Route learning in virtual environments: Landmark knowledge

The development of the ability to understand landmark usefulness 

Landmarks are an important feature of route-learning, and more generally, are important to the development of spatial cognition. Some landmarks are more useful than others. For example, a landmark at a junction is more useful than a landmark that is far away from a junction. Similarly, unique landmarks (e.g. a particular building) are more useful than non-unique landmarks (e.g. a streetlamp). Research has shown that from as young as 7 years, after learning a route in a virtual environment, recall is stronger for landmarks that were adjacent to a correct path, and thus more useful, than other landmarks. In addition, the use of distant landmarks emerges between 7 and 10 years. 

In this study, older children and adults with Williams syndrome (WS) and typically developing (TD) children aged six to nine years took part. In addition to comparing route knowledge across groups, we were interested in whether participants show an adult-like differentiation between ‘useful’ and ‘less useful’ landmarks when learning a route. Each virtual environment consisted of a brick-wall maze with 6 junctions. There were sixteen landmarks in the maze, half of which were on the correct path and half on incorrect paths. Results showed that both groups could learn each route. In the learning phase, the WS group produced more errors than the TD group and took longer to accurately learn the route. This was predominantly due to the large number of perseverative errors (errors that were made at the same junction on consecutive learning trials) made by the WS group relative to the TD children. This could reflect a difficulty with inhibiting erroneous responses in WS. When memory for the landmarks was tested after the participants had learnt the route, the TD group showed stronger recall of landmarks adjacent to junctions (more useful landmarks) than landmarks along path sections (less useful landmarks). This pattern was also evident in the WS group, but was related to level of non-verbal maturation; the differentiation between recall of junction and path landmarks increased as non-verbal ability increased across WS participants. Overall, the results demonstrate that individuals with WS can learn a route, but that the development of this ability is atypical.

The use of colour-cues when learning at route

In a natural environment, landmarks such as a distinctive building or a tall tree provide perceptually salient cues and can be used as beacons or reference points. Other cues such as colour, particularly in man-made environments like buildings, can also be useful. In this study we used colour as an environmental cue because they are easy to verbalise and have been shown to be a useful cue to route-learning for typically developing children and adults. 

Typically developing (TD) 6-year-olds and 9-year-olds, and participants with Williams syndrome (WS) navigated through brick-wall mazes in a virtual environment. Similar to study 1 above, participants were shown a route through a number of mazes, each with 6 turns. In each maze the floor of each path section was a different colour such that colour acted as an environmental cue. All groups could learn the routes; the WS group required more learning trials to learn the route and when asked which colours had featured on the route, achieved lower memory scores than both of the TD groups. Furthermore, for all three participants groups, when asked which colours featured in each route, higher memory scores were achieved for colours that were easy to verbalise than colours that were not easy to verbalise. This suggests that, in both young children and individuals with WS, once a route has been learnt, the nature of the environmental cues within it can impact an individual’s representation of that route.