Common sense and simple experiment have already indicated certain ways in which some of the more common forms of Upper Palaeolithic implements may have been held. Thus for example, there is a general consensus of opinion that knife blades were held either by the butt end only, or by the butt with the index finger extended along the back of the tool. When however, we come to consider other types of tools, such as the scrapers, we find that there are a number of possible ways in which such tools may be held. The actual way or ways in which these tools were held becomes therefore, largely a matter of conjecture unless we can fortify our opinion by relevant facts relating to some particular mode or modes of prehension.
To guide us in selecting the particular way in which a tool was held from the many possible ways in which it could be held, we have the following factors:—
(i) The general shape of the tool.
(ii) The character of the traces of wear on the cutting edge due to use.
(iii) The situation and character of any special trimming which may have been made to facilitate prehension.
(iv) The degree of comfort or freedom from constraint with which a tool may be used in a given position.
(v) The frequency of occurrence of tools of certain lengths and widths which are comparable with the average dimensions of the human hand when gripping an object in certain ways.
(vi) The mode of prehension of stone tools adopted by existing primitive races.