Long-Term Memory
Long-term memoryis the relatively permanent and practically unlimited capacity memory
system into which information from short-term memory may pass. LTM is subdivided into
explicit memory and implicit memory. Explicit memory,also called declarative memory,is
our LTM of facts and experiences we consciously know and can verbalize. Explicit memory is
further divided into semantic memoryof facts and general knowledge, and episodic memory
of personally experienced events. Implicit memory,also called nondeclarative memory,is our
long-term memory for skills and procedures to do things affected by previous experience with-
out that experience being consciously recalled. Implicit memory is further divided into proce-
dural memoryof motor and cognitive skills, and classical and operant conditioning effects,
such as automatic associations between stimuli. Procedural memories are tasks that we perform
automatically without thinking, such as tying our shoelaces or swimming.Organization of Memories
How is information in long-term memory organized? Four major models account for organ-
ization of LTM: hierarchies, semantic networks, schemas, and connectionist networks.
Hierarchiesare systems in which concepts are arranged from more general to more specific
classes.Concepts,mental representations of related things, may represent physical objects,
events, organisms, attributes, or even abstractions. Concepts can be simple or complex.
Many concepts have prototypes,which are the most typical examples of the concept. For
example, a robin is a prototype for the concept bird; but penguin, emu, and ostrich are not.
The basic level in the hierarchy, such as bird in our example, gives us as much detail as we
normally need. Superordinate concepts include clusters of basic concepts, such as the concept
vertebrates, which includes birds. Subordinate concepts are instances of basic concepts.
Semantic networksare more irregular and distorted systems than strict hierarchies, with
multiple links from one concept to others. Elements of semantic networks are not limited
to particular aspects of items. For example, in a semantic network, the concept of bird can
be linked to fly, feathers, wings, animals, vertebrate, robin, canary, and others, which can
be linked to many other concepts. We build mental maps that organize and connect con-
cepts to let us process complex experiences. Dr. Steve Kosslyn showed that we seem to scan
a visual image of a picture (mental map) in our mind when asked questions. Schemasare
preexisting mental frameworks that start as basic operations, then get more and more com-
plex as we gain additional information. These frameworks enable us to organize and inter-
pret new information, and can be easily expanded. These large knowledge structures
influence the way we encode, make inferences about, and recall information. A scriptis a
schema for an event. For example, because we have a script for elementary school, even if
we’ve never been to a particular elementary school, we expect it to have teachers, young stu-
dents, a principal, classrooms with desks and chairs, etc. Connectionismtheory states that
memory is stored throughout the brain in connections between neurons,many of which
work together to process a single memory. Changes in the strength of synaptic connections
are the basis of memory. Cognitive psychologists and computer scientists interested in artifi-
cial intelligence(AI) have designed the neural networkorparallel processing modelthat
emphasizes the simultaneous processing of information, which occurs automatically and
without our awareness. Neural network computer models are based on neuron-like systems,
which are biological rather than artificially contrived computer codes; they can learn, adapt to
new situations, and deal with imprecise and incomplete information.Biology of Long-Term Memory
According to neuroscientists, learning involves strengthening of neural connections at
the synapses, called long-term potentiation(or LTP). LTP involves an increase in the130 ❯ STEP 4. Review the Knowledge You Need to Score High