
Abstract Three experiments examined the effects of semantic characteristics of word pairs on memory using the encoding specificity paradigm. The paradigm involved four phases: (a) an encoding phase to relate cues and targets, (b) a phase in which words were generated to new cues, (c) a phase for recognition of generated targets, and (d) a cued-recall phase using the original encoding cues. Encoding pairs were classified a priori as either semantically similar (e.g., alluringPRETTY), semantically contrasting (e.g., drab-PRETTY), or semantically unrelated (e.g., sore-PRETTY). Generation pairs were classified a priori as either semantically similar (e.g., beautiful-PRETTY) or semantically contrasting (e.g., ugly-PRETTY). For recall, the results showed that both the semantic relations between the encoding cue and target and the reprovision of the encoding cue at retrieval were important factors. In the case of recognition, however, both the semantic congruence between the encoding and generation contexts and the amount of semantic elaboration provided by the encoding context were important factors.
The concept of encoding specificity was initially proposed by Endel Tulving and his colleagues to give an account of when and how retrieval cues are effective for episodic memory. "Specific encoding operations performed on what is perceived determine what is stored, and what is stored determines what retrieval cues are effective in providing access to what is stored" (Tulving & Thomson, 1973, p. 369). The essential idea is that a retrieval cue is effective only if information in the cue was incorporated in the memory trace of the target event at the time of its original encoding. In a later discussion of the concept, Tulving (1983) commented that "It is no more just an answer to the question concerning effectiveness of retrieval cues. It is now a theory about the relationship between encoding and retrieval conditions that is necessary for the recollection of an event to occur. We could now say that recollection of an event, or a certain aspect of it, occurs if and only if properties of the trace of the event are sufficiently similar to the properties of the retrieval information" (p. 223). This similarity between encoded information and information provided at retrieval (by cues or context) was also stressed by proponents of the concept of transfer-appropriate processing (Morris, Bransford, & Franks, 1977; Roediger, Weldon, & Challis, 1989) and was the central idea in the concept of repetition of operations proposed by Kolers (1973). It is difficult to see why this commonsense notion should be at all controversial (yet see Tulving, 1983, pp. 223-299).
The present study investigated the role of semantics in episodic memory for words. Tulving and Thomson (1973) drew the distinction between the semantic characteristics of words as lexical units and words as to-beremembered events. A semantically related cue should be effective in retrieving a word presented on a specific occasion only to the extent that the semantic information in question was encoded in the trace of the target word. Thus the word BRIDGE encoded as "an engineering structure" will not be easily recalled by the later cue "a card game." More subtly, the word WATER encoded in the pair whisky-WATER is not well recalled by the cue lake because whisky and lake emphasize rather different aspects of the word WATER Most dramatically, the same word re-presented in a recognition test may not be recognized because the word's context at encoding differs from its context at the time of recognition. This outcome was demonstrated in an ingenious paradigm devised by Tulving and Thomson (1973). They cast doubt on the influential generationrecognition model of retrieval by showing that when participants are explicitly induced to generate candidate responses and then given the opportunity to recognize target words from those generated, performance is quite poor.
The paradigm used by Tulving and Thomson to demonstrate this effect involved four major phases: (a) an encoding phase, (b) a generation phase, (c) a recognition phase for the words generated, and finally (d) a cued recall phase. During the encoding phase, weakly associated word pairs (e.g., whisky-WATER) designed to bias the capitalized words toward specific meanings, were presented. Participants were instructed not only to learn the capitalized words (e.g., WATER) but also to note that the preceding words (e.g., whisky) may help during retrieval. Thus the instructions influenced the encoding of the capitalized words to be semantically biased toward specific meanings (e.g., WATER as something you drink). During the generation phase, generation cues (e.g., lake) were presented. These cues were strongly associated to the capitalized words but they emphasized a different semantic meaning from that emphasized during encoding (e.g., WATER as something you swim in). Participants looked at each generation cue (e.g., lake) and then generated six related words (e.g., water, swim, cup, blue, fish, boat). During the recognition test that followed the generation phase, participants scanned their lists of generated words and circled those words that they believed were the capitalized words (e.g., WATER) previously shown in the encoding phase. Finally, participants completed a cued recall task by responding to the original cues (e.g., whisky) that were presented with the capitalized words at encoding. Tulving and Thomson observed a strong superiority of cued recall (63%) over recognition (24% of those targets generated in the generation phase) (Tulving & Thomson, 1973, Experiment 1). That is, cued recall was substantially higher than recognition memory, presumably because pairs such as whiskyWATER were encoded in a specific manner that made whisky an effective cue, but that made WATER itself, generated as a response to lake, relatively ineffective.
Tulving and Thomson's (1973) results thus questioned the generation-recognition account of retrieval, and favoured the encoding specificity principle. There was, however, an unexpected finding in their study. This finding was that certain target words were consistently recognized more frequently than others. Some words, such as CUT, BUG, WASH, STUPID, QUEEN, and BEING, were recognized more than 50% of the time, whereas other words, such as COLD, LIGHT, HIGH, SHORT, and WATER, were never recognized, even though each word was generated by anywhere from 13 to 21 participants. One plausible explanation for this puzzling result is that it again demonstrates the concept of encoding specificity. That is, high levels of recognition will be observed in the Tulving and Thomson paradigm when encoding processes and generation processes are semantically congruent, whereas recognition failure will occur when these two sets of processes are semantically incongruent. For example, the target word WEAK was well recognized in the Tulving and Thomson studies when its encoding context was brave-WEAK and the cue presented in the generation phase was strong. The senses of WEAK evoked by brave-WEAK and strong-WEAK are semantically congruent, and therefore the target word was well recognized. Conversely, it seems possible that the target words resulting in 0% recognition lacked this congruency relation. For example, somewhat different senses of COLD may be evoked by the encoding pair groundCOLD and the generation pair hot-COLD, and different senses of LIGHT may be evoked by the pairs headLIGHT and dark-LIGHT.
