Generalizing the dynamic field theory of the A-not-B error beyond infancy: three-year-olds' delay- and experience-dependent location memory biases

Thelen and colleagues recently proposed a dynamic field theory (DFT) to capture the general processes that give rise to infants' performance in the Piagetian A-not-B task. According to this theory, the same general processes should operate in noncanonical A-not-B-type tasks with children older than 12 months. Three predictions of the DFT were tested by examining 3-year-olds' location memory errors in a task with a homogeneous task space. Children pointed to remembered locations after delays of 0 s to 10 s. The spatial layout of the possible targets and the frequency with which children moved to each target was varied. As predicted by the DFT, children's responses showed a continuous spatial drift during delays toward a longer term memory of previously moved-to locations. Furthermore, these delay-dependent effects were reduced when children moved to an "A" location on successive trials, and were magnified on the first trial to a nearby "B" location. Thus, the DFT generalized to capture the performance of 3-year-old children in a new task. In contrast to predictions of the DFT, however, 3-year-olds' responses were also biased toward the midline of the task space-an effect predicted by the category adjustment (CA) model. These data suggest that young children's spatial memory responses are affected by delay- and experience-dependent processes as well as the geometric structure of the task space. Consequently, two current models of spatial memory-the DFT and the CA model-provide incomplete accounts of children's location memory abilities.     

Do young children always say yes to yes-no questions? A metadevelopmental study of the affirmation bias

The present study investigated whether yes-no questions would lead to a yes bias in young children. Four experiments were conducted in which 2- to 5-year-olds were asked comprehensible and incomprehensible yes-no questions concerning familiar and unfamiliar objects. Consistent findings were obtained: (a) 2-year-olds displayed a consistent yes bias; (b) 4- and 5-year-olds exhibited no response bias toward comprehensible questions and a nay-saying bias toward incomprehensible questions; and (c) 3-year-olds' results were mixed, suggesting that the age of 3 years is a period of developmental transition in response tendency toward yes-no questions. The findings suggest that yes-no questions are suitable for older children, providing they are comprehensible, but may result in biased results when used with younger children and when incomprehensible.     

Foraging on the radial-arm maze: Effects of altering the reward at a target location

Thirsty rats were trained to collect small water rewards from the end of each arm of an eight-arm radial maze. During these training trials and subsequent testing trials, the subjects were allowed to choose a maximum of eight arms. “Preference” for a target maze location was studied by noting when, in the sequence of eight choices, the target was selected. During testing, when one maze location was consistently devoid of water, rats decreased their preference for this arm over trials (Experiment 1). Similarly, rats that learned a saccharin-lithium association demonstrated lower preferences for a maze location that consistently held the conditioned saccharin solution. This was true for animals that received saccharin-lithium conditioning on the maze (Experiment 3A) and for animals conditioned to saccharin in a separate context (Experiment 3B). An increase in preference for a target maze location consistently containing a sweet chocolate milk solution was observed in animals that were water- and food-deprived (Experiment 2). These studies demonstrate that animals will modify their responses toward (preferences for) maze locations that predictably contain an altered reward.     

The development of memory for location: what role do spatial prototypes play?

Two experiments investigated the role of spatial prototypes in estimates of location. In Experiment 1 (N = 144), children and adults learned the locations of 20 objects in an open, square box designed to look like a model house. In two conditions, opaque lines or walls divided the house into four regions, and in the other condition, no boundaries were present. Following learning, the dots marking the locations were removed, and participants attempted to replace the objects. Children and adults overestimated distances between target locations in different regions. Contrary to Huttenlocher, Hedges, and Duncan's hierarchical theory of spatial memory, none of the groups displaced the objects toward the region centers. In Experiment 2 (N = 96), boundaries were removed during testing to determine whether children and adults were more likely to displace objects toward region centers when uncertainty about location increased. Again, all age groups overestimated distances between target objects in different regions. In addition, adults and 11-year-olds in the most salient boundary condition displaced objects toward the region centers. Discussion focuses on the implications of these results for understanding how children and adults estimate location.     

Tests of a Dynamic Systems Account of the A-not-B Error: The Influence of Prior Experience on the Spatial Memory Abilities of Two-Year-Olds

Recently, Smith, Thelen, and colleagues proposed a dynamic systems account of the Piagetian "A-not-B" error in which infants' errors result from general processes that make goal-directed actions to remembered locations. Based on this account, the A-not-B error should be a general phenomenon, observable in different tasks and at different points in development. Smith, Thelen, et al.'s proposal was tested using an A-not-B version of a sandbox task. During three training trials and three "A" trials, 2-year-olds watched as a toy was buried in a sandbox at Location A. Following a 10-s delay, children searched for the object. Across five experiments, children's (total N = 92) performance on the A trials was accurate. After the A trials, children watched as a toy was hidden at Location B, 8 to 10 inches from Location A. In all experiments, children's searches after a 10-s delay were significantly biased in the direction of Location A. Furthermore, this bias toward Location A decreased with repeated trials to Location B, as well as when children completed fewer trials to Location A. Together, these data suggest that A-not-B-type errors are pervasive across tasks and development.     

