Origin of Individual Differences

Here is an opportunity to synthesize some recent discussion topics in HT100 with Universal Design. The class has been talking about genetics and neurobiology and their relation to the origin of individual differences. (Heavy stuff, right? You're telling me!) One conclusion I think the class has reached is that genetic expression and environment interact in such a complex, bidirectional manner that individual differences are bound to arise, even in identical twins. Guest speakers Elena Grigorenko and Charles Nelson had in depth explanations on this account.

On a related note, we've explored the idea of defining a disability. The debate is whether there are clear categories where a disability boundary is defined, or whether all differences in functioning are defined along a continuum. In other words, is it continuous and quantifiable or is it discrete and qualitatively defined? The UDL perspective, of course, would be in favor of a continuum of abilities and disabilities overlapping one another.

Another of our HT100 readings, Pennington, argues for the continuous definition as well (2006). He explains that "disabilities" such as dyslexia and ADHD are the result of a multiple deficit model in which liability for a disorder is probabilistic; that is, it comes from multiple risk and protective factors. No single factor causes a disorder to arise. That is the dilemma when gene and environmental interactions take place...

Now to apply these ideas to a function like reading, remember that reading involves various tasks. Processing syntax and processing semantics are not the same. These different tasks activate different brain areas. However, the activation level for each depends on: a) the brain's developmental level (how much those genes have been expressed!), and b) the level of experience that brain has, both with reading and with content. How's that for educational implication?