The following three experiments examined this hypothesis directly. To specify semantic congruency and incongruency more precisely, we created word pairs for the encoding and generation phases that exemplified either similar or contrasting semantic relations between the cue and target words. Word pairs classified as semantically similar have meanings that greatly overlap, for example, female-WOMAN, infantBABY, beautiful-PRETTY (e.g., Chaffin & Herrmann, 1984). Conversely, word pairs classified as semantically contrasting contain words whose meanings are opposed or contradictory in nature, for example, manWOMAN, white-BLACK, ugly-PRETTY Congruency between encoding and generation pairs was then achieved by using (for example) similar word pairs (e.g., female-WOMAN and lady-WOMAM, whereas an incongruent relation between encoding and generation was achieved by using (for example) a similar pair at encoding and a contrasting pair at generation (e.g., female-WOMAN and man-WOMAN, respectively). We used high-frequency noun pairs in Experiment 1, and high-frequency adjective pairs in Experiments 2 and 3. High-frequency noun and adjective pairs were chosen to avoid potential confounds with previous research investigating the effects of word type differences and word frequency on encoding specificity (e.g., Bartling, 1992; Reder, Anderson, & Bjork, 1974).
Our basic experimental design involved the presentation of weakly related cue-target pairs to be learned in Phase 1, presentation of a strongly related generation cue in Phase 2, recognition of generated targets in Phase 3, and finally cued recall of target words using the original weakly related cues in Phase 4. The encoding-target pairs and generation-target pairs were themselves rated as either similar, contrasting, or unrelated by independent judges. In the encoding phase (Phase 1), semantically similar (e.g., milkmaid WOMAN, contrasting (e.g., groom-WOMAN), or unrelated word pairs (e.g., floor-WOMAN) were presented, and these three encoding conditions were crossed with similar (e.g., female) or contrasting generation cues (e.g., man) in Phase 2. The major predictions were that target recognition would be high in the two cases of semantic congruency (similar/similar and contrasting/contrasting pairs) between encoding and generation, and that recognition would be low in the two cases of semantic incongruency (similar/contrasting and contrasting/similar pairs) between these phases. It was assumed that the conditions unrelated/similar and unrelated/contrasting would yield intermediate levels of recognition memory.
Experiment 1
METHOD
Participants. There were 62 participants who performed the main experiment: 37 were undergraduate psychology students from the University of Toronto who participated in the experiment for course credit, and 25 were students who were paid $5 for their participation. All participants were fluent in English and were tested individually. Data from two participants were not analyzed as they treated the final phase as free recall, rather than using the cues. In addition, a group of 39 participants generated free associates for norming purposes, and a further group of 20 participants rated semantic relations. None of these additional participants took part in the main experiments.
Encoding specificity task. The encoding specificity task was identical to that used by Tulving and Thomson (1973) with the exception that participants generated four words instead of six during the generation phase. This reduction in the number of words was not deemed problematic because Tulving and Thomson observed that 70% of their targeted words were generated as first responses. During the encoding phase, word pairs (e.g., milkmaid-WOMAN were presented in the centre of a computer screen and participants learned these word pairs for a subsequent memory test. In the generation phase, cues (e.g., man) were presented and participants wrote the first four words that came to mind (e.g., woman, bride, female, boy). During the recognition phase, participants scanned their generated words and circled those words that they believed were the capitalized words (e.g., WOMAN) previously shown during encoding. Finally, participants completed a cued recall task for the original targets by responding to the original encoding cues (e.g., milkmaid- ?).
Materials. Ali target words were high-frequency nouns with a Kucera and Francis (1967) average rating of 123 and a Thorndyke and Lorge (1944) rating of AA or A. The only exceptions were the targets medicine, basement, robber, and loser, which had Thorndyke and Lorge ratings of 46, 8, 27, and 2, respectively.
As prescribed by Tulving and Thomson (1973), the word pairs used in the encoding phase were only weakly related. To measure the associative strength for the pairs used, we had 39 participants, who were naive with respect to the purpose of the study, generate one free association to each encoding cue. In this preliminary part of the study, participants were given a sheet containing the encoding cues and were asked to write down the first word that came to mind after reading each cue. The target words used in the experiment were generated in 12%, 3%, and 2% of the trials to encoding cues that were similar, contrasting, and unrelated, respectively.
The word pairs in the encoding phase were classified a priori as semantically similar, contrasting, or unrelated, as described previously. These classifications were checked by having 20 norming participants rate the strength of the semantic relations between words in each pair on a scale running from 0 to 4, where ratings of 0.0 to 1.0 were defined as strongly opposite in meaning, ratings from 1.5 to 2.5 were defined as unrelated, and ratings from 3.0 to 4.0 were highly similar in meaning. As Table 1 shows, the experimenters' judgments were supported, in that contrasting pairs received a lower mean rating than both unrelated and similar pairs, and unrelated pairs received a lower mean rating than similar pairs. The semantic relations between the generation cues and target words were also classified a priori as similar or contrasting. The same 20 judges verified these classifications on the same scale of semantic associations. In this case, contrasting pairs were rated lower than similar pairs. Finally, the associative relations between the generation cues and targets, as well as those between the generation cues and encoding cues, followed the criteria set forth by Tulving and Thomson (1973). That is, all generation cues and targets had moderate to strong associative relations (36% for similar generation cues, and 27% for contrasting generation cues) and all generation cues and encoding cues had very weak associative relations (on average 0%). Associative relation norms were determined by having 40 norming participants generate one free association to each generation cue.
