Twin studies found the following correlation coefficients (r) for monozygotic (MZ) vs. dizygotic (DZ) twins: $\begin{array} { | l | l | l | } \hline& \mathrm { rMZ } & \mathrm { rDZ } \\\hline \text { Alcoholism (males) } & 0.4 & 0.21 \\\hline \text { Autism } & 0.65 & 0.1 \\\hline \text { Reading disability } & 0.75 & 0.45 \\\hline \text { Schizophrenia } & 0.5 & 0.19 \\\hline\end{array}$ Data from Plomin R, Owen MJ & McGuffin P (1994) Science 264:1733-1739.
Which mental trait has the lowest heritability (contribution of genetic differences to trait differences)? Briefly explain your reasoning.

Question

Twin studies found the following correlation coefficients (r) for monozygotic (MZ) vs. dizygotic (DZ) twins:

\begin{array} { | l | l | l | } \hline& \mathrm { rMZ } & \mathrm { rDZ } \\\hline \text { Alcoholism (males) } & 0.4 & 0.21 \\\hline \text { Autism } & 0.65 & 0.1 \\\hline \text { Reading disability } & 0.75 & 0.45 \\\hline \text { Schizophrenia } & 0.5 & 0.19 \\\hline\end{array}

Data from Plomin R, Owen MJ & McGuffin P (1994) Science 264:1733-1739.
Which mental trait has the lowest heritability (contribution of genetic differences to trait differences)? Briefly explain your reasoning.