By analysing non-metrical data from the two tribes, Bacon has suggested absence of any kind of family relationship between the two tribes. Bacon has taken the lower part of the tibia of the bones from the Isbister, Quanterness and also present day adult amputaions, and compare them with one another. This comparison allowed them to get an idea about how the lifestyle in the Neolithic is different to the modern days which is mentioned in the previous post. Figure 1 in the article “The dependence of human bone texture on life style” by Bacon, G.E. shows the difference in tibia in between the two tribes and also present day humans. He has looked at the radial distance of the tibia from which he studied the ability of the bones to withstand stress in the chosen direction for the 12 individuals in total.
They were also able to estimate the life expectancy during the Neolithic era as around 28 years which now, in the modern day is above 80 years of age for healthy individuals.
Bacon, G.E. (1990). The dependence of human bone texture on life style. Great Britain, 240, 363-370. Available from http://www.jstor.org.ezproxy.westminster.ac.uk/stable/49517?sid=primo&seq=1#page_scan_tab_contents