We also checked how the senses of the targets varied from encoding to generation. Twenty norming participants compared the senses of targets at encoding (e.g., milkmaid-WOMAN) to their respective senses at generation (e.g., female-WOMAN) on a scale running from 0 to 10, where a rating of 0 was defined as absolutely no similarity, a rating of 5 was defined as quite similar yet many differences too, and a rating of 10 was identical. As Table 1 shows, the average ratings for the congruent similar/similar condition yielded higher ratings than all other conditions, and the congruent contrasting/contrasting condition yielded higher ratings than all of the incongruent conditions. The pattern of these ratings suggests that semantic congruency between encoding and generation is more likely to evoke similar senses in the target words than semantic incongruency between encoding and generation.
Design and procedure. Prior to presentation of the critical list, two practice lists composed of 30 word pairs each were presented. To avoid proactive interference with the critical list, the words in the practice lists (e.g., ostrich-AUSTRALIA, bluejay-GREENLAND) were unrelated to the words in the critical list. There was no generation phase for these practice lists because their purpose was to encourage participants to relate the words in the word pairs. Therefore each practice list was followed by only a cued recall task, given after a 30-s arithmetic distractor task.
During the encoding of the critical list, 30 word pairs (3 primacy, 8 similar, 8 contrasting, 8 unrelated, and 3 recency) were presented in the centre of a computer screen for a duration of 3 s each. The primacy and recency pairs were presented in a fixed order, whereas the 24 critical stimuli were presented in a different random order for each participant. Each target was presented in upper-case directly below the encoding cue, which was presented in lower case letters. Participants were instructed not only to learn the capitalized words but to also note that the preceding words may help during subsequent retrieval. After the presentation of the critical list, participants performed a 30-s distractor task, namely, counting backwards from 100 by 3 s.
At this point, they were informed that the memory task, would come later, but that they would now perform a generation task, namely writing down four associates to a series of words. In this generation phase, the cues were presented on the computer screen at a self-paced rate. The generation cues were related to the targets in either a similar or contrasting fashion and each semantic generation type was divided equally among the semantic encoding types. For example, four of the eight similar word pairs from the encoding phase were matched with similar generation cues while the other four similar word pairs were matched with contrasting generation cues. Thus there were four word pairs in each of the six encoding/generation combinations: similar/similar, similar/contrasting, contrasting/similar, contrasting/contrasting, unrelated/similar, and unrelated/contrasting. All target words were counterbalanced across these six combinations.
During the recognition phase, participants were given as much time as they needed to review their generated words and circle those words that they believed were the capitalized words presented during the encoding phase. In the subsequent cued recall phase, participants were given up to 4.5 min to review the encoding cues and respond with the original targets. All recall cues were identical to the lowercase words presented during the encoding phase.
RESULTS
All ps reported are less than .05, unless otherwise reported. The proportions of targets generated to similar generation cues were 0.72, 0.63, and 0.58 for the conditions similar encoding, contrasting encoding, and unrelated encoding, respectively. The corresponding proportions for contrasting generation cues were 0.52, 0.48, and 0.39, respectively. Thus the similar generation cues were more effective than contrasting generation cues in generating target words.
Table 2 shows the proportions of generated target words recognized in the six conditions, conditionalized on generation of the targets. The main prediction was that these recognition proportions would be relatively large for the congruent conditions (similar/similar and contrasting/contrasting) and relatively small for the semantically incongruent conditions (similar/contrasting and contrasting/similar). Table 2 shows that whereas recognition proportions for the congruent conditions were large as predicted (0.46 and 0.53), and the incongruent contrasting/similar condition yielded a smaller recognition proportion, as predicted (0.32), the similar/contrasting recognition proportion was substantially higher than predicted (0.46). For both the similar and contrasting generation cues, words encoded with an unrelated encoding cue were least well recognized (0.27 and 0.36, respectively).
The predicted interaction between similar/contrasting encoding and similar/contrasting generation was found, F(1, 59) = 6.88, MSE = .01.(1) However, subsequent t-tests showed that whereas the similar/similar (0.46) and contrasting/contrasting (0.53) conditions yielded reliably higher recognition proportions than the contrasting/similar (0.32) condition, t(59) = 2.76, SE = .05 and t(59) = 3.69, SE = .05 respectively, neither the similar/similar nor contrasting/contrasting proportions reliably exceeded the value for the similar/contrasting (0.46) condition, t(59) = .06, SE = .05 and t(59) = 1.08, SE = .05, respectively, both ps > .28. The incongruent similar/contrasting condition thus yielded a recognition proportion that was higher than predicted. Table 2 also shows the results of the final cued recall phase. An ANOVA showed a highly significant effect of encoding condition, F(2,118) = 43.03, MSE = .03, and all pairwise t-tests were significant. The minimum t-value was t(59) = 4.21, SE = .03.
DISCUSSION
The incongruent similar/contrasting condition yielded a recognition proportion that was comparable to the recognition proportions for the congruent similar/simifar and contrasting/contrasting conditions. Therefore, the recognition results only partly supported our main prediction that recognition proportions would be relatively large for the congruent conditions and relatively small for the semantically incongruent conditions. One way of accounting for the unexpected high recognition proportion in the similar/contrasting condition is to suggest that a second factor besides semantic congruency is operating. For example, recognition proportions may be high following similar encoding conditions, regardless of the generation condition. Alternatively, recognition may be high following contrasting generation, regardless of the encoding condition. By this type of account, recognition would be high for those encoding and generation types that are either congruent or involve the second factor. Of the two possibilities, perhaps the factor of similar encoding relations is the more plausible as it may be associated with greater amounts of elaboration (cf. Craik & Tulving, 1975). On the other hand, the unrelated/contrasting condition (0.36) gave a higher recognition proportion than the unrelated/similar condition (0.27), so perhaps the generation of a contrasting target leads to better recognition. Further discussion is deferred until the results of Experiment 2 are considered.
