An expert team of scientists compared 1,000 sets of monozygotic twins reared by their biological parents (caspi et al., 2004). the researchers asked the mothers to describe each twin. descriptions ranged from very positive to very negative. the researchers measured personality at age 5 (including antisocial behavior as reported by kindergarten teachers) and then measured each twin's personality two years later. the results revealed that
a. if mothers were more negative toward one of their twins, that twin became more antisocial at age 7 than at age 5
b. if mothers were less negative toward one of their twins, that twin became more antisocial at age 7 than at age 5
c. if mothers were more negative toward one of their twins, that twin became less antisocial at age 7 than at age 5
d. that there was no relation between maternal negativity and child antisocial behavior.