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This investigation examined whether the mode of locomotion matters in how 8-, 10-, 12-, and 14-year-old children (N = 91) judge dynamic affordances in a complex perception-action task with significant safety risks. The primarily European American children in the sample came from the area of Iowa City, Iowa and were balanced for gender. The same children crossed a single lane of continuous traffic on foot and on bike (order counterbalanced) in identical immersive virtual environments. We found that although 8-year-olds chose significantly larger gaps when crossing on bike than on foot, these gaps were not large enough to compensate for their delay in entering the gap and their slowness in crossing the road. As a result, they ended up with less time to spare when exiting the roadway on bike than on foot. In contrast, 14-year-olds exhibited no difference in their gap choices on bike than on foot, nor did they exhibit a difference in their timing of entry into the gap. However, they crossed the road much more quickly on bike, resulting in significantly more time to spare when crossing on bike than on foot. The 10- and 12-year-olds' performance fit neatly between that of the 8- and 14-year-olds. We conclude that as children gained better control over the bike with age, they were better able to match their gap decisions with their crossing movements such that bicycling afforded even safer road-crossing than walking for 14-year-olds.

Objective: This study used a virtual environment to examine how older and younger pedestrians responded to simulated augmented reality (AR) overlays that indicated the crossability of gaps in a continuous stream of traffic. Background: Older adults represent a vulnerable group of pedestrians. AR has the potential to make the task of street-crossing safer and easier for older adults. Method: We used an immersive virtual environment to conduct a study with age group and condition as between-subjects factors. In the control condition, older and younger participants crossed a continuous stream of traffic without simulated AR overlays. In the AR condition, older and younger participants crossed with simulated AR overlays signaling whether gaps between vehicles were safe or unsafe to cross. Participants were subsequently interviewed about their experience. Results: We found that participants were more selective in their crossing decisions and took safer gaps in the AR condition as compared to the control condition. Older adult participants also reported reduced mental and physical demand in the AR condition compared to the control condition. Conclusion: AR overlays that display the crossability of gaps between vehicles have the potential to make street-crossing safer and easier for older adults. Additional research is needed in more complex real-world scenarios to further examine how AR overlays impact pedestrian behavior. Application: With rapid advances in autonomous vehicle and vehicle-to-pedestrian communication technologies, it is critical to study how pedestrians can be better supported. Our research provides key insights for ways to improve pedestrian safety applications using emerging technologies like AR. [ABSTRACT FROM AUTHOR]

Objective Collisions between bicycles and motor vehicles are one of the leading risk factors for injury and death in childhood and adolescence. We examined longitudinal and concurrent effortful control (EC) as predictors of risky bicycling behavior in early- to mid-adolescence, with age and gender as moderators. We also examined whether EC was associated with parent-reported real-world bicycling behavior and all lifetime unintentional injuries. Methods Parent-reported EC measures were collected when children (N  =   85) were 4 years old and when they were either 10 years (N  =   42) or 15 years (N  =   43) old. We assessed risky bicycling behavior by asking the adolescents to bicycle across roads with high-density traffic in an immersive virtual environment. Parents also reported on children's real-world bicycling behavior and lifetime unintentional injuries at the time of the bicycling session. Results We found that both longitudinal and concurrent EC predicted adolescents' gap choices, though these effects were moderated by age and gender. Lower parent-reported early EC in younger and older girls predicted a greater willingness to take tight gaps (3.5 s). Lower parent-reported concurrent EC in older boys predicted a greater willingness to take gaps of any size. Children lower in early EC started bicycling earlier and were rated as less cautious bicyclists as adolescents. Adolescents lower in concurrent EC were also rated as less cautious bicyclists and had experienced more lifetime unintentional injuries requiring medical attention. Conclusion Early measures of child temperament may help to identify at-risk populations who may benefit from parent-based interventions. [ABSTRACT FROM AUTHOR]

