english: We could look across time at the same people -- people, for example, who were genetically vulnerable to schizophrenia -- and ask what the contribution of mothering, of genetics are, and we could isolate third variables by doing experiments on the mental illnesses.
non_english: Da lahko gledamo preko časa na iste ljudi -- ljudje, na primer, ki si genetsko ranjivi za shizofrenijo -- in se vprašali, kakšna je prispevek materinske vloge neodvisno od genetike in smo tako lahko izolirali tretje spremenljivke z izvajanjem eksperimentov o mentalnih bolezni.