Abstract
Introduction: This study examines individual differences in navigational strategy to test and translate between active spatial reasoning models in human and rodent research. We built a real-world, 50-foot diameter, 11-arm walk-through Human Radial-Arm Maze (HRAM) to parallel the Rodent Radial-Arm Maze (RRAM). Methods: 157 participants performed the HRAM and cognitive tests. The HRAM required participants to traverse all 11 arms and recover money hidden under mats at the end of each arm with the fewest number of repeat errors. Participants were not allowed to use strategies of simple ordered chaining of arms or of every second arm. Participants were classified by self-reported use of navigational strategies, including use of external cues. Results: The accumulation of arm-repetition errors over time was similar to RRAMs, but consistent with a higher memory capacity. We found two primary strategies: (1) Systematic procedural heuristics (repeatedly crossing over to opposing arms, or complex chaining such as traversing every third arm), and (2) Unsystematic, brute-force memorization (patterns that relied on remembering features and global orientation cues). The 43% who used systematic heuristics made significantly less errors than the 57% who relied on brute-force memory. Those using external cues (48%) revealed that our two principal behavioral strategy categories did not correspond well with classic navigational strategy dichotomies like allocentric, map-based representations versus egocentric, landmark-based representations. For example, Strategy 1 can be achieved via either allocentric or egocentric representations, and Strategy 2 can be coded from either allocentric or egocentric perspectives. Nevertheless, testing humans in similar real-world environments as rats provides a foundational tool to translate models of spatial cognition and reasoning across species. Conclusions: The HRAM resulted in two behavioral classes of strategies, systematic heuristics versus brute force memory. The HRAM is a useful, ecologically-valid instrument for testing functional cognitive, memory, and navigational principles that translate between rodents and humans.
Meeting abstract presented at VSS 2013