We conducted 2 experiments to examine how mothers structure directions to young children for finding hidden objects and how young children use these directions to guide their searches. In Experiment 1, we examined the reference frames mothers use to communicate with their 2.5-, 3-, and 3.5-year-old children about location by asking mothers to verbally disambiguate a target hiding container from an identical nontarget hiding container. We found that mothers' reference frame use was primarily governed by the relative proximity of the target container to the landmark and themselves. Older children were more successful in following directions than were younger children, and children were more likely to search successfully in response to a person than to a landmark frame of reference. In Experiment 2, we further investigated how 3-year-old children follow directions involving person and landmark frames of reference by asking mothers to use either only themselves or only the landmark to describe the target location. Children in the person reference frame condition successfully followed their mother's directions when the target was relatively close to the mother, but not when the target was relatively far from the mother. Children in the landmark reference frame condition were at chance regardless of the relative proximity of the target to the landmark. The discussion focuses on the roles of spatial proximity and reference frames in mother-child spatial communication. (Contains 3 tables and 6 figures.)

We conducted two experiments to address questions over whether 9-month-old infants believe that objects depicted in realistic photographs can be picked up. In Experiment 1, we presented 9-month-old infants with realistic color photographs of objects, colored outlines of objects, abstract colored "blobs," and blank pages. Infants most commonly rubbed or patted depictions of all types. They also showed significantly more grasps toward the realistic photographs than toward the colored outlines, blobs, and blank pages, but only 24% of infants directed grasping exclusively at the photographs. In Experiment 2, we further explored infants' actions toward objects and pictures while controlling for tactile information. We presented 9-month-old infants with objects and pictures of objects under a glass cover in a false-bottom table. Although there were no significant differences between the proportion of rubs and pats infants directed toward the objects versus the photographs, infants exhibited significantly more grasping toward the objects than the photographs. Together, these findings show that 9-month-old infants largely direct appropriate actions toward realistic photographs and real objects, indicating that they perceive different affordances for pictures and objects. (Contains 4 figures and 2 footnotes.)

This investigation examined short-term changes in child and adult cyclists' gap decisions and movement timing in response to general and specific road-crossing experiences. Children (10- and 12-year-olds) and adults rode a bicycle through a virtual environment with 12 intersections. Participants faced continuous cross traffic and waited for gaps they judged were adequate for crossing. In the control condition, participants encountered randomly ordered gaps ranging from 1.5 to 5.0 s at all intersections. In the high-density condition, participants encountered high-density intersections sandwiched between sets of control intersections. These high-density intersections were designed to push participants toward taking tighter gaps. Participants in both conditions were more likely to accept 3.5-, 4.0-, 4.5-, and 5.0-s gaps at the last set of intersections than at the first set of intersections, whereas participants in the high-density condition were also more likely to accept very tight 3.0-s gaps at the last intersections than at the first intersections. Moreover, individuals in the high-density condition who waited less and took shorter gaps at the middle intersections were also more likely to take very tight 3.0-s gaps at the last intersections. The 10-year-olds in both conditions had more time to spare when they cleared the path of the oncoming car at the last intersections, whereas the 12-year-olds and adults showed no change in time to spare across intersections. The discussion focuses on linking short-term change in perceptual-motor functioning to longer term perceptual-motor development. (Contains 6 figures.)

Two experiments examined how 10- and 12-year-old children and adults intercept moving gaps while bicycling in an immersive virtual environment. Participants rode an actual bicycle along a virtual roadway. At 12 test intersections, participants attempted to pass through a gap between 2 moving, car-sized blocks without stopping. The blocks were timed such that it was sometimes necessary for participants to adjust their speed in order to pass through the gap. We manipulated available visual information by presenting the target blocks in isolation in Experiment 1 and in streams of blocks in Experiment 2. In both experiments, adults had more time to spare than did children. Both groups had more time to spare when they were required to slow down than when they were required to speed up. Participants' behavior revealed a multistage interception strategy that cannot be explained by the use of a monotonic control law such as the constant bearing angle strategy. The General Discussion section focuses on possible sources of changes in perception-action coupling over development and on task-specific constraints that could underlie the observed interception strategy. (Contains 9 figures.)