A second interesting result was that for the final cued recall phase there were large differences among the three encoding conditions despite the fact that the original encoding cues were reprovided in all cases. This result may simply reflect the greater associative strength inherent in similar (12%) than in contrasting (3%) or unrelated (2%) pairs, although the difference between the second two types remains puzzling if associative strength is the sole explanation for the differences among the three encoding conditions. To test the robustness of both the recognition and cued recall results, a second experiment was carried out using adjective pairs as stimuli instead of nouns.
Experiment 2
METHOD
Participants. There were 62 participants who performed the main experiment: Fifty-two were undergraduate psychology students from the University of Toronto who participated in this experiment for course credit, and 10 were students who were paid $5 for their participation. All participants were fluent in English and were tested individually. Data from two participants were excluded from further analysis: one because of lack of compliance with instructions and one because of experimenter error. In addition, a group of 40 participants generated free associates for norming purposes, and a further group of 20 participants rated semantic relations. None of these additional participants took part in the main experiment.
Materials. The target words in this experiment were common adjectives with an average rating of 173 in the Kucera and Francis (1967) norms and Thorndyke and Lorge (1994) ratings of AA or A. Encoding cues and generation cues were also adjectives. As in Experiment 1, the associative relations between encoding cues and targets were determined by having 40 norming participants generate one free associate to each encoding cue. Participants generated the target word on 14%, 0%, and 2% of occasions for similar, contrasting, and unrelated encoding cues, respectively. The relations between generation cues and the target words were measured in the same way. In this case, 41 participants generated the target words on 47% of occasions for similar generation cues, and on 31% of occasions for contrasting cues.
As in Experiment 1, 20 norming participants rated the encoding cue-target pairs a priori as similar, contrasting, or unrelated using a scale ranging from 0.0 to 4.0. As Table I shows, the experimenters' judgements were supported in that the contrasting pairs received a lower mean rating than both unrelated and similar pairs, and unrelated pairs received a lower mean rating than similar pairs. The semantic relations between the generation cues and target words were also classified a priori as similar or contrasting. The same 20 judges verified these classifications on the same scale of semantic associations. In this case contrasting pairs were rated lower than similar pairs.
As in Experiment 1, 20 norming participants also evaluated how the senses of the targets varied from encoding to generation by comparing the senses of targets at encoding (e.g., alluring-PRETTY to their respective senses at generation (e.g., beautiful-PRETTY) on a scale running from 0 to 10. As Table 1 shows, the average ratings for the congruent similar/similar condition yielded higher ratings than all other conditions, and the congruent contrasting/contrasting condition yielded higher ratings than all of the incongruent conditions. The pattern of these ratings suggests that semantic congruency between encoding and generation is more likely to evoke similar senses in the target words than semantic incongruency between encoding and generation.
Design and procedure. The procedure was identical to that used in the first experiment except that in Experiment 1 the presentation duration for word pairs during the encoding phase was 3 s each, whereas in Experiment 2 the presentation duration was 8 s each. The longer presentation duration was used because pilot testing had shown that it was needed to yield appropriate levels of performance.
RESULTS
In the generation phase of Experiment 2, an average proportion of 0.79 target words were generated to similar generation cues, and an average proportion of 0.52 target words were generated to contrasting generation cues. In the case of similar generation cues, the overall rate of 0.79 was made up of individual rates of 0.80, 0.80, and 0.76 for similar, contrasting, and unrelated encoding cues, respectively. The corresponding proportions for the contrasting generation cues were 0.45, 0.59, and 0.51, respectively.
Table 2 shows the proportions recognized, conditionalized on target generation. The original prediction was that congruent encoding/generation conditions (i.e., similar/similar and contrasting/contrasting) would yield comparatively high levels of recognition, whereas the incongruent conditions (i.e., similar/contrasting and contrasting/similar) would yield low levels, with the unrelated encoding conditions yielding intermediate levels. This pattern was obtained in the case of the similar generation cues (0.40, 0.20, and 0.28 for similar, contrasting, and unrelated encoding cues, respectively), but not for the contrasting generation cues, where the corresponding proportions were 0.43, 0.42, and 0,26, respectively. That is, as in Experiment 1, the semantically incongruent similar-encoding/contrasting-generation condition yielded an anomalously high proportion - in this case the highest value of recognition. As in Experiment 1, these findings were supported by a significant Encoding x Generation interaction F(2, 118) = 6.07, MSE = .066.(2) A series of t-tests among the recognition proportions revealed the presence of two clusters. The values 0.40, 0.43, and 0.42 did not differ statistically among themselves, maximum t-value was t(59) = .63, p > .53, and the values 0.20, 0.28, and 0.26 did not differ among themselves, maximum t-value was t(59) = 1.29, p > .20. However, all pairs of proportions across the clusters were significantly different, minim u m t-value was t(59) = 2.83.
Table 2 also shows the values for cued recall. As in Experiment 1, recall levels decreased from similar to contrasting to unrelated encoding conditions. An ANOVA showed a reliable effect of encoding condition, F(2,118) = 33.82, MSE = .032, with all proportions differing statistically as shown by subsequent t-tests, minimum t-value was t(59) = 2.98.
