, , , . (McGue, 1997). / , , , .
, , . , (Neisser et al., 1996). , IQ , , . . , (Neisser et al., 1996). , , 0 100% .
, , ? , . , 50%, , , (McGue, Bouchard, Iacono & Lykken, 1993; Plomin & Neiderhiser, 1991).
, . , , (Plomin, 1995; Rowe, 1994). , , (Ramey, Campbell, & Ramey, 1999). , , , , IQ , , (Capron & Duyme, 1989).
IQ , . /, , , ( , ) 20% IQ , 5% /, (Devlin, Daniels & Rodin, 1997). , , , , , (McGue, 1997). : () , , , , .