Priming and Implicit Memory: a Review and a Synthesis Relevant For Consumer Behavior

Abhijit Sanyal, University of Massachusetts at Amherst
ABSTRACT - The idea of implicit memory have recently seen a resurgence of interest in the memory and cognition literature. A major issue is that of dissociations or independence between explicit and implicit memory systems. An ongoing and unresolved debate is how to reconcile the data with various theoretical frameworks. The findings and issues from the psychological literature are briefly discussed followed by some of these issues which could have relevance for consumer behavior.
[ to cite ]:
Abhijit Sanyal (1992) ,"Priming and Implicit Memory: a Review and a Synthesis Relevant For Consumer Behavior", in NA - Advances in Consumer Research Volume 19, eds. John F. Sherry, Jr. and Brian Sternthal, Provo, UT : Association for Consumer Research, Pages: 795-805.

Advances in Consumer Research Volume 19, 1992      Pages 795-805

PRIMING AND IMPLICIT MEMORY: A REVIEW AND A SYNTHESIS RELEVANT FOR CONSUMER BEHAVIOR

Abhijit Sanyal, University of Massachusetts at Amherst

ABSTRACT -

The idea of implicit memory have recently seen a resurgence of interest in the memory and cognition literature. A major issue is that of dissociations or independence between explicit and implicit memory systems. An ongoing and unresolved debate is how to reconcile the data with various theoretical frameworks. The findings and issues from the psychological literature are briefly discussed followed by some of these issues which could have relevance for consumer behavior.

INTRODUCTION

Schacter (1987) and Tulving and Schacter (1990) posit that there is now increasing evidence of yet another category of learning and memory which cannot be classified as belonging to any of the existing memory structures. This type of memory has been labeled as "implicit memory" (Graf and Schacter; 1985, 1987;). Consumer researchers should be aware of the progress and problems faced in this area as it might provide some insights into consumer decision making. The Wall Street Journal (McCarthy, pp B3; March 22, 1991) in a special report have also raised this issue and the subject may become increasingly important for advertisers and practitioners.

Implicit memory is revealed when previous experiences facilitate performance on a task that does not require conscious or intentional recollection of those experiences. This is to be distinguished from "explicit memory" which refers to conscious recollection of recently presented information found in traditional test of free recall, cued recall and recognition. A key issue in this area is that implicit and explicit forms of memory can be quite independent of each other (Graf and Schacter, 1985; Schacter, 1987) which is refered to as dissociation. In other words, implicit memory appears to be less affected by the kinds of interference manipulations that reduce retention in explicit tasks (Jacoby, 1983a; Graf and Schacter, 1985).

In this article I review some key aspects of implicit memory relevant to consumer behavior and discuss some possible areas of research.

IMPLICIT MEMORY AND PRIMING

Definitional and procedural aspects of Priming

The operative word "priming" has been used in various fields and sub-fields of psychology. Priming refers to the process by which previous experience increases the general accessibility of a conceptual category, thereby increasing the likelihood of that category being used to encode new information (Fiske and Taylor 1990). In social cognition, priming has been mostly exhibited with the usage of trait terms. Thus exposing people to positive or negative trait terms (e.g., reckless versus adventurous) causes people soon afterwards to interpret ambiguous behavior (e.g., shooting rapids in a canoe) as correspondingly positive or negative depending on the trait being primed and its corresponding meaning (Higgins, Rholes and Jones, 1977; Bargh and Pietromonaco, 1982; Srull and Wyer, 1979, 1980).

Graf and Schacter (1985) introduced the concept of implicit versus explicit memory, which was more of a descriptive as opposed to a process distinction. They stated that "implicit memory is revealed when performance on a task is facilitated in the absence of conscious recollection; explicit memory is revealed when performance on a task requires conscious recollection of previous experiences". Thus performance on implicit memory measures is revealed only when priming occurs. It should be clarified here that priming does not always imply the operation of the hypothetical implicit memory system. Priming being an activation process can also underlie explicit memory (Ratcliff and McKoon 1988). In some of the literature however (Schacter, Delaney and Merikle, 1990) the term "priming" has been used interchangeably with implicit memory and is therefore a source of considerable confusion.

Priming experiments whether from social cognition or repetition priming typically consists of two (or three) stages with exposure to the prime (positive or negative trait terms; e.g., adventurous versus reckless) followed by the target stimulus in a seemingly unrelated context (reading about the un/ambiguous behavior of the targeted individual ; e.g., shooting rapids) An evaluative test of the individual (positive/negative) is thereafter taken to determine the extent of the priming effect (Higgins, Rholes and Jones, 1977). Caution is usually exercised in separating out the prime from the target with some intervening distractor task so as to ensure that subjects are unaware of the prime (Bargh and Pietromonaco, 1982).

The task flow in other priming studies is the same although researchers in this area combine the target stimulus and rating stages into two stages; study and test (Tulving and Schacter, 1990). In the first stage - the study phase, the subject is presented with a stimulus object. This stimulus object may comprise words (semantic and verbal) or line drawings of object, drawings of faces and so forth. In the second (test) stage which follows the first after an interval of maybe a few seconds to days or weeks, the subject is given reduced perceptual information about the object and asked to name or categorize it. These reduced cues may consist of initial letters or fragments of words, incomplete words or figures, originally presented faces in a more schematized form or tachistoscopic presentation of stimuli. Direct priming is a situation when the cues are the same as the stimulus. Priming is said to have been displayed if the probability of the identification of the previously encountered stimulus object is increased. It is also evidenced if the latency measures for nonstudied control items. A magnitude of the priming effect is provided by the difference between performance on the target items and the nonstudied items.

Definitional aspects of Implicit Memory

Implicit memory should be defined (to avoid any ambiguity) in terms of unintentional or involuntary retrieval processes and the concept is restricted to those cases in which it is possible to demonstrate that test performance is facilitated by information acquired during a study episode without any recollective re-experiencing or awareness of remembering on the subject's part (Schacter, Bowers, and Booker; 1989). It should also be demonstrated that explicit memory performance is at or near chance levels, which in turn would imply that priming effects do not involve awareness of the study episode. This is discussed later under the "retrieval intentionality criterion".

The explicit/implicit memory distinction that Schacter and his colleagues have made is a widely used taxonomy. The above definition of implicit memory therefore can refer to two classes of phenomena (Dunn and Kirsner, 1989). The first consists of observable properties of the experimental situation, such as prior presentation of stimulus material, facilitation in performance and the nature of instructions viz., task characteristics. The second consists of unobservable mental events, such as conscious recollection which accompany the different forms of memory - a process perspective. It is possible therefore to distinguish between explicit and implicit memory tasks on one hand and processes on the other hand, although it is not clear whether the task distinction maps in any direct way onto the process distinction. A necessary assumption (the transparency assumption, Dunn and Kirsner, 1989) made in the literature in order to support "dissociation" effects is that there is a one to one mapping from task to process.

