Psych 2210 1st Edition Lecture 15 Outline of Last LectureI. Working HypothesisII. PredictionsIII. Sexual Orientation as Sexually Differentiated TraitIV. Experimental EvidenceV. ConclusionVI. What About Humans? VII. Relationship between prenatal testosterone levels and sexual orientation in humansVIII. John/Joan Case StudyIX. Genetic and Immunological Factors Outline of Current Lecture I. Genes linked with Sexual OrientationII. Epigenetics III. Fraternal Birth Order EffectIV. BNSTV. Simon Baron-Cohen StudiesVI. Testosterone Correlated with male-typical patternsV. Cognitive & Behavioral Differences: consequences of pre-natal hormones VI. Linked to Brain DifferencesVII. Cognitive function and Sexual Orientation VIII. Summary Current LectureGenes linked with Sexual Orientation - Gene expression is complicated - Not just a single geneEpigenetics: interaction with environmental factors These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Early stress: o Prenatal stress results in female—typical patterns in male mice Gene expressions in brain Altered genital development - Testosterone sensitivity in parento Parent with high testosterone transfers decreased sensitivity to son—can affect sexual and gender development in male offspringFraternal Birth Order Effect- The more older brothers a boy has, the more likely he is to be homosexual- The incidence of homosexuality increases for each older brother- More antibodies to mullerian inhibiting factor - Accumulation of antibodies in the mother during successive pregnancies against one or more proteins expressed specifically by the male brain - Possibly MIH (mullerian inhibiting hormone) Gender Identity - Sexual dimorphism: bed nucleus stria terminalis- Larger in males, compared to females BNST: Gender Identity (diagram in book)—size male vs. female - Gender Identity not orientation- Larger in males vs. females- Equal in gay vs. heterosexual men- Smaller in M-F Trans-gendered individual Direct Evidence of Pre-Natal TestosteroneSimon Baron-Cohen Studies- Measured amniotic levels of testosterone- Followed subjects out for 8-11 years, looked at behavior Testosterone correlated with male-typical patterns- Eye contact: at 12 months, decreased eye contact linked to increased fetal testosterone- Play behavior: male-typical play behavior associated with increased fetal testosterone - Asymmetry in Corpus Callosum (connects the two hemispheres): more asymmetrical in subject with high fetal testosterone Cognitive & Behavioral Differences: consequences of pre-natal hormones - Verbal fluency tasks (how many words start with L)- Spatial tasks (rotating and matching objects mentally)—men score higher- Women do better on verbal fluency tasksLinked to brain differences- Males: o Larger right hemisphereo More specialized for spatial processing- Females:o More equal hemisphereso Larger corpus callosum Cognitive function and Sexual Orientation - Verbal Fluency/Spatial tests (see graphs in textbooks) Summary- Verbal tests: o Gay men perform as well or better than heterosexual womeno Lesbian women underperform relative to heterosexual women- Spatial tests: o Gay men underperform relative to heterosexual men o Lesbian women outperform relative to heterosexual women- Hemisphere sizes: o Gay men have equal-sized Right and Left hemisphereso Lesbian women are more likely to have larger, male-typical right