A note on the kinematcis of drawing movements in children

The relationship between instantaneous tangential velocity and radius of curvature (power 1/3) that is characteristic of adult subjects was found to be already present in children 3 to 11 years old. The correlation coefficient between these two parameters increases gradually with age without apparent discontinuities. However, even at the upper limit of the age range examined, the values are still lower than in the adults.     

A model of perceptual classification in children and adults

The developmental trend from overall-similarity to dimensional-identity classifications is explained by a quantitative model. I begin with the assumption that objects are represented in terms of constituent dimensions and that the representation of objects changes little with development. Given this assumption, the model has three major parts. First, the similarity between objects is a function of the combination of the constituent dimensional differences. I propose developmental change in the likelihood that dimensions are differentially weighted in the calculation of similarity. Second, the perceived similarities between objects are valued for the purpose of constructing classifications. I propose that similarities are valued more dichotomously with age, such that identity becomes increasingly special. Third, the valued similarities are used to choose the best classification of those possible. The model provides good qualitative fits to the extant data. Three experiments examining classifications in 2- to 8-year-olds and in adults support specific new claims of the model. The data and the model provide new insights about development, classification, and similarity.     

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 narrowing in children and adults

The memory narrowing effect posits that stress enhances memory for central information at the expense of memory for peripheral details. This effect is well established in adults, but not in children, although studies have not directly compared children's and adults' memory for central versus peripheral details of an identical distressing experience. In the present study, 9–12 year‐old and adult participants completed a laboratory stressor during which measures of self‐reported stress was collected. Two weeks later, participants returned for a surprise memory test regarding central and peripheral details of the laboratory stressor. Greater stress predicted memory narrowing in both children and adults, as indexed via decreased correct responses and increased don't know responses to questions about peripheral relative to central details. Findings have implications for theories concerning stress and memory, particularly in children, and for evaluating eyewitness memory in legal contexts. Copyright © 2010 John Wiley & Sons, Ltd.     

A note on notes: note taking and containment

In extreme situations of massive projective identification, both the analyst and the patient may come to share a fantasy or belief that his or her own psychic reality will be annihilated if the psychic reality of the other is accepted or adopted (Britton 1998). In the example of' Dr. M and his patient, the paradoxical dilemma around note taking had highly specific transference meanings; it was not simply an instance of the generalized human response of distracted attention that Freud (1912) had spoken of, nor was it the destabilization of analytic functioning that I tried to describe in my work with Mr. L. Whether such meanings will always exist in these situations remains a matter to be determined by further clinical experience. In reopening a dialogue about note taking during sessions, I have attempted to move the discussion away from categorical injunctions about what analysis should or should not do, and instead to foster a more nuanced, dynamic, and pair-specific consideration of the analyst's functioning in the immediate context of the analytic relationship. There is, of course, a wide variety of listening styles among analysts, and each analyst's mental functioning may be affected differently by each patient whom the analyst sees. I have raised many questions in the hopes of stimulating an expanded discussion that will allow us to share our experiences and perhaps reach additional conclusions. Further consideration may lead us to decide whether note taking may have very different meanings for other analysts and analyst-patient pairs, and whether it may serve useful functions in addition to the one that I have described.     

Effect of age on dual-task performance in children and adults

Age effects on dual-task costs were examined in healthy adults (Exp. 1) and in typically developing children (Exp. 2). In both experiments, individual differences in performance on the single-task components were titrated so that any age differences in dual-task costs could not be attributed to differences in single-task performance. Dual-task costs were found, but there were no age-related differences in these costs in older relative to younger adults, in 7-year-old relative to 9-year-old children, or across all four age groups. The results from these experiments suggest that previously reported age differences in dual-task costs, in both healthy ageing and child development, may be due to a failure to adequately equate single-task difficulty.     

Effects of distraction on visual enumeration in children and adults

Speeded enumeration of visual stimuli typically produces a bilinear function, with a shallow subitizing rate (<100 ms/item) up to 3-4 items (subitizing span) and a steeper counting rate (~300 ms/item) thereafter. FINST theory (L. M. Trick & Z. W. Pylyshyn, 1993, 1994) suggests that subitizing of targets is possible in the presence of distractors if attention is not required for target detection, but this has not been tested in children. The present study explored enumeration without distractors (Os alone) and with distractors (Os among Xs) in 35 children aged 6-11 years and 17 adults. Subitizing span increased significantly from childhood to adulthood, and counting rate increased significantly with age. Bilinear functions were significantly better than linear fits to the data for most children and adults both without distractors (97% and 100%, respectively) and with distractors (89% and 94%), consistent with their efficient visual search for a single O among multiple Xs. These findings are discussed in comparison with those from new modeling of earlier enumeration data from young and older adults, revealing striking asymmetries in subitizing with distractors between development and aging.     

