500Procedural Memory and Skill Acquisition
influential ACT* (and ACT-R) model of the development of
cognitive skill, Anderson (1982, 1983, 1993) calls the first
stage in the development of skill the declarative stage.
Anderson’s work will be more fully described in a later
section. At this point it is sufficient to note that the declarative
stage is one in which verbal mediation is used to maintain
facts in working memory so that they can be used to execute
the task at hand. In other words, performance at this level
depends heavily on declarative memory. Fitts (1962/1990,
1964; Fitts & Posner, 1967) called the first phase of skill
acquisition by a different name, but his cognitive phasealso
depends heavily on declarative memory for comprehending
instructions and maintaining a description of the cues that
must be attended to and the relevance of the feedback that is
provided during performance. In the frameworks of both
Anderson and Fitts, the development of skill is characterized
by reduced dependence on declarative memory.
Atleastoneaccountofskillacquisition,Logan’s(1988,
1990)instancetheoryofautomaticity,suggeststhatmemory
demandsofperformancedonotqualitativelychangeasa
functionofskill,atleastnotoncethebasicinstructionshave
beenmastered.Logan’stheorymaynotapplytoskillacquisi-
tioninabroadsense,butithasbeentoshowntoprovidea
gooddescriptionofthedevelopmentofskilledperformance
inarangeofcognitivetasks.Logandescribesthedevelop-
mentofautomaticityastheshiftfromadependenceongen-
eralalgorithmsthatdonotrelyonpreviousexperiencebut
thataresufficienttoproducesolutionstoproblemsposed
bythetask,toarelianceontheretrievalofperformance
episodes.Memoryplaysacriticalroleinthismodelinwhich
skilled,automaticperformanceentailsashiftfromalgorithm-
basedperformancetomemory-basedperformance.
The instance theory of automaticity rests on several as-
sumptions. The first of these assumptions is that encoding
isobligatory, such that attention to an object or event is
sufficient for it to be encoded into memory. The second as-
sumption calls for obligatory retrieval, in which attention to
an object or event is sufficient to cause things associated with
it to be retrieved. An additional, critical assumption is that
each encounter with an object or event is encoded, stored,
and retrieved separately, and on every encounter. These en-
counters are the instances in the instance theory of auto-
maticity. As mentioned above, the instance theory assumes
that automaticity involves a transition from performance
based on general rules or algorithms for performing a task to
performance based on the retrieval of instances. Once perfor-
mance is instance based, it continues to speed up because the
number of instances continues to increase as long as the task
is practiced. This speed-up is predicted on the basis of the sta-
tistical properties of the distribution of retrieval times for
instances: As the number of instances increases, the mini-
mum time to retrieve an instance decreases. Because retrieval
is obligatory, according to the theory, performance time will
decrease as a function of practice due to this faster retrieval
time. An important aspect of the theory is that it predicts that
changes in performance will follow a power function. This is
consistent with the power law of practice,which reflects the
finding that performance improvements in many tasks follow
a power function (see Figure 18.1).
It can be argued that the early dependence on an algorithm
for task performance can be likened to the declarative or cog-
nitive phase of the frameworks of Fitts (1962/1990, 1964)
and Anderson (1982, 1983). At this stage, the rules or guide-
lines for performing a task presumably must be active in
working memory, and performance is relatively deliberative
and slow. As a result of experience, and of paying attention to
the right things at the right time, a collection of memory
traces, or instances, builds up and gradually comes to domi-
nate performance.The Roles of Attention and Intention
in Memory and SkillAttention has assumed a curious place in the study of skill ac-
quisition. Often, it seems that the goal of researchers has been
to show that attention may not be necessary at all once a skill
has been learned. The traditional view of attentive processing
(or “controlled” processing; Atkinson & Shiffrin, 1968) is
that it is relatively slow, requires effort, and involves con-
sciousness of one’s actions. Skill is described as a gradual
(orabrupt) freeing of resources and shift to a capacity-free,Figure 18.1Performance speed-up in various tasks illustrating the power
law of practice.Note:When plotted in log-log coordinates, a power func-
tion appears as a straight line. CRT=choice reaction time; S-R =stimulus-
response.