Figure 3.jpg (228.89 kB)
Logic behind twin research
figure
posted on 2020-08-01, 17:34 authored by Sara HartSara Hart, Callie LittleCallie Little, Elsje van BergenElsje van BergenThe
logic behind twin research. The scatter plots depict how much the two types of
(reared-together) twins resemble their co-twin on reading ability. Each dot
represents the reading scores of both children within a pair. It can be seen
that monozygotic twins are much more alike. From this it can be concluded that
differences between children are largely due to genetic differences. The data
come from van Bergen et al. (2018) and represent word-reading fluency test
scores in Grade 2 of twin pairs with complete data. The score is the number of
words read correctly within 1 minute. In this sample the monozygotic and
dizygotic twin correlations were .84 and .46 respectively, which yield
estimates using the Falconer formulas (Falconer, 1960) of A = .76, C = .08, and
E = .16
