Memory for instances and categories in children and adults

College subjects and 7-year-olds were trained in sorting 16 words into two conceptual categories. Training consisted of either three list presentations (Experiment I) or training to solution (Experiment II). Then either immediately or after a 3 to 4 week delay subjects received a recognition test which assessed memory for the instance vs categorical properties of the task stimuli by embedding words from the original list and from the list categories with confusion items from either the same or different categories as those on the original list. The data indicated that learning and memory were controlled primarily by categorical properties of the task items in adults and by specific instance properties in children. However, there was evidence that children had learned the categorical attributes of the task and may have differed from adults chiefly in their failure to utilize these attributes to assist learning and memory performance. The age differences in learning and memory were independent of the degree of initial training.     

Memory complaints in younger and older adults

Two samples of older and younger subjects were administered a series of memory tasks and questionnaires tapping their perceptions about their own memory functioning. As in previous research, memory performance was usually better in the younger than in the older sample. In contrast, perceptions about memory varied little as a function of age, and these subjective reports were not related to objective memory performances. These results are relevant to theories that metacognition plays an important role in mediating performance declines with advancing age. If metacognition is implicated in age-related memory differences, it is some aspect of metacognition other than long-term beliefs about memory functioning (e. g. short-term perceptions that occur while attempting to perform memory tasks).     

Memory performance awareness in younger and older adults

Reports on the course of memory-monitoring skills across adulthood are discrepant in conclusions and limited in scope. The purpose of this study was to build a large data base (3 samples and 7 different tasks) to assess performance awareness. Younger (19-41 years) and older (59-93 years) Ss estimated performance either before (i.e., predictions) or after (i.e., postdictions) completing each task. Predictions were less accurate than postdictions at both age levels, suggesting Ss monitored performance during the study-test cycle. Overall, the data suggested no consistent age effects in performance awareness: Age differences in monitoring occurred only in predictions and only for some tasks. Between-tasks differences in age effects could not be attributed to a single mediating mechanism like those suggested in previous reports. Why previous research has produced conflicting conclusions about metacognitive development in adulthood is discussed in light of these data.     

Memory for news in young and old adults

Memory for news stories was studied in 48 young and 48 old adults (20-40 and 60-80 years of age, respectively). Three stories selected from actual news programs were presented in print, audio, and TV formats for study. Young adults recalled a higher proportion of news content than old adults and performed better on source recognition tests. Presentation of the information in a TV format led to better performance than in an audio format for both young and old adults. Hierarchical regression analysis revealed that approximately 86% of the age-related variance in news recall was mediated by measures of sensory acuity and processing speed, and commonality analysis revealed that 75% of the age-related variance was mediated jointly by acuity and speed. Findings support common-cause and generalized slowing views of memory impairment in old age.     

Memory and brain volume in adults prenatally exposed to alcohol

The impact of prenatal alcohol exposure on memory and brain development was investigated in 92 African-American, young adults who were first identified in the prenatal period. Three groups (Control, n=26; Alcohol-related Neurodevelopmental Disorder, n=36; and Dysmorphic, n=30) were imaged using structural MRI with brain volume calculated for multiple regions of interest. Memory was measured using the Verbal Selective Reminding Memory Test and its nonverbal counterpart, the Nonverbal Selective Reminding Memory Test, which each yielding measures of learning and recall. For both Verbal and Nonverbal Recall and Slope, linear trends were observed demonstrating a spectrum of deficits associated with prenatal alcohol exposure. Dysmorphic individuals performed significantly poorer than unexposed controls on 5 of 6 memory outcomes. Alcohol-exposed individuals demonstrated significantly lower total brain volume than controls, as well as lower volume in a number of specific regions including hippocampus. Mediation analyses indicated that memory performance associated with effects of prenatal alcohol exposure was mediated from dysmorphic severity through hippocampal volume, particularly right hippocampus. These results indicate that the association between the physical effects of prenatal alcohol exposure and deficits in memory are mediated by volumetric reduction in specific brain regions.     

Sequential pointing in children and adults

The development of visuomotor control in sequential pointing was investigated in 6- to 10-year-old children and in adults. In 3 experiments we manipulated task difficulty by changing the number, the size, and the spacing of the targets in the sequences. In Experiment 4, only 1 movement was required; we varied independently the distance between targets and the distance of the starting point from the participant's body. Children's temporal and spatial parameters of the motor sequences showed large age-dependent trends, but did not reach the adult values. Comparison of performance across levels of difficulty and ages suggests that motor development is not a uniform fine-tuning of stable strategies. Instead, we argue that each stage of development is best characterized by the set of strategic components potentially available at that stage, and by the (age-dependent) rules for the selection of components in a given context.     

