ROCs in recognition with and without identification

Receiver operating characteristics (ROCs) for the recognition of unidentified word fragments were analysed and compared with ROCs for the recognition of identified word fragments. In all conditions reported here, the z-transformed ROCs (z-ROCs) for recognition without identification were linear, with slopes near 1.0. In contrast, the z-ROCs for recognition with identification each had both a linear and a quadratic component, and a slope of substantially less than 1.0. Because the recognition of unidentified word fragments likely results from a familiarity process, the present study examined how well the effect can be explained by global matching variants of signal detection theory. Global matching models predict that memory should be better for strong items from a mixed list than for strong items from a pure list, and should be worse for weak items from a mixed list than for weak items from a pure list; however, only the latter pattern was shown for the recognition of unidentified items.     

Recognition memory for faces: When familiarity supports associative recognition judgments

Recognition memory for single items can be dissociated from recognition memory for the associations between items. For example, recognition tests for single words produce curvilinear receiver operating characteristics (ROCs), but associative recognition tests for word pairs produce linear ROCs. These dissociations are consistent with dual-process theories of recognition and suggest that associative recognition relies on recollection but that item recognition relies on a combination of recollection and assessments of familiarity. In the present study, we examined associative recognition ROCs for facial stimuli by manipulating the central and external features, in order to determine whether linear ROCs would be observed for stimuli other than arbitrary word pairs. When the faces were presented upright, familiarity estimates were significantly above zero, and the associative ROCs were curvilinear, suggesting that familiarity contributed to associative judgments. However, presenting the faces upside down effectively eliminated the contribution of familiarity to associative recognition, and the ROCs were linear. The results suggest that familiarity can support associative recognition judgments, if the associated components are encoded as a coherent gestalt, as in upright faces.     

Recognition memory ROCs for item and associative information: The contribution of recollection and familiarity

Receiver-operating characteristics (ROCs) were examined in three recognition memory experiments. ROCs for item information (i.e., was this word presented?) were found to be curvilinear. However, ROCs for associative information (i.e., were these two words presented together?) were found to be linear. The results are in agreement with the predictions of a dual-process model that assumes that recognition judgments are -based on familiarity and recollection. Familiarity reflects the assessment of a continuous strength dimension and is well described as a signal detection process, whereas recollection reflects the retrieval of qualitative information about the study episode and behaves like a discrete threshold process. The results showed that memory judgments about items relied on a combination of recollection and familiarity, but that judgments about associations relied primarily on recollection. Further examination of the associative ROCs suggested that subjects were able to recollect that old pairs of items were in the study list, and, under some conditions, that new pairs were not in the study list.     

Recognition with and without identification: dissociative effects of meaningful encoding

In a series of four experiments, the effects of levels of processing and generation on the recognition of identified versus unidentified word fragments were examined. After studying a list of words, participants took a word fragment completion test in which half of the fragments came from studied words and half came from nonstudied words. Regardless of whether they could complete a given fragment, the participants were asked to rate the likelihood that it came from a studied word. Recognition of identified fragments was best whenever the focus of the encoding task was on meaning. Recognition of unidentified fragments did not benefit from meaningful encoding in any of the experiments reported here but did benefit from generation. It is suggested that whereas recognition with identification involves the use of meaning, recognition without identification involves the use of abstract orthographic information in memory.     

Regularities of source recognition: ROC analysis

Source memory has become the focus of a growing number of investigations in a variety of fields. An appropriate model for source memory is, therefore, of increasing importance. A simple 2-dimensional signal-detection model of source recognition is presented. The receiver operating characteristics (ROCs) obtained from 3 experiments are then used to test the model. The data demonstrate 3 regularities: convex ROCs, z-ROCs with linear slopes of 1.00, and slightly concave z-ROCs. Two of these regularities support the model. The 3rd requires a revision of the model. This revised model is fitted to the data. The implications of these regularities for other theories are also discussed.     