To mitigate the likely problems arising from this transparency assumption, Johnson and Hasher (1987) and Richardson-Klavehn and Bjork (1988) have used the terms direct and indirect tests to characterize the two classes of memory measures. Direct memory tests (recall, recognition) make reference to a target event and success is achieved when the respondent/subject gives behavioral evidence of knowledge concerning that event. Indirect tests require the subjects to engage in some form of cognitive or motor activity with no reference being made to prior events. The measures of interest in this case are shown to be facilitated in terms of task performance by relevant prior experience even though no explicit reference was made to them.

Richardson-Klavehn and Bjork (1988) have argued that there are a few major negative consequences of using the explicit/implicit memory distinctions to refer to both tasks and forms of memory. They use the terms direct/indirect to refer to tasks and methods of measurement. In the literature the terms implicit and explicit memory has been used interchangeably to refer to tasks and methods of measurement or also to indicate hypothetical forms of memory - a term descriptive of mental content. Implicit memory can be a task-based definition (Schacter 1985) and it can also be inferred from dissociation between two measures of memory (Graf and Schacter, 1985). Similarly direct memory tests which have been defined as "conscious recollection" (Graf and Schacter, 1985) or "conscious awareness" (Roediger and Blaxton, 1987a, p 351) imply that in the test stage, awareness is based on task instructions and consequent intention to retrieve material from the study episode. This is a task based definition while subjective awareness is again a case of reexperiencing the episode, the existence of which is inferred from the data.

An assumption is usually made in the literature that a particular method of testing reveals only one underlying form of memory and therefore different methods of testing would indicate evidence of different forms of memory (Graf and Schacter, 1987). Different testing methods reveal different forms of memory only when dissociations between those methods of measurement are observed. Direct and indirect measures are sometimes influenced similarly by certain variables (Richardson-Klavehn and Bjork; 1988). In this case we do not know whether two different forms of memory are being affected or whether the same form of memory is being engaged by both types of tasks.

In the earlier definition of implicit memory given by Schacter and his colleagues, implicit memory is inferred from dissociation between explicit and implicit forms of memory. Thus if intentional retrieval is equated with explicit memory then this would rule out cases when subjects might become aware of a prior event without attempting to do so - a situation of involuntary explicit memory. Some untenable assumptions are necessary about the mental states or processes which ignores the complexity of such processes.

It is therefore suggested that the terms direct and indirect be used to distinguish memory tests which would be based on instructions and methods of measurement. This would make minimal a priori assumptions assumptions concerning the mental states and processes involved in performing the tasks. The terms explicit and implicit memory should be therefore used to refer to the effects of an episode that are expressed without awareness of remembering, and with awareness of remembering, respectively (Richardson-Klavehn and Bjork; 1988). An useful taxonomy adapted from Richardson-Klavehn and Bjork (1988) for only normal subjects is given below:

Schacter, Bowers, and Booker (1989) advise in using the retrieval intentionality criterion (RIC) to provide a non-circular, empirical testable way of distinguishing between explicit and implicit tests. This criterion consists of three key components: (1) the same nominal cues should be presented to subjects on implicit and explicit tests.; (2) only the implicit/explicit nature of test instructions should be varied, and (3) an experimental or subject variable should be identified that produces dissociations between implicit and explicit task performance. When an implicit/explicit dissociation is observed under these conditions, then only can the possibility that subjects use explicit strategies on the implicit test be ruled out.

TABLE 1

FREQUENCY WITH WHICH A GIVEN FORM OF MEMORY CONTRIBUTES TO PERFORMANCE IN DIRECT AND INDIRECT TEST

It is suggested that the framework provided by Richardson-Klavehn and Bjork (1988) with regard to direct and indirect tests and the retrieval intentionality criterion (RIC) be used in future research. The above frameworks does not appear to have been used in consumer research and is a fruitful area of inquiry. As a starting point it can be useful to determine, using the RIC, whether the construct of implicit memory using the implicit memory measures can be replicated in the consumer research context. Nedungadi (1990) has used word completion - an implicit memory measure in one of his studies.

THEORETICAL ACCOUNTS:

In the social cognition literature the theoretical background assumed is mostly activation theory (detailed below) and the studies are at a more molar level without any debate regarding the appropriate memory system being used. There is however considerable turmoil regarding this issue in direct priming (see below) and the issue is analyzed at a more molecular level with no discernible agreement in the research community as to the appropriate theoretical (memory) framework.

Multiple Memory Systems View

Schacter (1987) has forwarded three main classes of theory to explain the distinction between explicit and implicit memory systems. The first of these is called the multiple memory systems view. and its major support arises from the observed independence or dissociation between explicit and implicit memory systems (Schacter, 1987)

These dissociations as Schacter (1987) Tulving and Schacter (1990) argue lead to the possibility of a single perceptual representation (PRS) which may exist separately from other memory systems and suggest that implicit and explicit memory performance are reflections of the operation of separate subsystems in memory.

These separate subsystems are characterized by different rules and operations and different candidate subsystems have been proposed as underlying the distinction (Squire; 1986). Squire and Cohen (1984) have argued that conscious or explicit recall is a property of and supported by a declarative memory system that is involved in the formation of new representations of data structures. Implicit memory such as learning of skills and repetition priming effects are attributed to a procedural system of memory characterized by online modification of procedures or processing operations.

The distinction between episodic and semantic memory has also been invoked to to account for this dissociation, (Tulving, 1972, Cermak et al., 1985; Kinsbourne and Wood, 1975; Parkin, 1982; Tulving and Schacter, 1982; Tulving, 1983). The episodic memory system is viewed as the basis for explicit recollection of specific events, whereas semantic memory is seen as responsible for performance on tasks such as word completion, lexical decision, and word identification which require subjects to make use of pre-existing knowledge of words and concepts. Other multiple memory systems have also been proposed to account for the observed data with regard to explicit and implicit memory systems (Johnson, 1985; Schacter and Moscovitch, 1984; Warrington and Weiskrantz, 1978).

Another related issue is that of the strong view versus the weaker account (Sherry and Schacter, 1987; Parkin, 1989). A strong view would argue that these systems are completely independent of each other and the operation of one exerts no influence on the operation of the other. A weaker account proposes that different systems exist but their outputs can influence the performance of each other. The results and arguments forwarded by Parkin (1989), Schacter, Delaney and Merikle (1990) favors the weaker version of a multiple memory system.

If performance on implicit priming tests is mediated by a single memory system then stochastic dependence between two implicit tests should be found. However results by Witherspoon and Moscovitch (1989) show stochastic independence between word-fragment completion and perceptual identification. These results are not consistent with the multiple memory systems view and one interpretation is to argue that the the degree of dependence between performances on direct or indirect memory tests is determined by the similarity (or dissimilarity) of information usage and of the different parts or component processes that the tests use.

