440 THE FACTORS OF THE MIND

but little bias in either direction doubtless find it easier to conform
to the stereotyped and conventional pattern of behaviour, and so,
in later years, present personalities which, to the outward observer,
appear unusually correct and well-balanced.1

We may, therefore, conclude that the distribution under-
lying the alleged antithetical c types' is a continuous,
unimodal, bipolar distribution, closely approximating to a
normal distribution. But we must add that in any par-
ticular group the perfect symmetry of the normal curve is
likely to be appreciably disturbed, partly by the inevitable
inclusion of mild pathological cases and probably by other

1 A footnote should perhaps be added dealing with one or two criticisms
that have appeared since the above was written. Dr. Jameson asks whether
the conclusions drawn in my previous paper [114] are not inconsistent with
my own earlier acceptance of Mendelian principles as applicable to mental
as well as to physical inheritance ([22], [23]): " do not these very laws lead
us to expect sharply segregated types, ' objective ' and £ subjective,' to use
Hurt's own designations, * extravert' and i introvert,' * cyclothyme ? and
* schizophrene' to use the more recent, and (in my view) more precise and
informative terms I " Similarly, Dr. Stephenson in his latest paper on
Jungs Typology argues, as we have seen (pp. 418-19 above), that the
temperamental types distinguished by Kretschmer and Jung are to be
regarded as * definitely limited species,' not c extreme ends of a normal
frequency distribution*: " mental types," he insists, " are as distinct as the
genera and species of animals in the present epcch of fauna—as cats from
dogs, and buttercups from daisies." In reply to Dr. Jameson's argument
it may be said that, where a character appears relatively simple in its
causal origin (e.g. to take the instances he quotes from my earlier paper,
sex-characteristics or red-green colour-blindness), there we may expect
sharply separated types: even in colour-blindness, however, experimental
tests do not reveal distinctions by any means as clear cut as is popularly
supposed. But where a character appears relatively complex in its causal
origin (e.g. stature or temperament) there Mendelian principles them-
selves lead us to expect £ tendencies rather than clear-cut types' (cf. above,
p. 246). In another paper I hope to show how the physical types popularly
associated with distinctive temperamental qualities can themselves be meas-
ured by factorial means, and then proved to follow a continuous and approxi-
mately normal distribution. The * types' that Stephenson cites from the
plant and animal world are mutually sterile ; hence there would seem to be
no possibility of such types merging. But man and his * types ' are peculiar
in two ways. First, man seems to have gone further than any other animal
in producing markedly different varieties, which are nevertheless mutually
fertile; moreover, in an intelligent and adaptable species like man a larger
proportion of the more eccentric variations are able to survive and breed.