Handbook of Psychology, Volume 4: Experimental Psychology

Repetition Priming 463

Instance Theory

Logan (1988, 1990) has taken a different approach to eluci-
dating the processes that may underlie repetition priming. In
an effort to bridge the gap between research on repetition
priming (the effects ofoneprior exposure on performance)
and research on automaticity (the effects ofvery manyexpo-
sures on performance), Logan proposed that repetition prim-
ing may be a form of skill acquisition governed by a power
function of the number of practice trials. Essentially, Logan
has suggested that repetition priming and automaticity may
reflect two ends of the same continuum. According to Logan’s
instance theory, initial performance on a task is determined by
a general problem-solving algorithm. As the task progresses,
every encounter with a stimulus is stored as a separate in-
stance, even if it is identical to a previous episode. Eventually
a level of proficiency with the task may be reached at which
the algorithm can be abandoned and responses can be made
solely on the basis of instances (i.e., automatically). Presum-
ably, the retrieval of instances can be more efficient than per-
formance of the algorithm. Performance between these two
extremes may be automatic for some trials, but not for others.
As more instances of a particular stimulus are encoded, the
likelihood that the stimulus will receive an automatic re-
sponse increases. Thus, repetition priming reflects the
increased likelihood of an automatic response’s following a
single prior exposure to a stimulus. A problem for the instance
theory is that experiments by Kirsner and Speelman (1996)
have provided evidence suggesting that repetition priming
can be indifferent to practice and may in fact be a one-shot ef-
fect. These findings certainly cast some doubt on the notion
that repetition priming and skill acquisition reflect the opera-
tion of the same underlying mechanism.

Distributed Network Models

Repetition priming can be explained in distributed network
models in much the same way as semantic priming is ex-
plained in these models. Indeed, repetition priming can be
viewed as an example of semantic priming in which the
prime’s and the target’s semantic representations (as well as
orthographic and phonological representations) are identical.
Relatively few distributed network models have been applied
to repetition priming (but see McClelland & Rumelhart,
1985; Stark & McClelland, 2000), although repetition-
priming effects are often interpreted in the context of these
models (e.g., Rueckl, Mikolinski, Raveh, Miner, & Mars,
1997). Distributed network models of repetition priming
have not been investigated in as much depth as have distrib-
uted network models of semantic priming, and little is known

about their abilities to account for the major results in the

literature.

Major Issues and Findings

As mentioned earlier, research on repetition priming began

with studies of patients suffering from impairments of explicit

memory. It is not surprising, therefore, that from these earliest

observations repetition priming has often been viewed as a

form of memory, a type of implicit memory that remains intact

in amnesics. Today the termimplicit memoryencompasses a

variety of phenomena (e.g., semantic priming, classical con-

ditioning) whose common feature is the influence of prior

episodes on behavior without effortful, or explicit, retrieval of

those episodes (for reviews, see Richardson-Klavehn &

Bjork, 1988; Squire et al., 1993). Repetition priming repre-

sents one of the most thoroughly researched of these phenom-

ena. The discussion that follows highlights some of the major

findings in the repetition-priming literature, as well as the pri-

mary theoretical approaches that have guided the research.

Dissociations from Explicit Memory

If studies of implicit and explicit memory measures produced

differences only in an amnesic population, the results of such

studies might be of limited interest. However, similar dissoci-

ations between implicit and explicit memory performance

have been repeatedly demonstrated in normal participants (for

a review, see Richardson-Klavehn & Bjork, 1988). Disso-

ciations between implicit and explicit memory performance in

normal participants, however, are typically of a different na-

ture. Rather than demonstrating apresenceof implicit mem-

ory and anabsenceof explicit memory as in amnesic patients,

dissociations in normal participants are typically demon-

strated through differential effects of manipulating an inde-

pendent variable on measures of implicit and explicit memory.

Levels of Processing. Jacoby and Dallas (1981) demon-

strated that manipulating the level of processing of study

words did not affect the magnitude of repetition priming in a

perceptual identification task (i.e., accuracy of correctly iden-

tifying briefly presented stimuli), but it produced large effects

on an explicit recognition task (prior semantic processing of

words yielded better performance than phonemic or ortho-

graphic processing). Insensitivity of repetition priming to

level of processing manipulations has also been demon-

strated using word fragment completion (e.g., Graf &

Mandler, 1984), lexical decision (e.g., Monsell, 1985), per-

ceptual identification of pictures (e.g., Carroll, Byrne, &

Kirsner, 1985) and picture naming (e.g., Carroll et al., 1985).