Memory as discrimination 1 Memory as Discrimination : A Challenge to the Encoding-Retrieval Match Principle

Four experiments contrasted the predictions of a general encoding-retrieval match hypothesis with those of a view claiming that the distinctiveness of the cue-target relationship is the causal factor in retrieval. In Experiments 1, 2, and 4 participants learned the relationships between four targets and trios of cues; in Experiment 3 there were three targets, each associated with a pair of cues. A learning phase was followed by a cued-recognition task where the correct target had to be identified based on one or more of the cues. The main performance measurement was response time. Learning was designed to lead to high accuracy so effects could be attributed to retrieval efficiency rather than to variations in encoding. The nature of the cues and targets was varied across experiments. The critical factor was whether each cue was uniquely associated with the to-be-recalled target or not. All experiments orthogonally manipulated 1) how discriminative—or uniquely associated with a target—each cue was and 2) the degree of overlap between the cues present during learning and those present at retrieval. The novel finding reported here is that increasing the encoding retrieval match can hinder performance if the increase simultaneously reduces how specifically cues predict a target—that is, a cue’s diagnostic value. Encoding-retrieval match was not the factor that determined the effectiveness of retrieval. Our findings suggest that increasing the encoding-retrieval match can lead to no change, an increase, or a decrease in retrieval performance. Memory as discrimination 3 Memory as Discrimination: A Challenge to the Encoding-Retrieval Match Principle One of the most fundamental questions that research on human cognition has to answer is how we remember – or retrieve information from memory. A better knowledge of this process will contribute to our understanding of normal memory functioning, of forgetting, and of the memory problems that accompany various illnesses and brain disorders. When considering memory from this perspective, we are referring to explicit and conscious attempts to retrieve events or information from our past —we are referring to recollection— or what is typically known as retrieval from explicit/episodic memory (Tulving, 2002). One of the most widely held views in this field is that memory performance depends on the encoding-retrieval match—the extent to which encoded retrieval information overlaps with or matches the to-be-recalled representation (e.g. Eysenck and Keane, 2010). In this paper, we set out to test a controversial view that insists that the encoding-retrieval match, as it is habitually construed and portrayed, cannot predict retrieval efficiency. Below, we first briefly introduce and differentiate some of the major ideas in the field: encoding specificity, encoding-retrieval match, and cue overload. After concurring that the encoding-retrieval match view is very influential, we review a proposal that challenges the value of the encoding-retrieval match idea. Nairne’s (2005) championed this view and clarified its implications; like Hunt (2003), he insisted that successful retrieval is not just about selecting the correct target; it is about rejecting the incorrect ones also. This perspective, hereafter identified as memory-asdiscrimination, requires a more systematic consideration of the conjoint roles that encodingretrieval match and cue overload play in memory retrieval. Adopting the perspective of memory-as-discrimination led us to the realisation that their mutual influence should be Formatted: English (U.S.), Do not check spelling or grammar, Highlight Formatted: English (U.S.), Do not check spelling or grammar, Highlight Memory as discrimination 4 studied together. More specifically, the suggestion is that without considering both encodingretrieval match and cue overload being in concert, clear predictions relative to retrieval cannot be made. By considering both in a more formal way, memory-as-discrimination ascribes a role to each and insists that a) both play a role in all cases of memory retrieval and b) clear predictions about retrieval cannot be made without considering their simultaneous influence. Importantly, adopting the memory-as-discrimination perspective led us to a counterintuitive prediction—one that would not be derived from the more usual perspectives: under a number of circumstances increasing the encoding-retrieval match will hinder retrieval. We present four experiments that systematically tested this hypothesis in the context of a cuedrecognition task where retrieval efficiency is measured through response time. Before describing these ideas more fully and formally, we first briefly revisit the main related concepts. Encoding specificity Although many equate encoding specificity and encoding-retrieval match, the concepts are not the same. When the encoding-specificity concept was first introduced, its predictions were contrasted with those of the generate-recognise models of the time (e.g. Bahrick, 1969; Anderson & Bower, 1972). These models suggested that any cue that was suitably related to a target could support and enhance retrieval—even if it was not encoded with the to-be-recalled event. Simply put, the logic was that such extra-event cues, because of their prior relationship with the targets, would increase the probability that the target would be generated and then recognised as a desired retrieval object. Through a series of studies— including, notably, those on the recognition failure of recallable words—Tulving and his collaborators refuted this idea and suggested in its stead the encoding-specificity hypothesis [see Tulving (1984) for a summary of this debate]. In this context, the essential meaning of Memory as discrimination 5 encoding specificity was captured in the following (where TBR stands for to-be-retrieved): “The encoding specificity hypothesis, among other things, clearly implies that no cue, however strongly associated with the TBR item or otherwise related to it, can be effective unless the TBR item is specifically encoded with respect to that cue at the time of its storage. ” (Thomson & Tulving, 1970, p. 255). In other words, the encoding-specificity hypothesis insists on the necessary relationship between the retrieval cue and what was processed at encoding; the idea is that unless the cue was part of the encoded information it cannot lead to successful retrieval. However—and importantly—encoding-specificity is often considered synonymous with the encoding-retrieval match idea; in other words, encoding-specificity is often misrepresented to imply that an increase in the encoding-retrieval match will lead to an increase in the probability of recall or recollection. Encoding-retrieval match There are currently many areas of research where the encoding-retrieval match idea is used to predict and interpret findings. In contemporary research, encoding-retrieval match has underpinned work examining context-dependent, mood-dependent, and state-dependent memory (Roediger & Guynn, 1996; Smith & Vela, 2001). This is because it is often suggested that when attempting to recall a given episode, the re-instatement of the environmental context, or of the mood or state that accompanied the original encoding, can support retrieval by increasing the match between the current cueing information and the tobe-retrieved event. There are numerous other recent examples of research calling upon this hypothesis. A sample includes: work examining the role of colour in memory for natural scenes (Spence, Wong, Rusan, & Rastegar, 2006), experiments exploring the influence of encoding-retrieval match on prospective memory performance (Hannon & Daneman, 2007), Memory as discrimination 6 and studies investigating the misinformation effect (Campbell, Edwards, Horswill, & Helman, 2007). Moreover, a related concept is proving influential in cognitive neuroscience namely, the reinstatement hypothesis. This hypothesis stipulates that the recollection of a recent episode is possible when a pattern of cortical activity corresponding to the episode is reinstated in the brain via processing of the retrieval information. The hypothesis has been the focus of several studies using techniques such as functional magnetic resonance imaging and its discussion typically refers back to the encoding-retrieval match idea [see for example Johnson & Rugg (2007) and Polyn, Natu, Cohen & Norman (2005)]. In effect, a perusal of current literature makes it fairly straightforward to conclude that with a few exceptions, the encoding-retrieval match hypothesis is as uncontroversial as they come in cognitive psychology and cognitive neuroscience.