsoShoot
No shootAbout
perpetratorAbout
victimShooting decreases details recalled604080100Percent details recalled 200
About
weapon
●FIGURE 8.19 Results of Stanny and Johnson’s (2000) weapons focus
experiment. Presence of a weapon that was fi red is associated with a decrease in
memory about the perpetrator, the victim, and the weapon.Copyright 2011 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part.