Processing View

A second theoretical account is proposed by the processing view in which the interaction between encoding and retrieval is the focus (Jacoby, 1983; Roediger and Blaxton, 1987a, Hunt and Toth, 1990). This relies on the distinction between conceptually-driven (top-down) and data driven (bottom-up) processing. Conceptually driven processes reflect subject-initiated activities such as elaborating, organizing and reconstructing; data-driven processes are initiated by the information or data that is presented in test materials. The major argument is that information encoded via one of these general types of processes is best retrieved using the same or similar process. Thus most explicit tests emphasize concept-driven processing while most implicit tests draw on data-driven processing and performance dissociations between implicit and explicit tests are attributed to differences between conceptually driven and data driven processes. Hunt and Toth (1990) have reported some limitations in using this framework with regard to the effect of orthographic distinctiveness of words.

Activation View

The third class of theories are those espousing the activation view. Activation holds that priming effects on implicit memory are attributable to the temporary activation of preexisting representations, knowledge structures or logogens (Graf and Mandler, 1984; Morton, 1979). This activation is automatic and decontextualized and is not affected by any ongoing elaborative processing. An activated representation readily pops into mind on an implicit memory test but since it is decontextualized, does not contribute to explicit remembering of the episode. Priming studies in the social cognition area mostly use this class of theoretical framework (Fiske and Taylor, 1990).

As Schacter's (1987) review suggest, none of the three existing theoretical approaches can accommodate all of the available data. Another perspective suggests whether the current theoretical debate with regard to implicit memory is a spurious debate in the sense that the problem is impossible to solve (Snodgrass, 1989; Lockhart, 1989).

FINDINGS IN "PRIMING AND IMPLICIT MEMORY" RELEVANT

FOR CONSUMER BEHAVIOR

In the next few pages I will make an attempt to briefly present what I feel are some of the relevant findings in priming and implicit memory that may be of some importance in studying consumer behavior.

Factors from studies in social cognition known to affect priming

Several factors in social cognition have been found to influence the accessibility of using a primed trait. In other words the effects of priming on dimensions descriptively or evaluatively related to the primed trait are increased (or assimilated) by: (a) increasing the number of trait-relevant items used during the priming task (Srull and Wyer, 1979; 1980); (b) decreasing the time interval between the priming task and the presentation of information about the target character (Srull and Wyer, 1979,1980); (c) increasing time interval between the target character's information (behaviors) and the judgment (Srull and Wyer, 1980); (d) increasing the ambiguity of the target character's behavior (Srull and Wyer, 1979); (e) increasing expectations that category-relevant events will occur (Higgins, Kuiper and Olson, 1980); (f) increasing frequency of activation of the category (Wyer and Srull, 1980) and (g) increasing the strength of semantic relationships between the category and other activated concepts (Collins and Loftus, 1975; Warren 1972).

In the above it can be observed that the activation view of memory systems is used as a theoretical background. Consumer researchers have used some of the above factors in several studies eg., time interval effects (Wyer and Hong, 1990), ambiguity of the target's attributes (Herr, 1988).

Dissociations between implicit and explicit memory:

As stated earlier dissociation in performance on the two types of memory tests (explicit or implicit) has sparked significant research interest in implicit memory. An useful framework to review these dissociations is to think of them as arising from "subject variables" or "experimental variables". With respect to "subject variables" the two factors that have shown robust dissociations are (1) performances by amnesics on implicit memory as compared to recall and recognition measures and (2) age effects also called developmental effects. Many experimental variables also produce dissociations but the more important ones are retention interval, semantic encoding or the level of processing, and modality shifts between study and test. Other relevant factors of interest to consumer research including semantic priming and the specificity of priming effects, will be also briefly discussed.

Developmental Effects

Though recognition memory increases with age, priming effects can be as large as in 3-year olds as in college students (Gollin, 1962; 1966) Similarly elderly subjects have difficulty with recall and recognition, but their priming effects are indistinguishable from that of young adults (Caroll, Byrne and Kirsner, 1985; Mitchell, 1989).

Priming effects of nonverbal information are reasonably robust across age groups (Mitchell, 1989). Mitchell (1989), observed a robust facilitation of naming latency (as compared to explicit memory tests) in young and old subjects at different intervals between presentation of the prime and the target stimulus. Similarly Light and Singh (1987) have also found that although young subjects had a differential advantage over older subjects on recall and recognition, the two age groups performed equivalently on word completion and recognition. Studies by Gollin (1960, 1962), Parkin and Streete (1988), Caroll, Byrne and Kirsner (1985) all point to strong priming effects regardless of age of the subjects.

The robust priming effects across age groups has implications in terms of research of advertising and brand name effects on children and the elderly. The elderly consumer may have weak recall or recognition of ad message or contents but may be primed with the brand name or other memory based cues so as to influence judgment and choice.

Effects of retention interval:

Retention interval indicates the time interval between study and test or also between test and taking the final rating. Forgetting on implicit memory tasks is slower than forgetting on explicit memory tasks and the duration of priming effects in implicit memory can be as long as one year (Mitchell and Brown, 1988; Tulving, Schacter and Stark, 1982). Priming effects on implicit memory tests have been found to be greater for subjects who experienced a delay between the stimulus and the rating than other subjects who experienced a delay between the priming and the stimulus paragraph (Srull and Wyer 1980). It is therefore important that the prime and target stimulus occur in close temporal contiguity, as the effect depends on the target stimulus being encoded in terms of the prime. Implicit memory test performance have been found to decrease with wider gaps between a prime (study) and stimulus (test) (Fiske and Taylor, 1990). The wider gap possibly interferes with the process of encoding the stimulus in terms of the prime.

Priming effects have also been found to actually increase with greater time intervals between the target stimulus (test) and the rating, holding the time interval between the prime (study) and the stimulus (target) constant (Fiske and Taylor, 1990). Once a stimulus has been encoded in terms of the prime, then the longer it sits in memory linked to that particular prime, the stronger the prime's effects. This evidence suggests an encoding explanation for priming because the delayed rating must be less dependent on ability to use the initial prime itself as retrieval cue, since retrieval of the prime becomes more difficult over time. As the effect increases with time, it suggests that the details of the original stimulus are lost and the primed representation becomes relatively important.

Results by Musen and Triesman (1990) suggest that a single exposure to novel, nonverbal stimuli was sufficient to establish a long duration of perceptual priming as compared to recognition memory loss over the same time period.

Level of processing:

Level of processing (LOP) or semantic processing produces better recognition and recall (Craik and Lockhart, 1972; Craik and Tulving, 1975) but does not seem to affect implicit memory performance (Jacoby and Dallas, 1981). In Jacoby and Dallas (1981) manipulating the LOP of study words had no affect on repetition priming in perceptual identification (implicit memory test) but semantically processed words yielded superior performance on recall and recognition than phonemically or orthographically processed words. Null effects of study LOP on repetition priming have been also found for word completion (Graf and Mandler 1984) lexical decision (Kirsner, Milech and Standen, 1983, Expts 2 and 3) picture naming latency (Caroll, Byrne and Kirsner; 1985, Expts 1-3) and perceptual identification of pictures (Caroll, Byrne and Kirsner; 1985, Expt 4). In all these studies, explicit memory tests showed a large LOP effect for the same study and test stimuli. Jacoby (1983) has shown that while generation (high LOP) produced better recognition memory than a reading task (low LOP), there were opposite effects in perceptual identification (implicit memory task) ie., read tasks produced better performance than generate.

