General Psychology PSY2012 Exam 2 Study Guide Nature and Nurture Natural Selection principle that organisms that possess adaptations survive and reproduce at a higher rate than other organisms o Adaptations physical and psychological traits passed down because they helped our ancestors to survive and reproduce o Two components of natural selection Environmental Challenge what did they have to overcome Adaptation what came from this environmental challenge o Ex Phobia of spiders snakes Those who avoided spiders and snakes were more likely to survive and reproduce Environmental challenge they had to overcome spiders and snakes that killed people Adaptation The adaptation that came from this was to avoid spiders and snakes Genes units of heredity segment of DNA capable of synthesizing proteins o Genotype our genetic makeup The set of genes an organism receives from its parents Ex the gene of brown hair o Phenotype observable traits Ex having brown hair Heritability the extent to which the differences among individuals can be attributed to differing genes o So if the heritability of a trait is 60 that means more than half of the differences among individuals in their levels of that trait are due to differences in their genes While the other 40 is due to differences in environment As differences in environment decrease the heritability of that trait increases and vice versa o Twin Studies analysis of how traits differ in identical versus fraternal twins This tells us that since identical twins are more similar genetically the fraternal twins if they are more alike in a characteristic than fraternal twin we can infer that this characteristic is genetically influenced given the environmental influences are the same o Adoption Studies analysis of how traits vary in individuals raised apart from their biological relatives We can assume traits are genetically influenced if adopted children resemble their biological parent s psychological characteristic o Case of Oskar and Jack Identical twins that were separated at 6 months old that were later reunited Shared many similarities aggressive speech patterns gait quirks Major difference was that Oskar was Catholic and joined the Nazi Youth while Jack was Jewish Shows that personality has a strong genetic component but beliefs have a strong environmental component Environmental Influences o Influence of Parents mainly education discipline responsibility o Influence of Peers social interaction romantic relationships o Influence of experiences More enriched environments give the brain more ability to grow and more synaptic connections Role of Heredity and Environment o Heredity Plays an important role in personality Determines reaction ranges limits o Environment Plays an important role in attitudes beliefs values manners religion politics Determines where we fall in the reaction range Sensory and Perception Sensation detection of physical energy by our sense organs which then send information to the brain o Transduction the process by which external stimuli is converted into electrical o Sense receptors specific receptors for each of our five sense transduces signals within neurons specific stimuli Ex vision light transduces into neural signals by specialized sense receptors called photoreceptors o Psychophysics study of how we perceive sensory stimuli based on their physical characteristics Absolute Threshold the lowest level of a stimulus needed for the nervous system to detect a change 50 of the time Ex on a clear night our visual systems can detect a single candle from 30 miles away Just Noticeable Difference JND the smallest change in intensity of sensory stimulus that we can detect Ex playing a song on an iPod but the volume is too low to hear it if you nudge the volume up to the point at which we can just begin to make out the song that s JND Weber s Law states that there is a constant proportional relationship between the JND and original stimulus intensity Perception how the brain interprets raw sensory inputs o Our brain integrates sensory data into meaningful concepts Brain perceives by integrating What s currently in our sensory field What was there a moment ago What we remember from our past o Often we sacrifice small details when we perceive for the bigger picture o Parallel processing the ability to attend to multiple sense modalities at the same time o Cross modality processing info from multiple senses that produces a different perception that that of any one sense Ex McGurk effect this effect demonstrates that we integrate visual and auditory information when processing spoken language and our brains automatically calculate the most probable sound given the information from the two sources Synesthesia an extreme version of cross modality Ex hearing sounds when they see colors tasting colors o Bottom up processing constructing a whole stimulus from its parts Starts with raw stimuli we perceive and ends with our synthesizing them into a meaningful concept Begins with activity in the primary visual cortex followed by processing in the association cortex Ex perceiving an object on the basis of its edges o Top down processing conceptually driven processing influenced by beliefs and expectancies Starts with processing in the association cortex followed by processing in the primary visual cortex Important because Allows us to focus on what s important Allows us to process our environment quickly More efficient Examples Perceptual Sets occur when our expectations influence our perceptions Ex we may perceive a misshapen letter as an H or as an A depending on the surrounding letters and the words that would result from our interpretation Perceptual Constancy process of perceiving stimuli consistently across varied conditions o Size Constancy our ability to perceive objects as the same size no matter how far away they are from us o Color Constancy our ability to perceive color consistently across different levels of lighting o Shape Constancy our ability to perceive the shape of an object despite differences in the viewing angle Gestalt Principles rules governing how we perceive objects as wholes within their overall context o Proximity objects physically close to each other tend to be perceived as unified wholes o Similarity we see similar objects as comprising a whole much more so than dissimilar objects If red and yellow circles are lined up horizontally we perceive separate rows of circles o Continuity we still perceive objects as
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