In his 2011 paper "Cultural cobbles or a load of old cobblers? The detection of iconography and identification of artefactuality in lithics" Richard J. Wilson writes:
The human visual system devotes specialised resources to face perception which are neurologically well determined (Helvenston and Hodgson 2010, 2006; Hodgson 2008a). As Hodgson and others elaborate, there is a deal of evidence that there is a biologically determined preference for perceiving the hominin face (Watson 2010, Helvenston and Hodgson 2010,2006). Likewise, Sinha et al (2006) note that the visual system of humans begins with a rudimentary preference for face-like patterns. Recognition of a face is thus usually associated from an early stage with an emotionally satisfying reward through maternal contact (Hodgson 2010). A reward system intertwined from birth with that of face recognition offers one theoretical motivation for collecting ‘face-like’ stones and rocks such as the Boucher de Perthes object presented earlier – regardless of whether or not they were enhanced further. A predilection for collecting stones which resemble ‘faces’ is comprehensible in the context of the “neurological value” elicited in a system designed to detect and respond to faces.