The Acquisition of Survey Knowledge by Individuals With Down Syndrome.

People with Down syndrome often exhibit deficiencies in wayfinding activities, particularly route learning (e.g., Courbois et al., 2013; Davis et al., 2014; Farran et al., 2015). Evidence concerning more sophisticated survey learning has been sparse. In the research reported here, two experiments are reported that evaluated survey learning of youth with DS and typically developing children (TD) matched on mental age. In Experiment 1, participants learned two overlapping routes consisting of three turns each through a virtual environment depicting 9 square city blocks. Following acquisition, they were tested on multiple measures of survey knowledge: finding a shortcut, identifying the direction of landmarks not currently visible from their location in the environment, and recognizing a bird's-eye representation of the overall environment. Under these conditions, which should provide relatively optimal opportunities for survey learning, the participants with DS performed comparably to TD participants matched on non-verbal ability on all of our measures of survey learning. Hence, we concluded that people with DS can acquire some survey knowledge when tasked with learning a small environment and given the opportunity to do so. In Experiment 2, the experimenter navigated participants through a large, relatively complex, virtual environment along a circuitous path, beginning and ending at a target landmark. Then, the participants were placed at a pre-specified location in the environment that they had viewed previously and instructed to navigate to the same target (a door) using the shortest possible path from their current location. They completed the task three times: once after being shown the environment one time, once after three exposures, and once after five exposures. Results indicated that the participants with DS exhibited significantly less skill at identifying the shortcut than did the TD participants, with differences emerging as the number of exposures increased. Participants with DS were also less able to recall landmarks at the end of the experiment. Overall, however, the performance of both groups was relatively poor in both experiments - with the performance of participants with DS being worse as conditions became less optimal. These results were discussed in terms of underlying mechanisms that may account for variations in survey learning as environmental complexity increases.

Sex Differences in Using Spatial and Verbal Abilities Influence Route Learning Performance in a Virtual Environment: A Comparison of 6- to 12-Year Old Boys and Girls.

Previous studies have reported sex differences in wayfinding performance among adults. Men are typically better at using Euclidean information and survey strategies while women are better at using landmark information and route strategies. However, relatively few studies have examined sex differences in wayfinding in children. This research investigated relationships between route learning performance and two general abilities: spatial ability and verbal memory in 153 boys and girls between 6- to 12-years-old. Children completed a battery of spatial ability tasks (a two-dimension mental rotation task, a paper folding task, a visuo-spatial working memory task, and a Piagetian water level task) and a verbal memory task. In the route learning task, they had to learn a route through a series of hallways presented via computer. Boys had better overall route learning performance than did girls. In fact, the difference between boys and girls was constant across the age range tested. Structural equation modeling of the children's performance revealed that spatial abilities and verbal memory were significant contributors to route learning performance. However, there were different patterns of correlates for boys and girls. For boys, spatial abilities contributed to route learning while verbal memory did not. In contrast, for girls both spatial abilities and verbal memory contributed to their route learning performance. This difference may reflect the precursor of a strategic difference between boys and girls in wayfinding that is commonly observed in adults.

Single-destination navigation in a multiple-destination environment: a new "later-destination attractor" bias in route choice.

People choose different routes depending on the size of the environment. However, the size of the environment is often confounded by cognitive load. The current study investigated whether changes in route choice varied as a function of memory load while keeping the size of the environment constant. Also, a new situation was used: route choice to a single destination as a function of the location of follow-up destinations. Critically, there were two routes of equal length to the first destination. The results showed that route choice to the first destination was influenced by the locations of later destinations. This (new) "later-destination attractor" bias is the tendency to take a route to the first destination that begins in the direction of subsequent destinations even when the route to the first destination is logically independent of the locations of subsequent destinations. In Experiment 1, all destinations were visible, and the bias was seen for both second and third subsequent destinations. In Experiments 2 and 3, only the first destination was visible, and the locations of the subsequent destinations were indicated on a diagram and had to be remembered by participants. In Experiment 3, the diagrams were misaligned by 180 degrees. Route choice to the first destination was still influenced by later destinations, but only by the nearer, second destination, and the extent of the bias was reduced as memory load increased. Indications are that differences in route choice between small- and large-scale environments may be due more to cognitive load than to environmental size.

Patterns of differences in wayfinding performance and correlations among abilities between persons with and without Down syndrome and typically developing children.

Down syndrome (DS) impacts several brain regions including the hippocampus and surrounding structures that have responsibility for important aspects of navigation and wayfinding. Hence it is reasonable to expect that DS may result in a reduced ability to engage in these skills. Two experiments are reported that evaluated route-learning of youth with DS, youth with intellectual disability (ID) and not DS, and typically developing (TD) children matched on mental age (MA). In both experiments, participants learned routes with eight choice point presented via computer. Several objects were placed along the route that could be used as landmarks. Participants navigated the route once with turn indicators pointing the way and then retraced the route without them. In Experiment 1 we found that the TD children and ID participants performed very similarly. They learned the route in the same number of attempts, committed the same number of errors while learning the route, and recalled approximately the same number of landmarks. The participants with DS performed significantly worse on both measures of navigation (attempts and errors) and also recalled significantly fewer landmarks. In Experiment 2, we attempted to reduce TD and ID vs DS differences by focusing participants' attention on the landmarks. Half of the participants in each group were instructed to identify the landmarks as they passed them the first time. The participants with DS again committed more errors than the participants in the ID and TD groups in the navigation task. In addition, they recalled fewer landmarks. While landmark identification improved landmark memory for both groups, it did not have a significant impact on navigation. Participants with DS still performed more poorly than did the TD and ID participants. Of additional interest, we observed that the performance of persons with DS correlated with different ability measures than did the performance of the other groups. The results the two experiments point to a problem in navigation for persons with DS that exceeds expectations based solely on intellectual level.

Contextual cueing effects across the lifespan.

The authors evaluated age-related variations in contextual cueing, which reflects the extent to which visuospatial regularities can facilitate search for a target. Previous research produced inconsistent results regarding contextual cueing effects in young children and in older adults, and no study has investigated the phenomenon across the life span. Three groups (6, 20, and 70 years old) were compared. Participants located a designated target stimulus embedded in a context of distractor stimuli. During exposure, the location of the target could be predicted from the location of the distracters in each display. During test, these predictable displays were intermixed with new displays that did not predict the target location. Response times to locating predictable relative to unpredictable targets were compared. All groups exhibited facilitation effects greater than 0 (95% CIs [.02, .11], d = .4; [.01, .12], d = .4; and [.01, .10], d = .4, for the children, young adults, and older adults, respectively) indicating that contextual cueing is robust across a wide age range. The relative magnitude of contextual cueing effects was essentially identical across the age range tested, F(2, 103) = 1.71, eta rho2 = .02. The authors argue that a mechanism that uses environmental covariation is available to all age ranges, but the expression of the contextual cueing may depend on the way it is measured.