Andrew is attending the 14th European Workshop on Ecological Psychology presenting his affordance research on prehistoric objects (see the full program). Hope to see some of you there!
Task dynamics and the affordances of prehistoric spheroids for throwing
Andrew Wilson, Qin Zhu, Ian Stanistreet, Larry Barham, & Geoffrey Bingham
Spheroids are ball-shaped stone objects found at African archaeological sites dating from 1.8 million years ago (Early Stone Age) to at least 200,000 years ago (Middle Stone Age), making them one of the longest-used technologies on record. Most hypotheses about their use presume they were held in one hand and used to shape or grind other materials. However, their size and spherical shape make them potentially useful as projectile weapons, a property that, uniquely, humans have been specialised to exploit for millions of years. Here we show (via simulations of projectile motions parameterised by recent affordance research on throwing) that 88% of the spheroids found at the Cave of Hearths site afford being thrown by a human so as to inflict worthwhile damage to an animal roughly the size of an impala over distances up to 25m. Most of the objects have weights that produce optimal levels of damage from throwing, rather than being as heavy as possible (as would suit other functions). Our results support the hypothesis that these objects were selected because they afford being thrown to inflict damage, and demonstrates how research on the task dynamics of affordances can inform and constrain our theories about prehistoric artifacts.