Pictorial representations in adults and children

Reaction time to make same-object judgements was measured for pairs of identical pictures, picture synonyms, identical words, word synonyms, and picture-word combinations in adults and children. At all ages, synonym comparisons took longer than identical comparisons. Adults, but not children responded no faster to picture-word pairs than to picture synonym pairs. This is taken as evidence for the use of abstract pictorial information by adults but not by children. Children seem to compare two different exemplars of the same object verbally in the absence of well-integrated abstract pictorial representations.     

Memory for companions in preschool children

Memory of preschool children (4 years of age) for companions was investigated by comparing interview data using a picture sociometric technique with observational data on actual play companions. Accuracy decreased with successive nominations, and length of recall period. However children were able to name companions played with today, yesterday, last week and at the beginning of term, at well above chance levels. Accuracies improved during the term. The relevance of friendships and social experience for memory and cognitive processes in young children is discussed.     

Memory development in Libyan and Dutch school children

Cross-cultural similarities and differences in memory were examined in two studies with Libyan and Dutch school children of two different grades. The first study analysed effects of word length and pronunciation speed on recall. Baddeley's phonological loop hypothesis could fully account for the somewhat larger digit span of the Dutch children. The second study investigated effects of rehearsal training on recall. Experimental groups showed a higher performance increase after training than did control groups; Libyan children with the same pretest scores as Dutch children showed higher posttest scores, which could be a consequence of sample differences in age or test-wiseness. The studies demonstrated that current theories provide more precise explanations of cross-cultural differences in structural memory features than in control processes. Implications for instructional practice are discussed.     

Synchrony and emotion in children and adults

This study examined both the development of synchronisation activities and the way emotion affects these activities in children and adults. Children aged from 3 to 8 years, as well as adults, performed a spontaneous motor tempo (SMT) task and a synchronisation task with a 500‐millisecond and 700‐millisecond inter‐stimulus interval (ISI), followed by a continuation task, in both an emotion‐free and an emotional context (High‐Arousal, Low‐Arousal, and Neutral). The results showed that the SMT was faster and more variable in the younger children. In addition, the younger children found it more difficult to slow down their tapping rate in synchrony with the 700‐millisecond ISI, with the result that they quickly returned to their internal tempo in the continuation phase. In contrast, the 8‐year‐olds' synchronisation performance was close to that of the adults. However, despite developmental changes in synchronisation skills, all the participants produced faster tempi in both the SMT and the synchronisation task for the High‐Arousal emotion than for the other emotions. This suggests that emotions induce an automatic distortion of motor timing as has also been observed for the perception of time.     

Excuse inference modification in children and adults

The ability of first- and third-grade children and college adults to make excuse inferences about a speaker's use of an utterance and to modify those inferences appropriately upon receiving later information was examined in four experiments. Short stories containing an utterance by a speaker were read aloud. Utterances in the story were preceded by contextual information that suggested either that the speaker was truthful or making an excuse. Utterances were followed by information that confirmed or disconfirmed the excuse interpretation. The results of Experiment 1 indicated that even first and third graders can make excuse inferences, but these children rarely modify these interpretations upon receiving disconfirming information. In Experiments 2–4 possible reasons for the children's interpretive inflexibility were examined by varying the difficulty of relating the excuse interpretation and succeeding information. Results suggested processing difficulty, as well as an interpretive “set,” contributed to the children's inflexibility.     

Global gist extraction in children and adults

The DRM paradigm was used to examine the role of global gist extraction in producing false memories in children and adults. First-graders, third-graders, and adults watched a videotape of a woman reading seven DRM lists, and then took a recognition memory test. Blocked (vs random) presentation and instructions to attend to the theme of lists were manipulated to enhance gist processing. In the first experiment, blocked presentation increased false recognition relative to random presentation in adults but not in first-graders or third-graders. In the second experiment, instructions to attend to list themes increased false recognition in third-graders and not in adults or first-graders. The results suggest a developmental pattern in which children become more adept at global gist extraction as they get older. These results are consistent with fuzzy trace theory's prediction of better gist processing as children grow older.     

Feature binding in children and young adults

The authors measured memory for individual features (objects only or locations only) and the combination of those features (objects and locations) in 9-, 12-, and 21-year-old students with a yes or no recognition task. Analysis of recognition memory performance (d' scores) revealed that although age differences existed in memory for individual features, age differences were greater in the tasks that required memory for combined features (objects and locations). Hierarchical multiple regression analyses indicated that age remained a significant predictor of memory performance in the combination condition even after the authors statistically removed memory performance in object and location conditions and the interaction effects of object and location. These results provide evidence for developmental differences in the binding of features in memory.     