The LOP variable has been used in consumer research (Bettman and Sujan, 1987) but LOP variable effects on implicit memory tests have not to the knowledge of the author been used in consumer behavior.

Modality Effects

Under the processing view (Jacoby, 1983; Roediger, Weldon and Challis, 1989; Roediger and Blaxton, 1987, a,b), explicit tests emphasize elaborated, semantic information in memory and therefore are not sensitive to modality (visual versus auditory) differences. Most implicit tests being data driven, are quite sensitive to the modality match between study and test (Graf, Shimamura and Squire, 1985; Kirsner, Milech and Standen, 1983). The above is an issue of modality sensitivity across explicit and implicit memories.

A related issue is that of priming across modality within the same implicit test. Thus Jacoby and Dallas (1981) had subjects study words either visually or auditorily and then try to identify visually degraded words. There was substantial priming effects on the visual implicit test for visually studied words but not for auditorily studied words.

Winnick and Daniel (1970) found that recall was higher following study of a picture than study of the corresponding word, but priming effects on the word-identification test were greater following study of the word than study of the picture (see also Weldon and Roediger; 1987). This was further corroborated in lexical decision making (Scarborough et al. 1979) and fragment completion (Ellis and Collins, 1983). The more common pattern is to observe a gradient of priming - more priming within modality (A-A or V-V) than across modality (A-V, V-A), but significant priming even across modality (Bassili, Smith and MacLeod, 1989). This pattern also appears in word fragment completion (Roediger and Blaxton, 1987,a,b), word identification (Kirsner et al., 1983; Postman and Rosenzweig, 1956) and lexical decision (Kirsner and Smith, 1974; Kirsner et al., 1983).

Despite some inconsistencies and variabilities in the results it can be concluded that there is generally less priming from pictures to words and words to pictures than from words to words or pictures to pictures. In other words priming is reduced in intermodal conditions as compared to intramodal conditions. This also indicates that the physical form of a stimulus plays a large role in priming and is consistent with the data processing point of view. The finding that studying familiar pictures enhances recall and recognition while producing little or no priming effects on word identification, fragment completion and lexical decision tasks, (Graf et al., 1985; Kirsner et al 1983) also indicates that form based information plays a different role in priming as compared to explicit memory. This is also consistent with the idea that most explicit tests are largely conceptually driven. The importance of form information of a stimulus is observed only for repetition or direct priming. In semantic priming or associative priming there is evidence of extensive and even complete transfer between pictures and words. (Vanderwart, 1984).

Semantic Priming and Brand Names

In a typical semantic priming experiment,the subjects performs a "lexical decision" task, in which words must be discriminated from nonword letter strings. Nonwords conform to the orthographic (spelling systems) rules of the language and therefore a subject has to semantically encode the word before being able to decide that it is a word. The speed and accuracy with which subjects classifies words is taken as a measure of the efficiency of a semantic coding of the word. If a word is preceded by a semantically related cue (word or sentence), lexical decision for words proceeds more efficiently (Fischler, 1981; Meyer and Schanveldt, 1971, Morton, 1969; Neely, 1977).

Brand names provide labels by which firms identify and promote their products and services. The effect of a brand is of course not merely in the name but represents the rich configurations of symbols and meanings that are are embodied by products (Levy, 1978). Brand names can be either everyday words used in the language (Tide, Dial, ...) invested with product attributes or they can also be constructed words (Sentra, Compaq, Accord) which are not in the normal lexicon of words. The multiple meaning of everyday words being used as brand names can be understood in terms of the literature on word meanings {imagery, vividness, meaningfulness, concreteness-abstractness, (Taylor, 1976) association set size, (Meyers-Levy, 1989), functional or usage based vs concept or symbolic (Park, Lawson and Milberg, 1989)}.

A relevant question is at what stage does a constructed word become part of the mental lexicon of consumers and what role would priming play in understanding this transition. A constructed brand name entering the mental lexicon of consumers is of course a function of the firm's marketing investment and strategic acumen. An interesting question is whether multiple lexical representations exist for several meanings of a brand name - normal or constructed, only some of which are activated when a stimulus is presented. Morton's (1970) "logogen model" which explicitly defines a "logogen" as representing a meaning as opposed to a mere spelling pattern is an example of a useful framework for studying common words being used as brand names.

There are two findings that are often cited as evidence for support of the activation theory with regard to repetition priming for nonwords and therefore could be used for understanding brand name (constructed) priming effects. First repetition priming in amnesic patients is only short-lived (Graf, Squire and Mandler, 1984; Squire, Shimamura and Graf, 1987) and secondly amnesic patients do not show repetition priming for non-words. The first finding is consistent with the idea of an independent decay implied by the concept of activation and the second can be predicted from the notion that repetition priming should be found only with stimulus materials that have pre-existing internal representations.

This activation account is however inconsistent with the current debate in implicit memory research where there is evidence about the formation of implicit new associations which can be acquired, used or retrieved implicitly (Graf and Schacter's; 1985,1987). If something has no prior representation in memory - such as the association between two unrelated items- and can be learned implicitly, it is obvious that the activation account cannot be sustained. Hayes and Broadbent (1988) suggest that even complex cognitive skills can be acquired through an implicit mode of learning. Lewandowsky, Kirsner and Bainbridge (1989) have suggested a sense-activation view to reflect implicit memory for new associations.Their data suggest that it is the re-instatement at the rating stage (after target stimulus or at the test stage) of the encoded sense of the word rather than the use of a new association between the cue (or context) and target that gives rise to implicit new associations.

Specificity of priming effects

The specificity of priming effects is an interesting issue worthy of future research. Is the phenomenon of priming based on the activation of some generic or abstract code that represents the target object's prototypical features or does priming reflect certain specific characteristics of the object encoded by subjects during exposure to the priming stimulus. Gollin (1960) found evidence that initial "training" on a fragmented version of a picture produced greater subsequent priming effects in identifying that fragment than initial training by exposure to the entire picture. Further Snodgrass and Feenan (1989, as cited by Schacter, Delaney and Merikle, 1990) have also shown that priming is greater when the same picture fragment is presented for identification during the study and test periods than when different fragments are presented. These results suggest that priming is based in part on a representation of the specific characteristics of objects presented for study and does not seem to rely on a abstract, generic code. However explicit memory processes may have played some role in these observed specificity effects. Warren and Morton's (1982) study suggests that priming may be based on the activation of a more abstract object representation and the contribution of explicit memory processes needs further scrutiny. Herr (1989) in a consumer research setting has also found evidence that the effect of priming seems to be highly specific to the category primed. In his study only judgements of price were influenced by priming, while other evaluative measures taken at the same time on quality, reliability, and prestige were not influenced by the activated category of price.