Lexical and semantic influences on item and order memory in immediate serial recognition: Evidence from a novel task

Previous studies have reported that, in contrast to the effect on immediate serial recall, lexical/semantic factors have little effect on immediate serial recognition. This has been taken as evidence that linguistic knowledge contributes to verbal short-term memory in a redintegrative process at recall. Contrary to this view, we found that lexicality, frequency, and imageability all influenced matching span. The standard matching span task, requiring changes in item order to be detected, was less susceptible to lexical/semantic factors than was a novel task involving the detection of phoneme order and hence item identity changes. Therefore, in both immediate recognition and immediate serial recall, lexical/semantic knowledge makes a greater contribution to item identity than to item order memory. Task sensitivity, and not the absence of overt recall, may have underpinned previous failures to show effects of these variables in immediate recognition. We also compared matching span for pure and unpredictable mixed lists of words and nonwords. Lexicality had a larger impact on immediate recognition for pure than for mixed lists, in line with findings for immediate serial recall. List composition affected the detection of phoneme but not item order changes in matching span; similarly, in recall, mixed lists produce more frequent word phoneme migrations but not migrations of entire items. These results point to strong similarities between immediate serial recall and recognition. Lexical/semantic knowledge may contribute to phonological stability in both tasks.     

Lexical and semantic influences on item and order memory in immediate serial recognition: evidence from a novel task

Previous studies have reported that, in contrast to the effect on immediate serial recall, lexical/semantic factors have little effect on immediate serial recognition. This has been taken as evidence that linguistic knowledge contributes to verbal short-term memory in a redintegrative process at recall. Contrary to this view, we found that lexicality, frequency, and imageability all influenced matching span. The standard matching span task, requiring changes in item order to be detected, was less susceptible to lexical/semantic factors than was a novel task involving the detection of phoneme order and hence item identity changes. Therefore, in both immediate recognition and immediate serial recall, lexical/semantic knowledge makes a greater contribution to item identity than to item order memory. Task sensitivity, and not the absence of overt recall, may have underpinned previous failures to show effects of these variables in immediate recognition. We also compared matching span for pure and unpredictable mixed lists of words and nonwords. Lexicality had a larger impact on immediate recognition for pure than for mixed lists, in line with findings for immediate serial recall. List composition affected the detection of phoneme but not item order changes in matching span; similarly, in recall, mixed lists produce more frequent word phoneme migrations but not migrations of entire items. These results point to strong similarities between immediate serial recall and recognition. Lexical/semantic knowledge may contribute to phonological stability in both tasks.     

The strength-based mirror effect in subjective strength ratings: The evidence for differentiation can be produced without differentiation

Criss (Cognitive Psychology 59:297?C319, 2009) reported that subjective ratings of memory strength showed a mirror effect pattern in which strengthening the studied words increased ratings for targets and decreased ratings for lures. She interpreted the effect on lure items as evidence for differentiation, a process whereby lures produce a poorer match to strong than to weak memory traces. However, she also noted that participants might use different mappings between memory evidence and levels of the rating scale when they expected strong versus weak targets; that is, the effect might be produced by decision processes rather than differentiation. We report two experiments designed to distinguish these accounts. Some participants studied pure lists of weak or strong items (presented once or five times, respectively), while others studied mixed lists of half weak and half strong items. The participants from both groups had pure-strength tests: Only strong or only weak items were tested, and the participants were informed of which it would be before the test. The results showed that strength ratings for lures were lower when strong versus weak targets were tested, regardless of whether the study list was pure or mixed. In the mixed-study condition, the effect was produced even after identical study lists, and thus the same degree of differentiation in the studied traces. Therefore, our results suggest that the strength-rating mirror effect is produced by changes in decision processes.     

Similarity, global matching, and judgments of frequency

In the test-pair similarity effect, forced-choice recognition is more accurate for similar test pairs, such as leopard-cheetah, than it is for unrelated test pairs, such as leopard-turnip. According to global matching models, this occurs because the retrieved familiarities of similar items are correlated. In the Minerva 2 model, global matching underlies frequency judgments as well as recognition memory. One implication of this model is that judged frequencies of similar items should be correlated. Another implication is that judgments of summed frequency for pairs of words (how many presentations were there of word1 and word2 combined?) should have higher variance when word1 and word2 are similar than when they are unrelated. These predictions were tested and confirmed in two experiments. A review of these and other results suggests that theories of recognition memory should also be applicable to frequency-judgment tasks.     