DISCUSSION
The recognition results of Experiment 2 thus replicated the essential findings from Experiment 1. That is, recognition was comparatively high both in the cases of semantic congruence between encoding and generation, and in the case of similar encoding followed by contrasting generation. The other possible interpretation from Experiment 1, that good recognition performance is associated with contrasting generation, is essentially ruled out here by the finding of a low recognition score for the unrelated/contrasting case (0.26). Rather, it seems that a similarity relation at encoding ensures a comparatively high proportion of subsequent recognition regardless of how the target word is generated. A contrasting relation at encoding yields good recognition only if the generation cue is also contrasting, and the unrelated encoding conditions yield low levels of recognition in all cases.
The cued recall results of Experiment 2 also replicated the essential findings from Experiment 1. That is, despite the use of the original encoding cues as retrieval cues, recall performance varied substantially as a function of the semantic relations between cues and targets. As in Experiment 1, this result may simply reflect the greater associative strength inherent in similar (14%) than in contrasting (0%) or unrelated pairs (2%), although by this account the difference between the contrasting and unrelated pairs cannot be explained by using an associative strength argument.
Thus, it appears that the pattern of results for recognition and cued recall in Experiment 2 is identical to that of Experiment 1. Our explanation for this pattern of results is that another factor, in addition to semantic congruency, influences recognition and recall. This factor is that the three types of semantic encoding have varying levels of semantic elaboration. Under standard encoding conditions, similar encoding yields rich semantic elaboration, contrasting encoding yields moderate semantic elaboration, and unrelated encoding yields relatively impoverished semantic elaboration. By this account, recognition should be high for those encoding and generation types that have either rich elaboration at encoding or semantic congruency between encoding and generation. In contrast, recognition for moderate to poor levels of elaboration at encoding should be high only if there is congruence in semantics between encoding and generation types. If there is no semantic congruence between encoding and generation types then recognition should be low. In respect to cued recall, recall scores should decline as the amount of semantic elaboration at encoding decreases - from extensive to moderate to restricted.
To test this hypothesis, in Experiment 3 we controlled semantic elaboration at encoding. The participants were presented word pairs that were either read (erg., alluring-PRETTY), generated easily (e.g., alluring PRETT -), or generated with effort (e.g., alluring-PRE - ). Because words that are generated have higher recognition levels than those read (e.g., Slamecka & Graf, 1978) we anticipated that those requiring minimal generation (i.e., generated easily) should yield intermediate recognition levels between read and effortful. Indeed, pilot research in our lab showed that hard-generate, easy-generate, and read types of encoding yielded three distinct levels of recognition (0.76, 0.58, 0.32, respectively) and cued recall (0.81, 0.66, 0.40, respectively). To add further control to our experiment, we used only the semantically similar word pairs from Experiment 2.
As in Experiments 1 and 2, our basic experimental design involved encoding, generation (similar, contrasting), recognition, and cued recall phases. However, during the encoding phase participants read, generated easily, or generated with effort the critical targets. The major predictions were that target recognition would be high in the three conditions that included either effortful generation at encoding and/or semantic congruency between encoding and generation, and recognition would be low in the three conditions that included either easier generation/reading at encoding and/or semantic incongruency between encoding and generation. For cued recall, we predicted that performance levels would decline from hard generate to easy generate to read encoding conditions.
Experiment 3
METHOD
Participants. The 36 participants were students from the University of Toronto who were paid $5 for their participation. All participants were fluent in English and were tested individually.
Encoding specificity task. The encoding specificity task was identical to that used in Experiments 1 and 2, with the exception that the encoding phase was changed from an intentional task to an incidental one in which participants either read (e.g., alluring-PRETTY or generated the critical targets (e.g., alluring-PRETT, or alluringPRE---).
Materials. The word pairs used in the encoding phase consisted of 66 pairs: 24 critical, 36 filler, 3 primacy, and 3 recency. The 24 critical pairs were the semantically similar ones taken from Experiment 2. Semantically similar pairs were chosen in order to yield reasonably high levels of recognition, given the switch from intentional learning in Experiments 1 and 2 to incidental learning in this experiment. Three versions of each critical word pair were created: hard-generate, easy-generate, and read. Hard-generate pairs consisted of a lowercase cue and a capitalized word stem with more than one letter missing (e.g., alluring-PRE - - ). Easygenerate pairs consisted of a lowercase cue and a capitalized word stem with the last letter missing (e.g., alluring-PRETT-). Read pairs consisted of a lowercase cue and a capitalized word (e.g., alluring-PRETTY).
The 36 filler pairs were not semantically related to the critical pairs. Moreover, 12 were read, 12 were easy-generate, and 12 were hard-generate. Six of the filler pairs were semantically similar (e.g., expandINCREASE) and 30 were semantically contrasting (eg., good-EVIL). The semantically contrasting pairs were included to prevent participants from adopting a "similar relation strategy" for generating words.
Design and procedure. As in Experiments 1 and 2, two practice lists were presented. However, prior to the retrieval phase of the second practice list, participants were informed that there was another task for them to do and that this task was designed to interfere with their remembering of the words they had just learned. This "interference" task was our incidental task that contained the critical target words. In this incidental task, each target word was presented in upper case directly below the encoding cue, which was presented in lower case letters. Participants were told that when they see word pairs on the computer screen (e.g., tie SHIRT) they should read them out loud. They were also told that when they see word pairs with letters missing (e.g., polite-RUD - or keyboard-PI - - -) they should read the first word out loud and then complete the word stem out loud with a word related to the first word (e.g., RUDE, PIANO).