The reason for this specificity is not exactly known but it may be found in a categorization theory explanation of the priming effect. This assumes also an activation view. Priming effects are mostly obtained at the same category level as the category primed. If priming takes place with the priming stimulus at a "prototypical features" level then the priming effects are unlikely to be specific but more abstract and generic. Another related issue worth exploring is the contribution of explicit memory processes to priming and how it relates to observed specificity effects (Warren and Morton, 1982; Jacoby, Baker and Brooks (1989).

MEASURES OF IMPLICIT MEMORY

An important issue is what are relevant measures of implicit memory and explicit memory. This discussion also has to be within the context of the earlier discussion on the retrieval internationality criterion (Schacter, Bowers, and Booker; 1989). Recall and recognition are the usual task based explicit memory measures. Stem completion, fragment completion, and perceptual identification are some of the implicit memory measures used. Perceptual identification or fluency is usually measured in terms of how well an item can be identified under impoverished conditions. Other implicit measures used are solving anagrams (Srinivas and Roediger; 1990). Schoen, Ciofalo and Rudow (1989) compared word fragment completion to an anagram solution word-completion task and found no differences between the measures suggesting that the anagram solution is an adequate measure of implicit memory.

IMPLICIT MEMORY AND JUDGMENT

What is the relationship between implicit memory tests and judgment ? Bacon (1979), Begg et al (1985) have found that prior exposure to statements, or components of statements increases the truth rating of those statements. Lewecki (1986) presents an interesting aspect of the influence of implicit learning on judgment. This study focussed on the processing of covariation (among features) present in the stimulus material that could be implicitly learned. A latency of response measure which would result in increase of processing time for the questions considered relevant to the covariation was used. His results show that subjects had learned the rule implied by the covariation and used it in their subsequent judgments but were unable to articulate it later. A relevant question, is do consumers implicitly learn about covariations in their environment which influence their judgments and purchase behavior. Covariation assessment research (Bettman, John and Scott, 1986) shows consumers' estimate of covariation was accurate and unaffected by prior beliefs. Investigations at the implicit level of how covariations can affect judgment does not appear to have been carried out.

Research by Zajonc and his co-workers show that exposure to stimuli increases affective preferences for those stimuli (Zajonc, 1984; Zajonc and Markus, 1982). Their research centers on the finding that people can form preferences for stimuli in the absence of recognition memory. Zajonc interprets his results with the proposition that affective responses are independent of cognitive processing and affect can precede cognition. Lazarus (1982) however defends the cognitive-affective model and contends that the absence of recognition does not imply the absence of cognition. The debate between these two contending viewpoints depends on how each side defines cognition and affect (Anand and Sternthal, 1991). In consumer research Anand, Holbrook and Stephens (1988) have used a dichotic learning task to find support for the cognitive-affective model over the independence hypothesis. Heath (1990) has contested the independence of affect-cognition based on the results of Anand, Holbrook and Stephens (1988).

Research on recognition shows that two processes - labelled here as perceptual fluency and directed search, are used to determine recognition judgments.(Mandler, 1980; Johnston, Dark and Jacoby; 1985, Gillund and Shifrin, 1984). Perceptual fluency (PF) is usually measured in terms of how well an item can be identified under impoverished presentation conditions (Johnston, Dark and Jacoby; 1985) or the relative ease with which people can perceive a stimulus (Anand and Sternthal, 1988) and is an implicit memory measure. A directed search would involve the generation of contextual or episodic information related to the target stimulus.

Using a two stage priming framework and signal detection techniques Johnston, Dark and Jacoby (1985), presented subjects with a series of target stimulus items after which the recognition judgments of these old target items as well as new foil items were assessed. There were two measures of perceptual fluency - (1) the time taken to identify the word correctly since PF was inversely related to latency of identification; and (2) accuracy of identification. A two by two classification of actual exposure status and judged status was then used with: hit (old item judged to be old), miss (old item judged to be new), false alarm (new item judged to be old), correct rejection (new item judged to be new). If subjects relied only on perceptual fluency then the pattern of recognition outcomes would be hits > false alarms > misses > correct rejections. If they relied only on the search factor then perceptual fluency might not affect judged repetition status and perceptual fluency would vary across recognition outcomes in the following manner: hits = misses > false alarms = correct rejections.

Johnston, et al (1985) first experiment showed perceptual fluency for misses to exceed that for false alarms therefore indicating that the search factor was also in operation. In their second experiment they reduced the contribution of the search factor by using nonwords rather than words and found that recognition judgments were much more dependent on speed of identification than they were on actual old/new status. Their conclusion is that perceptual fluency plays a significant role in recognition judgments and may be the basis of the feeling of familiarity.

Anand and Sternthal (1988) used a dichotic learning task to investigate the affect without recognition phenomenon. Using the same experimental framework as Johnston, et al (1985) they investigated how perceptual fluency influences judgments when search fails. If one subscribes to Zajonc's view, perceptual fluency is viewed as a function of stimulus repetition or objective familiarity with the greater the repetition, the higher the perceptual fluency and the more positive the affective judgments. If however you favor Lazarus's view that cognitive appraisal is a necessary condition of affective appraisal, then the greater the subjective familiarity of a stimulus the greater the perceptual fluency and the more positive the affect. If subjective familiarity was the dominant factor, affective responses would be more positive for false alarms than for misses. Anand and Sternthal (1991) results supports the dominance of subjective familiarity (but see Heath, 1990 for an alternative viewpoint). This would also imply that affect without recognition involves some sort of cognitive process, although this would again depend on the definition of cognition and affect (Zajonc, 1984; Lazarus, 1984)

Perceptual fluency is an implicit memory test and the previous discussion suggests that when directed search fails then perceptual fluency influences judgments. If one accepts some fallibility of recall and recognition then to what extent is implicit memory directing judgment? What are the likely effects for the elderly consumer where the age deficits that are obtained so consistently on direct tests are reduced or eliminated when indirect tests are used (Howard, in press). What independent variables can impact on the relative utilities of the perceptual fluency and search factors. One variable that may cause variations is item meaningfulness. Reliance on perceptual fluency has been greatest with nonwords (Expt 2; Witherspoon, 1984 as quoted in Jacoby et al 1985) whose item meaningfulness has been low and least with words (with high item meaningfulness) (Tulving et al., 1982). Decrease in item meaningfulness clearly reduces the utility of the search factor. It should be noted that item meaningfulness is possibly a "cognitive" variable and these arguments assumes that affect is based on cognition. Other variables worthy of interest are retention intervals (discussed earlier) and repetition lag (Tulving et al., 1982). Longer repetition lags may lead to lower utilization of the search factor and increasing dependence on the perceptual fluency factor.

