Acta Psychologica 72 (1989) 193-196

North-Holland

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BOOK REVIEW

G.M. Davies and D.M. Thomson (eds.), Memory in Context: Context in Memory. John Wiley & Sons, Chichester, 1988. E34.95.

Contemporary research in memory places much emphasis on the role of context. Context does not, however, seem to refer to a unitary concept. On the one hand, it is assumed to determine the meaning attributed to to-be-remem- bered items (words, sentences, stories), on the other hand, it is thought of as a cue in the retrieval process (as in ‘context-dependent memory’). In this

volume, Davies and Thomson have brought together an interesting collection of papers that covers all of these areas.

The book is divided in five main sections. The first three sections each cover a specific type of context, i.e. environmental context, internal context, and semantic context. Smith presents a thoughtful review of a large number of studies on so-called environmental context-dependent memory, where conflict- ing observations are quite common. Davies discusses what is perhaps the best known everyday example of context effects: the effect on the recognition of faces. The studies reviewed here highlight one of the problems surrounding this area of research, viz., the proper definition of context. For example, is a verbal description paired with a face ‘context’?

The next two chapters discuss the effects of internal context. Guenther examines the role of mood in memory, both on the storage and on the retrieval of information. Special attention is given to methodological problems sur- rounding such studies. Another aspect of internal context concerns the dis- sociative effects of drugs. Drugs such as alcohol and amphetamine have been shown to lead to state-dependent retrieval effects: material learned in one state is best recalled when the state at retrieval matches the state at encoding. In their chapter, Eich and Birnbaum report an experiment designed to test the hypothesis that such effects are due to the effects such drugs have on the mood state. That is, is the effect due to the reinstatement of the pharmacological state or to the reinstatement of the mood state associated with the drug (e.g. the feeling of being ‘high’)?

The section on the effect on semantic context consists of two long chapters. Bain and Humphreys discuss their independent cues model for the recognition of intact and rearranged pairs of study items (paired associates). This mode1 is based on the assumption that recognition of an item (B) from a pair (AB) can

OOOl-6918/89/$3.50 0 1989, Elsevier Science Publishers B.V. (North-Holland)

be based on two independent sources of information: item information (b ---) B) and relational information (a + B). Such a model. although interest- ing, is difficult to judge because of the possible confounding of its predictions by subject/item differences. In the next chapter, Tiberghien reviews the facilitating effects of various types of linguistic context on language compre- hension.

The fourth section deals with applied studies in such areas as amnesia, eyewitness memory, and education. Mayes discusses two common hypotheses about the deficit underlying amnesia, i.e. as a deficit in the use of the semantic context and as a deficit in remembering the background contextual informa- tion. It is concluded that the latter hypothesis is best supported by the available evidence. Even so, the evidence is not very strong and is compatible with a large variety of explanations.

Three chapters deal with context effects in eyewitness memory. The central issue here is whether various recently proposed techniques that rely on the mental reinstatement of the event context, have a beneficial effect on the completeness and accuracy of the eyewitness testimony. McSpadden, Schooler and Loftus argue that the effects are small at best. Cutler and Penrod, on the other hand, conclude that context reinstatement is an effective procedure. Geiselman describes a number of studies that demonstrate the superiority of one such technique, the Cognitive Interview, over techniques conventionally used by police personnel.

Another important practical issue, discussed by Howe. concerns the role of context in education. He argues that the cognitive abilities of children are much more context-bound than is usually assumed and that it is incorrect to attribute good performance at certain school tasks to superior basic skills, that generalize from one task to another.

The fifth section contains three chapters that are said to consider the issue of how context should be conceptualized, but that do not seem to be related in some obvious way. Thomson focuses on the various ways in which context may influence the likelihood of false recognition and shows that these do not always parallel the effects observed for correct recognition. Bekerian and Conway make a distinction between ‘molecular’ and ‘everyday’ contexts. The first refers to internal and environmental contexts that are presumably auto- matically activated. The second category refers to expectations (schemata, scripts, etc.) that lead the person to expect subsequent events. Lockhart draws a parallel between context effects in memory and in problem solving. It is argued that in both domains context influences performance by shaping the conception of the stimuli.

In addition, the editors have provided an introductory chapter and a final chapter with conclusions, appropriately titled: Context in context. As is evident from the above listing, there is no such thing as the effect of context.

Book review 195

Instead, there is a whole variety of context effects. Davies and Thomson propose that a distinction should be made between ‘figure’ and ‘ground’. It is not clear whether they wish to reserve the term context for those situations where context is the ‘ground’ and not part of the ‘figure’ or stimulus itself. Alternatively, this distinction might lead to two classes of context effects (similar to the interactive/independent distinction proposed by Baddeley). I doubt that this solves all problems.

Perhaps context is a term that cannot be defined without reference to a particular theory or model of storage and retrieval processes. First, the context information may be part of the same memory unit (trace, episode) or encoded separately. In the latter case, the term ‘relational context’ might be used (following Bain and Humphreys). The term ‘episodic context information’ might be reserved for that information that is part of the same memory unit but does not constitute the ‘focal’ elements of the memory trace (the encoded item information). Although it is difficult to define what those ‘focal’ elements are, I believe that such a distinction is important. What is called ‘focal’ presumably depends on the question that is being asked (e.g. what item was on the list, how did that person look like). Hence, what is context in one case, might be focal in another case. Thus, there may be three different types of context effects: relational, episodic, and semantic. The latter type refers to those cases where other information affects the semantic elements of the memory unit (as with the encoding of homographs, e.g. traffic jam vs. strawberry jam).

In addition to these definitional problems, the research on context effects in memory suffers from an apparent unreliability of the results: now you see it and now you don’t. The problem seems to be caused by the fact that context is not an additive effect that is independent of other aspects of the retrieval situation. As proposed by Smith and others, the magnitude of the observed effect depends on the other retrieval cues that are available to the subject. If other, more specific cues are available, context will not have a significant effect. This assumption is termed the Outshining principle by Smith, but may also be derived from more elaborate models of retrieval processes (e.g. SAM or ACT*). This would explain why context effects are especially likely in those cases where there are relatively few other cues (e.g. free recall).

Although the various chapters cover almost all aspects of context, one aspect is missing: the effects of learning in varied contexts. This not only refers to the traditional research on distributed learning and spacing effects, but also to the role of contextual variation in the formation of semantic memories. That is, it is often assumed that semantic knowledge is char- acterized by the property that its retrieval does not depend on context. Given that such knowledge is originally learned and stored in the same way as other experiences (i.e. in a context-bound fashion), it might be assumed that

196 Book reuirw

repeated presentation in a variety of contexts makes its retrieval independent of any particular context. Alternatively, it could be assumed that information is always stored in parallel in (at least) two quite distinct memory systems, an episodic and a semantic system. The answer to this question seems to me to be of fundamental importance for any theory of memory that deals with both semantic and episodic memory.

All in all, this collection of original papers gives a good overview of all the different manifestations of context effects in human memory. However, given the diversity of these effects, it would be a mistake to expect this book to provide a single, coherent framework for the effect of context on memory. What it might provide is a stimulus for the closer examination of the theoretical and practical implications of such effects.

Jeroen G.W. Raaijmakers TN0 Institute for Perception

P. 0. Box 23 3769 ZG Soesterherg

The Netherlunds