During the encoding phase of the incidental task, 66 word pairs (3 primacy, 24 critical: 8 read, 8 easy-generate, 8 hard-generate; 36 filler: 12 read, 12 easy-generate, 12 hard-generate, and 3 recency) were presented in the centre of a computer screen at a self-paced rate. The primacy and recency pairs were presented in a fixed order, whereas the 24 critical and 36 filler stimuli were presented in a different random order for each participant. Participants were given 10 seconds to generate words. Once 10 seconds had elapsed the experimenter provided the appropriate word. Occasionally (less than 2% of the time) participants generated words that were not the critical targets. In instances such as this, the experimenter recorded the anomaly and the word was removed from the critical target list for that participant.
As in Experiments 1 and 2, participants completed a recognition phase in which they free-associated words to recognition-generation cues and then circled those free associates that they believed were the capitalized words that they either read or generated during the encoding phase of the incidental task. The two types of generation cues for the recognition phase (i.e., similar, contrasting) were identical to those used in Experiment 2, and each of the semantic generation types for recognition were divided equally among the three generation types for encoding. Participants also completed a cued recall task containing recall cues that were identical to the lower case words presented during the encoding phase of the incidental task. Thus, there were four word pairs in each of the six encoding/generation combinations. All target words were counterbalanced across these six combinations.
RESULTS
In the recognition-generation phase of Experiment 3, an average proportion of 0.77 target words were generated to similar generation cues, and an average proportion of 0.50 target words were generated to contrasting generation cues. In the case of similar generation cues, the overall rate of 0.77 was made up of individual rates of 0.80, 0.71, and 0.79 for similar, contrasting, and unrelated encoding cues, respectively. The corresponding proportions for the contrasting generation cues were 0.48, 0.52, and 0.51, respectively.
Table 2 shows the proportions recognized, conditionalized on target generation. Our prediction was that conditions that had either effortful generation at encoding or were semantically congruent would yield comparatively high levels of recognition, whereas conditions that had easier generation/reading at encoding or were semantically incongruent would yield low levels of recognition. As Table 2 shows this prediction was confirmed. Conditions that had either effortful generation at encoding or were semantically congruent yielded higher recognition levels (i.e., .50, .51, and .50) than those that had easier generation/reading at encoding or were semantically incongruent (e.g., .32, .23, and .27). This pattern of results was supported by a marginal Encoding x Generation interaction, F(2, 70) = 2.92, MSE = .09, p < .06. A series of t-tests among the recognition proportions revealed the presence of two clusters. The values .50, .51, and .50 did not differ statistically among themselves, maximum t-value was t(35) = .19, p > .85 and the values .32, .23, .27 did not differ among themselves, maximum t-value was t(35) = 1.65, p > .10. However, all pairs of proportions across the clusters were significantly different, minimum t-value was t(35) = 2.69.
Table 2 also shows the results of the final cued recall phase. Cued recall scores were highest in the hard-generate condition, intermediate in the easy-generate condition, and lowest in the read encoding condition, despite the facts that the original cues were reprovided in all cases and that all the critical word pairs were semantically related with the same associative relation. An ANOVA showed a highly significant effect of encoding condition, F(2, 70) = 46.51, MSE = .03 and all pairwise t-tests were significant. The minimum tvalue was t(35) = 3.51. These findings clearly confirm that recall increases as the difficulty level of generation at encoding increases (Jacoby, 1978; Slamecka & Graf, 1978).
DISCUSSION
The patterns of results for recognition and cued recall in Experiment 3 lend support to our suggestion that another factor besides semantic congruency influences recognition and recall. This factor is the extent of elaboration at encoding. This account is discussed further in the next section. With regard to cued recall, similar beneficial effects of effortful or difficult initial processing on subsequent memory performance have been found in experiments on interference effects with initial stimulus identification (e.g., Hirshman, Trembath, & Mulligan, 1994; Mulligan, 1996) and in cases in which textual coherence is established with effort during initial reading (Duffy, Shinjo, & Myers, 1990; Myers, Shinjo, & Duffy, 1987). In all cases, the higher memory performance appears to be attributable to the enhanced processing of higher-order perceptual or semantic representations at the time of initial encoding (Craik & Lockhart, 1972).
General Discussion
The starting point of our study was the observation by Tulving and Thomson (1973) that recognition rates in their generate-recognize paradigm were quite variable, depending on the particular word pairs examined. Our suggested explanation was that recognition would be high in cases where the encoding cue-target relation and the generation cue-target relation were semantically congruent, and that recognition of generated targets would be low when these relations were semantically incongruent. However, the observed pattern of results in Experiments I and 2 conformed to this prediction only partly. In both experiments recognition levels were comparatively high in cases of semantic congruence (similar encoding/similar generation, and contrasting encoding/contrasting generation) in line with our explanation, but recognition was also high in the incongruent combinations of similar encoding/contrasting generation. Recognition levels were comparatively low in the contrasting encoding/similar generation combination, and in combinations involving unrelated encoding cue-target pairs. Our modified account of these results is that apparently word recognition can be good either if the encoding/generation contexts are semantically congruent, or if the encoding cue-target relation is one of richer elaboration as in the case of semantic similarity. It is also clear from Table 2 that recognition performance is no higher when both of these factors hold (i.e., in the case of similar encoding/similar generation).
The original suggestion that semantic congruency between encoding cue-target pairs and generation cuetarget pairs would be associated with comparatively high levels of target recognition is parallel with the notions of encoding specificity and transfer-appropriate processing. That is, the encoding cue modifies and specifies the exact sense of the target word, and when the generation cue produces the target word with the same semantic nuance, it will be recognized comparatively well because the encoded and generated targets share many of the same semantic features. By this account, recognition levels should be low when encoding and generation induce somewhat different senses of the target word, and we argue that this is the case for the contrasting/similar condition, and for the cases involving unrelated encoding cues.
