Since this paper will be chiefly concerned with the suggestion of methods for the investigation of a specific problem, it is necessary first to define the problem as clearly as possible.

In the Huxley Memorial Lecture for 1943 I said, ‘Every culture has its “hard” and its “soft” points. If change is first sought at the former it will provoke resistance and very likely open discord, while the latter are yielding and it is from them that reformation will spread.’ There seems to be no possible dispute about the fact. But to admit the fact carries us only a very little way towards solving the problems to which the existence of yielding and unyielding features of culture gives rise. In the lecture I attempted to go no farther than a very general discussion of these problems. I was therefore pleased when, some time ago, I received a letter from the Editor of this Journal inviting me to discuss more fully what psychological methods may be applied, not merely to recognize those ‘hard’ and ‘soft’ points of culture which history has demonstrated, but to predict them before such demonstration.