Two Roads Diverged: Young Children's Ability to Judge Distance

In the present studies, we investigated 4- and 5- to 6-year-olds' ability to compare the distances covered by a direct route to a location and an indirect route to the same location. The distances ranged between 16 and 22 feet. The routes were visible from a single vantage point, and objects serving as landmarks were sometimes located along the routes. We found clear demonstrations of the two classic Piagetian distance errors—the direct-indirect error , in which children judge that a direct route and an indirect route cover the same distance, and the interposed object error , in which children judge that a route is shorter when it is segmented by an object located somewhere along the route. The interposed object error occurred because children focused on only one segment of the route, which was consistent with Piaget's explanation of the error. However, in contrast to Piaget, we found that about 40% of 4-year-olds could successfully avoid the direct-indirect error, and in addition, when the routes were visually displayed, they could also avoid the interposed object error. It is important that they also gave correct explanations for why the indirect route was longer, by referring to the fact that it was not straight. For these children at least, the interposed object error was due to difficulty they had representing routes, rather than to a misconception of distance. We suggest that future research should examine whether that may also be true for younger children.     

城市道路通过远引掉头间接左转最佳位置选取方案

由于掉头口位置选取是城市道路远引掉头技术中的重要因素,为了提高远引掉头实施效果,从安全和运行效率2个方面对远引掉头口和上游支路出口之间的距离对远引掉头实施效果的影响进行了分析.对美国佛罗里达州开展了广泛的数据采集,共得到179个不同路段的历史事故数据,采用录像观测法获得了29个不同路段的交通流运行数据.在实测数据的基础上构建了事故率模型和车辆运行时间模型.研究表明,掉头口和上游支路之间的间距对掉头车辆的安全性和运行效率有显著影响.根据研究结果,提出了针对不同道路条件下设置掉头口和上游支路出口应保证的最短距离以方便司机使用掉头口.分析研究结果可为国内交叉口改造提供借鉴.     

Infant search and object permanence: a meta-analysis of the A-not-B error

Research on Piaget's stage 4 object concept has failed to reveal a clear or consistent pattern of results. Piaget found that 8-12-month-old infants would make perserverative errors; his explanation for this phenomenon was that the infant's concept of the object was contextually dependent on his or her actions. Some studies designed to test Piaget's explanation have replicated Piaget's basic finding, yet many have found no preference for the A location or the B location or an actual preference for the B location. More recently, researchers have attempted to uncover the causes for these results concerning the A-not-B error. Again, however, different studies have yielded different results, and qualitative reviews have failed to yield a consistent explanation for the results of the individual studies. This state of affairs suggests that the phenomenon may simply be too complex to be captured by individual studies varying 1 factor at a time and by reviews based on similar qualitative considerations. Therefore, the current investigation undertook a meta-analysis, a synthesis capturing the quantitative information across the now sizable number of studies. We entered several important factors into the meta-analysis, including the effects of age, the number of A trials, the length of delay between hiding and search, the number of locations, the distances between locations, and the distinctive visual properties of the hiding arrays. Of these, the analysis consistently indicated that age, delay, and number of hiding locations strongly influence infants' search. The pattern of specific findings also yielded new information about infant search. A general characterization of the results is that, at every age, both above-chance and below-chance performance was observed. That is, at each age at least 1 combination of delay and number of locations yielded above-chance A-not-B errors or significant perseverative search. At the same time, at each age at least 1 alternative combination of delay and number of locations yielded below-chance errors and significant above-chance correct performance, that is, significantly accurate search. These 2 findings, appropriately elaborated, allow us to evaluate all extant theories of stage 4 infant search. When this is done, all these extant accounts prove to be incorrect. That is, they are incommensurate with one aspect or another of the pooled findings in the meta-analysis. Therefore, we end by proposing a new account that is consistent with the entire data set.     

Hearing Where the Eyes See: Children Use an Irrelevant Visual Cue When Localizing Sounds

To reduce sensory uncertainty, humans combine cues from multiple senses. However, in everyday life, many co‐occurring cues are irrelevant to the task at hand. How do humans know which cues to ignore? And does this ability change with development? This study shows the ability to ignore cross‐modal irrelevant information develops late in childhood. Participants performed a sound discrimination task, with or without an irrelevant visual flash, presented synchronously in front of them. Adults ignored the irrelevant visual information, while 7‐ to 10‐year‐olds' responses were biased toward the flash location. The findings show that acquiring mature cue combination mechanisms is a multifaceted process that includes learning to ignore irrelevant cues, as well as to optimally combine relevant cues.     