But why should similar encoding yield good recognition regardless of how the recognition target was generated? Our explanation is that, under standard encoding conditions, the similar encoding cue elaborates and enriches the target word in much the same way as positive semantic orienting task questions do in the levels of processing paradigm (Craik & Tulving, 1975). In this latter paradigm, it is well established that question-target pairs that yield positive responses (e.g., "type of furniture?-SETTEE') are associated with higher levels of subsequent target word recognition than pairs that yield negative responses (e.g., "a jungle animal?POTATO"). Craik and Tulving suggested that recognition superiority was a function of the greater ease of forming a richly elaborated trace in the case of positive question-target pairs. Consistent with this suggestion, the results in Experiment 3 showed that richly elaborated targets may be recognized well despite a shift in semantic context from encoding to retrieval.
Our suggestion that similar encoding cues yield comparatively well-elaborated traces is supported by the further finding in Experiments 1 and 2 that cued recall is significantly higher for similar encodings than for contrasting or unrelated encodings. The notion that, in general, recognition performance is less affected by contextual change than recall, for example, is supported by findings from the state-dependent learning literature. In several studies of this type, researchers have reported large changes in recall performance, but relatively small changes in recognition performance, as a function of state or context changes between encoding and retrieval (e.g., Baddeley, 1976; Eich, 1980; Godden & Baddeley, 1975). The present data suggest the interesting possibility that as the encoded trace is made richer and more elaborate, it becomes progressively less dependent on reinstatement of the original encoding context for later recognition to occur successfully.
Finally, our suggestion that well-elaborated memory traces may be recognized well despite a shift in semantic context from encoding to retrieval is supported by our results in Experiment 3. In this experiment, we observed that targets that had richer elaboration at encoding (i.e., hard-generate condition) yielded high recognition levels even when there was a shift from similar semantic encoding to contrasting semantic generation. However, the results in Experiment 3 also suggested that when semantic elaboration is only moderate at encoding, as in the easy-generate condition, recognition is strongly affected by a shift from similar-semantic encoding to contrasting-semantic generation.
Other possible factors affecting recognition variability, such as word frequency or word type differences, are essentially ruled out by the present results. For example, it is well known that low-frequency words are better recognized than high-frequency words (Gregg, 1976), and consistent with this finding, Reder, Anderson, and Bjork (1974) observed this same result using the encoding specificity task. Nevertheless, in the present study, recognition levels varied considerably despite the fact that only high-frequency targets were used. Similarly, it has been suggested that recognition failure occurs when adjectives are the target words and nouns are the encoding cues and not when just noun-noun (milkmaid-WOMAN) and adjectiveadjective (alluring-PRETTY pairs are used (Bartling, 1992; Bartling & Thompson, 1977; Nilsson & Gardiner, 1993). However, the present results demonstrated that recognition levels can be comparatively high or low, regardless of whether the encoding pairs are adjectives or nouns.
The cued recall findings are more straightforward. In both Experiments 1 and 2, cued recall levels were highest for words encoded with (and retrieved by) a cue that bore a similar relation to the target word, and recall was significantly lower for contrasting cues and lowest for unrelated cues. These variations in cued recall occurred despite the fact that the encoding cue was reprovided at retrieval in all cases, and thus in a sense the conditions for the encoding specificity principle to work positively were always present. The associative norms collected in the course of this study seemed to support the argument of stronger associative relations between cues and targets for similar cues than for the other two types (means of 13% compared with 2%, respectively). However, the contrasting and unrelated associative norms had the same generation rate yet still resulted in significantly different levels of cued recall. Moreover, when associative relations were held constant by using only semantically similar pairs (as in Experiment 3), cued recall still varied as a function of elaboration at encoding. Thus, it seems that the cued recall performances in all three experiments are accounted for by the amount of elaboration afforded by the semantic relation between cue and target (e.g., similar > contrasting > unrelated) rather than by preexisting associative relations.
One possible problem with the cued recall results is that cued recall always followed recognition in this paradigm, so it is possible that the pattern of recall was influenced, or even caused, by prior recognition. The potential seriousness of this point is underlined by the fact that the mean recognition probabilities in all three experiments are ordered similar > contrasting > unrelated (or hard-generate > easy-generate > read for Experiment 3), in the same way recall is ordered. Further analysis reduced this concern, however. For each condition, we multiplied the generation probability by the conditional probability of recognition to find the proportion of encoded items that were recognized in that condition. For example, in the similar encoding condition in Experiment 1, the two generation probabilities were 0.72 and 0.52 for similar and contrasting generation, respectively. When these generation probabilities are multiplied by the conditional recognition probabilities given in Table 2 (0.46 and 0.46, respectively), we observed 0.72 x 0.46 = 0.33 and 0.52 x 0.46 = 0.24. The average of 0.33 and 0.24 is 0.29; thus for the similar encoding condition in Experiment 1, 0.29 of the original items were generated and recognized. The corresponding recognition probabilities for the contrasting and unrelated conditions were 0.23 and 0.15, respectively. If we make the extreme assumption that all recognized items were subsequently recalled, we can simply subtract these "contaminated" items from the cued recall results to yield a measure of recall that is uninfluenced by prior recognition. After subtraction, the cued recall results for Experiment 1 were 0.35, 0.27, and 0.19 for the similar, contrasting, and unrelated conditions, respectively. The corresponding proportions for the other experiments were 0.21, 0.15, and 0.02 for Experiment 2, and 0.30, 0.22, and 0.09 for Experiment 3. The finding that the pattern of cued recall is maintained in all three experiments after removing the effects of prior recognition argues strongly in favour of cued recall reflecting the degree of elaboration achieved in the initial encoding phase.