Skin temperature biofeedback in children and adults

Skin temperature biofeedback performance was studied in 38 children, ages 6 to 10, and 38 of their parents, across two sessions of audio biofeedback segments in which the participants alternately attempted hand-warming and hand-cooling. Skin temperature from each hand was monitored throughout, but only one hand at a time was in the feedback loop. The major finding was that children were superior to adults in controlling skin temperature in the presence of biofeedback (p < .001). Adults showed no skin temperature control. For children, temperature changes were greater for the hand in the feedback loop as compared to the contralateral hand (p < .001). Children were equally successful in increasing and decreasing skin temperature. The results are consistent with earlier studies and suggest that children have considerable potential for neuropsychological self-regulation.     

Non-symbolic arithmetic in adults and young children

Five experiments investigated whether adults and preschool children can perform simple arithmetic calculations on non-symbolic numerosities. Previous research has demonstrated that human adults, human infants, and non-human animals can process numerical quantities through approximate representations of their magnitudes. Here we consider whether these non-symbolic numerical representations might serve as a building block of uniquely human, learned mathematics. Both adults and children with no training in arithmetic successfully performed approximate arithmetic on large sets of elements. Success at these tasks did not depend on non-numerical continuous quantities, modality-specific quantity information, the adoption of alternative non-arithmetic strategies, or learned symbolic arithmetic knowledge. Abstract numerical quantity representations therefore are computationally functional and may provide a foundation for formal mathematics.     

Hierarchical forms processing in adults and children

Two experiments examined child and adult processing of hierarchical stimuli composed of geometric forms. Adults (ages 18-23 years) and children (ages 7-10 years) performed a forced-choice task gauging similarity between visual stimuli consisting of large geometric objects (global level) composed of small geometric objects (local level). The stimuli spatial arrangement was manipulated to assess child and adult reaction times and predisposition toward local or global form categorization under two distinct trial conditions, with varied density of the local forms comprising the global forms. In Experiment 1, children and adults were presented with common, simple geometric shape hierarchical forms composed of ovals and rectangles. In Experiment 2, adults were presented with hierarchical forms composed of the simple geometric shapes, ovals and rectangles, and additional novel complex geometric shapes, “posts” and “arches.” Results show a clear increase of global processing bias across the age ranges of the individuals in the study, with children at 10 years performing similarly to adults on the simple stimuli. In addition, adults presented with the novel complex geometric shapes showed a significant reduction in global processing bias, indicating that form novelty and complexity lead to additional attention to local features in categorization tasks.     

Global gist extraction in children and adults

The DRM paradigm was used to examine the role of global gist extraction in producing false memories in children and adults. First-graders, third-graders, and adults watched a videotape of a woman reading seven DRM lists, and then took a recognition memory test. Blocked (vs random) presentation and instructions to attend to the theme of lists were manipulated to enhance gist processing. In the first experiment, blocked presentation increased false recognition relative to random presentation in adults but not in first-graders or third-graders. In the second experiment, instructions to attend to list themes increased false recognition in third-graders and not in adults or first-graders. The results suggest a developmental pattern in which children become more adept at global gist extraction as they get older. These results are consistent with fuzzy trace theory's prediction of better gist processing as children grow older.     

Object identification in preschool children and adults

We introduce computer-based methodologies for investigating object identification in 3- to 5-year-old children. In two experiments, preschool children and adults indicated when they could identify degraded pictures of common objects as those pictures either gradually improved or degraded in clarity. Clarity transformations were implemented in four ways: blurring, decreasing the picture's physical size, decreasing the pixel signal-to-noise ratio, and cropping. In Experiment 1, all age groups correctly identified objects at a more degraded state when those objects began moderately, as opposed to very, degraded and then clarified. This finding supports the notion that previous perceptual hypotheses interfere with object identification (i.e. the perceptual interference effect). In Experiment 2, children, but not adults, overestimated their ability to recognize objects in a degraded state when the object's identity was given to them beforehand. This suggests that for young children knowledge of the object's true identity cannot be ignored when evaluating their current perceptions. This is the first demonstration of the perceptual interference effect in children. We discuss both methodological and theoretical implications of the findings for research on object perception and theory of mind.     

Lexical search speed in children and adults

The retrieval of words from lexical memory was investigated in kindergartners (Age 6), first-graders (Age 7), third-graders (Age 9), and adults. A lexical decision task with auditorily presented words and nonwords was used, with decision latency as the dependent variable. Multiple regression analyses were used to examine the effects of word frequency, age of word acquisition, and number of word meanings. Results showed that word frequency contributed to decision latency for all age groups, age of word acquisition contributed to all groups but the third-grade subjects, and number of word meanings did not contribute for any age group. Results are discussed in relation to a model of the lexicon in children and adults. It is suggested that factors from the external linguistic community are internalized in the lexicon at an early age.