CONCLUSION

Implicit memory is a reasonably robust framework for many applications in consumer behavior. If the idea of consumer memory is restricted to existing recall/recognition tests then consumer researchers maybe ignoring a potentially influential dimension of consumer evaluation and decision making.

The notion of consumer memory may thus need to be expanded to include the concept of implicit memory. Researchers should be however aware of the major debates still remaining unresolved mostly with regard to the "correct" theoretical framework and with regard to the distinction between task and process. It is a still evolving and exciting framework rich with opportunities for use in consumer behavior.

REFERENCES

Anand, Punam and Brian Sternthal (1991), "Perceptual Fluency and Affect without Recognition," Memory and Cognition, 19 (3), 293-300

Anand, Punam, Morris B. Holbrook, and Debra Stephens (1988), "The Formation of Affective Judgments: The Cognitive-Affective Model versus the Independence Hypothesis," Journal of Consumer Research, 15 (December), 386-391.

Anderson J.R. (1983), The Architecture of Cognition, Cambridge, Mass.: Harvard University Press.

Bacon, F.T. (1979), "Credibility of Repeated Statements: Memory for Trivia," Journal of Experimental Psychology: Learning, Memory and Cognition, 5, 241-252.

Bargh, J.A. and P.Pietromonaco, (1982), "Automatic Information Processing and Social Perception: The Influence of Trait Information Presented Outside of Conscious Awareness on Impression Information, Journal of Personality and Social Psychology, 43, 437-499.

Begg, I., V. Armour and T. Kerr, (1985), "On Believing What we Remember," Canadian Journal of Behavioral Science, 17, 199-214.

Bettman James R. and Mita Sujan (1987), "Effects of Framing on Evaluation of Comparable and Non-Comparable Alternatives by Expert and Novice Consumers," Journal of Consumer Research, 14, September, 141-154.

Bettman James R., D. R. John and C. A . Scott (1986), "Covariation Assessment by Consumers," Journal of Consumer Research, 13 (3), 327-336.

Caroll,M., B.Byrne, K.Kirsner (1985), "Autobiographical Memory and Perceptual Learning: A Developmental Study Using Picture Recognition, Naming Latency, and Perceptual Recognition, Memory and Cognition,13, 273-279.

Cermak, L.S., N.Talbot, K.Chandler and L.R.Wolbarst (1985), "The Perceptual Priming Phenomenon in Amnesia," Neuropsychologia, 23, 615-622.

Collins, A. M., and E. F. Loftus (1975), "A Spreading Activation Theory of Semantic Processing," Psychological Review, 82, 407-428.

Dunn, J.C. and K.Kirsner (1988), Discovering Functionally Independent Mental Processes: The Principles of Reversed Association," Psychological Review, 95,91-101.

Dunn, J.C. and K.Kirsner (1989), "Implicit Memory: Task or Process," In S. Lewandowsky, J.C.Dunn and K.Kirsner (Eds.) Implicit Memory: Theoretical Issues. Hillsdale, N.J. Erlbaum.

Ellis, A.W. and A.F. Collins (1983), "Repetition Priming of Fragment Completion is Modality Specific and Independent of Conscious Episodic Memory: A Replication and Extension of Tulving, Schacter and Stark (1982)," Unpublished Manuscript, University of Lancaster, U,K.

Farah, M. (1989), "Semantic and Perceptual Priming: How Similar are the Underlying Mechanisms?" Journal of Experimental Psychology: Human Perception and Performance, 15, 188-194.

Fischler, I. (1981), "Research on Context Effects in Word Recognition: Ten Years Back and Forth, Cognition, 10, 89-95.

Fiske, Susan and Shelley E. Taylor (1990), Social Cognition, Mc-Graw Hill (in press).

Gollin,E.S., (1960), "Developmental Studies of Visual recognition of Incomplete Objects," Perceptual and Motor Skills, 11,289-298.

Gollin,E.S., (1962), "Factors Affecting the Visual Recognition of Incomplete Objects: A Comparative Investigation of Children and Adults, Perceptual and Motor Skills, 15,583-590.

Gollin, E.S. (1962), "Serial Learning and Perceptual Recognition in Children: Training, Delay, and Order Effects," Perceptual and Motor Skills, 23,751-758.

Graf,P. and D.Schacter (1985), "Implicit and Explicit Memory for New Associations in Normal and Amnesic Subjects," Journal of Experimental Psychology: Learning, Memory and Cognition, 11, 501-518.

Graf,P. and D.Schacter (1985), "Implicit and Explicit Memory for New Associations in Normal and Amnesic Patients," Journal of Experimental Psychology: Learning, Memory and Cognition, 11, 501-518.

Graf,P. and D.Schacter (1987), "Selective Effects of Interference on Implicit and Explicit Memory for New Associations," Journal of Experimental Psychology: Learning, Memory and Cognition, 13, 45-53.

Graf,P., L.R.Squire and G.Mandler (1984), " The Information that Amnesic Patients do not Forget," Journal of Experimental Psychology: Learning, Memory and Cognition, 10, 164-178.

Gillund, G and R.M. Shiffrin (1984), "A Retrieval Model for both Recognition and Recall," Psychological Review, 91, 1-67.

Hashtroudi,S. E.S.Parker, L.E.Delesi, R.J.Wyatt, S.A.Mutter (1984), "Intact Retention in Acute Alcohol Amnesia," Journal of Experimental Psychology: Learning, Memory and Cognition, 10,156-.163.

Hayes, N.A. and D.E.Broadbent (1988), "Two Modes of Learning for Interactive Tasks," Cognition, 28, 249-276.

Heath, Timothy B. (1990), "The Logic of Mere Exposure: A Reinterpretation of Anand, Holbrook and Stephens, (1988)," Journal of Consumer Research, 17, (September), 240-244.

Herr, Paul M., (1989), "Priming Price: Prior Knowledge and Context Effects," Journal of Consumer Research, 16, 1, (June), 67-75.

Higgins, E. T., W. S. Rholes and C. R. Jones (1977), "Category Accessibility and Impression Formation," Journal of Experimental and Social Psychology, 13, 141-154.

Higgins, E. T., Kuipper, N. A. and J. M. Olson (1980), "Social Cognition: A Need to Get Personal," in E. T. Higgins, C. P. Herman and M. P. Zanna (Eds), Social Cognition: The Ontario Symposium, Hillsdale, N.J. : Erlbaum, 1980.

Howard, D.V., (in press), Implicit Memory: An Expanding Picture of Cognitive Aging," In K. W. Schaie (ed) Annual Review of Gerentology and Geriatrics (Vol 11), New York:Springer.

Hunt R.R. and J.P. Toth (1990),"Perceptual Identification, Fragment Completion, and Free Recall: Concepts and Data," Journal of Experimental Psychology: Learning, Memory and Cognition, 16, 282-290.

Jacoby, L.L. and M. Dallas (1981), "On the Relationship between Autobiographical Memory and Perceptual Learning," Journal of Experimental Psychology: General, 110, 306-340.

