How and when infants learn to climb stairs

Seven hundred and thirty-two parents reported when and how their infants learned to climb stairs. Children typically mastered stair ascent (mean age=10.97 months) several months after crawling onset and several weeks prior to descent (mean age=12.53 months). Most infants (94%) crawled upstairs the first time they ascended independently. Most infants (76%) turned around and backed at initial descent. Other descent strategies included scooting down sitting, walking, and sliding down face first. Children with stairs in their home were more likely to learn to ascend stairs at a younger age, devise backing as a descent strategy, and be explicitly taught to descend by their parents than children without stairs in their home. However, all infants learned to descend stairs at the same age, regardless of the presence of stairs in their home. Parents' teaching strategies and infants' access to stairs worked together to constrain development and to influence the acquisition of stair climbing milestones.     

Children’s choice strategies: the effects of age and task demands

Two experiments examined the effect of age and cognitive demands on children’s choice strategies. Children aged 8–9 and 12–13 years were asked to choose among either two or four products that differed in several attributes of varying importance to them. Choice tasks were designed to differentiate between the lexicographic and the equal-weighting strategies that the children used. The results showed that older children use the two strategies more appropriately than younger children do. The choice of strategies reflects the demands of the task. All children were more likely to use the strategies correctly when choosing between two alternatives and tended to rely on the relatively less cognitive-demanding lexicographic strategy to choose among four alternatives. However, they were less likely to employ the lexicographic strategy in simpler tasks and when its use was difficult to justify, indicating an adaptive use.     

Learning from others in 9‐18‐month‐old infants

The use of an adult as a resource for help and instruction in a problem solving situation was examined in 9, 14, and 18‐month‐old infants. Infants were placed in various situations ranging from a simple means‐end task where a toy was placed beyond infants' prehensile space on a mat, to instances where an attractive toy was placed inside closed transparent boxes that were more or less difficult for the child to open. The experimenter gave hints and modelled the solution each time the infant made a request (pointing, reaching, or showing a box to the experimenter), or if the infant was unable to solve the problem. Infants' success on the problems, sensitivity to the experimenter's modelling, and communicative gestures (requests, co‐occurrence of looking behaviour and requests) were analysed. Results show that older infants had better success in solving problems although they exhibited difficulties in solving the simple means‐end task compared to the younger infants. Moreover, 14‐ and 18‐month‐olds were sensitive to the experimenter's modelling and used her demonstration cues to solve problems. By contrast, 9‐month‐olds did not show such sensitivity. Finally, 9‐month‐old infants displayed significantly fewer communicative gestures toward the adult compared to the other age groups, although in general, all infants tended to increase their frequency of requests as a function of problem difficulty. These observations support the idea that during the first half of the second year infants develop a new collaborative stance toward others. The stance is interpreted as foundational to teaching and instruction, two mechanisms of social learning that are sometime considered as specifically human. Copyright © 2006 John Wiley & Sons, Ltd.     

Does switching between strategies within the same task involve a cost?

In two experiments, participants had to switch regularly between two cognitive strategies of a different complexity in the context of a numerosity judgement task. Expt 1 comprised bivalent stimuli (i.e. allowing the application of the two strategies), whereas Expt 2 involved univalent stimuli (i.e. allowing the application of only one strategy). Both experiments revealed that switching between strategies entailed a cognitive cost that was reflected in longer response times on switch compared to non‐switch trials but not in reduced accuracy. The size of this switch cost did not differ as a function of strategy complexity but tended to diminish as a strategy became more appropriate for solving a particular problem. We discuss the extent to which current theories of task switching can account for these findings.     

认知抑制——问题解决研究的新视角

抑制是一种领域一般(domain-general)的认知过程,它使儿童和成人能够抗拒习惯、自动化、诱惑、分心物或干扰从而适应存在冲突的情境(Diamond,2013)。抑制控制模型认为儿童或成人在问题解决中的失败并非是缺少相关知识与概念,而是抑制控制失败造成的。研究者采用负启动研究范式和脑成像技术在类皮杰任务、数学和科学问题解决中证实了认知抑制的作用。未来研究应把认知抑制与元认知的研究结合起来,探究认知抑制的发展轨迹及二者在问题解决中的相对重要性。同时,针对认知抑制训练的干预研究也值得重视。     

The cost of simplifying complex developmental phenomena: a new perspective on learning to walk

