Are there gender differences in brain structure? paul j whalen, phd university of wisconsin - madison Projects funded by NIMH, Howard Hughes Medical Institute, & NARSAD Taylor

1. the high-powered job hypothesis 2. different availability of aptitude at the high end 3. different socialization and patterns of discrimination in a search Lawrence H Summers NBER conference January 14, 2005

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What’s your N?

In the present study, a cross-sectional design was used with healthy children (n=7), adolescents (n= 12), and adults (n= 10) who underwent functional magnetic resonance imaging (fMRI) during a task that required perceiving fearful faces. Males and females differed in the asymmetry of activation of the amygdala and prefrontal cortex across the three age groups. Killgore et al 2004

The problem with post hoc explanations

Recognition memory test 3 weeks after scanning. highly emotional pictures were remembered best, and remembered better by women than by men. Men activated significantly more structures than women in a network that included the right amygdala. Women activated significantly fewer structures in a network that included the left amygdala. Canli et al 2002

Cahill et al 2004

What about structural differences in the brain?

malesfemales Range = Range = Luders 2004

What about my work?

shady

r =.70 p = Valence Ratings of Surprised Faces VN N NN P VP Response to Surprised vs. Neutral Faces (z-score) R L

r =.70 p = Valence Ratings of Surprised Faces VN N NN P VP Response to Surprised vs. Neutral Faces (z-score) R L

Where are your predictions coming from?

Women were chosen in this study because they are more likely to report intense emotional experiences Canli et al 2000

Enhanced occipital and anterior cingulate activation in men but not in women during exposure to angry and fearful male faces. Fischer et al 2004

Sometimes predictions come from observed incidence of pathology across genders

Unpleasant words associated with body image activated left medial prefrontal cortex and hippocampus only among men - the left amygdala was activated only among women Shirao et al 2005

Depression > Females

Autism > Males

The second empirical problem is that girls are persisting longer and longer. Lawrence H Summers NBER conference January 14, 2005

The second empirical problem is that girls are persisting longer and longer. Lawrence H Summers NBER conference January 14, 2005

I would like nothing better than to be proved wrong... Lawrence H Summers NBER conference January 14, 2005