J.— PSYCHOLOGY 211 



producing a retinal image of a certain size is seen as larger when it is located 

 at greater distance from the observer. 



The rarity of this condition might seem to make it of little practical 

 interest. It may, however, be of considerable importance in motor driving. 

 Following the same argument as before, we may see that the probable 

 effect of this condition will be that the subject driving a car will see a gap 

 at a distance as big enough to get through when, in fact, it is too small. 

 Unless he has learned to make correct judgments to counteract this per- 

 ceptual peculiarity, this would be as dangerous a condition for the motor 

 driver as one can imagine. Further research is necessary, but at present 

 there are indications that the condition may be dangerous. One of my 

 subjects did drive a car but admitted having smashed a wing in getting 

 through a gate. The other had found himself unable to learn to drive 

 because he drove into gaps where he had no room to pass, and I have had 

 one other case like the last reported to me. A condition which may be 

 lethal to the motor driver is not unimportant even if it is found in only 

 about I % of individuals. 



The effect of drugs on individual organisation of phenomenal space is 

 an interesting problem. I have made only preliminary experiments on 

 one subject in the hope that someone better equipped to experiment on 

 drugs will take the enquiry further. The indication I obtained was that 

 (as might be expected) alcohol decreased phenomenal regression while 

 caffeine increased it. I think that it might be worth while for those 

 investigating the effect of alcohol on motor driving to consider the 

 possibility of disturbance of spatial perception as well as of speed of motor 

 responses. That a change of spatial organisation can affect driving I am 

 sure from personal experience. I was driving one night towards Buxton 

 suffering from the effects not of alcohol but of fatigue (which probably 

 affects spatial organisation in the same way as alcohol). At one point, 

 I found my perception of the road so much disturbed that I had to stop 

 my car and get out. The road seemed to narrow almost to a point in 

 front of me ; I seemed to be driving not on a parallel-sided track but 

 into a funnel. I recognise the condition now as one of extreme reduction 

 of phenomenal regression. One result of this condition was an almost 

 irresistible impulse to drive in the centre of the road. A persistent 

 tendency to drive on the crown of the road is a common fault of many 

 drivers. I suggest that it may be a fault characteristic of an individual 

 with low phenomenal regression, and that if this were proved to be its 

 origin, an understanding by the driver of the cause of his fault would put 

 him into the way of correcting it. 



Mist and fog may disturb the perceptual world even of the motorist 

 who is wise enough to avoid the effects of alcohol and fatigue. It is a 

 matter of common experience that the apparent sizes and distances of 

 objects undergo strange changes even in a slight mist. Exact measurement 

 of the effects of fog and of such veiling glare as that of headlights shining 

 through mist have been made by Martin and Pickford. 



I have one last indication of a possible practical importance in individual 

 differences in phenomenal regression for which I am indebted to Dr. S. 

 Bernfeld. He had a patient suffering from anxiety. One of her causes 

 of fear was the change that took place in the sizes of objects as they 



