All of the heads are realistic , unidealised and frank descriptions of the men . It is likely that they were portraits of living ( or recently deceased ) rulers well known to the sculptors . Each head is distinct and naturalistic , displaying individualised features . They were once thought to represent ballplayers although this theory is no longer widely held ; it is possible , however , that they represent rulers equipped for the Mesoamerican ballgame . Facial expressions depicted on the heads vary from stern through placid to smiling . The most naturalistic Olmec art is the earliest , appearing suddenly without surviving antecedents , with a tendency towards more stylised sculpture as time progressed . Some surviving examples of wooden sculpture recovered from El Manatí demonstrate that the Olmecs are likely to have created many more perishable sculptures than works sculpted from stone .