Infants' delayed recognition memory and forgetting

Infants 21- to 25-weeks-old devoted more visual fixation to novel than to previously exposed stimuli on immediate and delayed tests of recognition. Abstract black and white patterns were recognized following a 48-hour delay and photos of faces after a 2-week delay. A decline in recognition over 3 hours for targets (face masks) most akin to objects (real faces) in S's environment led to studies of the effect on delayed recognition of exposure to stimuli similar to those to be retained. One-minute delayed recognition for face photos was disrupted by intervening exposure to intermediate similarity stimuli (rotated photos) but was unaffected by exposure to either high (upright photos) or low (rotated line drawings) similarity stimuli. Differentiation among intervening stimuli occurred only for the upright photos used as high-similarity intervening material. In addition, immediate exposure to rotated photos also prevented 3-hour-delayed recognition of upright photos but had no such effect when delayed for 3 hours. The present experiments confirm the existence of long-term recognition memory for pictorial stimuli in the early months of life and show that one source of forgetting is due to a diversion of the infant's attention to material bearing some perceptual similarity to the material to be retained. This diversion of attention must occur soon after immediate recognition testing to produce a reduction of recognition and such deleterious effects last for an appreciable period of time.     

Infants' recognition memory for a series of visual stimuli

The tendency of infants to distribute attention selectively to novel and familiar visual stimuli was employed to study infants' recognition memory for a series of visual targets. Infants 5 months of age demonstrated an unequal distribution of visual fixation to novel and familiar stimuli, with more attention to the novel, on both immediate and delayed stimulus-recognition tests for each of three novelty problems administered during a single testing session. The degree of differential fixation to novel targets exhibited no reliable decline from immediate to delayed testing and was not significantly altered by the serial order which the problem occupied during immediate recognition testing.     

Infants' recognition memory, forgetting, and savings.

In four experiments infants of 5–6 months of age were tested for recognition memory of briefly presented visual stimuli. In the first experiment infants showed relatively more looking at a novel picture when it was paired with a picture they had just studied for 10 or 20 sec. This differential response to novelty served as evidence of immediate recognition memory. In the second experiment these same 10- or 20-sec study times were used but were not sufficient to produce reliable evidence of memory over a long (48 hr) retention interval or even as short an interval as 40 sec. The third experiment demonstrated substantial delayed recognition if a brief reexposure of materials was introduced immediately prior to the recognition test. This reminder required less than the minimal study time found necessary to produce immediate recognition memory in Experiment 1. The results of the fourth experiment indicated that the savings effects that occurred in Experiment 3 were not solely due to familiarity with the testing procedures. The implications of savings effects in infants' memory are discussed.     

Infants' memory for musical performances

We evaluated 6- and 7-month-olds' preference and memory for expressive recordings of sung lullabies. In Experiment 1, both age groups preferred lower-pitched to higher-pitched renditions of unfamiliar lullabies. In Experiment 2, infants were tested after 2 weeks of daily exposure to a lullaby at one pitch level. Seven-month-olds listened significantly longer to the lullaby at a novel pitch level than at the original pitch level. Six-month-olds showed no preference but their low-pitch preference was eliminated. We conclude that infants' memory for musical performances is enhanced by the ecological validity of the materials. Moreover, infants' pitch preferences are influenced by their previous exposure and by the nature of the music.     

Visual memory for colour

Two colours were either simultaneously or successively presented. In both cases the time taken to determine whether the colours differed increased as the visual similarity of the colours increased. In another experiment, colours or names of colours were presented successively in different blocks of trials. Here colour similarity affected the discrimination reaction times whenever the second stimulus was a colour. This was taken to suggest that visual mnemonic representations can be generated from the first stimulus.     

Achievement motivation and memory: achievement goals differentially influence immediate and delayed remember-know recognition memory

Little research has been conducted on achievement motivation and memory and, more specifically, on achievement goals and memory. In the present research, the authors conducted two experiments designed to examine the influence of mastery-approach and performance-approach goals on immediate and delayed remember-know recognition memory. The experiments revealed differential effects for achievement goals over time: Performance-approach goals showed higher correct remember responding on an immediate recognition test, whereas mastery-approach goals showed higher correct remember responding on a delayed recognition test. Achievement goals had no influence on overall recognition memory and no consistent influence on know responding across experiments. These findings indicate that it is important to consider quality, not just quantity, in both motivation and memory, when studying relations between these constructs.     

