Recognition hypermnesia: How to get it

Although recall hypermnesia (enhanced recall) over time with repeated testing has by now become an established empirical fact, its recognition counterpart, recognition hypermnesia, has defied clear-cut laboratory confirmation. In four studies, which relied on the retrieval component of recognition memory, it was shown that recognition memory, indexed by d′, reliably improved over three successive recognition tests. The stimuli consisted of 140 cartoons, each comprising a picture and a verbal caption. Recognition memory was tested on transforms or part-forms (parts) of the original stimulus material (pictures only, verbal paraphrases of the pictures, the latent content of the cartoons, or the combination of paraphrases and latent contents). The strongest effects were obtained when the originally presented cartoons were tested on their latent (deep semantic) contents. Recognition hypermnesia for part-forms or transforms of earlier presented stimuli has potentially wide-ranging implications since real-world recognition—of faces, texts, visual scenes—usually involves recognising stimuli that are variants, not exact copies, of the originally encountered materials.     

Recognition hypermnesia: The growth of recognition memory (d') over time with repeated testing

This study sought to determine whether recognition hypermnesia (unforgetting) might be obtained over time with repeated testing of recognition memory. Four types of stimuli were investigated: pictures or words (captions) from configured (funny) or non-configured (non-funny) cartoons. Three recognition tests, each comprising the same stimulus and distractor items, were successively administered after the presentation of a large set of captioned cartoons. Silent think intervals of 5 min were interpolated between recognition tests. Recognition hypermnesia, measured by increasing d' estimates of accessible recognition memory, was obtained with the pictures from configured (funny) cartoons but not with any of the other groups.     

Recall and recognition hypermnesia for Socratic stimuli

In two experiments, we investigate hypermnesia, net memory improvements with repeated testing of the same material after a single study trial. In the first experiment, we found hypermnesia across three trials for the recall of word solutions to Socratic stimuli (dictionary-like definitions of concepts) replicating Erdelyi, Buschke, and Finkelstein and, for the first time using these materials, for their recognition. In the second experiment, we had two “yes/no” recognition groups, a Socratic stimuli group presented with concrete and abstract verbal materials and a word-only control group. Using signal detection measures, we found hypermnesia for concrete Socratic stimuli—and stable performance for abstract stimuli across three recognition tests. The control group showed memory decrements across tests. We interpret these findings with the alternative retrieval pathways (ARP) hypothesis, contrasting it with alternative theories of hypermnesia, such as depth of processing, generation and retrieve–recognise. We conclude that recognition hypermnesia for concrete Socratic stimuli is a reliable phenomenon, which we found in two experiments involving both forced-choice and yes/no recognition procedures.     

Selective disruption of hypermnesia for pictures and words

In this study, we investigated the effects of various interpolated tasks on hypermnesia (improved recall across repeated tests) for pictures and words. In five experiments, subjects studied either pictures or words and then completed two free-recall tests, with varying activities interpolated between the tests. The tasks performed between tests were varied to test several hypotheses concerning the possible factor(s) responsible for disruption of the hypermnesic effect. In each experiment, hypermnesia was obtained in a control condition in which there was no interpolated task between tests. The remaining conditions showed that the effect of the interpolated tasks was related to the overlap of the cognitive processes involved in encoding the target items and performing the interpolated tasks. When pictures were used as the target items, no hypermnesia was obtained when subjects engaged in imaginal processing interpolated tasks, even when these tasks involved materials that were very distinct from the target items. When words were used as the target items, no hypermnesia was obtained when the interpolated tasks required verbal/linguistic processing, even when the items used in these tasks were auditorily presented. The results are discussed in terms of a strength-based model of associative memory.     

Learning 10000 pictures

Four experiments are reported which examined memory capacity and retrieval speed for pictures and for words. Single-trial learning tasks were employed throughout, with memory performance assessed by forced-choice recognition, recall measures or choice reaction-time tasks. The main experimental findings were: (1) memory capacity, as a function of the amount of material presented, follows a general power law with a characteristic exponent for each task; (2) pictorial material obeys this power law and shows an overall superiority to verbal material. The capacity of recognition memory for pictures is almost limitless, when measured under appropriate conditions; (3) when the recognition task is made harder by using more alternatives, memory capacity stays constant and the superiority of pictures is maintained; (4) picture memory also exceeds verbal memory in terms of verbal recall; comparable recognition/recall ratios are obtained for pictures, words and nonsense syllables; (5) verbal memory shows a higher retrieval speed than picture memory, as inferred from reaction-time measures. Both types of material obey a power law, when reaction-time is measured for various sizes of learning set, and both show very rapid rates of memory search.

From a consideration of the experimental results and other data it is concluded that the superiority of the pictorial mode in recognition and free recall learning tasks is well established and cannot be attributed to methodological artifact.     