Face Adaptation and Attractiveness Aftereffects in 8-Year-Olds and Adults

A novel method was used to investigate developmental changes in face processing: attractiveness aftereffects. Consistent with the norm-based coding model, viewing consistently distorted faces shifts adults' attractiveness preferences toward the adapting stimuli. Thus, adults' attractiveness judgments are influenced by a continuously updated face prototype. To investigate the development of this process, a novel method was developed for 8-year-olds. After reading a storybook composed of faces with either compressed or expanded features, 8-year-olds' ratings of faces distorted in the direction of the adapting stimuli increased. Nonetheless, they required larger distortions than adults to rate undistorted faces as most attractive preadaptation. Thus, although 8-year-olds' attractiveness preferences are influenced by a continuously updated prototype, their face space is less refined than that of adults.     

Anticipatory contrast as a function of access time and spatial location

Intake of a 0.15% saccharin solution was suppressed when it was followed by a 32% sucrose solution in brief daily pairings. With equal access durations to the two solutions, intervals of intermediate duration (2 or 3 min) produced a larger contrast than more extreme intervals (1 or 10 min). There was no evidence of inhibition of delay with the 10-min interval (Experiments 1A and 1B). When access times were asymmetrical, longer access time to the first solution reduced contrast, whereas longer access time to the second solution enhanced contrast (Experiment 2). Contrast was greater when the two solutions were presented at consistent and separate spatial locations than when location was changed randomly or when both solutions were presented in sequence at the same location. However, a degree of contrast occurred in all conditions (Experiment 3). Experiment 4, conducted with the solutions in opposite arms of a T-maze, showed that anticipatory approach to the location correlated with the 32% sucrose solution developed prior to lick suppression on the saccharin solution. However, within daily sessions, there was a reliable increase in contrast without correlated changes in anticipatory-approach behavior. Access-time effects were attributed to altered reward values, whereas spatial-separation effects suggest that goal-directed responses contribute to, but do not cause, anticipatory contrast.     

Effects of Pointing Gestures on Memory for (In)Congruent Stimuli in Children and Young Adults

We investigated whether finger pointing toward picture locations can be used as an external cognitive control tool to guide attention and compensate for the immature cognitive control functions in children compared with young adults. Item and source memory performance was compared for picture‐location pairs that were either semantically congruent (e.g., a cloud presented at the upper half of the screen) or incongruent (e.g., a cloud presented at the lower part of the screen). Contrary to our expectations, pointing had an adverse effect on source memory compared to visual observation only, in both age groups. As expected, superior source memory performance was found for congruent compared to incongruent picture‐locations pairs in both age groups. These findings suggest that pointing toward pictures compared to only viewing may hamper memory, and that congruent picture locations are easier to remember than incongruent ones.     

Attachment Patterns at Age Six in South Germany: Predictability from Infancy and Implications for Preschool Behavior

A cross-cultural replication of concordance between attachment patterns to mother in infancy and patterns of reunion responses to mother at age 6 was tested for 40 children in Regensburg, South Germany. Concordance between the 4 types of attachment status (A, B, C, D) in infancy and at age 6 was 82%. When observed in preschool at age 5, children classified securely attached (B) at age 6 were more competent in their play quality and conflict resolution, showed fewer behavior problems, and attributed less hostility in a social perception picture test compared to the insecurely attached (A, D) children. Children classified disorganized (D) at age 6 were found almost as often in the incompetent preschool behavior groups as the avoidantly attached (A) children, independent of best-fitting alternative attachment pattern. Thus, disorganization at age 6 may be considered as an insecure attachment.     

Simultaneous temporal and spatial processing

Rats searched for food that was contingent on time and place in an open field. One location was active at a time, the active location moved in a clockwise direction after each reward, and each location was repeated several times on each daily session. When a location was active, the first response after a fixed interval produced food. The intervals associated with each of the four locations were consistently 60, 30, 30, and 60 sec. For independent groups, inspecting an inactive location had no consequence (n = 7) or reduced the amount of food delivered at the active location (n = 6). The rates of inspecting active and inactive locations increased before the associated intervals elapsed, with preferential responding at the active locations. Rates of anticipation at active locations failed to superimpose when plotted as a function of proportional time. Simultaneous temporal and spatial processing contributed to the failure of proportional timing.     

