Psychology Lecture 7 - Prof. Neil Fournier PDF

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Prof. Neil Fournier...

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Psychology Lecture 7 Intelligence and Psychogenetics 11 November Assessing and Quantifying Intelligence Standardization: defining meaningful scores by comparison with the performance of a pretested ‘standardization group’ Normal Distribution or Bell Curve the symmetrical bell-shaped curve that describes the distribution of many physical and psychological attributes; most scores fall near the average, and few lie near the extremes Calculating Standardized Scores: Z score (individual mark subtracted by average divided by standard deviation) Z = Xi – x SD Ex: Psych Average is 96%, Neil scores 90% should he brag to his parents? 90-96 = -3 2 Effect size: how much variability can be explained by x. a measure of the magnitude of difference between two groups Genes - functional units of heredity - composed of DNA - every person has two copies of each gene, one inherited from each parent - located on chromosomes Chromosomes - thread like structures found in the nucleus of every cell - sperm cell and each egg cell contain 23 chromosomes (human) - fertilized egg contains 46 arranged pairs (23 male, 23 female) - crossing over: exchange of genes - chromosomes contain thousands of genes (human: 20,000-25,000) - made of four amino acids: guanine, cytosine, adenine, thymine The Genetic Process - each inherited factor is a gene - two genes that control the same trait are called alleles (homozygous: 2 identical alleles; heterozygous: 2 different alleles) Genotype: set of genetic information carried by the organism Phenotype: the physical (observable and measurable) characteristics of the genotype; can be impacted by biological and environmental factors

Gene Combinations and Interactions dominant: one gene will govern outcome over other gene (dimples) recessive: an allele that will affect phenotype only if it matches the allele of a parent gene (same received allele from each parent) polygenic: expression of some traits controlled by more than one gene pair and environment (anorexia) pleiotropy: a single allele that has multiple,, correlated phenotypic effects (autosomal recessive disorder) Nature: Gene expression Nurture: Environment experience Identical twins: monozygotic Fraternal twins: dizygotic Heritability of major personality trait - 50% of individual differences are due to genetic factors - 50% of individual differences are due to environmental factors Natural Selection Environmental pressure > Competition > Selection of the fittest phenotype > Reproductive success > Frequency of that genotype increases...