Jacoby, L.L. and D. Witherspoon (1982), "Remembering without Awareness, Canadian Journal of Psychology,36,300-324.

Jacoby, L. L. (1983a) "Perceptual Enhancement: Persistent Effects of an Experience," Journal of Experimental Psychology: Learning, Memory and Cognition,9, 21-38.

Jacoby, L. L. (1983b), "Remembering the Data: Analyzing Interactive Processes in Reading," Journal of Verbal Learning and Verbal Behavior, 22, 485-508.

Jacoby, L.L. J.G. Baker and L.R. Brooks (1989), "Episodic Effects on Picture Identification: Implications for Theories of Concept Learning and Theories of Memory," Journal of Experimental Psychology: Learning, Memory and Cognition, 15, 275-281.

Johnson, M.K., J.K.Kim and G. Risse (1985), "Do Alcoholic Korsakoff's Syndrome Patients Acquire Affective Reactions? Journal of Experimental Psychology: Learning, Memory and Cognition, 11,27-36.

Johnson, M.K., and L. Hasher (1987), "Human Learning and Memory," Annual Review of Psychology, 38, 631-668.

Johnston, William A. Veronica J. Dark and Larry L. Jacoby, (1985), "Perceptual Fluency and Recognition Judgments," Journal of Experimental Psychology: Learning, Memory and Cognition, 11 (1), 3-11.

Kinsbourne, M. F.Wood (1975) "Short Term Memory Processes and the Amnesic Syndrome", In D.Deutsch and J.A.Deutsch (Eds.) Short Term Memory, 257-291, New York: Academic Press.

Kirsner, K. D.Milech and P.Standen (1983), "Common and Modality-Specific Processes in the Mental Lexicon," Memory and Cognition,14,398-408.

Lazarus, R.S.(1982), "Thoughts on the relation between emotion and cognition, " American Psychologist, 37, 1019-1024.

Lazarus, R.S (1984), "On the Primacy of Cognition", American Psychologist, 39, 124-129.

Levy, Sidney J. (1978), Marketplace Behavior-Its Meaning for Management, New York: AMACOM.

Lewicki, Pawel (1986), "Processing Information about Covariations That Cannot be Articulated," Journal of Experimental Psychology: Learning, Memory and Cognition, 12 (1) 135-146.

Lewandowsky S., K.Kirsner and Vivien Bainbridge, (1989), "Context Effects in Implicit Memory: A Sense-Specific Account," In S. Lewandowsky, J.C.Dunn and K.Kirsner (Eds.) Implicit Memory: Theoretical Issues. Hillsdale, N.J. Erlbaum.

Light, L., and A. Singh, (1987), "Implicit and Explicit Memory in Younger and Older Adults," Journal of Experimental Psychology: Learning, Memory and Cognition, 13, 531-541.

Lockart Robert S. (1989), "The Role of Theory in Understanding Implicit Memory," In S. Lewandowsky, J.C.Dunn and K.Kirsner (Eds.) Implicit Memory: Theoretical Issues. Hillsdale, N.J. Erlbaum.

MacLeod, Colin M. and John N. Bassili (1989), "Are Implicit and Explicit Tests Differentially Sensitive to Item-Specific vs Relational Information," In S. Lewandowsky, J.C.Dunn and K.Kirsner (Eds.) Implicit Memory: Theoretical Issues. Hillsdale, N.J. Erlbaum.

Mandler, G. (1980), "Recognizing: The Judgment of Previous Occurrence," Psychological Review, 73, 44-58.

Meyer, D.E. and R.W. Schvaneveldt (1971), "Facilitation in Recognizing Pairs of Words: Evidence for a Dependence Between Retrieval Operations," Journal of Experimental Psychology, 90, 227-234.

Meyers-Levy Joan, (1989), "The Influence of a Brand Name's Association Set Size and Word Frequency on Brand Memory," Journal of Consumer Research, 16, (September), 197-207.

Mitchell,D.B. (1989), "How Many Memory Systems? Evidence from Aging," Journal of Experimental Psychology: Learning, Memory and Cognition,,15,41-49.

Mitchell, D. and A. Brown (1988), "Persistent Repetition Priming in Picture Naming and its Dissociation from Recognition Memory," Journal of Experimental Psychology: Learning, Memory and Cognition, 14, 213-223.

Morton, J. (1969), "Interaction of Information in Word Recognition," Psychological Review, 76, 165-178.

Morton, J. (1970), "A Functional Model for Memory," In Models of Human Memory, 203-254, New York: Academic Press.

Morton, J. (1979), "Facilitation in Word Recognition: Experiments Causing Change in the Logogen Model." In P.A. Kolers, M.E. Wrolstad and H.Bouma (Eds.) Processing Models of Visible Language, 259-268. New York: Plenum.

Musen Gail and Anne Treisman (1990), "Implicit and Explicit Memory for Visual Patterns," Journal of Experimental Psychology: Learning, Memory and Cognition, 16 (1), 127-137.

Nedungadi, P. (1990), " Recall and Consumer Consideration Sets: Influencing Choice without Altering Brand Evaluations " Journal of Consumer Research, 17 (3), 263-276.

Neely, J.H. (1977), "Semantic Priming and Retrieval from Lexical Memory: Role of Inhibitionless Spreading Activation and Limited Capacity Attention," Journal of Experimental Psychology: General, 106, 226-254.

Nissen, M.J. D.Knopman and D.Schacter (1987), "Neurochemical Dissociation of Memory Systems," Neurology, 37,789.

Norman, D.A. (1976), Memory and Attention: An Introduction to Human Information Processing, New York: Wiley, 1976.

Park, Whan C., Robert Lawson and Sandra Milberg, (1989) "Memory Structure of Brand Names," Advances in Consumer Research, 16, Association for Consumer Research, Thomas Srull (ed.) Provo, Utah, 726-731.

Parkin, A.J. (1982), "Residual Learning Capability in Organic Amnesia," Cortex, 18,417-440.

Parkin, A.J. and S. Streete (1988), "Implicit and Explicit Memory in Young Children and Adults," British Journal Of Psychology, 79, 361-369.

Parkin, A.J. (1989), "The Development and Nature of Implicit Memory," In S. Lewandowsky, J.C.Dunn and K.Kirsner (Eds.) Implicit Memory: Theoretical Issues. Hillsdale, N.J. Erlbaum.

Ratcliff Roger, and Gail McKoon (1988), "A Retrieval Theory of Priming in Memory," Psychological Review, 95 (3), 385-408.

Richardson_Klavehn, A and R. A. Bjork (1988), "Measures of Memory," Annual Review of Psychology, 39, 475-543.

Roediger, H. L. and T. Blaxton (1987a), "Effects of Varying Modality, Surface Features, and Retention Interval on Priming in Word Fragment Completion," Memory and Cognition, 15, 379-388.

