212 SECTIONAL ADDRESSES 



approached her. An object at a distance looked very small, but be- 

 came terrifyingly big as it approached her. Dr. Bernfeld was not 

 able to make any experimental measurements of the variation for this 

 patient of seen size vs^ith distance, but the condition is clearly recog- 

 nisable from her description as one of extreme loss of the tendency to 

 phenomenal regression. As to why approaching objects should look 

 terrifying if phenomenal regression is very small, we can only guess. 

 There is one observation in biology which suggests a clue. It has been 

 pointed out to me by Dr. Cott that many creatures protect themselves 

 from their enemies by sudden increases of size. It looks as if sudden 

 increase of size of an object may be one of the situations innately provoca- 

 tive of fear. We might even be tempted to speculate that one reason 

 for the development of phenomenal regression might be as a protection 

 of the individual against the fear-provoking situation of approaching 

 objects increasing in apparent size. There seem to me to be other 

 more likely explanations of the biological function of phenomenal re- 

 gression to real size. I mention this only because it seems interesting to 

 explore all possibilities, the improbable as well as the probable. 



Conclusion. 



The change that has taken place in the psychological study of vision 

 during the last twenty-five years may be expressed in a summary way 

 as a change from the time when it was treated as if vision were a function 

 of the eye alone to a time when the eye and higher centres are regarded as 

 co-operating in visual perception. The psychology of vision is not and 

 cannot be merely the sensory physiology of the eye. At the present time, 

 these wider aspects of visual perception offer a more fruitful field of re- 

 search than do those of sensory physiology which have been so adequately 

 dealt with in the past. Particularly, I should' like to suggest that indi- 

 vidual differences in visual perception and the statistical study of these 

 differences is a field whose surface has hardly yet been scratched. Let 

 us hope that, in the next twenty-five years, psychologists may be as 

 successful in resolving the many remaining problems of visual perception 

 as were the great Helmholtz and his contemporaries in making a scientific 

 study of the sensory physiology of the eye. 



