Chapter 9: Memory
The Phenomenon of Memory
Information Processing
Memory is the persistence of learning over time. Psychologists have proposed several information-processing
models of memory. We will use the influential three-stage processing model, which suggests that we (1)
register fleeting sensory memories, some of which are (2) processed into on-screen short-term or working
memories, a tiny fraction of which are (3) encoded for long-term memory and, possibly, later retrieval.
Encoding: Getting Information In
How and What We Encode
Some types of information, notably information concerning space, time, and frequency, we encode mostly
automatically. Other types of information, including much of our processing of meaning, imagery, and
organization, require effort. Mnemonic devices depend on the memorability of visual images and of information
that is organized into chunks. Organizing information into chunks and hierarchies also aids memory.
Storage: Retaining Information
Sensory Memory
Information first enters the memory system through the senses. We register and briefly store visual images via
iconic memory and sounds via echoic memory.
Working/Short-Term and Long-Term Memory
Our short-term memory span for information just presented is limited—a seconds-long retention of up to about
seven items, depending on the information and how it is presented. Our capacity for storing information
permanently in long-term memory is essentially unlimited.
Storing Memories in the Brain
The search for the physical basis of memory has recently focused on the synapses and their neurotransmitters;
on the long-term potentiation of brain circuits, such as those running through the hippocampus; and on the
effects of stress hormones on memory. Studies of people with brain damage reveal that we have two types of
memory operating together—explicit (declarative) memories processed by the hippocampus, and implicit
(procedural) memories processed by the cerebellum and the amygdala.
Retrieval: Getting Information Out
Retrieval Cues
To be remembered, information must be encoded, stored, and then retrieved. Memory is recall, recognition, and
relearning. With the aid of associations (cues) that prime the memory, we retrieve the information we want to
remember. Cues sometimes come from returning to the original context. We use our senses as cues-a taste,
smell, or sight may evoke us to recall a memory. Mood affects memory, too. While in a good or bad mood, we
tend to retrieve memories congruent with that mood.
Forgetting
Encoding Failure
One explanation of forgetting is that we fail to encode information for entry into our memory system. Without
effortful processing, we never notice or process much of what we sense. Age affects encoding efficiency, which
explains age-related decline.
Storage Decay
Memories may also fade after storage—often rapidly at first, and then leveling off. This is the basis for one of
psychology’s laws, the forgetting curve.
Retrieval Failure
Forgetting also results from retrieval failure. Retrieval-related forgetting may be caused by a lack of retrieval
cues, by proactive or retroactive interference, or even, said Freud, by motivated forgetting.
Memory Construction
Misinformation and Imagination Effects
Memories are not stored as exact copies, and they certainly are not retrieved as such. Rather, we construct our
memories, using both stored and new information. Thus, when child or adult eyewitnesses are subtly exposed
to misinformation after an event, they often believe they saw the misleading details as part of the event.
Source Amnesia
People also exhibit source amnesia, by attributing something heard, read, or imagined to a wrong source.
Because false memories feel like true memories and are equally durable, sincerity need not signify reality.
Discerning True and False Memories
Determining the validity of a memory is difficult. A false memory may feel real and it may be persistent.
Interviewers may ask leading questions, contributing to the misinformation effect. True memories tend to be
more detailed than imagined ones, which tend to be the gist of the meaning and feelings associated with an
event.
Children’s Eyewitness Recall
Children are suggestible and, if asked leading questions, can report false events. On the other hand, if children
are interviewed using the cognitive interview technique in developmentally-appropriate language, recalled
memories can be accurate.
Repressed or Constructed Memories of Abuse?
Memory researchers are especially suspicious of claims of long-repressed memories of sexual abuse, UFO
abduction, or other traumas "recovered" with the aid of a therapist or suggestive book. More than we once
supposed, incest and abuse happen. But unless the victim was a child too young to remember any early
experiences, such traumas are usually remembered vividly, not banished into an active but inaccessible
unconscious.
Improving Memory
The psychology of memory suggests concrete strategies for improving memory. These include spaced study;
active rehearsal; encoding of well-organized, vivid, meaningful associations; mnemonic techniques; returning to
contexts and moods that are rich with associations; recording memories before misinformation can corrupt
them; minimizing interference; and self-testing and rehearsal.