Familiarity from orthographic information: Extensions of the recognition without identification effect

Two experiments were conducted to investigate the effect of letter location information in recognition memory judgments. The experiments used the recognition without identification paradigm (Peynircioglu, 1990), in which participants first attempt to identify the test item and then make a recognition decision as to whether or not the item was studied. In these studies, items that are not identified but that correspond to items that were presented are typically still rated as more likely to have been studied than those that were not presented. The present experiments demonstrated this finding with a variant of the conjunction lure paradigm. In Experiments 1 and 2, participants were tested with word fragments that were made from the letters of two words. When the letters were from studied items, fragments were rated higher than when the test items were derived from two unstudied items, or one studied item and one unstudied item, suggesting that recognition without identification is prone to the same types of errors as recognition with identification. Results are discussed in terms of familiarity effects in recognition memory.     

The syllable-based word length effect and stimulus set specificity

The word length effect is the finding that a list of items that take less time to pronounce is better recalled on an immediate serial recall test than an otherwise equivalent list of items that take more time to pronounce. Contrary to the predictions of all major models of the word length effect, Hulme, Suprenant, Bireta, Stuart, and Neath (2004) found that short and long items presented within the same list were recalled equally as well as short items presented in lists of just short items. Different results were reported by Cowan, Baddeley, Elliot, and Norris (2003), who found that mixed lists were recalled worse than pure short lists, but better than pure long lists. The experiments reported here suggest that the different empirical findings are due to properties of the stimulus sets used: one stimulus set produces results that replicate Cowan et al., whereas all other sets tested so far yield results that replicate Hulme et al.     

Classification and recognition in artificial grammar learning: Analysis of receiver operating characteristics

In two experiments we investigated recognition and classification judgements using an artificial grammar learning paradigm. In Experiment 1, when only new test items had to be judged, analysis of z-transformed receiver operating characteristics (z-ROCs) revealed no differences between classification and recognition. In Experiment 2, where we included old test items, z-ROCs in the two tasks differed, suggesting that judgements relied on different types of information. The results are interpreted in terms of heuristics that people use when making classification and recognition judgements.     

Effects of study list composition on the word frequency effect and metacognitive attributions in recognition memory

In two experiments, study-list composition was manipulated and its impact was observed on metacognitive judgements associated with recognition hits (Hs) and false alarms (FAs). Both studies involved recognition of high-frequency (HF) and low-frequency (LF) words, and focused on the FA portion of the word frequency effect. Our hypothesis was that participants can actively reject items that are distinctive from the study list, and that this effect may be strong enough to overcome the FA word frequency effect. Experiment 1 manipulated list composition with a conjunctive rule and Experiment 2 varied it by having participants study either HF or LF items prior to a test consisting of words of both frequencies. In each study H rate, FA rate, and metacognitive attributions underlying recognition decisions were investigated. In both studies, participants reported rejecting test items predominantly through a process of active rejection, which was more often reported for LF items. This effect was strong enough to reverse the FA portion of the word frequency effect in Experiment 2, but not Experiment 1. The results are discussed in terms of metacognitive rejection mechanisms in recognition memory.     

Effects of study list composition on the word frequency effect and metacognitive attributions in recognition memory

In two experiments, study-list composition was manipulated and its impact was observed on metacognitive judgements associated with recognition hits (Hs) and false alarms (FAs). Both studies involved recognition of high-frequency (HF) and low-frequency (LF) words, and focused on the FA portion of the word frequency effect. Our hypothesis was that participants can actively reject items that are distinctive from the study list, and that this effect may be strong enough to overcome the FA word frequency effect. Experiment 1 manipulated list composition with a conjunctive rule and Experiment 2 varied it by having participants study either HF or LF items prior to a test consisting of words of both frequencies. In each study H rate, FA rate, and metacognitive attributions underlying recognition decisions were investigated. In both studies, participants reported rejecting test items predominantly through a process of active rejection, which was more often reported for LF items. This effect was strong enough to reverse the FA portion of the word frequency effect in Experiment 2, but not Experiment 1. The results are discussed in terms of metacognitive rejection mechanisms in recognition memory.     

