When Culture Looks Innate: Reconsidering Evidence for Human Left-Turn Bias

This paper examines a methodological problem in the interpretation of behavioral asymmetries. Using recent studies of human left-turn bias as a case study, it argues that stable and cross-cultural behavioral regularities do not, by themselves, justify biological explanations when plausible mechanisms of cultural transmission remain available. The paper develops the concept of the attribution gap—the logical distance between observing a behavioral pattern and identifying its causal origin. A formal representation of the problem is proposed together with a falsification-oriented framework for distinguishing between biological and cultural transmission mechanisms. Particular attention is devoted to motor-pattern transmission through family instruction, schooling, military drill, sports training, and other forms of long-term behavioral standardization. Historical examples from British military traditions, Meiji-era Japan, and nineteenth-century Prussian physical education are discussed as evidence that societies possess mechanisms capable of shaping motor behavior on population scales. The paper does not argue that human left-turn bias is cultural in origin. Rather, it argues that biological explanations cannot be regarded as evidentially privileged until competing cultural mechanisms have been independently excluded. More broadly, the analysis proposes an Attribution Principle for behavioral research and outlines a general framework for causal attribution applicable to motor asymmetries, navigation preferences, gesture systems, social conventions, and other persistent behavioral regularities.