BABS1201 Lecture Notes - Lecture 4: Twin Study, Longitudinal Study, Heritability
17 May 2018
School
Department
Course
Professor
PSYC1001
7TH MARCH 2018
DEVELOPMENTAL PSYCHOLOGY
× How to answer questions about research designs
1. Determine whether the question is talking about a longitudinal design or cross-
sectional design
a. Are there separate groups that differ with age, or
b. Are the same participants tested repeatedly?
2. Is the problem about generalising the results to a different sample, or
3. Is the problem about a variable other than age, differing between the groups and
influencing the results of the study?
× Nature and nurture ® genes and environments
- In reference to genetic predispositions- they only play out in response to particular
environmental circumstances
- Genes: basic units of heredity, which contain “instructions” for building a specific
protein- a gene is ‘expressed’ if it has been turned on to make its protein
× Chromosome: thread-like structure found in the nucleus ® each
chromosome, or long-stranded molecule of DNA, contains thousands of
genes
× DNA: double-stranded molecule that makes up the chromosomes
- All humans started as a single cell, the zygote, which was formed when the sperm
from a male (containing 23 chromosomes) fused with the egg from a female (also
containing 23 chromosomes) ® therefore each parent contributed half of the
offspring’s genetic makeup
- The same gene has different forms; these are called alleles- in humans, there are
normally 2 alleles for every gene, one from each parent
× If the 2 alleles for a specific gene are the same form- homozygous
× If the 2 alleles for a specific gene are different forms- heterozygous
- Making the distinction between genotype and phenotype-
× Genotype: genetic blueprint; DNA passed from parents to child
× Phenotype: observable physical or psychological attributes or qualities
× Behaviour genetics is a subfield of psychology (has nothing to do with the
molecular side of genetics) concerned with understanding how genetic and
environmental factors interact to produce phenotypes, or differences in
behaviour/psychological traits
- Researchers in behaviour genetics estimate heritability
× Heritability refers to the extent to which variation in a population can be
attributed to genetic differences among individuals, as opposed to
environmental experience
× Varies from 0 (no heritability) to 1 (completely heritable)
× Heritability determined in kinship studies, e.g. family studies, twin studies,
adoption studies
× We can use what we know about degree of relatedness to work out the
relative contribution of genes and environment to a particular phenotype-
i.e. estimating how much of the variability is due to genetics, as opposed to
environmental factors
- Twins are particularly useful to study- they differ in degrees of relatedness
depending on how they were formed
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Is the problem about generalising the results to a different sample, or. Nature and nurture genes and environments. In reference to genetic predispositions- they only play out in response to particular environmental circumstances. Genes: basic units of heredity, which contain instructions for building a specific protein- a gene is expressed" if it has been turned on to make its protein. Chromosome: thread-like structure found in the nucleus each chromosome, or long-stranded molecule of dna, contains thousands of genes. Dna: double-stranded molecule that makes up the chromosomes. The same gene has different forms; these are called alleles- in humans, there are normally 2 alleles for every gene, one from each parent. If the 2 alleles for a specific gene are the same form- homozygous. If the 2 alleles for a specific gene are different forms- heterozygous. Making the distinction between genotype and phenotype- Genotype: genetic blueprint; dna passed from parents to child. Phenotype: observable physical or psychological attributes or qualities.