Audiovisual perception of noise vocoded speech in dyslexic and non-dyslexic adults: The role of low-frequency visual modulations

Visual speech inputs can enhance auditory speech information, particularly in noisy or degraded conditions. The natural statistics of audiovisual speech highlight the temporal correspondence between visual and auditory prosody, with lip, jaw, cheek and head movements conveying information about the speech envelope. Low-frequency spatial and temporal modulations in the 2–7 Hz range are of particular importance. Dyslexic individuals have specific problems in perceiving speech envelope cues. In the current study, we used an audiovisual noise-vocoded speech task to investigate the contribution of low-frequency visual information to intelligibility of 4-channel and 16-channel noise vocoded speech in participants with and without dyslexia. For the 4-channel speech, noise vocoding preserves amplitude information that is entirely congruent with dynamic visual information. All participants were significantly more accurate with 4-channel speech when visual information was present, even when this information was purely spatio-temporal (pixelated stimuli changing in luminance). Possible underlying mechanisms 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.     

The role of locomotion in the acquisition and transfer of spatial knowledge in children

The role of locomotion in the acquisition and transfer of spatial knowledge was investigated in 144 five-, seven- and eleven-year-old children. Two experiments were conducted in the Kiel locomotor maze. In the first experiment, one group of children explored the spatial layout by walking through the maze, while another learned the maze by surveying the layout. In the second experiment, children were exposed to one of two orientation tests in the maze, one of which could be solved using "landmark orientation", the other only using a "relational place orientation". Children sitting by the side of the experimental chamber surveying the maze needed fewer trials to learn the spatial layout than children exploring the environment in the locomotion condition, but in the orientation test demanding the "relational place orientation" children who had explored the maze in the locomotion condition outperformed the children in the non-locomotion condition. Results are discussed in the context of cognitive mapping models.     

Development of and change in cognitive control: A comparison of children, young adults, and older adults

Cognitive control involves adjustments in behavior to conflicting information, develops throughout childhood, and declines in aging. Accordingly, developmental and age-related changes in cognitive control and response-conflict detection were assessed in a response-compatibility task. We recorded performance measures, pre-response time (pre-RT) activity and medial frontal negativity (MFN)—sequentially occurring, putative event-related potential (ERP) indexes, respectively, of cognitive control and response-conflict detection. When response conflict reached the highest levels by requiring incompatible responses on posterror trials, children and older adults showed the greatest performance decrements. ERPs indicated that young adults implemented control (pre-RT) and detected the increased conflict (MFN) only when that conflict was at the highest levels, whereas children and older adults did so at lower levels (e.g., posterror, compatible responses). Consequently, the developmental and age-related performance decrements observed here may be due to the undifferentiated and inefficient manner in which children and older adults recruited the processes associated with both cognitive control and response-conflict detection.     

Active vision in passive locomotion: real‐world free viewing in infants and adults

Visual exploration in infants and adults has been studied using two very different paradigms: free viewing of flat screen displays in desk‐mounted eye‐tracking studies and real‐world visual guidance of action in head‐mounted eye‐tracking studies. To test whether classic findings from screen‐based studies generalize to real‐world visual exploration and to compare natural visual exploration in infants and adults, we tested observers in a new paradigm that combines critical aspects of both previous techniques: free viewing during real‐world visual exploration. Mothers and their 9‐month‐old infants wore head‐mounted eye trackers while mothers carried their infants in a forward‐facing infant carrier through a series of indoor hallways. Demands for visual guidance of action were minimal in mothers and absent for infants, so both engaged in free viewing while moving through the environment. Similar to screen‐based studies, during free viewing in the real world low‐level saliency was related to gaze direction. In contrast to screen‐based studies, only infants – not adults – were biased to look at people, participants of both ages did not show a classic center bias, and mothers and infants did not display high levels of inter‐observer consistency. Results indicate that several aspects of visual exploration of a flat screen display do not generalize to visual exploration in the real world.     

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.