Infants' long-term memory for the sound patterns of words and voices

Infants' long-term memory for the phonological patterns of words versus the indexical properties of talkers' voices was examined in 3 experiments using the Headturn Preference Procedure (D. G. Kemler Nelson et al., 1995). Infants were familiarized with repetitions of 2 words and tested on the next day for their orientation times to 4 passages--2 of which included the familiarized words. At 7.5 months of age, infants oriented longer to passages containing familiarized words when these were produced by the original talker. At 7.5 and 10.5 months of age, infants did not recognize words in passages produced by a novel female talker. In contrast, 7.5-month-olds demonstrated word recognition in both talker conditions when presented with passages produced by both the original and the novel talker. The findings suggest that talker-specific information can prime infants' memory for words and facilitate word recognition across talkers.     

Collaboration can improve individual recognition memory: Evidence from immediate and delayed tests

In two experiments, we tested the effects of collaboration on individual recognition memory. In Experiment 1, participants studied pictures and words either for meaning or for surface properties and made recognition memory judgments individually either following group discussion among 3 members (collaborative condition) or in the absence of discussion (noncollaborative condition). Levels of processing and picture superiority effects were replicated, and collaboration significantly increased individual recognition memory. Experiment 2 replicated this positive effect and showed that even though memory sensitivity declined at longer delays (48 h and 1 week), collaboration continued to exert a positive influence. These findings show that (1) consensus is not necessary for producing benefits of collaboration on individual recognition, (2) collaborative facilitation on individual memory is robust, and (3) collaboration enhances individual memory further if conditions predispose individual accuracy in the absence of collaboration. Psychonomic Society, Inc. nt]pra|Parts of the research reported in this article were presented at the 77th Annual Meeting of the Eastern Psychological Association, Baltimore.     

Infants' learning,memory, and generalization of learning for bimodal events

Study 1 investigated whether infants 3 and 7 months of age show differential learning of and memory for sight-sound pairs depending on whether or not temporal synchrony was present; memory was assessed after a 10-min and 1-week interval. Study 2 examined whether 7-month-olds show generalization of learning when they encounter novel bimodal events that are similar (changes in size, orientation, or color, and spectral sound properties) to the sight-sound pairs learned 1 week earlier based on temporal synchrony. For Study 1, infants received a familiarization phase followed by a paired-comparison preference procedure to assess for learning of the sight-sound pairs. One week later a memory test was given. Results confirmed that 7-month-olds had no difficulty learning auditory-visual pairings regardless of whether or not events were temporally synchronous, and they remembered these 10 min and 1 week later. In contrast, 3-month-olds showed poorer learning of sight-sound associations in the no-synchrony than synchrony conditions, and memory for sight-sound pairs 1 week later was shown only for the synchrony conditions. Results for Study 2 revealed generalization of learning of bimodal pairings under all stimulus conditions after a 1-week interval at 7 months of age. Implications of these findings for development of intersensory knowledge are discussed.     

True and false memory for colour names versus actual colours: Support for the visual distinctiveness heuristic in memory for colour information

In a colour variation of the Deese–Roediger–McDermott (DRM) false memory paradigm, participants studied lists of words critically related to a nonstudied colour name (e.g., “blood, cherry, scarlet, rouge … ”); they later showed false memory for the critical colour name (e.g., “red”). Two additional experiments suggest that participants generate colour imagery in response to such colour-related DRM lists. First, participants claim to experience colour imagery more often following colour-related than standard non-colour-related DRM lists; they also rate their colour imagery as more vivid following colour-related lists. Second, participants exhibit facilitative priming for critical colours in a dot selection task that follows words in the colour-related DRM list, suggesting that colour-related DRM lists prime participants for the actual critical colours themselves. Despite these findings, false memory for critical colour names does not extend to the actual colours themselves (font colours). Rather than leading to source confusion about which colours were self-generated and which were studied, presenting the study lists in varied font colours actually worked to reduce false memory overall. Results are interpreted within the framework of the visual distinctiveness hypothesis.     

Moderate-to-vigorous intensity cycling exercise immediately after visual learning enhances delayed recognition memory performance