Researchers can study complex developmental phenomena with all the inherent noise and complexity or simplify behaviors to hone in on the essential aspects of a phenomenon. We used the development of walking as a model system to compare the costs and benefits of simplifying a complex, noisy behavior. Traditionally, researchers simplify infant walking by recording gait measures as infants take continuous, forward steps along straight paths. Here, we compared the traditional straight‐path task with spontaneous walking during 20 minutes of free play in 97 infants (10.75–19.99 months of age). We recorded infants’ footfalls on an instrumented floor to calculate gait measures in the straight‐path and free‐play tasks. In addition, we scored videos for other critical aspects of spontaneous walking—steps per bout, shape of walking path, and step direction. Studying infant walking during free play incurred no cost compared with the straight‐path task, but considerable benefits. Straight‐path gait was highly correlated with spontaneous gait and both sets of measures improved with walking age, validating use of the straight‐path task as an index of development. However, a large proportion of free‐play bouts were too short to permit standard gait measures, and most bouts were curved with omnidirectional steps. The high prevalence of these “non‐canonical” bouts was constant over development. We propose that a focus on spontaneous walking, the phenomenon we ostensibly wish to explain, yields important insights into the problems infants solve while learning to walk. Other areas of developmental research may also benefit from retaining the complexity of complex phenomena.     

Strategy selection in a task with spatial and nonspatial components: effects of fimbria-fornix lesions in rats.

The main purpose of the present research was to investigate the ability of rats to learn a 12-arm radial maze task that requires the concurrent utilization of both spatial and intramaze cue information. The task involves in a single trial both place and cue learning as well as reference memory (RM) and working memory (WM). Since the animal can choose place and cue arms in any order, the strategies employed to learn the task can be studied as well as the kinds of memory errors that are made. The results of Experiment 1 showed that the number of errors made on the place and cue components of the task did not differ, and that more RM than WM errors were made early during learning. As the task was learned, the animals tended to choose the place arms before choosing the intramaze cue arms, thus suggesting that a spatial strategy was employed first followed by a cue strategy. In Experiment 2 lesions of the fimbria-fornix resulted in temporary impairments in both RM and WM that were especially apparent on the spatial component of the task. The lesioned rats also switched from choosing mostly place arms early during the trial to choosing more cue arms. While fimbria-fornix lesioned rats recovered from the memory impairments with training, the change in response strategy persisted throughout postoperative testing. The procedure of combining both spatial and non-spatial components concurrently in the same task should prove of value in studying response strategies in animals.     

Adults' age-related differences in adaptivity of strategy choices: evidence from computational estimation

Four experiments document adults' age-related changes in computational estimation performance and in adaptivity of strategy choices (i.e., the ability to choose the most precise strategy on each trial). Young and older adults were asked to provide estimates of 2-by-2-digit multiplication problems (e.g., 43 x 78) under varying conditions of speed and accuracy emphasis. The main findings showed that (a) older adults provided less accurate estimates and took more time to estimate, especially on the most difficult problems or when using harder strategies; (b) young and older adults had similar strategy preferences; and (c) older adults chose estimation strategies less adaptively than young adults. Implications of these findings for understanding strategic changes during adulthood in a wide variety of cognitive domains are discussed.     

The Critical Point to Step into a Hole is Similar in Young and Older Adults

Abstract

The avoidance of a hole in the pathway while walking has been systematically investigated; however, depending on the dimensions of the hole, the option to avoid it is infeasible, and it is necessary to use the so-called accommodation strategy to step into the hole. We investigated the critical point between the avoidance and accommodation strategies when dealing with a hole in the ground during locomotion of young and older adults. Young and older adults performed two tasks: verbal estimation and walking. We used holes of different lengths and constant depth (12?cm). In the verbal estimation task, participants stood and looked at each hole and verbally respond if they would step into or avoid it. In the walking task, they walked and chose to either step or avoid the hole. Both age groups preferred to step into the hole when it was larger than 1.3 times their foot length in both tasks. The perception of affordances of young and older adults to step into a hole was similar, and it was unaffected by the investigated tasks. Thus, our participants preferred to have a safety margin that was large enough to guarantee that the whole foot would accommodate within the hole.     

The Experience of Insight Follows Incubation in the Compound Remote Associates Task

The phenomenon of insight is frequently characterized by the experience of a sudden and certain solution. Anecdotal accounts suggest that insight frequently occurs after the problem solver has taken some time away from the problem (i.e., incubation). However, the mechanism by which incubation may facilitate insight problem‐solving remains unclear. Here, we used compound remote associates problems to explore the likely mechanisms by which incubation may facilitate problem‐solving. First, we manipulated problem fixation to explore whether forgetting can explain incubation effects. Second, leveraging previous work linking the experience of insight to unconscious semantic integration, we asked participants to report their experience of insight after each problem solution, including problems solved after a period of distracted incubation. We hypothesized that incubation was not principally important for forgetting but rather frequently causes a shift to a more unconscious semantic integration strategy. Consistent with this we found that initial problem fixation did not predict the improvement in problem‐solving after incubation and that participants were more likely to report insight on problems solved after incubation. Our findings suggest that incubation may facilitate insight problem‐solving leading to a mind‐set shift to a more unconscious problem‐solving strategy involving semantic integration.     

