SECTIONAL TRANSACTIONS.—J. 439 
coloured signals are used by sea or land and the test is used to ascertain 
whether the examinee can distinguish the colours of the lights used. When 
a test is used for any other purpose, as, for instance, ability to match colours, 
it should show the extent of this ability. 
(3) The test should be of such a character that the examinee cannot be 
coached to pass it. 
Mr. C. B. Nickatts.—A liminal method of determining colour sensitivity 
suitable for group testing (4.0). 
An attempt to grade people, both colour-blinds and colour-normals, with 
regard to colour sensitivity. The subject is shown a number of cards 
containing circular patches of colour of varying hue and saturation. Some 
of the patches are above and some below the limen for that colour. The 
score obtained indicates the colour sensitivity. 
The tests have been applied to school children in groups and the results 
indicate that a fairly fine grading is obtained and that the tests are reliable. 
A demonstration of the application of the tests accompanies the paper. 
Monday, September 9. 
Jornt Discussion with Section L (Educational Science) on The place of 
psychology in the training and work of teachers (Section L room) 
(10.0). See under Section L, p. 461. 
AFTERNOON. 
Miss M. D. Vernon.—The perception of distance (2.0). 
It is important in determining the factors subserving the perception of 
depth and distance to distinguish the various modes of experience connected 
with spatial perception, viz.: direct and immediate experience of distance, 
similar experience of depth or relief, immediate quantitative estimation of 
distance, secondary ideational inference and judgment of depth or distance. 
It is probable that the mode of experience differs according to the type of 
perceptual and ideational data supplied by the experimental situation. 
If a conflict is set up experimentally between the various types of data, 
there may result: (1) a direct and immediate response to a single set of 
important sensory data, e.g. the convergence sensations, or (2) a deliberate 
inferential judgment based upon other less obvious data, or (3) if the conflict 
is severe, a complete breakdown and inability to judge distance. Even if 
much of the important data is eliminated, provided that the remaining data 
are mutually consistent, the observer will in general be able to make some 
type of inferential judgment, and may with practice develop an adequate 
mode of immediate reaction. Thus it is the structural relationship which is 
important, rather than the actual nature and extent of these data. 
Mr. L. S. HearNsHaw.—Some recent advances in selection tests (2.45). 
The selection of personnel on a scientific basis depends on research into 
human abilities and the determination of group factors, and also a scientific 
analysis of jobs to determine what factors enter into their performance. 
Research of this nature has been undertaken, but not on an extensive scale. 
Meanwhile the work of selection must proceed on an empirical basis. 
The experience of the psychologist, however, enters in making the job 
analyses, devising tests, and in validating the tests. ‘This procedure may 
not add much to our knowledge of human abilities, but often provides a 
