A novel virtual-reality-based route-learning test suite: Assessing the effects of cognitive aging on navigation

Abstract

Most research groups studying human navigational behavior with virtual environment (VE) technology develop their own tasks and protocols. This makes it difficult to compare results between groups and to create normative data sets for any specific navigational task. Such norms, however, are prerequisites for the use of navigation assessments as diagnostic tools-for example, to support the early and differential diagnosis of atypical aging. Here we start addressing these problems by presenting and evaluating a new navigation test suite that we make freely available to other researchers (https://osf.io/mx52y/). Specifically, we designed three navigational tasks, which are adaptations of earlier published tasks used to study the effects of typical and atypical aging on navigation: a route-repetition task that can be solved using egocentric navigation strategies, and route-retracing and directional-approach tasks that both require allocentric spatial processing. Despite introducing a number of changes to the original tasks to make them look more realistic and ecologically valid, and therefore easy to explain to people unfamiliar with a VE or who have cognitive impairments, we replicated the findings from the original studies. Specifically, we found general age-related declines in navigation performance and additional specific difficulties in tasks that required allocentric processes. These findings demonstrate that our new tasks have task demands similar to those of the original tasks, and are thus suited to be used more widely.

Keywords: Cognitive aging; Navigation; Navigation test; Route learning.

Figures

Fig. 1

(Top row) Screenshots taken during the learning phase of the route-repetition task. (a) Participants “stand” at the starting position and start the passive transportation along a route by pressing the SPACE bar. (b) Screenshot taken along the route while approaching an intersection. (c) Screenshot taken at the end of the route. Participants initiated the test phase by pressing the SPACE bar. (Bottom row) Screenshots taken during the test phase. (d) Participants were transported from the start point toward the first intersection. (e) Screenshot taken before the distinctive landmarks at the upcoming intersection were visible. (f) Screenshot taken at the end of the navigation phase of a test trial, before the participant has responded

Fig. 2

Schematic illustrating the directional-approach task, with an overview of one of the environments used in that task. (a) During the encoding phase, participants always approached the intersection with two distinct landmarks positioned at diagonally opposite corners from the street to the south, starting at the black car (c). During the test phase, they approached the same intersection from the street to the east, the west, or the north. Note that the car could not be seen when participants were asked to give their response. Critically, the approaches to the intersection from the east and west were misaligned with the encoding situation by 90°, whereas an approach from the north was misaligned with the encoding situation by 180° (b)

Fig. 3

Screenshots taken during the directional-approach task. (Upper row) Encoding phase: (a) Participants initiate translation at the beginning of the encoding phase. (b) Screenshot taken during passive transportation toward the intersection. (c) Final position during the encoding phase. Participants then initiate the test phase. (Lower row) Screenshots taken at the end of the translation in the test phase, when approaching the intersection from the west (d), north (e), and east (f)

Fig. 4

Performance (a, b) and response times (c, d) for the older and younger participants in the route-repetition and the route-retracing tasks as a function of experimental sessions. The horizontal lines in panels a and b represent chance-level performance. The bars represent mean values, the error bars represent standard errors of the means, and we have overlaid the probability density of the participants’ performance or response times at different values. The plots were generated using the ggplot 2 package in R (Wickham, 2016)

Fig. 5

Performance (left) and response times (right) for the older and younger participant groups in the directional-approach task. The horizontal line in the left plot represents chance level. Note that approaching the intersection from the east or west was misaligned with the encoding view by 90°, whereas approaching the intersection from the north was misaligned with the encoding view by 180°. Bars represent mean values, error bars represent standard errors of the means, and we have overlaid the probability density of participants’ performance or response times at different values. The plots were generated using the ggplot 2 package in R (Wickham, 2016)