Memory 235the fact that they can actually tie them. Nondeclarative memories also include emotional
associations, habits, and simple conditioned reflexes that may or may not be in conscious
awareness, which are often very strong memories (Schacter & Wagner, 2013; Squire &
Kandel, 2009). to Learning Objective 5.2, 5.3, 5.5. Referring to Chapter Two, the
amygdala is the most probable location for emotional associations, such as fear, and the cer-
ebellum in the hind-brain is responsible for storage of memories of conditioned responses,
skills, and habits (Dębiec et al., 2010; Kandel & Siegelbaum, 2013; Squire et al., 1993).
Evidence that separate areas of the brain control nondeclarative memory comes
from studies of people with damage to the hippocampal area of the brain. This damage
causes them to have anterograde amnesia, in which new long-term declarative mem-
ories cannot be formed. (This disorder is fairly accurately represented by the character
of Lenny in the 2000 motion picture Memento.) One of the more famous anterograde
amnesia patients, H.M., is discussed in detail later in this chapter.
In one study of nondeclarative memory (Cohen et al., 1985), patients with this
disorder were taught how to solve a particular puzzle called the Tower of Hanoi (see
Figure 6. 3 ). Although the patients were able to learn the sequence of moves necessary to
solve the puzzle, when brought back into the testing room at a later time, they could not
remember ever having seen the puzzle before—or, for that matter, the examiner. Yet they
were able to solve the puzzle even while claiming that they had never seen it before. Their
nondeclarative memories for how to solve the puzzle were evidently formed and stored
in a part of the brain separate from the part controlling the memories they could no longer
form. Even people with Alzheimer ’s disease, who also suffer from anterograde amnesia,
do not forget how to walk, talk, fasten clothing, or even tie shoes (although they do lose
motor ability because the brain eventually fails to send the proper signals). These are all
implicit, nondeclarative memories. In fact, it would be rare to find someone who has lost
nondeclarative memory. Literally, these are the kind of memories people “never forget.”
Nondeclarative memories are not easily retrieved into conscious awareness. Have
you ever tried to tell someone how to tie shoes without using your hands to show them?
The subjects in the Tower of Hanoi study also provide a good example of implicit mem-
ory, as they could solve the puzzle but had no conscious knowledge of how to do so. Such
knowledge is in people’s memories because they use this information, but they are often
not consciously aware of this knowledge (Roediger, 1990). A memory from one’s early
childhood of being frightened by a dog, for example, may not be a conscious memory
in later childhood but may still be the cause of that older child’s fear of dogs. Conscious
memories for events in childhood, on the other hand, are usually considered to be a dif-
ferent kind of long-term memory called declarative memory.
DECLARATIVE (EXPLICIT) LTM Nondeclarative memory is about the things that people can
do, but declarative (explicit) memory is about all the things that people can know—the
facts and information that make up knowledge. People know things such as the names
of the planets in the solar system, that adding 2 and 2 makes 4, and that a noun is the
name of a person, place, or thing. These are general facts, but people also know about the
things that have happened to them personally. For example, I know what I ate for break-
fast this morning and what I saw on the way to work, but I don’t know what you had
for breakfast or what you might have seen. There are two types of declarative long-term
memories, semantic and episodic (Nyberg & Tulving, 1996).
One type of declarative memory is general knowledge that anyone has the ability to
know. Most of this information is what is learned in school or by reading. This kind of LTM
is called semantic memory. The word semantic refers to meaning, so this kind of knowledge is
the awareness of the meanings of words, concepts, and terms as well as names of objects, math
skills, and so on. This is also the type of knowledge that is used on game shows such as Jeop-
ardy. Semantic memories, like nondeclarative memories, are relatively permanent. But it is pos-
sible to “lose the way” to this kind of memory, as discussed later in the section on forgetting.
anterograde amnesia
loss of memory from the point of
injury or trauma forward, or the inabil-
ity to form new long-term memories.declarative (explicit) memory
type of long-term memory containing
information that is conscious and
known.semantic memory
type of declarative memory containing
general knowledge, such as knowledge
of language and information learned
in formal education.Figure 6.3 Tower of Hanoi
The Tower of Hanoi is a puzzle that is solved in
a series of steps by moving one disk at a time.
The goal is to move all of the disks from peg A
to peg C; the rules are that a larger disk cannot
be moved on top of a smaller one and a disk
cannot be moved if there are other disks on top
of it. Amnesic patients were able to learn the
procedure for solving the puzzle but could not
remember that they knew how to solve it.ABC
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