Sun, age and test location affect spatial orientation in human foragers in rainforests

• Published in: Proceedings of the Royal Society. B, Biological sciences Vol. 286; no. 1907; p. 20190934
• Main Authors: Jang, Haneul, Boesch, Christophe, Mundry, Roger, Kandza, Vidrich, Janmaat, Karline R L
• Format: Journal Article
• Language: English
• Published: England The Royal Society 24.07.2019
• Subjects: African Continental Ancestry Group; Age Factors; Behaviour; Congo; Cues; Feeding Behavior; Humans; Orientation, Spatial; Rainforest; Sex Factors; Solar System; Congo; pointing accuracy; spatial experience; rainforest; Mbendjele BaYaka people; spatial orientation; sun navigation
• ISSN: 0962-8452; 1471-2954
• DOI: 10.1098/rspb.2019.0934

The ability to know the direction of food sources is important for the foraging success of hunter-gatherers, especially in rainforests where dense vegetation limits visual detection distances. Besides sex and age, prior experience with the environment and the use of environmental cues are known to influence orientation abilities of humans. Among environmental cues, the position of the sun in the sky is important for orientation of diurnal animal species. However, whether or to what extent humans use the sun is largely unknown. Here, we investigated orientation abilities of the Mbendjele BaYaka people in the Republic of Congo, by conducting pointing tests (N = 54, age: 6-76 years) in different locations in the rainforest. The Mbendjele were overall highly accurate at pointing to out-of-sight targets (median error: 6°). Pointing accuracy increased with age, but sex did not affect accuracy. Crucially, sun visibility increased pointing accuracy in young participants, especially when they were far from the camp. However, this effect became less apparent in older participants who exhibited high pointing accuracy, also when the sun was not visible. This study extends our understandings of orientation abilities of human foragers and provides the first behavioural evidence for sun compass use in humans.