FUNCTIONAL CHANGES INDUCED BY RADIATIONS 497 



practical problem, and one of particular concern in the field of radiobiology, 

 is whether low levels of environmental radiation affect in any way powers of 

 the intellect. 



Effects on the nervous system or any of its parts, including effects on 

 storage and use of information, affect the intellect, and we can develop 

 some ideas about effects of radiation on the mind by examining the frag- 

 mentary information at hand. 



If by low level environmental radiation we mean intensities only a few 

 times natural levels, there is no information at all, so far as the writer is 

 aware, indicating whether there is an effect or not. If, by low le\el, we mean 

 exposures below those required to produce clinical symptoms, say 0.01-1 r 

 (100-10,000 times background, such as might exist in accidents), we have 

 mostly the Soviet evidence indicating detectable changes. If by low level 

 we mean exposures just below the lethal range, say 100-500 r (something 

 over 100,000 times background, such as might occur in nuclear catastrophy), 

 we are, with refined techniques, beginning to see some changes, mainly of 

 the prompt response type. 



On the basis of such evidence, we might be tempted to conclude that 

 environmental radiation is not a vei*y serious practical problem, so far as 

 effects on the power of the intellect are concerned, and with further inves- 

 tigation this may prove to be the case. However, on the basis of the same 

 evidence, one gains the impression that the more refined the techniques 

 and the more advanced the specialization of the nervous system in intel- 

 lectual power, the easier it is to demonstrate effects. 



If this impression is to be regarded as having merit, we would scarcely be 

 justified in concluding at this time that levels even a few times background 

 are inconsequential — particularly, if we take into account the still more 

 complex intellectual powers of population groups. Group intellect involves 

 moods, emotional tone, and temperament, as well as ability to think. At 

 this stage in human history, when so much depends on such limited indi- 

 vidual and group intelligence, it is important to ask whether even a small 

 loss in mental fitness, due to a lack of learning abilities, or abilities to think, 

 may not be a serious loss. 



Evaluation of Lov^ Level Effects 



I wish to outline a philosophy and approach for dealing with effects of 

 low level en\ ironmental radiation in the general situation and to identify 

 some important underlying radioneurologic problems. 



At the beginning of this presentation, attention was called to the adap- 

 tiveness of eeoentities, the abilities of cells, tissues, organisms, and population 

 groups to perform, and to the idea that each ecoentity possesses an ecojorce 