We conducted three experiments to investigate how opportunities to view objects together in time influence memory for location. Children and adults learned the locations of 20 objects marked by dots on the floor of an open, square box. During learning, participants viewed the objects either simultaneously or in isolation. At test, participants replaced the objects without the aid of the dots. Experiment 1 showed that when the box was divided into quadrants and the objects in each quadrant were categorically related, 7-, 9-, and 11-year-olds and adults in the simultaneous viewing condition exhibited categorical bias, but only 11-year-olds and adults in the isolated viewing condition exhibited categorical bias. Experiment 2 showed that when the objects were categorically related but no boundaries were present, 11-year-olds and adults in the simultaneous viewing condition exhibited categorical bias, but only adults showed bias in the isolated viewing condition. Experiment 3 revealed that adults exhibited bias in both simultaneous and isolated viewing conditions when boundaries were present but the objects were not related. These findings suggest that opportunities to see objects together in time interact with cues available for grouping objects to help children form spatial groups. (Contains 3 figures.)

This investigation tracked changes in categorical bias (i.e., placing objects belonging to the same spatial group closer together than they really are) while 7-, 9-, and 11-year-olds and adults were learning a set of locations. Participants learned the locations of 20 objects marked by dots on the floor of an open square box divided into quadrants. At test, participants attempted to place the objects in the correct locations without the dots and boundaries. In Experiment 1, we probed categorical bias during learning by alternating learning and test trials. Categorical bias was high during the first test trial and decreased over the second and third test trials. In Experiment 2, we manipulated opportunities for learning by providing participants with either one, two, three, or four learning trials prior to test. Participants who experienced one or two learning trials exhibited more bias at test than did those who experienced four learning trials. The discussion focuses on how categorical bias emerges through interactions between the cognitive system and task structure.

We conducted four experiments to examine developmental differences in preferences for using color, size, and location information to disambiguate hiding places. Three- and 4-year-olds and adults described how to find a miniature mouse that was hidden in one of two highly similar small objects in a dollhouse. In Experiment 1, the hiding places could be disambiguated by either color or location. Three-year-olds preferred color to location whereas adults preferred location to color information. Four-year-olds showed no preferences. In Experiment 2, the hiding places could be disambiguated by either size or location. Four-year-olds preferred size to location information whereas adults preferred location to size information. Three-year-olds showed no preferences. In Experiment 3, the hiding places could be disambiguated by either color or size information. Adults preferred size to color information, but 3- and 4-year-olds showed no preference for either type of information. Experiment 4 revealed that when only location information was available for disambiguating the hiding places, 4-year-olds referred to disambiguating location information on a significantly greater percentage of trials than did 3-year-olds. Discussion focuses on the role of relational complexity and pragmatic knowledge in producing preferences for disambiguating information in spatial communication tasks. (Contains 4 figures, 3 tables and 1 footnote.)

The authors investigated how 3- and 4-year-old children and adults use relative distance to judge nearbyness. Participants judged whether several blocks were by a landmark. The absolute and relative distance of the blocks from the landmark varied. In Experiment 1, judgments of nearbyness decreased as the distance from the landmark increased, particularly for 4-year-olds and adults. In Experiment 2, 4-year-olds and adults were more likely to judge objects at an intermediate distance as by the landmark when intervening objects were absent than when intervening objects were present. In Experiment 3, participants of all ages were more likely to judge objects at a short distance as by the landmark when intervening objects were absent. Reliance on relative distance to judge nearbyness becomes more systematic and applicable to larger spatial extents across development.

Four experiments examined the flexibility and stability with which children and adults organize locations into categories based on their spatiotemporal experience with locations. Seven-, 9-, 11-year-olds, and adults learned the locations of 20 objects in an open, square box. During learning, participants experienced the locations in four spatiotemporally defined groups (i.e., four sets of nearby locations learned together in time). At test, participants attempted to place the objects in the correct locations without the aid of the dots marking the locations. Children and adults displaced the objects toward the corners of the box consistent with the organization they experienced during learning, suggesting that they used spatiotemporal experience to organize the locations into groups. Importantly, the pattern of organization remained the same following a long delay for all four age groups, demonstrating stability. For adults, this organization shifted after a new pattern of spatiotemporal experience was introduced, suggesting that adults' categories based on spatiotemporal experience are quite flexible. Children only exhibited flexibility when the new pattern of spatiotemporal organization was consistent with available perceptual cues, demonstrating that the flexibility with which children organize locations into categories is intimately tied to both remembered and perceptual sources of information.