A single bout of acute aerobic exercise has been shown to improve long-term memory, though it is unclear if exercise before learning or after learning is optimal for memory enhancement. Although some research has demonstrated that exercise before learning is ideal, investigations have consistently shown that acute arousal post-learning is a powerful memory enhancer. Therefore, the purpose of this investigation was to compare the effects of self-perceived hard cycling before or after learning on recognition memory for emotional and neutral images, and examine the relationship between central noradrenergic activity and memory performance. Seventy-two males and females (18–35 years of age) participated in this between-subjects study. Participants were randomly assigned to one of the following groups: exercise before learning, exercise after learning, and control. Participants in the exercise groups engaged in 20 min of cycling at a rating of perceived exertion (RPE) of 15 (“hard”) on the Borg RPE scale before or after viewing a series of 90 pleasant, unpleasant, and neutral images (30 each). Participants in the control group engaged in no exercise before or after image viewing. At several time points throughout the experiment, saliva was collected to measure salivary alpha amylase (sAA), a marker of central noradrenergic activity. One-week later, recognition memory was assessed where participants viewed 180 images (90 new) and had to identify which images were previously viewed. Participants in the exercise after learning group had significantly higher recognition memory compared to the control group, but this was not seen with exercise before learning. sAA was not correlated with memory in any group, though it did increase during exercise. These results demonstrate that acute self-perceived hard cycling post-learning, but not pre-learning, improves recognition memory, though this was unrelated to the exercise-induced increase in central noradrenergic activity as measured in saliva.     

Immediate recognition memory for wine

We describe a preliminary investigation concerning the short-term recognition memory function for gustatory stimuli (wines). In Experiment 1A, 24 non-expert wine drinkers completed a yes/no recognition task for 3-wine sequences. For the raw recognition scores, the serial position function comprised both primacy and recency. Recency did not, however, achieve significance for the d′ scores. In Experiment 1B, 24 participants completed the same yes/no recognition task for 3-visual matrix sequences. In contrast to Experiment 1A, the serial position function comprised recency and an absence of primacy. We argue that the presence of primacy for the wine sequences cannot be interpreted via a verbal labelling strategy, nor can it be interpreted via proactive interference from the first wine in the list on subsequent list items. The result suggests qualitative differences in the memory processing for gustatory and non-verbal visual stimuli.     

Long-term recognition memory for sentences

The present studies examined immediate and one-week delayed recognition performance for active and passive sentences. Recognition tests included distractor sentences wherein the logical subject, verb, of logical object of a sentence was replaced by a semantically confusable, visually confusable, or unrelated distractor. Results indicated that logical subjects, verbs, and logical objects of sentences were recognized equally well during immediate testing. During delayed testing, changes in the logical object or recipient of the action were not detected as well as verb changes of logical subject changes. The implications of these results for current sentence memory models were discussed.     

Stability of memory for colour in context.

Memory for colours presented in isolation was compared with that for colours presented as part of a clip-art image or as part of a non-meaningful, Mondrian-like image. The area under the Receiver Operating Characteristic for deciding that two colours, presented at different delay intervals, were the same or different provided an index of memory for colour. The provision of a context reduced the decay of memory, regardless of whether the context was meaningful (clip-art images) or non-meaningful (Mondrian-like images). The result was seen as a generalisation of the auditory phenomenon of profile analysis, in which memory for the amplitude of a single component of a complex sound is more stable than that for the component in isolation.     

What colour is the car? Implicit memory for colour information in children

Three experiments were conducted to examine age-related differences in colour memory. In Experiment 1, preschool age and elementary school age children were given a conceptual test of implicit colour memory (a colour-choice task). They were presented with the names or achromatic versions of previously studied coloured line drawings and asked to select an appropriate colour. Significant priming could be demonstrated: The children chose the previously seen colours more often than was expected by chance. Equivalent priming was found for both versions (pictorial and verbal) suggesting that colour priming may be conceptually mediated. Moreover, colour priming proved to be age invariant. Experiment 2 replicated and extended this finding by using a wider age group (preschool, elementary school, and young adults) and by giving a perceptual implicit task (picture identification) in addition to a verbal colour-choice task. Colour did not affect priming in the perceptual task. Whereas priming showed no developmental change, agerelated improvements were observed on an explicit colour memory task that differed only in the test instructions from the implicit colour-choice task (Experiments 2 and 3). Taken together, the results suggest that implicit colour memory may be mediated by conceptual processes that are age invariant.     

Competition between two memory traces for long-term recognition memory

Previous studies investigating the processes which underlie memory consolidation focused almost exclusively on isolated learning events. Here I studied the competition of two similar memory traces for consolidation non-conditioned recognition memory in adult male C57BL/6JOlaHsd mice using the olfactory cues based social discrimination procedure. My results show that the interference phenomena that cause forgetting are time-dependent, and that retroactive interference can be discriminated from proactive interference. Furthermore, both types of interference can be suppressed by subcutaneous anisomycin treatment immediately after presentation of the interference stimulus. These findings imply that interference phenomena, which result from the competition of two similar memory traces for long-term recognition memory, are related to the progress of memory consolidation and linked to protein synthesis.