学习困难儿童的问题解决特点研究

本研究选取学习困难儿童和正常儿童各 3 2名 ,设置河内塔问题解决的情境 ,采用临床观察法 ,对学习困难儿童在问题解决中的特点作了初步的探究。研究发现 :1与正常儿童相比 ,学习困难儿童在发现和有效运用策略方面明显不足 ,但当学习困难儿童对问题情境比较熟悉后 ,有明显的进步 ;2一定的提示并不能帮助学习困难儿童最有效地应用策略。     

The value of proactive goal setting and choice in 3‐ to 7‐year‐olds' use of working memory gating strategies in a naturalistic task

Rule‐guided behavior depends on the ability to strategically update and act on content held in working memory. Proactive and reactive control strategies were contrasted across two experiments using an adapted input/output gating paradigm (Neuron, 81, 2014 and 930). Behavioral accuracies of 3‐, 5‐, and 7‐year‐olds were higher when a contextual cue appeared at the beginning of the task (input gating) rather than at the end (output gating). This finding supports prior work in older children, suggesting that children are better when input gating but rely on the more effortful output gating strategy for goal‐oriented action selection (Cognition, 155, 2016 and 8). A manipulation was added to investigate whether children's use of working memory strategies becomes more flexible when task goals are specified internally rather than externally provided by the experimenter. A shift toward more proactive control was observed when children chose the task goal among two alternatives. Scan path analyses of saccadic eye movement indicated that giving children agency and choice over the task goal resulted in less use of a reactive strategy than when the goal was determined by the experimenter.     

The relationship between sustained attention and cognitive performance in 17–24‐month old toddlers

The purpose of this study was to investigate individual differences in sustained attention and task performance with toddlers. Participants were 61 17–24‐month old toddlers. Indices of sustained attention (duration of attention and frequency of off‐task glances) were assessed during two 4 min problem solving tasks, and then related to problem solving and the mental scale of the Bayley scales of infant development‐II (BSID‐II). As expected, toddlers who attended to tasks for longer periods of time were more successful at problem solving, and had higher scores on the BSID‐II than toddlers who attended for shorter periods of time. In addition, older toddlers had longer attention spans, more frequent off‐task glances, and were more successful at problem solving than younger toddlers. Interestingly, toddlers with more frequent off‐task glances had longer attention spans, were more successful at problem solving, and had higher BSID‐II scores than peers with fewer off‐task glances. These findings suggest that although behavioural indices can be used to identify sustained attention, the relationship between behaviours thought to capture distractibility and attention is more complex than had been previously assumed. Results are discussed in the context of current theories of infant attention and cognitive performance. Copyright © 2000 John Wiley & Sons, Ltd.     

Patterns of problem‐solving in children's literacy and arithmetic

Patterns of problem‐solving among 5‐to‐7 year‐olds' were examined on a range of literacy (reading and spelling) and arithmetic‐based (addition and subtraction) problem‐solving tasks using verbal self‐reports to monitor strategy choice. The results showed higher levels of variability in the children's strategy choice across Years 1 and 2 on the arithmetic (addition and subtraction) than literacy‐based tasks (reading and spelling). However, across all four tasks, the children showed a tendency to move from less sophisticated procedural‐based strategies, which included phonological strategies for reading and spelling and counting‐all and finger modelling for addition and subtraction, to more efficient retrieval methods from Years 1 to 2. Distinct patterns in children's problem‐solving skill were identified on the literacy and arithmetic tasks using two separate cluster analyses. There was a strong association between these two profiles showing that those children with more advanced problem‐solving skills on the arithmetic tasks also showed more advanced profiles on the literacy tasks. The results highlight how different‐aged children show flexibility in their use of problem‐solving strategies across literacy and arithmetical contexts and reinforce the importance of studying variations in children's problem‐solving skill across different educational contexts.     

Postural Requirements and Progression Velocity in Young Walkers

This article describes developmental changes in gait velocity and relates these changes to gait parameters that index postural stability (step width and lateral acceleration) and two components of velocity (cadence and step length).

