After, or before AND after? A cautionary tale

An article by Bendict Carey in the New York Times' "Science Times" section, Feb. 24, 2009, was entitled "After abuse, changes in the brain." What was missing from this title? Well, a question mark would have made it a much better summary of the material below it. Evidence in the article implied, but did not justify, the conclusion that brain characteristics existed after abusive treatment, but had not existed before.

Carey described research by Patrick McGowan et al., published in Nature Neuroscience, which compared the brains of 12 suicides who had suffered abuse in childhood with those of 12 other suicides who had not been abused. Genetic analysis showed that the first group had a good deal less genetic activity in genes that govern certain receptors on neurons than did the second group. The receptors in question function to help clear stress hormones that affect neurons.

It is plausible that experience of abuse could change the relevant genetic functions. But are there other equally plausible explanations? For example, what if children whose brains cleared stress hormones poorly behaved in ways that made adults more likely to abuse them? Children who do not calm down after being scolded or punished may trigger escalation of adult hostility, even to the point where punishment becomes abuse. Thus, genetic characteristics could determine the experience of abuse rather than the other way around.

If there is only one plausible explanation for an event, we often accept it (rightly or wrongly) even without any empirical support for the idea. But if there is more than one plausible explanation, we should certainly accept neither on the basis of plausibility alone. In this case, a good deal more evidence will be needed before we can accept the article headline with its present punctuation.

Something to read-- critically

An article that appeared in Monitor on Psychology, Feb. 2009-- "Programmed for life?", by Michael Price-- offers food for critical thought. According to the sub-headline, "Your developmental environment can... even predict how you'll treat your children." In support of this claim, the article offers discussion of mouse maternal behavior and the ways it is affected by the mouse mothers' early experiences.

Maternal behavior in all species is a fascinating and fruitful research topic. Maternal care involves a complex set of cues exchanged by mother and young, with sights, smells, sounds, and touch sensations all triggering or modulating an essential exchange of behaviors. But... can research into mouse mothering tell us what we need to know about human child-rearing? Is the analogy between mouse and human behavior good enough for us to use the former to draw conclusions about the latter?

The way to answer this question is to look at details of the two phenomena that are being compared. If relevant details are shared by the two, it may be safe to use one to give us information about the other; if they do not overlap by much, conclusions from the comparison may amount to "abusing the analogy"

What do mother mice do to care for their pups? They permit pups to find the nipples and nurse. They lick the pups' rears to stimulate urination and defecation. They clean the nest by eating waste products, afterbirth, and any dead pups they find. When pups get out of the nest (where they may get cold or be in danger), the mother follows their squeaks and retrieves them, picking them up in her mouth. This pattern lasts as long as the pups are hairless, but when they start to grow fur, the mother responds to them much less.

What do human mothers (and fathers) do for their offspring? They place the baby at the breast or offer other food sources. They use diapers or hold the baby away from them to deal with elimination, which by the way they don't need to stimulate. They clean the baby with water. They carry the baby around for many months, usually even after it is able to walk. And they continue to care for their children for many years, even after they are sexually mature.

Is there much overlap between these maternal behavior patterns? No, it doesn't seem that there is. Is the
Monitor writer guilty of abusing an analogy? That seems very possible.

It is possible that parallels between human and mouse maternal behavior are appropriate, but some direct evidence is needed to show this. A loose analogy alone can't do the job.

Presentation schedule: April 1, 2009

I will be presenting at the Developmental Science Teaching Institute, a preconference meeting of the Society for Research in Child Development, April 1, 2009, in Denver, CO. The title of the presentation is "Don't be so [un]critical! Using critical thinking to foster mastery of child development concepts." This presentation will draw some parallels between concerns about general science education and about undergraduate child development courses, and will look at general critical thinking skills like inference as they apply to the study of child development. Reasons for students' weak critical thinking abilities will be explored, and concerns about both textbooks and instructor practices will be discussed. Specific problems of critical thinking about child development-- for example, the heavy use of analogies in developmental science-- will be addressed. Finally, some suggestions will be given for ways in which line-by-line reading and analysis can encourage critical thinking and the mastery of child development theory and fact.

Myths and Misunderstandings: What's It About?

This blog is an extension of the web site childmyths.com, which contains information about my recent book
Child Development: Myths and Misunderstandings (Sage, 2009).

I'll use the blog to announce my presentation schedule and to pass on references to recently-published books and articles that may help readers analyze common myths and misunderstandings about child development.