Delay-induced bias in children's memory for location

Two experiments examined how imposing a delay between learning and reproducing locations influences children's memory for location. In Experiment 1, ninety-six 7-, 9-, and 11-year-old children and adults learned the locations of 20 objects in an open, square box divided into four regions by opaque walls. During test, participants attempted to place the objects in the correct locations without the aid of the dots that had marked the locations or the boundaries that had divided the space. The test phase began either immediately following learning or following a 12-min delay. As predicted by the Category-Adjustment model, bias toward category centers increased significantly following an intervening delay. Moreover, the magnitude of categorical bias followed a systematic U-shaped developmental pattern. Results from a second study (N = 72) replicated this developmental pattern. Discussion focuses on the implications of these results for understanding how children and adults remember locations.     

Consequences of learning about historical racism among European American and African American children

Knowledge about racism is a critical component of educational curricula and contemporary race relations. To examine children's responses to learning about racism, European American (Study 1; N= 48) and African American (Study 2; N= 69) elementary-aged children (ages 6-11) received history lessons that included information about racism experienced by African Americans (racism condition), or otherwise identical lessons that omitted this information (control condition). Children's racial attitudes and cognitive and affective responses to the lessons were assessed. Among European American children, racism condition participants showed less biased attitudes toward African Americans than control condition participants. Among African American children, attitudes did not vary by condition. Children in the two conditions showed several different cognitive and affective responses to the lessons.     

Children's judgments of emotion from conflicting cues in speech: why 6-year-olds are so inflexible

Six-year-old children can judge a speaker's feelings either from content or paralanguage but have difficulty switching the basis of their judgments when these cues conflict. This inflexibility may relate to a lexical bias in 6-year-olds' judgments. Two experiments tested this claim. In Experiment 1, 6-year-olds (n = 40) were as inflexible when switching from paralanguage to content as when switching from content to paralanguage. In Experiment 2, 6-year-olds (n = 32) and adults (n = 32) had more difficulty when switching between conflicting emotion cues than conflicting nonemotional cues. Thus, 6-year-olds' inflexibility appears to be tied to the presence of conflicting emotion cues in speech rather than a bias to judge a speaker's feelings from content.     

The A-Not-B Error: Results from a Logistic Meta-Analysis

A meta-analysis of the A-not-B error was conducted using logistic regression on studies conducted before September 1997 (107 data points). An earlier meta-analysis by Wellman, Cross, and Bartsch revealed that age, delay between hiding and retrieval, and number of hiding locations were significant predictors of both the proportion of infants who searched correctly on B trials and the proportion of infants who searched perseveratively. The current analysis replicated these findings with two exceptions: (1) The number of trials at the A location was a significant predictor, and (2) the number of locations was a significant predictor of the proportion of infants who searched perseveratively, but not the proportion of infants who searched correctly. Implications of these findings are discussed and a quantitative version of a hierarchical competing-systems model of infant search is proposed.     

Inferences and recall at ages four and seven

Inferences and recall at ages 4 and 7 were studied as a function of the cause of a target event, the presence and timing of questions prior to recall, and the type of inference demanded by the questions. 7-year-olds inferred and recalled well with stories containing any of the causal connections employed in the study. 4-year-olds performed better when physical causes, rather than either psychological causes or enabling relations, connected events. Timing of questions did not affect the 7-year-olds' inferences, but asking questions interfered with their recall. Questions about story events aided the 4-year-olds' ability to make inferences and to recall, especially when causal connections were least specified and when questions were asked following the story. 4- and 7-year-olds also differed in responding to demands for 3 specific types of inference. 4-year-olds produced significantly more unconstrained inferences than logical or constrained informational inferences. 7-year-olds were most responsive to logical inference questions, and produced significantly more logical than constrained inferences.     

Differential acquisition of discriminated autoshaping as a function of stimulus qualities and locations

In each of two experiments, different groups of pigeons were required to discriminate between one of two basic kinds of stimulus differences: stimulus quality or stimulus location. For stimulus-quality groups, a key was illuminated by one of two colors on trials ending with food delivery and by the other color on trials ending with no food. For stimulus-location groups, a key was illuminated at one of two locations on trials ending with food delivery and at the other location on trials ending with no food. The birds began to respond differentially to the stimuli (i.e., peck the keys on food trials and not peck the keys on no-food trials) earlier in acquisiton if the stimulus qualities served as the signals for trial outcomes than if the stimulus locations served as those signals. The results from both experiments are consistent with predictions from a hypothesis regarding interactions among the qualities and locations of stimuli and responses (the “quality-location hypothesis”). Furthermore, the present results support other recent demonstrations of the important role that spatial relations among stimuli can play in classical conditioning.