TIMELINE INTERPRETATION AND TIME SCALE COGNITION EXPERIMENTS FOR THE TRAIL OF TIME AT GRAND CANYON NATIONAL PARK

The Trail of Time is a walking timeline trail now under construction along the South Rim of Grand Canyon, from Yavapai Observation Station to Grand Canyon Village. It will extend 4.5 km, with each meter marked to represent one million years of geologic time. Interpretative resources on Grand Canyon geology and culture will be deployed along its route. The Trail of Time will be the world's largest geoscience exhibit at the world's grandest geoheritage site. A Time Accelerator Trail (TAT), a logarithmically scaled timeline approximately 250 m long and appended to the main Trail, will help visitors adjust their temporal frames of reference from personal or familiar time scales (years to decades), through historic and archaeological time scales (centuries to millennia) to deep time (millions of years), by periodic changes in scale enroute, from one meter per year to one meter per million years. The time interval marked by the TAT begins at the present and ends at 6 Ma, when Grand Canyon downcutting started.

While linear timelines are constructs commonly used to teach about geologic time in formal and informal settings, their effectiveness has not been fully assessed. The logarithmic time scale introduces complexities that should be understood before the TAT is implemented. The TAT also represents a unique laboratory for the study of learning about deep time. We are implementing off-Canyon studies of the proposed TAT, in which different subjects recruited locally represent typical Grand Canyon visitors. The experimental setting is a scaled-down (74 m), portable rolled paper version of the TAT, on which realistic time markers and placards can be readily placed and adjusted. Research questions include: (1) Do subjects understand the purpose of the TAT?; (2) What happens cognitively when subjects walk the variably-scaled timeline?; (3) Can subjects correctly identify the time represented at any point along the TAT?; and (4) What cognitive challenges will subjects reveal while traversing the TAT? More than 50 subjects of diverse age, ethnicity, and background have participated. The experiments have yielded useful pedagogical recommendations for the full-scale TAT, especially clarity of scale changes and comprehensive labeling of time markers. Coding and analysis of recordings for time cognition studies are in progress.