Hypermnesia for pictures: Incremental memory for pictures but not words in multiple recall trials

Two studies are reported on multiple forced recall following a single visual presentation of a sequence of pictures or words. In both experiments, a hypermnesic memory function (in which performance improved with repeated recall) was obtained for pictures, while a flat, nonincremental function was obtained for words. Interpolation of intervals of thinking between recall trials further enhanced hypermnesia for pictorial items. Retrieval, whether overt (recall trials) or covert (thinking), apparently produces increased net recovery of pictures but not words.     

Does the generation effect occur for pictures?

The generation effect is the finding that self-generated stimuli are recalled and recognized better than read stimuli. The effect has been demonstrated primarily with words. This article examines the effect for pictures in two experiments: Subjects named complete pictures (name condition) and fragmented pictures (generation condition). In Experiment 1, memory was tested in 3 explicit tasks: free recall, yes/no recognition, and a source-monitoring task on whether each picture was complete or fragmented (the complete/incomplete task). The generation effect was found for all 3 tasks. However, in the recognition and source-monitoring tasks, the generation effect was observed only in the generation condition. We hypothesized that absence of the effect in the name condition was due to the sensory or process match effect between study and test pictures and the superior identification of pictures in the name condition. Therefore, stimuli were changed from pictures to their names in Experiment 2. Memory was tested in the recognition task, complete/incomplete task, and second source-monitoring task (success/failure) on whether each picture had been identified successfully. The generation effect was observed for all 3 tasks. These results suggest that memory of structural and semantic characteristics and of success in identification of generated pictures may contribute to the generation effect.     

Visual recognition memory for complex configurations

Previous studies of recognition memory for heterogeneous pictorial stimuli suggest an unusually large storage and retrieval capacity. In the first experiment, three series of homogeneous pictures (faces, ink blots, snow crystals) were presented to six independent groups of Ss, and recognition was tested immediately or 48 h later. Accuracy and sex were related to stimulus configuration; at both time intervals, accuracy was best for faces and poorest for snow crystals. Levels of accuracy were below those attained in studies using heterogeneous arrays. The results of two other experiments suggest the relative unimportance of verbal mediation in recognition of homogeneous pictorial stimuli.     

Hypermnesia for high-imagery words: The effects of interpolated tasks

The purpose of this study was to determine whether hypermnesia (improved net recall over time) can be differentially affected by manipulating the nature of tasks performed during the intervals between successive recall trials. In Experiment 1, all subjects were asked to imaginally encode separate words and were tested three times for recall. The control group (no interpolated task) produced the hypermnesia effect. Both groups performing interpolated tasks showed significantly lower recall. A second experiment was conducted in order to replicate these results and to examine the effects of intertest rehearsal on hypermnesia. In Experiment 2, subjects were asked to encode pairs of words using interactive-imagery instructions. Six different interpolated task conditions were employed, varying in the degree to which subsystems of working memory were used. Groups performing imaginal interpolated tasks showed no hypermnesia, whereas those performing nonimaginal tasks did. These findings suggest that access to working memory (see Baddeley, 1986) is not necessary for hypermnesia.     

Eye fixations in prediction of recognition and recall

Eye fixations were recorded at viewing of picture-label stimuli presented under either recall or recognition instructions; both retention tests were administered. Ss performed substantially better on the retention test of which they were informed, indicating differential encoding of the same stimuli in anticipation of test type. There was no correlation between recognition and recall of items, evidence that different information from the encoded stimuli was utilized in performing each test. Encoding strategies had no effect on how Ss regarded the stimuli, but viewing patterns were related to memory performance: More word fixations was associated with better verbal recall, while fewer picture fixations was associated with better recall and with better picture recognition.     

Exploring the superadditive effects of scent and pictures on verbal recall: An extension of dual coding theory

This research extends the dual coding theory of memory retrieval (Paivio 1969, 2007) beyond its traditional focus on verbal and pictorial information to olfactory information. We manipulate the presence or absence of olfactory and pictorial stimuli at the time of encoding (study 1) or retrieval (study 2) and measure the impact on verbal recall. After a time delay, scent enhances recall of verbal information, and scent-based retrieval cues potentiate the facilitative effect of pictures on recall. These results cannot be attributed merely to increased elaboration at the time of exposure.     

Verbal and Nonverbal Emotional Memory Following Unilateral Amygdala Damage

The amygdala is involved in the normal facilitation of memory by emotion, but the separate contributions of the left and right amygdala to memory for verbal or nonverbal emotional material have not been investigated. Fourteen patients with damage to the medial temporal lobe including the amygdala (seven left, seven right), 18 brain-damaged, and 36 normal controls were exposed to emotional and neutral pictures accompanied by verbal narratives. Memory for both narratives and pictures was assessed with a free recall test 24 h later. Subjects with left amygdala damage failed to show the normally robust enhancement of memory for verbal and nonverbal emotional stimuli. The group with right amygdala damage showed the normal pattern of facilitation of memory by emotion for both verbal and nonverbal stimuli despite an overall reduction in memory performance. Furthermore, subjects with left amygdala damage were disproportionately impaired on memory for emotional narratives as compared with memory for emotional pictures. The latter finding offers partial support for a lateralized and material-specific pattern of the amygdala's contribution to emotional memory.     