The most striking finding in the original Tulving and Thomson (1973) study was that recognition levels were considerably lower than cued recall levels. In the present study, recognition was lower than recall in approximately half of the conditions. The important point is not the comparative levels of recognition and recall, but the fact that somewhat different factors affect these two measures of memory. This finding is consistent with the findings of Wiseman and Tulving (1976), who demonstrated that regardless of whether the overall level of recognition was higher or lower than the level of cued recall, substantial amounts of recognition failure were observed in all cases.
The main contribution of the present study is the demonstration that levels of recognition memory and cued recall can vary considerably between conditions in the Tulving and Thomson paradigm (recognition ranged from 0.20 to 0.53 and recall ranged for 0.20 to 0.64) and that somewhat different factors are important in the two cases. For recall, the crucial factors appear to be the depth and semantic richness of the initial encoding, the strength of the semantic relation between the encoding cue (or context) and the target, and the reprovision of the cue or context at the time of retrieval (Fisher & Craik, 1977; Morris et al., 1977; Roediger et al., 1989). In the case of recognition, the present results show that the semantic congruence between the encoding and retrieval contexts is an important factor as well as the amount of semantic elaboration provided by the encoding context. These results suggest that a semantically rich initial encoding may be associated with high levels of subsequent recognition regardless of the compatibility of the encoding and retrieval contexts.
We thank M. Masson and an anonymous reviewer for their helpful comments on an earlier draft of this paper. Correspondence concerning this article should be addressed to Brenda Hannon, University of Toronto, Mississauga, Ontario, L5L 1C6 (E-mail: brendah@psych.utoronto.ca).
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Date of acceptance: October 2, 2000
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Sommaire
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Selon le principe de l'encodage specifique, " les operations specifiques d'encodage de ce qui est percu determinent ce qui est emmagasine, et ce qui est emmagasine determine quel sont les indices de recouvrement dormant acces a ce qui est emmagasine. - (Tulving & Thomson, 1973, p. 369, traduction libre). En d'autres mots, le rappel indice est possible seulement si (information contenue dans le rappel est incorporee a la trace mnesique relative a l'evenement cible au moment de fencodage initial. Ce principe a ete illustre a l'aide d'un ingenieux modele en quatre phases, mis au point par Tulving et Thompson (1973), qui se resume ainsi a) une phase d'encodage de couples de mots a correspondance faible (p. ex., whisky-EAU) constitues de facon a induire un biais dans le sens du mot ecrit en lettres majuscules; b) une phase d'encodage basee sur la categorie, au cours de laquelle on donne aux participants des indices categoriels (p. ex., lac) laissant prevoir le rappel du mot-cible encode (p. ex., EAU)
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mais possedant un sens legerement different; c) une phase de reconnaissance au cours de laquelle on demande aux participants de reconnaitre tous les mots produits par les cibles encodees; et d) une phase de rappel indice pendant laquelle le mot indice est presente de nouveau. Les resultats ont demontre qu'a la troisieme phase la reconnaissance des mots produits etait considerablement plus faible que le rappel indice a la quatrieme phase. La discordance presente dans l'information semantique au test de reconnaissance a donne lieu a un rendement mnesique faible.
De facon inattendue, certains mots-cibles ont ete reconnus plutot frequemment a la troisieme phase, tandis que d'autres ne Pont ete par aucun participant. Le but de la presente recherche etait justement d'examiner ces ecarts. Dans les etudes de ce type, les couples de mots relies par association presentent parfois des significations apparentees (p. ex., neige-BLANC) et d'autres fois, des sens opposes (p. ex., noir-BLANC). Nous
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avons predit que la reconnaissance des mots produits serait elevee si le couple de mots a encoder et le couple de mots produits etaient similaires du point de vue semantique (p. ex., couple de mots au sens apparente ou couple de mots au sens oppose). Dans l'ensemble, les experiences 1 et 2 ont permis de confirmer cette provision, au moyen de couples de noms, dans la premiere experience, et d'adjectifs, dans la deuxieme. Nous avons cependant releve, au cours des deux experiences, un resultat anormal: la reconnaissance etait bonne lorsque des couples de mots au sens apparente etaient utilises pour l'encodage, qu'ils proviennent ou non d'une categorie apparentee a leur sens. Nous avons a ce sujet emis l'hypothese que les couples de mots semblables etaient encodees de facon tres elaboree et qu'un tel degre d'encodage en preservait des effets de legers changements de sens durant les phases subsequentes de production de mots et de
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reconnaissance. L'experience 3, au cours de laquelle variait le degre d'elaboration de l'encodage au moment de la presentation des categories, a confirme cette hypothese. Dans ce cas, les mots encodes avec difficulte etaient reconnus apres la presentation, a la phase 2, de mots faisant ou non partie d'une categorie apparentee; les mots encodes sans grande difficulte etaient aisement reconnus uniquement apres la presentation de mots de leur categorie d'appartenance et les mots simplement lus, sans difficulte aucune a l'encodage, etaient difficilement reconnus. Nous pouvons ainsi affirmer que le niveau de rappel indice releve a la quatrieme phase correspond a celui de l' elaboration semantique effectuee a la premiere phase. Dans (ensemble, notre etude met en evidence l'importance de la compatibility semantique entre la tache d'encodage et la tache de rappel pour arriver a des niveaux eleves de rendement run-m6monique.
[Author Affiliation]
BRENDA HANNON and FERGUS I. M. CRAIK, University of Toronto
We thank M. Masson and an anonymous reviewer for their helpful comments on an earlier draft of this paper. Correspondence concerning this article should be addressed to Brenda Hannon, University of Toronto, Mississauga, Ontario, L5L 1C6 (E-mail: brendah@psych.utoronto.ca).