The item and list methods of directed forgetting: test differences and the role of demand characteristics

In directed forgetting, the item method presents instructions to remember or to forget individual items; the list method presents a single mid-list instruction to forget the first half of the list. Initial free recall was better for remember (R) words than for forget (F) words under both methods. Offered 50 cents for each additional F word, subjects could recall almost no more items, eliminating a demand characteristics explanation. On a yes/no recognition test, only the item method showed directed forgetting. Retrospective instruction identification was good except for F words under the list method, where performance was at chance. There was no evidence of speed-accuracy tradeoff on the recognition or instruction identification tests. These results bring together the major findings concerning directed forgetting and support a method-based theoretical distinction.     

Auditory recognition without identification

When visual recognition test items are unidentifiable--through fragmentation, for example--participants can discriminate between unidentifiable items that were presented recently and those that were not. The present study extends this recognition without identification phenomenon to the auditory modality. In several experiments, participants listened to words and were then presented with spoken recognition test items that were embedded in white noise. Participants attempted to identify each spoken word through the white noise, then rated the likelihood that the word was studied. Auditory recognition without identification was found: Participants discriminated between studied and unstudied words in the absence of an ability to identify them through white noise, even when the voice changed from male to female and when the study list was presented visually. The effect was also found when identification was hindered through the isolation of particular phonemes, suggesting that phoneme information may be present in memory traces for recently spoken words.     

Memory strength and the decision process in recognition memory

We investigated the role that memory strength plays in the decision process by examining the extent to which strength is used as a cue to dynamically modify recognition criteria. The study list consisted of strong and weak items, with strength a function of study duration or repetition. The recognition test list was divided into two consecutive blocks; strong items appeared in one block, weak items in the other. If the change in item strength across blocks leads to a shift in criterion, the false alarm rate should change accordingly. In four experiments, the false alarm rates did not change across blocks, even when the difference between the strong and the weak items was magnified and marked with semantic cues. However, the strength of the items in the first test block affected the false alarm rate. Thus, strength cues influence initial criterion placement but fail to induce criterion shifts following permanent and even dramatic changes in item strength. These null findings are contrasted with those in a fifth experiment, in which accuracy feedback produced dynamic criterion shifts.     

Dissociative effects of orthographic distinctiveness in pure and mixed lists: an item-order account

We apply the item-order theory of list composition effects in free recall to the orthographic distinctiveness effect. The item-order account assumes that orthographically distinct items advantage item-specific encoding in both mixed and pure lists, but at the expense of exploiting relational information present in the list. Experiment 1 replicated the typical free recall advantage of orthographically distinct items in mixed lists and the elimination of that advantage in pure lists. Supporting the item-order account, recognition performances indicated that orthographically distinct items received greater item-specific encoding than did orthographically common items in mixed and pure lists (Experiments 1 and 2). Furthermore, order memory (input–output correspondence and sequential contiguity effects) was evident in recall of pure unstructured common lists, but not in recall of unstructured distinct lists (Experiment 1). These combined patterns, although not anticipated by prevailing views, are consistent with an item-order account.     

Recognition without identification

The ability of people to recognize words that they could not identify was examined. After studying a list of 15 words, participants completed a word fragment test consisting of 4-letter fragments of both studied and nonstudied words. Whether they were able to solve a particular fragment or not, participants then made an episodic recognition judgment. Even when participants were unable to solve a fragment, their recognition accuracy was significantly higher than chance. This effect was significant when list length was increased, when 2-letter fragments were used, when first letters were excluded from fragments, and when the letter casing and the presentation modality were changed from study to test. It also occurred when participants attempted to identify fragments at study and rated words at test. Recognition without identification is attributed to the use of orthographic information when determining the familiarity of a test item.     

Associative recognition and the list strength paradigm

When a subset of list items is strengthened, the discriminability of the nonstrengthened items is unaffected. This regularity has been dubbed the null list strength effect (LSE), and despite its many replications in item recognition, little research has investigated whether an LSE occurs in associative recognition. We conducted two experiments in which a set of pairs were studied once and a set of interference pairs were studied either once (pure-weak-list condition) or four times (mixed-list condition). Equivalent levels of performance for the nonstrengthened pairs were observed in both the pure-weak and mixed conditions using both yes–no and two-alternative forced choice testing. Additionally, equivalent false alarm rates were observed between rearranged pairs composed of weak and strong items. Both sets of results were found to be consistent with a matrix model that has no overlap among its item representations.