This study examined gap choices and crossing behavior in children and adults using an immersive, interactive bicycling simulator. Ten- and 12-year-olds and adults rode a bicycle mounted on a stationary trainer through a virtual environment consisting of a street with 6 intersections. Participants faced continuous cross traffic traveling at 25mph or 35mph and waited for gaps they judged were adequate for crossing. Children and adults chose the same size temporal gaps, but children left far less time to spare between themselves and the approaching vehicle when they crossed the intersection. Relative to adults, children delayed in getting started and took longer to reach the roadway. Discussion focuses on developmental changes in how children coordinate self movement with object movement.

Four experiments were conducted to investigate the role of the physical context in supporting 3- to 5-year-olds' use of spatiotemporal organization in recall. Children were familiarized with several target items and their corresponding landmarks arranged along a path in a model park. After familiarization, an experimenter removed the target items from the park. In Experiment 1, 3- and 4-year-olds recalled the missing items with the park either in view or out of view. When the park model was in view, 4- year-olds used the order of the items along the path to structure their recall. In Experiment 2, 4- and 5-year-olds recalled the missing items with the landmarks arranged either in the same order as in familiarization or in a new order. Children used the order of landmarks along the path at test to structure their recall, even though the order of landmarks changed from familiarization to test. Experiment 3 was identical to Experiment 2, except that the path was removed from the park. Five-year-olds used the order of landmarks along the path at test to structure their recall when the order of landmarks remained the same from familiarization to test, but had much more difficulty doing so when the order of landmarks changed from familiarization to test. Using a more difficult task, Experiment 4 revealed that spatiotemporal organization was positively related to amount recalled. Together, these findings suggest that the structure of the physical environment plays an important role in supporting young children's use of spatiotemporal organization in recall.

Two experiments examined how information about what objects are influences memory for where objects are located. Seven-, 9-, and 11-year-old children and adults learned the locations of 20 objects marked by dots on the floor of a box. The objects belonged to 4 categories. In one condition, objects belonging to the same category were located in the same quadrant of the box. In another condition, objects and locations were randomly paired. After learning, participants attempted to replace the objects without the aid of the dots. Children and adults placed the objects in the same quadrant closer together when they were related than when they were unrelated, indicating that object information led to systematic biases in location memory.

Three studies investigated how experiencing nearby locations together in time influenced memory for location in 7-, 9-, and 11- year-olds and adults. Findings suggested that experiencing nearby locations together in time increased the weight children assigned to categorical information in their later estimates of location. Results were similar when participants learned locations by region and then replaced objects by region or in a random order. (Author/KB)

Two experiments examined the influence of a delay between learning and reproducing locations on 7-, 9- and 11-year-old children's memory for location. Findings indicated that bias toward category centers when replacing objects in their original locations increased following an intervening delay, as predicted by the Category-Adjustment model, with the bias following a specific developmental pattern. (Author/JPB)

Two experiments investigated the role of spatial prototypes in estimates of location. Found that adults and children ages 7 to 11 years overestimated distances between target locations in different regions and that none displaced objects toward the region centers. Even with boundaries removed during testing, adults and children overestimated distances between target objects in different regions. (Author/KB)

Examined in 4 experiments 3- and 4-year-olds' ability to communicate about containment and proximity relations. Found that when describing where a toy mouse was hidden, children were more likely to successfully disambiguate a small landmark when it was in, rather than next to, the large landmark. Three-year-olds initiated searches faster when the small landmark was in the large landmark. (Author/KB)

Examined relations between temperament, ability estimation, and injury proneness from toddlerhood through school age. Found that children scoring high on Extroversion and low on Inhibitory Control as toddlers and preschoolers tended to overestimate their physical abilities and have more unintentional injuries at age 6. Children low on Extroversion and high on Inhibitory Control tended to underestimate their physical abilities. (Author/KB)

Examined relations between children's temperament, ability overestimation, and accidental injuries. Found that watching peer failure on physical tasks was related to conservative ability judgments for same task. Surgency/Undercontrol was related to 6-year-olds' judgment accuracy and to 8-year-olds' decision times. Ability overestimation was related to 6-year-old boys' accidental injuries whereas temperamental characteristics were related to 8-year-olds' accidental injuries. (Author)