Learning Styles: Theory and Practice

In a New York Times article dated September 6, 2010, about the efficacy of long-held study habits, author Benedict Carey writes, "Take the notion that children have specific learning styles, that some are visual learners and others are auditory; some are left-brain students, others right-brain."

In a recent review of the relevant research, published in the journal Psychological Science in the Public Interest, a team of psychologists found almost no support for such ideas. “The contrast between the enormous popularity of the learning-styles approach within education and the lack of credible evidence for its utility is, in our opinion, striking and disturbing,” the researchers concluded.

Carey refers to an article from a team of psychological scientists whose research seems to indicate that teaching to learning styles and differentiating education makes little or no difference in learning outcomes.
In the abstract for their original article, they conclude with

...at present, there is no adequate evidence base to justify incorporating learning-styles assessments into general educational practice. Thus, limited education resources would better be devoted to adopting other educational practices that have a strong evidence base, of which there are an increasing number. However, given the lack of methodologically sound studies of learning styles, it would be an error to conclude that all possible versions of learning styles have been tested and found wanting; many have simply not been tested at all. Further research on the use of learning-styles assessment in instruction may in some cases be warranted, but such research needs to be performed appropriately.
(http://psi.sagepub.com/content/9/3/105.full#sec-1; Pashler, McDaniel, Rohrer, Bjork, "Learning Styles: Concepts and Evidence," Psychological Science in the Public Interest, January, 2009.)

I admit feeling quite reactive about this.
I think I understand the point they are making about having evidence, or testable outcomes, but I think it is unfortunate to use the lack of "evidence" for the success of differentiating learning as a reason to go back to one-size-fits-most teaching. It also causes me to ask what sort of evidence would be necessary to satisfy a bunch of psychologists that teaching methods are successful.
Do they measure whether a student is excited about coming to school?
Do they measure the kinds of questions a student asks in class discussions? Or the way they mull over a problem before generating a response?
Do they measure test scores?

I wonder how did I have evidence concerning whether a child was learning? In my experience, there were children who perceived and could manipulate objects with great spatial acuity, whether in three dimensions or their mind. Both girls and boys possessed this skill with great ability. Still others had trouble with the simplest of concrete or abstract exercises in spatial relations. Some had a musical ear while others were tone deaf. Some gained energy and insight through interactions with peers, and others needed time alone to thoroughly process information. These observable differences to me suggest that a number of different approaches will allow for broader points of entry for learners.

The evidence comes through years of practical experience. From viewing the learner in a context over time, not from a snapshot derived through testing or a single data point. But the psychologist/authors do not state that teaching to different learning styles is wrong, only that there is a lack of valid evidence to support it. I wonder, what qualifies as valid evidence?

What have you observed in your classroom? What do you think about learning styles?