What is Nondeclarative Memory?
The functioning of many of our cognitive processes is not available to consciousness. This includes nondeclarative memory. Indeed, when we use it, we are generally not consciously aware that we are memorizing or recollecting anything at all.
Nondeclarative memory (sometimes called implicit memory) is a form long-term memory Opens in new window that influences behavior without involving one’s conscious awareness, as is involved in driving a motor car.
The nondeclarative memory which is roughly equivalent to remembering how to do something, is devoted to the retention of motor skills and is held to be manifest in the procedure called priming Opens in new window whereby one is better able to carry out procedures as a consequence of previous encounters or training.
Unlike declarative memories Opens in new window which can be expressed through conscious recollection with language, nondeclarative memories are usually expressed through some sort of performance, rather than recollection.
Skilled motor behavior, such as dancing or swinging a tennis racket, is not a name, date, place, fact, or event but a collection of finely tuned motor patterns, behaviors, and perceptual skills that one cannot verbally describe.
Again, unlike declarative memories which can be compared and revised, nondeclarative memories can only be slowly refined rather than radically changed. For example, once it is learned, a bad fingering for a passage on a musical instrument is very difficult to unlearn.
Nondeclarative memories are, however, quickly and automatically recallable, without conscious effort. In fact, conscious effort often impedes the use of nondeclarative memory (Reber, 1993: 47).
Most types of nondeclarative memory function to support gradual, incremental learning. That is, behavior is modified through laborious, repetitive practice, experience, or multiple trials. Perhaps as a result of its slow function, a rule of the operation of nondeclarative memory is that the learning is relatively infallible.
A typical example is riding a bicycle — one may not have ridden a bicycle in many years but when s/he rides one again, s/he just knows how.
Indeed, breaking an old nondeclarative pattern can be quite difficult, as exemplified by the tendency to, in a moment of panic, slam the pedals backward (as one does on his/her old 1-speed bike) instead of squeezing the hand brakes (as one should on his or her adult, multi-speed bike).
Types of Nondeclarative Memory
Just as declarative memory Opens in new window is subdivided, so too is nondeclarative memory. The most common categories of nondeclarative memory are
- procedural or motor skill learning,
- priming, and
- classical conditioning.
- Motor Skill
The range of motor skills Opens in new window that people acquire is limitless.
What they have in common is that although there might be a declarative component to them (to stop the bike, put on the brakes), their fluid execution is not accomplished via learning and frequent repetition of the declarative rules, but motor practice.
A tennis or dance instructor can tell one how to hold the racket or how to position one’s foot to produce certain steps, but it is not this knowledge on which accomplished athletes depend.
Closer to home, people all know that to stop cars that they are driving, they put their feet on the brakes. Yet few if any people know how many pounds of pressure they must put on the brake pedal to stop quickly versus more gradually. The information is encoded in their muscles and joints; it is not accessible to conscious access or description.
Priming is another form of nondeclarative memory, which is facilitated processing of a stimulus following prior exposure to the stimulus. Also known as repetitive priming Opens in new window, it consists in two forms.
- Perceptual priming occurs when subsequent processing of a stimulus is facilitated by prior perceptual exposure to it.
- Conceptual priming occurs when there is overlap between related concepts in memory (see below).
A person who has recently studied a list that included the word ‘Alaska’ would be more likely to include it in a list of states than an individual who had not studied the item.
With regard to the distinction between conscious (declarative) and unconscious (nondeclarative) memory, an important point to remember about priming is that it can occur without conscious awareness that the item had been studied earlier, or that subsequent processing was facilitated by earlier processing. That is, facilitated processing occurs even the absence of recognition or recall of the originally studied item.
- Classical Conditioning
Classical conditioning occurs when two stimuli that naturally do not co-occur become associated with one another through repeated pairing.
Typically, one of the stimuli—the unconditioned stimulus —evokes a high probability or even reflexive response termed the unconditioned response. For example, a puff of air to the eye (unconditioned stimulus) produces a blink (unconditioned response).
The other stimulus—the conditioned stimulus—is behaviorally neutral, such as a tone.
Classical conditioning occurs when, over time and repeated pairing of the two stimuli, the conditioned stimulus (the tone) takes on the same significance as the unconditioned stimulus, such that it alone is sufficient to produce the response: anticipatory eye closure at the sound of the tone.
This simple form of learning occurs across phyla (e.g., rodents, nonhuman primates, and humans), making it one of the clearest examples of learning and memory without awareness.
As might be expected, given the diversity of behaviors supported by nondeclarative memory, the different types of nondeclarative memory depend on different neural structures. For example, motor still learning and many types of conditioning are dependent on cerebellum and subcortical structures such as the basal ganglia and priming seems dependent on extrastriate cortex.