modern variation and evolutionary change in the hominin eye orbit

upward of 5 times for 23 different skulls at different museums over the course of 4 yearsof data collection. In each case dimensions were recorded from a randomly selectedskull, which was then set aside until later in the day or for the following day to ensurethat repeated measures wouldn’t be biased by consecutive quantification. Measurementerror was assessed following the method described in White (2000), page 307.Variables of the cranium and face were found to be slightly more consistent,deviating only 0.56% from the average of each measurement. By comparison, variablesof the orbit were found to diverge by 1.07% on average. Though most orbital variablesare as accurate or in some cases more accurate than those taken from other features of thecranium and face, interorbital breadth, orbital volume, and the distance from basion toorbitale have measurement errors above 1%, which acts to increase the average error forthese orbital variables (Tables 2.4 & 2.5).Seeds used to estimate volume of the orbit were sifted to ensure that each wasroughly the same size, and the same seeds were used at each museum where data werecollected. Additional precautions were taken to ensure that the measurement techniquewas consistent throughout, as it was recognized prior to beginning data collection thatsome error is inherent in volumetric estimations of the orbit using seed, partially due tothe less well defined border in the upper corner of the medial orbital margin (Schultz,1940). Even with these precautions and the meticulousness with which orbital volumewas taken, measurement of this trait is found to be the least repeatable of all variables,with an average difference from the mean measurement of 2.97%.35