psych ch 3 – Flashcards

To determine the influences of environment and heredity, the home environment needs to be controlled while heredity is varied. Identical twins, who develop from one egg that splits in two are genetically identical. Fraternal twins develop from two fertilized eggs and are genetically no more similar than brothers and sisters. Adoption studies allow us to determine if adopted children are more like their adopted families, who contribute to the home environment, or to their biological parents, who contributed their genes. Adoptees' traits bear more similarities to their biological parents than to their care giving adoptive parents. Environmental factors shared by a family's children have virtually no impact on their personalities. Studies of adoptive families have provided clues to hereditary and environmental influences. Adopted children share many values and attitudes with their adoptive parents, but adopted children's personalities tend to display the genetic legacy of their biological parents.

Behavioral genetics estimate trait heritability by mathematically estimating the heritability of a trait, which is the extent to which variation among individuals can be attributed to their genes. If a trait is found to be 50% heritable, it does not mean that an individual's intelligence is 50% genetic, it means that 50% of the variation is due to genetics. They describe how much of the differences are due to genetic.s

Molecular genetics can identify specific genes that influence behavior of cause diseases.

Neurons are overproduced because only neurons with functional connections survive. Neurons have to migrate and they must make the necessary connections and for that reason they are over produced. Neurons with improper or weak connections die off through a process known as neural pruning.

Radiation and alcohol have similar effects on the developing brain. Radiation disrupts the birth and migration of neurons and makes them stop short. It interrupts the journey of neurons to their destined location. Alcohol makes it so neurons don't know when to stop migrating and the cells end in the wrong places because they have moved too far.

Biological gender is determined at fertilization, based on the sex chromosomes of the gametes. Females can only contribute the X chromosome while males can contribute X or Y. XX is a female. XY is a male. The concentration of sex hormones has a large influence on development. In the seventh week of development, the hormone testosterone starts the development of external male sex organs. Another key period of differentiation occurs in the firth and fifth parental months when different brain wiring patterns for males and females develop under the influence of the male's greater testosterone and the female's ovarian hormones. Sex chromosomes control sex hormones that bathe the fetal brain and influence it's wiring. Research confirms male-female differences during development in brain areas with abundant sex hormone receptors.

rewards and punishments and observation and imitation of models→ gender-typed behavior - assumes children learn gender-linked behavior by observing and imitating and by being rewarded or punished. Children organize themselves into boy worlds and girl worlds guided by rules for what boys and girls do.

cultural learning→ gender schema → gender organized thinking and gender typed behavior - combines social learning with cognition: children form a concept of schema for their gender. Gender then becomes a lens through which they view their experiences. Children compare themselves with their concept of gender and adjust their behavior accordingly.