132 galton.org
132
Inquiries into Human Faculty
had to be mounted from the side next the wall. Another, a politician,
historian, and scholar, refers all his dates to the mental image of a nursery
diagram of the history of the world, which has since developed huge
bosses to support his later acquired information.
Our abstract ideas being mostly drawn from external experiences, their
character also must depend upon the events of our individual histories.
For example, the spoken words house and home must awaken ideas
derived from the houses and the homes with which the hearer is, in one
way or other, acquainted, and these could not be the same to persons of
various social positions and places of residence. The character of our
abstract ideas, therefore, depends, to a considerable degree, on our
nurture.
I doubt, however, whether “abstract idea” is a correct phrase in many
of the cases in which it is used, and whether “cumulative idea” would not
be more appropriate. The ideal faces obtained by the method of composite
portraiture appear to have a great deal in common with these so-called
abstract ideas. The composite portraits consist, as was explained, of
numerous superimposed pictures, forming a cumulative result in which
the features that are common to all the likenesses are clearly seen; those
that are common to a few are relatively faint and are more or less
overlooked, while those that are peculiar to single individuals leave no
sensible trace at all.
This analogy, which I pointed out in a Memoir on Generic Images,
[1]
has been extended and confirmed by subsequent experience of the
process. One objection to my view was that our so-called generalisations
are commonly no more than representative cases, our recollections being
apt to be unduly influenced by particular events, and not by the totality of
what we have seen; that the reason why some one recollection has
prevailed is that the case was sharply defined, or had something unusual
about it, or that our frame of mind was at the time of observation
susceptible to that particular kind of impression. I have had exactly the
same difficulties with the composites. If one of the individual portraits
has sharp outlines, or if it is
[1]
“Generic Images,” Proc. Royal Institute, Friday, April 25, 1879,—partly reprinted
in the Appendix.
