Rightward directional bias in art produced by cultures without a written language

ABSTRACT

In this study, we coded art painted on rocks located in southern Africa, which was painted with a mixture of ochre, blood, and clay by the San, a Neolithic culture with no written language. These images depict a mixture of humans and animals in a variety of contexts, including (but not limited to) hunts and dances. We calculated a laterality index for the collected available art from each region, finding that although there was variability across regions in the direction of the laterality scores, most regions contained a majority of figures facing rightward. This is in stark contrast with reports of artists drawing leftward facing animals and human profiles (an effect that is influenced by native language writing system direction, gender, and handedness), but interestingly our sample also contained regions with strong leftward biases. Our results are, however, in accord with studies that report people preferring images that depict left-to-right motion, as well as the left-to-right bias in depicting transitive actions, an effect that seems to result from greater right hemispheric activation in scene processing and interpretation. Thus, this study shows that in the absence of a writing system, right-lateralized neural architecture may guide the hands of artists.

KEYWORDS:

• Rock art
• San
• South Africa
• neuroaesthetics
• illiteracy

Acknowledgements

We would like to express our thanks to Azizo Da Fonseca, Director of the Ringing Rocks Digitising Laboratory & The African Rock Art Digital Archive at the Rock Art Research Institute in Johannesburg, South Africa. Thanks also to Janishta Daya, data analyst at same. Thank you to Dr David Lewis-Williams for information about the San rock art. And finally, thank you to the undergraduate researchers who assisted in coding images: Ansley Potter, Benjamin Zah, GJ De Guzman, Joel Rollins, Sophia Bertrand, and Victor Ortiz.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1 The majority of orthographic systems use a left-to-right script (e.g., English, Spanish), but several, including Hebrew and Arabic, employ right-to-left systems. A smaller minority (e.g., Japanese, Chinese) use a top-to-bottom one, but many of these adopted left-to-right systems as a result of western influences.

2 The data we analyzed are available at: doi:10.17605/OSF.IO/WMT4H.

3 Images were rated by T. W. B. and six other researchers independently rated subsets of the data. The raters agreed 80% on the overall directional bias of images, ĸ = 0.68. The results reported here reflect the conservative lateral counts of the images (i.e., taking the more conservative value of left- and right-facing figures from each image).

Additional information

Funding

This work was supported by Division of Behavioral and Cognitive Sciences: [Grant Number BCS0822617]; Office of Behavioral and Social Sciences Research: [Grant Number R21AG030445].