476 SECTIONAL TRANSACTIONS.—J. 
upon uniformity of time interval between successive strokes in typing can be seen 
to be mistaken. Moreover, the time needed to acquire speed in typing the most 
frequently used words and phrases may probably be reduced by indicating to the 
learner the most suitable rhythm to adopt. 
The same principle may well be extended to the teaching of many complex motor 
tasks. The best technique for applying rhythm in this way has still to be discovered, 
but it seems highly probable that for many beginners some indication of the rhythm 
to be adopted should form an important part of the preliminary instructions. 
Mr. C. A. Mace.—Influence of Indirect Incentives upon the Accuracy of 
Skilled Movements. 
There are grounds for supposing that rewards and penalties are not always 
practicable, and are sometimes detrimental incentives, particularly in the case of 
operations requiring delicate co-ordination. It is therefore of importance to examine 
the mode of operation of conditions which do not arouse complicating secondary 
impulses (such as the desire for reward) but affect favourably the primary intention 
relevant to the task in hand. (Such conditions will be called indirect incentives.) 
Among such conditions are those that produce an unwitting modification of the 
workers’ standard of work, a standard which, though only implicit and inarticulate, 
is almost invariably present as a factor upon which his efficiency depends. 
Experimental studies of two forms of aiming operations show that by modifications 
of the target the marksman’s efficiency may be enhanced from 12 to 17 per cent. 
Various considerations entitle us to interpret this as due to a change in the subjective — 
standard of efficiency imposed by the variation in the target. The principle would — 
seem to admit of a wide range of educational and industrial application. . 
Mr. 8. Wyatrr.—Some Personal Factors in Industrial Efficiency. 
Mr. Eric Farmer.—The Present Tendencies in Vocational Selection. 
Vocational selection has passed its initial stage, in which it had to be proved — 
that it was possible, by means of psychological tests, to measure certain functions 
involved in industrial proficiency. At present attention is mainly directed to 
critically examining its technique and experimenting with different types of tests. 
There is a tendency to give up tests involving psychological functions as far as possible 
in isolation for more complex tests involving several integrated functions. 
This is shown by the increased use of sample and analogous tests, and also general — 
analytic tests involving complex rather than simple functions. It cannot be expected 
that individual vocational tests will ever yield high correlations such as are found ~ 
between intelligence tests and scholastic performance, because industrial proficiency 
is determined by many variables, none of which plays such a predominant part in it 
as intelligence does in scholastic performance. Psychological tests will none the less 
be valuable in so far as they select more efficient workers than any alternative methods 
of selection, and, judged by this criterion, they have already justified themselves, — 
although much more research is necessary before they can be put to the fullest use. — 
42 
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AFTERNOON. 
Dr. A. Macrar.—Gwuidance in the Choice of an Occupation. (Public Lecture | 
at the London School of Economics, Houghton Street, Aldwych.) 
Tuesday, September 29. 
Prof. Frank AtLEN.—The Function of Induction in Colour Vision. 
When one eye has been stimulated by any spectral hue above a certain critical 
intensity it has been found experimentally that, in addition to the sensation of colour, 
certain uniocular and binocular effects follow which are invariably confined to the 
reception of the three colours, red, green and violet. If the stimulating colour is red, 
green or violet, the corresponding receptor mechanism in the stimulated area of the 
retina is depressed in sensitivity, while the receptors for the remaining two colour 