Hypermnesia occurs in recall but not in recognition

Two experiments investigated the effect of encoding conditions and type of test (recall vs. recognition) on the phenomenon of hypermnesia (improved performance across repeated tests). Subjects in Experiment 1 studied a list of words using either imaginal or semantic elaboration strategies and then received three successive tests. Different groups of subjects received either free recall, four-alternative forced-choice recognition, or yes/no recognition tests. Reliable hypermnesia was found only in the recall conditions, with the recognition conditions showing either no change in performance levels across tests (forced-choice tests) or significant forgetting (yes/no tests). In Experiment 2, subjects studied a list of words, and encoding was manipulated using three orienting tasks. Once again, hypermnesia was found with the recall tests but not with the forced choice recognition tests. Finding hypermnesia in recall but not in recognition indicates that retrieval processes in recall play a major role in producing hypermnesia. Also, the finding that the magnitude of the recall hypermnesias increased with an increase in total cumulative recall levels across study conditions suggests that cumulative recall levels are an important factor in determining the presence or absence of recall hypermnesia.     

The role of recall time in producing hypermnesia

In two experiments subjects presented with either words or pictures showed improved recall over three successive recall tests for both types of materials, partially replicating Erdelyi’s finding of hypermnesia. However, these subjects did not recall more unique items than other subjects who received only one test equated in time with the three shorter ones. It is concluded that hypermnesia results from simply allowing subjects additional recall time. In a third experiment subjects were shown to recall additional information even after a long recall period employed during an experimental session. This surprising amount of item recovery during long recall periods is attributed to the use of subjective retrieval cues that are thought to function in a manner analogous to externally manipulated cues.     

Individual differences in cognition: Relationship between verbal ability and memory for order

The crucial role of order information in language has led to the suggestion that psychometrically measured verbal ability may be related to memory for order. The literature pertaining to this hypothesis is briefly reviewed and various methodological difficulties discussed. The results of three experiments indicated that (a) order and item information may be retained separately; (b) verbal ability is related to the short-term recall of order; (c) verbal ability is unrelated to memory for order when testing involves recognition rather than recall; and (d) the relationship between verbal ability and memory for order is most pronounced when the originally presented order must be transformed at output (as in the “digits backward” task). An output process in which material is decoded and held in an output buffer until decoding is complete is viewed as the most likely locus of the verbal ability-memory for order relationship.     

Hypermnesia: A further examination of age differences between young and older adults

Previous studies that examined age differences in hypermnesia reported inconsistent results. The present experiment investigated whether the different study materials in these studies were responsible for the inconsistency. In particular, the present experiment examined whether the use of a video, as opposed to words and pictures, would eliminate previously reported age differences in hypermnesia. Fifteen college students and 15 older adults viewed a 3‐minute video clip followed by two free‐recall tests. The results indicated that older adults, as a whole, did not show hypermnesia. However, when older adults were divided into low and high memory groups based on test 1 performance, the high memory group showed hypermnesia whereas the low memory group did not show hypermnesia. The older adults in the low memory group were significantly older than the older adults in the high memory group – indicating that hypermnesia is inversely related to age in older adults. Reminiscence did not show an age‐related difference in either the low or high memory group whereas inter‐test forgetting did show an age difference in the low memory group. As expected, older adults showed greater inter‐test forgetting than young adults in the low memory group. Findings from the present experiment suggest that video produces a pattern of results that is similar to the patterns obtained when words and pictures are used as study material. Thus, it appears that the nature of study material is not the source of inconsistency across the previous studies.     

Coding modality vs. input modality in hypermnesia: Is a rose a rose a rose?

Recent experiments indicate that recall of pictures, unlike recall of words, may increase (hypermnesia) with time and effort. This study demonstrates that by recoding word inputs into ‘mental pictures’, i.e., images, subjects can transform inert word lists into hypermnesic ones. Thus, when word inputs are recoded into images, recall increases over time, and resembles in other respects the recall of pictures.     

Investigating the structure and age invariance of episodic memory across the adult lifespan

The structure of episodic memory was investigated by assessing different modalities of material (verbal, figural, and spatial) and different types of tests (recall, cued recall, and recognition). A 3-factor model that distinguished among modalities of material was found to be the best representation of memory and the verbal, figural, and spatial memory factors exhibiting construct validity. This 3-factor modality of material model also demonstrated configural, metric, and structural age invariance across a sample of adults (N = 327) between the ages of 18 and 94. There was evidence that latent constructs corresponding to recall, cued recall, and recognition could be distinguished from one another within the verbal domain but not within the figural and spatial domains. A mediation model examining the retrieval constructs was examined within the verbal domain, and there were unique age-related influences on cued recall and recall performance. This result is consistent with findings that increased age is associated with increased difficulty in retrieving information.