Five children were observed longitudinally over a 2-year period after onset of independent walking. Their range of speed increased threefold in the first 6 months of independent walking and then remained constant. In contrast, step width decreased approximately twofold. Whereas in adults, cadence and step length contribute approximately equally to speed, when infants first begin to walk independently, increase in velocity is due mostly to increased step length. After 5 months of independent walking, the pattern reverses, and increase in velocity is due primarly to increased cadence. The pattern remains constant over the next 18 months. From a developmental point of view, the data lead us to interpret early walking (the first 5 months) as a process of integration of postural constraints into the dynamic necessities of gait movement. A second phase, beginning after 4 to 5 months of independent walking, is considered to be a tuning phase characterized by a more precise adjustment of the gait parameters.     

Selection of strategies for narrowing choice options: Antecedents and consequences

This study investigates the antecedents (task and decision maker characteristics) and consequences (set size and decision quality) of prescreening strategy selection. In Experiment 1 we investigated which strategy, inclusion or exclusion, is more natural for narrowing choices in tasks with a single correct answer; about 70% of the participants selected exclusion. Experiment 2 directly contrasted correct answer tasks with personal judgment tasks, using the same foils for the two tasks. Participants were more likely to use exclusion for items with a correct answer than for personal judgments. In Experiment 3, participants could choose different strategies for different items and rated the difficulty of each item. The greater the perceived difficulty of an item, the more likely participants were to choose an exclusion strategy. In all three experiments exclusion led to larger set sizes, across task type and experimental design. There were no differences in decision quality as a function of strategy selection after correcting for set size. Individual differences based on personality inventories were not found to be good predictors of strategy selection, but had moderate effects on set size for personal judgment tasks. Results are discussed in terms of a status quo bias for adding or deleting options from an initial reference frame.     

A study of reaching actions in walking infants

Acquiring motor skills transforms the perceptual and cognitive world of infants and expands their exploratory engagement with objects. This study investigated how reaching is integrated with walking among infant walkers (n = 23, 14.5–15.5 months). In a walk-to-reach paradigm, diverse object retrieval strategies were observed. All infants were willing to use their upper and lower bodies in concert, and the timing of this coordination reflected features of their environment. Infants with an older walking age (months since walking onset) retrieved items more rapidly and exploited their non-reaching hand more effectively during object retrieval than did same-age infants with a younger walking age. This suggests that the actions of the upper- and lower-body are flexibly integrated and that this integration may change across development. Mechanisms that shape sophisticated upper-body use during upright object retrieval are discussed. Infants flexibly integrate emerging motor skills in the service of object retrieval in ways not previously documented.     

Stacking of irregularly shaped blocks in chimpanzees (Pan troglodytes) and young humans (Homo sapiens)

Stacking blocks provides a way to evaluate cognitive development in humans and other species using the same comparative measures. The present study used regular cubic blocks as well as cubic blocks with bumps on two sides. The bumps changed the physical properties of the blocks and increased the difficulty involved in stacking them. Subjects were required to choose the appropriate orientation for stacking the blocks. Three juvenile chimpanzees and 14 human children (aged 2–3 years) were tested under identical task settings in a face-to-face situation. The goal of a trial was to stack up four blocks (two cubic blocks and two cubic blocks with bumps). The results showed initial difficulty in stacking the blocks with bumps in both chimpanzees and humans. Experienced juvenile chimpanzees and humans older than 3 years became proficient at solving the task. Behavioral strategies adopted to succeed in the task were common to both species. The subjects spontaneously adopted a strategy of stacking as the last block of the tower a block with a bump facing upwards. The subjects also showed active change in the orientation of the blocks when necessary, although correct orientation changes were infrequent especially during the early phases of experiment. The results are discussed in the context of the underlying cognitive development in the domain of physical understanding in both species.     

Effects of occupational future time perspective on managing stressful work situations

According to the socioemotional selectivity theory (SST; Carstensen, 2006), older adults perceive their future time as increasingly limited, which motivates them to focus more on emotional goals and prefer passive emotion‐focused strategies. This study aims to investigate the effect of occupational future time perspective (OFTP) on the use of problem‐solving strategies in stressful work situations and to examine the effectiveness of these strategies on psychological well‐being. A sample of 199 Chinese clerical workers responded to a structured questionnaire on problem‐solving strategy use in relation to hypothetical work scenarios. Results revealed that relative to those with limited OFTP, workers with expansive OFTP preferred problem‐focused and proactive strategies in both low‐ and high‐emotionally salient scenarios. Workers with limited OFTP consistently preferred passive strategies irrespective of emotional salience. OFTP moderated the effect of problem‐focused strategies on psychological distress. In particular, there was a significant negative relationship between problem‐focused strategies and psychological distress among workers with expansive OFTP, but such pattern of relationship was not observed among workers with limited OFTP. Findings of this study inform the training strategies employed by practitioners to fit the developmental goals of workers in order to maximise their strengths at work.