Potentialities in the Control of Behaviour 
controlled countries. However, from the evidence available, this 
has not been the case. According to reliable reports, coercion 
of persons for the purpose of extracting confessions has involved 
methods similar to police state practices used since the time of 
Napoleon. Neither scientifically directed Pavlovian condi- 
tioned reflex procedure nor pharmacology appear to have been 
used in any significant way in breaking the morale of political 
prisoners. 
EMOTIONS, BEHAVIOUR AND BRAIN SURGERY 
Extensive work by neurophysiologists, using operations on the 
brains of animals, has shown that it is possible markedly to 
modify emotional and aggressive behaviour. When experimen- 
tal lesions in monkeys are carefully restricted to the pyriform 
lobe of the amygdaloid complex and hippocampus without 
interference with neocortical regions, most fear and anger 
responses disappear, without gross motor or sensory deficiencies. 
Although these animals can express anger and rage in response 
to appropriate stimuli, they are rendered remarkably docile 
and fearless, and their behaviour is accompanied by a reduction 
in sexual activity. Studies of cats, including the lynx, show 
there is marked docility following bilateral lesions of the pyri- 
form lobe. But the amygdalectomized cat can be turned into 
a vicious and rageful animal by additional superimposed lesions 
in the ventro-medial nucleus of the hypothalamus. Changes 
have been reported in the hierarchical position of individual 
rhesus monkeys from dominant to submissive positions in the 
pecking order following amygdalectomy, and clinical observa- 
tions indicate that some amygdala lesions in man are followed 
by diminished social aggressiveness. 
It thus appears that surgical operations on the brain’s limbic 
system can markedly change emotional behaviour. Presumably 
chemical agents may ultimately be found which will act selec- 
tively on specific brain centres and have similar effects. It has 
been reported that cats exposed to certain agents of potential 
use in chemical warfare are terrified at the sight of mice. Des- 
pite the values of the neurosurgical findings to medicine, it 1s 
399 
