Neural Correlates of Perceiving and Interpreting Engraved Prehistoric Patterns as Human Productions
1 Univ. Bordeaux, GIN, IMN UMR 5293, Bordeaux, France
2 CNRS, GIN, IMN UMR 5293, Bordeaux, France
3 CEA, GIN, IMN UMR 5293, Bordeaux, France
It has been proposed that engraved abstract patterns dating from the Middle and Lower Palaeolithic could have served as a communication medium. Identifying the brain regions involved in the visual processing of these marks can provide insights into the function they had in the past. In this study, brain activity was measured, using functional magnetic resonance imaging, during the perception of engraved patterns and natural patterns mimicking human-made engravings. Participants had to categorise Palaeolithic marks as being intentionally made by humans or due to natural processes (e.g. erosion, fossilisation). To simulate the putative familiarity of our ancestors with marks, expert archaeologists and control participants were compared, allowing to characterise the effect of previous knowledge on both behaviour and brain activity in marks perception.
Besides a set of regions common to both groups involved in visual analysis and decision-making, Experts exhibited greater activity in the inferior part of the lateral occipital cortex, ventral occipitotemporal cortex, and medial thalamic regions. Although they were in an unexplored area of expertise, these results were consistent with those reported in the visual expertise studies and confirm the importance of the integrative visual areas in the perception of engravings. Attributing a natural rather than a human origin to the marks elicited greater activity in the salience network in both groups, reflecting the uncertainty and perceptual ambiguity of natural marks and uncertainty in decision-making for natural patterns.