ABSTRACT
BEHAVIOR GENETIC S i s a vigorously growing fiel d i n psychology tha t trace s it s ancestry wi t h equa l relevanc e throug h th e historica l antecedents o f com -parative psycholog y an d individua l differenc e studies . McClear n (1965) , for example , documente d th e exten t t o whic h behavio r genetic s studie s o f animal s
have use d th e method s an d focuse d o n th e problem s o f comparativ e psychology ,
while Hirsc h (1962 ) detaile d th e centra l concer n o f thi s movement w i t h individ -
ual differences . A s Meissne r (1965 ) describe d th e moda l emphasis , th e focu s i s
"on th e determinatio n of th e genotype s correspondin g t o th e psychologica l phe -
notypes. Th e overridin g concer n [is ] to identif y th e geneti c factor s t o whic h th e
observed varianc e i n psychologica l abilities and performanc e coul d b e ascribed "
(p. 206) . Similarly , McClear n (1960 ) describe d th e tas k a s on e o f determinin g
"the relativ e contribution s of geneti c an d environmenta l difference s t o th e vari -
ability exhibite d among individuals " (p . 149) .
