What a wonderful way to start the day. Just read there’s a hot new study that claims parenting has no effect on adult IQ. Isn’t this what blogger JayMan has been trying to tell us for years? But I’m sure the HBD deniers will pull out the usual objections: The samples were not random or this assumes the Phenotype = Genotype + Environment model. I would like to challenge the HBD deniers to propose a realistic study that could actually be done that would be capable of falsifying their HBD denial. It’s easy to criticise existing research, but the true measure of science is the ability to formulate a hypothesis that can actually be tested. If the views of HBD deniers can never be falsified by an actual study that can realistically be done, then such views are not science; they’re ideology.

One of the authors of this new study, criminology professor Kevin Beaver states:

Previous research that has detected parenting-related behaviors affect intelligence is perhaps incorrect because it hasn’t taken into account genetic transmission…In previous research, it looks as though parenting is having an effect on child intelligence, but in reality the parents who are more intelligent are doing these things and it is masking the genetic transformation of intelligence to their children…The way you parent a child is not going to have a detectable effect on their IQ as long as that parenting is within normal bounds

Even the qualification of “normal bounds” might be too conservative. There’s anecdotal evidence that even when kids experience the most extreme cultural deprivation imaginable, it has no effect on later IQ. Take the case of Isabelle from the 1930s. Spent the first seven years of life in a dark room with only a deaf mute mother as contact, and thus did not even experience the most basic human interaction (language) for the critical first 6.75 years of life. When she was first discovered she scored at the mental level of a baby on IQ tests because she lacked the language to understand the instructions, but within a couple years of learning English, her IQ had leaped up to normal level, showing no trace of the extreme childhood deprivation she had endured.

Of course a single case study should not be taken as gospel, but it’s certainly food for thought.