Metric properties of spatial images generated from locomotion: The effect of absolute size on mental scanning

The mental scanning paradigm has demonstrated that the time taken to scan the mental visual image of a map is linearly related to the scanned distances. The experiments reported here aimed at exploring the influence of two factors on mental scanning: (1) the modality through which the environment is explored, that is visual locomotion; and (2) the size of the environment. Three groups of participants had to study three paths of different sizes: large, intermediate and small. After walking on the paths, participants had to mentally scan them. In Experiment 1 an effect of the absolute size was found, which was due to the participants who took longer and relied on a kinaesthetic strategy to study the path. Experiment 2 was a repetition of the first but the duration of the learning time was controlled. A significant difference between size conditions due to longer scanning times for the larger configuration was found. Experiment 3 compared two learning strategies: visual and kinaesthetic. Also in this case a significant size effect due to longer latencies for scanning over the larger configuration was found. In all experiments a significant effect of distance and the typical time–distance coefficients of mental scanning were also found. Results suggest that the learning time duration and the spatial kinaesthetic strategy are both important for encoding the actual size of the environment.