Roediger, H. L. and T. Blaxton (1987b), "Retrieval Modes Produce Dissociations in Memory for Surface Information," In D. Gorfein and R. R. Hoffman (Eds.), Memory and Cognitive Processes: The Ebbinghaus Centennial Conference; 349-377. Hillsdale, N.J: Erlbaum.

Scarborough, D. E. L. Gerard and C. Cortese, (1979), "Accessing Lexical Memory: The Transfer of Word Repetition Effects Across Task and Modality," Memory and Cognition, 7, 3-12.

Schacter, D. L. (1985), "Multiple Forms of Memory in Humans and Animals," Memory Systems of the Brain, N.M Weinberger, J.L . McGaugh, G.Lynch, (eds.), New York: Guilford.

Schacter, D. L. (1987) "Implicit Memory: History and Current Status, Journal of Experimental Psychology: Learning, Memory and Cognition, 13, 501-518.

Schacter, D.L., J.Bowers and J. Booker, (1989), "Intention, Awareness and Implicit Memory: The Retrieval Intentionality Criterion," In S. Lewandowsky, J.C.Dunn and K.Kirsner (Eds.) Implicit Memory: Theoretical Issues. Hillsdale, N.J. Erlbaum.

Schacter, D. L. and P. Graf, (1986), "Effects of Elaborative Processing on Implicit and Explicit Memory for New Associations," Journal of Experimental Psychology: Learning, Memory and Cognition,12, 432-444.

Schacter, D.L and M.Moscovitch, (1984), "Infants, Amnesics, and Dissociable Memory Systems. In M.Moscovitch (Ed.), Infant Memory, 173-216. New York: Plenum.

Schacter D.L. S.M.Delaney and E.P.Merikle (1990), "Priming of Nonverbal Information and the Nature of Implicit Memory," In The Psychology of Learning and Motivation, G.H.Bower (ed.), Vol 26, Academic Press.

Schoen Lawrence M., E. Ciofalo and E. Rudow, (1989), "Anagram versus Word-Fragment Solution: A comparison of Implicit Memory Measures," Bulletin of the Psychonomic Society, 27 (6) 551-552.

Sherry, D.F and D.L. Schacter, (1987), "The Evolution of Multiple Memory Systems," Psychological Review, 94, 439-454.

Shimamura, A. P. (1986), "Priming Effects in Amnesia: Evidence for a Dissociable Memory Function," Quarterly Journal of Experimental Psychology, 38A, 619-644.

Snodgrass, J.G. (1989), "Sources of Learning in the Picture Fragment Completion Task," In S. Lewandowsky, J.C.Dunn and K.Kirsner (Eds.) Implicit Memory: Theoretical Issues. Hillsdale, N.J. Erlbaum.

Snodgrass, J.G. and K. Feenan (1989), "Priming Effects in Picture Fragment Completion: Support for the Perceptual Closure Hypothesis. Working Paper.

Srull T. K. and R. S. Wyer (1979), " The Role of Category Accessibility in the Interpretation of Information about Persons: Some Determinants and Implications," Journal of Personality and Social Psychology, 37, 625-629.

Srull T. K. and R. S. Wyer (1980), "Category Activation and Social Perception: Some Implications for the Study of Person Memory and Interpersonal Judgments," Journal of Personality and Social Psychology, 38, 841-856.

Srinivas, K. and Henry L. Roediger (1990), "Classifying Implicit Memory Tests: Category Associations and Anagram Solution," Journal of Memory and Language, 29 (4), 389-412.

Squire, L.R. (1986), "Mechanisms of Memory," Science, 232, 1612-1619.

Squire L.R. and N.J.Cohen (1984), "Human Memory and Amnesia," In G.Lynch,J.L.McGaugh and N.M.Weinberger (Eds.), Neurobiology of Learning and Memory, 3-64, New York: Guilford Press.

Squire, L.R. A.P.Shimamura and P.Graf (1985), Independence of Recognition Memory and Priming Effects: A Neuropsychological Analysis," Journal of Experimental Psychology: Learning, Memory and Cognition, 11, 37-44.

Squire, L.R. A.P.Shimamura and P.Graf (1987), "Strength and Duration of Priming Effects in Normal and Amnesic Subjects," Neuropsychologia, 25,195-210.

Taylor, Insup (1976),"Introduction to Psycholinguistics" Holt Rinehart and Winston.

Tulving E. (1972), "Episodic and Semantic Memory," In E. Tulving and W. Donaldson (Eds.), Organization of Memory (381-403). New York: Academic Press.

Tulving E., D.Schacter and H.A.Stark (1982), "Priming Effects in Word-Fragment Completion are independent of Recognition Memory, Journal of Experimental Psychology: Learning, Memory and Cognition, 8, 336-342.

Tulving, E (1983), Elements of Episodic Memory. London: Oxford University Press (Clarendon).

Tulving, E. (1985), "How many Memory Systems are there? American Psychologist, 40, 385-398.

Tulving,E. and D. Schacter (1990), "Priming and Human Memory Systems," Science, 247, 301-306.

Vanderwert, M. (1984), "Priming by Pictures in Lexical Decision," Journal of Verbal Learning and Verbal Behavior, 23, 67-83.

McCarthy Michael J. (1991) "Marketing in the 90's: A Special Report," Wall Street Journal, March 22, pp B3.

Warren, R. E. (1972), "Stimulus Encoding and Memory," Journal of Experimental Psychology, 94, 90-100.

Warren, C., and J.Morton (1982), "The Effects of Priming on Picture Recognition," British Journal of Psychology, 73, 117-129.

Weldon, M.S. and H.L. Roediger (1987), "Altering Retrieval Demands Reverses the Picture Superiority Effect, Memory and Cognition, 15, 269-280.

Wickelgren, W.A. (1981), "Human Learning and Memory," Annual Review of Psychology, 32,pp 21-52.

Winnick, W.A. and S.A. Daniel (1970), "Two Kinds of Response Priming in Tachistoscopic Recognition, Journal of Experimental Psychology, 84, 74-81.

Witherspoon, D and Morris Moscovitch, (1989), "Stochastic Independence Between Two Implicit Tasks," Journal of Experimental Psychology: Learning, Memory and Cognition, 15 (1), 22-30.

Witherspoon, D. (1984), "The dissociation between tacit and reflective measures of memory," Unpublished doctoral dissertation, McMaster University, Hamilton, Ontario, Canada.

Wyer R. S., and T. K. Srull (1980), "Category Accessibility: Some Theoretical and Empirical Issues Concerning the Processing of Social Stimulus Information," in E. T. Higgins, C. P. Herman and M. P. Zanna (eds.), Social Cognition: The Ontario Symposium, Hillsdale, N.J.: Erlbaum.

Zajonc, R. B., and H. Markus, (1982), "Affective and Cognitive Factors in Preferences, Journal of Consumer Research, 9, 123-131.

Zajonc, R. B. (1984), "On the Primacy of Affect," American Psychologist, 39, 117-123.

----------------------------------------