8/9/2019 Developmental Psychology - Midterm

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1) The nature vs. nurture approach is incoherent because nature and nurture sit on the same 1-D continuum and

are viewed as opposites/tradeoffs. In comparison, the nature-nurture interaction approach is two-dimensional

and implies a causal interaction. From this perspective, just as length and width in their entireties are essential in

computing the area of a rectangle, both the developmental environment (nature) and genes (nurture) are essential

in giving rise to common abilities through developmental mechanisms. Since nature and nurture are not

constrained, this is more consistent with the scientific perspective because it allows for variance in commonabilities.

2) We discussed five counterintuitive properties of heritability in class. First, a trait (or common ability, behaviour

etc.) that is heritable does not mean it is inherited. Second, the heritability statistic does not give any information

about individuals. Third, this statistic cannot be used to indicate the causes of group differences. Fourth,

heritability cannot describe the malleability of a trait. Fifth, heritability depends on when (h2

is not independent of

age) and where (h2

is not independent of the population) it is measured.

A corn seed example is used to demonstrate how heritability cannot indicate group differences. Two planters (A &

B) contain corn plants. All the plants in Planter A receive copious sunshine and grow tall. Planter B receives very

little sunshine; the corn plants are short. Since the environment is constant for all the corn plants in planter A, the

differences in height between those plants are purely genetic; heritability is 100%. Likewise, the environment for

plants in planter B was also constant, therefore differences in height between those plants is also purely genetic;

heritability is also 100%. Therefore, heritability cannot be used as a measure to compare between groups.

Phenylketouria (PKU) has a heritability that approaches 1. This trait is almost purely a result of differences in

genes. Does this mean that children born with this condition are stuck with this illness and its phenotype? No.

PKU is treatable by removing phenylalanine from the childs diet. Therefore, h2tells us nothing about how

malleable a trait is.

3) Piagetian theorists do not favor nature or nurture but nature-nurture interaction. They predict that

development is primarily discontinuous. Cognitive development is subdivided in to four discontinuous stages: the

sensorimotor stage, the preoperational stage, the concrete operational stage, and the formal operational stage(although assimilation, accommodation, and equilibration contributes to some continuity). Piagets theory is most

consistent with the classical view of constructivism. Children are viewed as little scientists who are intrinsically

motivated to test the world through interactions and actively contribute to their own development.

4) Researchers habituated infants to a 510nm (green) light and then presented either a 480nm (blue) light, or a

540nm (green light). Dishabituation occurred for the 480nm light, but not the 540nm light. This study challenges

the blooming, buzzing confusion view because it suggests that infants possess the ability to categorize colors the

same way adults trichromats do. In another study, newborns were exposed to either a textured pacifier or a

smooth pacifier during a familiarization period. Following this, using a preferential looking technique, it was

shown that babies prefer to look at the pacifier they felt in their mouths over the other pacifier they were not

exposed to. This challenges the blooming, buzzing confusion view because it suggests that infants possess

amodal perception which allows them to integrate over vision and touch.