HUDSON HOAGLAND 
SUMMARY 
We have considered the nature of purposive behaviour in the 
light of concepts of cybernetic mechanisms and of the brain as 
an organ of adaptation. Recent advances have made available 
new psychological, pharmacological and surgical procedures 
for the modification and control of behaviour, and we have dis- 
cussed some of their applications and limitations. Human 
behaviour is controlled and directed by a variety of processes, 
many of them subconscious and irrational. It is argued that 
pharmacological agents and psycho-surgical techniques now 
known to be of value in psychiatry and for purposes of investiga- 
tion are not likely to be used as agents for the deliberate control 
of behaviour of normal persons. Recent studies of learning and 
memory may, however, in the not too distant future, come to 
have practical applications in education or for the exploitation 
of the public by propagandists. The major question is, who 
controls whom and for what purposes? The role of the be- 
havioural sciences in establishing ethical beliefs and the opera- 
tions of conscience are pregnant with potential benefits and 
dangers for mankind. 
Advances in sciences are doubling accumulated information 
every ten years. Nuclear weapons and the population explosion 
are examples of unprecedented changes which demand new 
ways of thinking and behaving, if we are to survive and continue 
cultural evolution. The behavioural and social sciences, if 
wisely used, can be of great assistance in meeting these and 
other new challenges. 
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