When I applied to graduate school in fall/winter 2012, one of the professors I hoped to work with asked me, "Are you also interested in working with typically developing children?" The intention behind this question was probably simple: "All of your research interests concern some sort of atypically developing children. Are you willing and able to work on our studies that involve only typically developing children, or will you get bored and do lackluster work?" However, I sensed some assumptions behind the question--ones she may or may not have actually intended--that seem worth discussing. Specifically: if you're a researcher primarily interested in atypical development, should you do at least some studies just on typical development?
Even if you study nothing but atypical populations (e.g., autism), you will be studying typically developing kids nearly all the time, because they almost always make up the comparison group. (Occasionally studies of autism will only include kids with intellectual disability or ADHD as a control group, but studies like these without typically developing kids are quite rare). So, whether or not you're interested in typically developing kids, you're studying them by default.
Since I've worked in developmental labs or conducted developmental studies for over five years, I know this well. I suppose part of the point of asking the question was to make sure that I knew this, as prospective graduate students can have unrealistic expectations about all sorts of things. But I digress.
Fortunately, typically developing kids interest me, I enjoy working with them, and look for every opportunity to do so. It just doesn't follow that interest in atypically developing kids means a lack of interest in typically developing ones; if anything, I've argued here that they're more similar than many researchers believe. So, I like that any study I would want to run includes typically developing kids by default.
But what made the question hard to answer was that I sensed that simply running studies with typically developing control groups isn't considered enough. You have to also run studies with just typically developing kids. But why?
Developmental psychology is a huge field full of brilliant people doing fascinating work. The average layperson may even know some of the big names, such as Rene Baillargeon or Alison Gopnik, who describe their work in the popular press. Honestly, developmental psychology does not need a new person hoping to make creative contributions. Yet another smart person can't offer that much, as they'll amount to just another drop in a very full bucket. However, atypical development research not only is a smaller field to begin with, but also desperately needs more rigor and fresh ideas. Anyone who's read Cracking the Enigma or The Autism Crisis realizes how much autism research needs new approaches, and compared to research on intellectual giftedness, autism research looks rigorous. As a new person entering the field and hoping to make creative discoveries, I'm more likely to actually make a meaningful contribution by studying atypical development.
Not only can one make more of a difference intellectually by researching atypical development--one also has a better chance of "repairing the world" in small ways. Insights from research on typical child development do inform education. However, whether because of or despite their education, most typically developing kids come out of their schooling functioning just fine academically and emotionally. Not so with atypical populations; kids with autism or learning disabilities struggle with education that rarely accommodates their needs while still challenging them. And heaven forbid they should actually be intellectually gifted; then no public, private, or homeschooling option will quite fit them. Looking beyond the educational world, atypically developing people face constant misinterpretations of their behavior as "rude" or "lazy" should they try to pass as normal, and degrading stereotypes if they reveal their diagnosis. Many people still think that autistic people lack emotions or concern for others or that people with ADHD can't ever pay attention, even though those affected and their families--and some researchers and clinicians--know better. And autistic, ADHD, and gifted people share one commonality: they vanish from discussion along with needed services in adulthood; it's as if people think they disappear as soon as they turn 18.
While this may be my youth and idealism speaking, I think that as the most reliable source of truth, scientific research could help dispel some of these harmful myths and create understanding and awareness of adults who currently "drop off the map." Again, if you have a choice between yet another study on how typically developing kids learn about words or numbers and this, why would you ever choose the former?
I imagine some people will say that one can't understand what differs in atypical development without understanding typical development well. Of course I agree with this to some extent; that's why we use typically developing comparison groups and why we must learn and cite the literature on typically developing kids.
But I wonder if one could learn even more about typical development by understanding what happens in atypical development. After all, in normal development everything develops at similar rates at roughly the same time; no huge gaps between abilities exist; and when all the subskills needed for an ability like, say, language, work fine, it's harder to tell what subskills might be involved. If you want to understand how an ability like language works, you need to see all the ways it can go wrong. If you want to understand how people's language and spatial abilities relate to each other, you need to study people with large gaps between the two. And if you want to know whether learning words teaches us concepts or vice versa, you'd better find people whose verbal learning and concept learning develop at different rates (e.g., nonverbal autistic kids, some of whom demonstrate their intelligence by using the few words they know in highly abstract and creative ways).
We've already learned much about language by studying people with brain damage. We've learned a lot about vision by presenting visual illusions to people (because processing becomes so much more visible when it gives you the wrong answer!). So why couldn't studying specific learning disabilities, or autism, or ADHD, or sensory processing disorder, or dyspraxia, work in a similar way?
Some researchers appear to assume that research on an atypical population only matters if it teaches us something about neurotypical people. I think the best research gives us the most information, so I prefer research that helps us understand both atypical and typical development. The only reason studies just on an atypical population should matter less to people than studies just on typically developing people is that there are more typical people, so more people benefit from the latter. But that's an issue of how to allocate limited research funding, not a reason for researchers to judge each other.
In short: as much as I love typically developing kids, I primarily want to study atypical development. That's what I have ideas about, that's what I'm passionate about, and that's where I can do the most good. Moreover, I don't think that focusing on atypical development should be considered any less legitimate than focusing on typical development.
Am I reading too much into this question, detecting assumptions that that particular questioner may not have intended? If I get this question in the future, should I address these issues (after addressing the major concern behind it, of course), or ignore them?