Chapter 2: female/male differences in VISION. The reality I was trying to understand in this section of chapter 2 is the fact that when you give young children a blank sheet of paper and a box of crayons, most girls draw people, pets, flowers and/or trees. Most boys try to draw a scene of action at a moment of dynamic change. That's a robust empirical finding, valid across race, ethnicity, and socioeconomic status. That doesn't mean that ALL boys try to draw a scene of action; some boys draw exactly what the girls draw. But boys are more likely to draw a scene of action, such as a monster attacking an alien; girls are more likely to draw people, pets, flowers, or trees, with lots of colors. The people in the girls' pictures usually have faces, eyes, hair, and clothes; the people in the boys' pictures (if there are any people) often are lacking hair, clothes, often the boys draw mere stick figures in one color. How come? The usual answer "Because that's what we teach them to do" is unpersuasive, as I explain in Why Gender Matters. On the contrary, many of these boys insist on drawing these pictures not because teachers tell them to draw such pictures, but in spite of the teacher's repeated pleas, "Why do you have to draw such violent pictures? Why can't you draw something nice - like what Emily drew?"
But my discussion here falters when I try to link this research to female/male differences in the retina of the rat. For a much better discussion of this topic -- female/male differences in VISION -- please see chapter 5 of my third book, Girls on the Edge, especially the sections "All our girls love physics" beginning on p. 132, "Would you rather play with a truck or a doll?" on p. 134, and "Monkeys, girls, boys, and toys" on p. 136, where I share Professor Gerianne Alexander's hypothesis regarding female/male differences in the "P system" and the "M system" in the human visual system. You will also find much stronger scholarly support provided in chapter 5 of Girls on the Edge than I provided in chapter 2 of Why Gender Matters. In my defence, many of the key articles I cited in 2010 in Girls on the Edge- such as Kim Wallen's work on female/male differences in the toy preferences of monkeys, or Katrin Amunt's work on female/male differences in human visual cortex - had not been published when Why Gender Matters was published in 2005.

Chapter 2: female/male differences in HEARING. The reality I was trying to understand in this section of chapter 2 was my own repeated observation, over many years of clinical practice, that some young boys who had been diagnosed by other practitioners as having ADHD, suddenly did much better in the classroom, and no longer needed to be on medication, simply by moving them to a classroom with a teacher who spoke more loudly - about 8 decibels more loudly. It was much less common to find a same-age girl who did much better in a classroom where the teacher spoke more loudly. So far so good. I tried to explain this observation with reference to female/male differences in threshold auditory acuity. That was simply a mistake on my part. Female/male differences in threshold auditory acuity 1) are pretty much irrelevant to any observation regarding supra-threshold stimuli, and 2) are much too small to account for the observation that these boys benefited when teachers spoke about 8 to 10 dB more loudly. Female/male differences in threshold auditory acuity - comparing girls and boys the same age - are only on the order of 3 dB or less, usually less.

In my defence, two of the key papers which lead to the correct explanation of this phenomenon - by Professor Ken Norwich and his colleagues at the University of Toronto - were only published in 2007 and 2009, respectively. Why Gender Matters was published in February 2005. For an updated and far more accurate explanation of why SOME boys need teachers to speak more loudly in the classroom, please read my October 2010 article entitled Sex differences in hearing, which you can download in full as a PDF by clicking on this link, along with two scholarly supplements not found in the print edition. My October 2010 article greatly expands, updates, and corrects my discussion of this topic in chapter 2 of Why Gender Matters.

Chapter 5: female/male differences in mathematics instruction. The reality I was trying to understand in this section of chapter 5 is the fact that many middle-school boys seem to learn algebra better when you start with numbers, whereas many same-age girls seem to be more engaged if you start with a word problem. For example, if you are teaching equations in multiple variables, the typical 7th-grade boy will do better if you begin by asking "If x + 2y = 60, and 2x + y = 90, how do we solve for x and y?" But the typical 7th-grade girl will be more engaged if you begin by asking "If a sweater and two blouses cost $60, and two sweaters and a blouse cost $90, how much does each blouse and each sweater cost?" That again is a robust finding, confirmed by classroom observation in diverse settings. I have visited more than 300 schools in the past 11 years, not only in the United States but also in Australia, Bermuda, Canada (Alberta, British Columbia, Nova Scotia, and Ontario), England, Mexico, New Zealand, and Scotland. (You can review lists of my visits to schools from 2005 to the present at "Gender Differences in the Functional and Structural Neuroanatomy of Mathematical Cognition".

Why Gender Matters