222 • CHAPTER 8 Everyday Memory and Memory Errors
essential for our survival—its great speed even when faced with incomplete information.
Our memory system works the same way. Although it may not come up with the correct
answers every time, it usually provides us with what we need to know to function rapidly
and effi ciently, even though we may not always have complete information.
Memory is clearly a highly functional system that serves us well. However, some-
times the requirements of modern life create situations that humans have not been
designed to handle. Consider, for example, driving a car. Evolution has not equipped
our perceptual and motor systems to deal with weaving in and out of heavy traffi c or
driving at high rates of speed. Of course, we do these things anyway, but accidents hap-
pen. Similarly, our perceptual and memory systems have not evolved to handle demands
such as providing eyewitness testimony in court. In a situation such as this, memory
should ideally be perfect. After all, another person’s freedom or life might be at stake.
And just as car accidents happen, memory accidents happen as well. We will shortly
consider what can happen when memory is put to the test in the courtroom, but fi rst
we will consider another aspect of memory that can potentially result in memory errors.- Source monitoring errors provide an example of the constructive nature of
memory. Describe what source monitoring and source monitoring errors are
and why they are considered “constructive.” How does Bartlett’s “War of the
Ghosts” experiment provide an example of source monitoring errors? - Describe the following examples of situations that involved source monitor-
ing errors: (a) familiarity (becoming famous experiment); (b) world knowledge
(gender stereotype experiment). Be sure you can describe the experiments
related to each example. - Describe the following examples of how memory errors can occur because of
a person’s knowledge of the world: (a) making inferences (pragmatic infer-
ence; “ birdhouse” experiment; baseball experiment); (b) schemas and scripts
(offi ce experiment; dentist experiment); (c) false recall and recognition (“sleep”
experiment). - What is the evidence from clinical case studies that “super memory” may have
some disadvantages? What are some advantages of constructive memory? - Why can we say that memory is highly functional but that it may not be per-
fectly suited to all situations?
Memory Can Be Modifi ed or Created by Suggestion
People are suggestible. Advertisements pitching the virtues of different products infl u-
ence what people purchase. Arguments put forth by politicians, opinion makers, and
friends infl uence how people vote. Advertisements and political arguments are examples
of things that might infl uence a person’s attitudes, beliefs, or behaviors. We will now
see that information presented by others can also infl uence a person’s memory for past
events. We fi rst consider a phenomenon called the misinformation effect, in which a per-
son’s memory for an event is modifi ed by things that happen after the event has occurred.THE MISINFORMATION EFFECT
In a typical memory experiment, a person sees or hears some stimulus, such as words,
letters, or sentences, or observes pictures or a fi lm of an event, and is asked to report
what he or she experienced. But what if the experimenter were to add information that
went beyond simply asking the person what he or she remembered? This is the question
that Elizabeth Loftus and coworkers (1978) asked in a series of pioneering experiments
that established the misinformation effect—misleading information presented after a
person witnesses an event can change how the person describes that event later. This
misleading information is referred to as misleading postevent information, or MPI.TEST YOURSELF 8.2
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