General Psychology PSY2012Exam 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 reproduceo Two components of natural selection Environmental Challenge – what did they have to overcome Adaptation – what came from this environmental challengeo 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 proteinso Genotype – our genetic makeup. The set of genes an organism receives from its parents Ex: the gene of brown hairo 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 intheir 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 astrong environmental component.- Environmental Influenceso Influence of Parents – mainly education, discipline, responsibility.o Influence of Peers – social interaction, romantic relationshipso Influence of experiences More enriched environments give the brain more ability to grow, and more synaptic connections- Role of Heredity and Environmento 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 rangeSensory and Perception- Sensation – detection of physical energy by our sense organs, which then send information to the braino Transduction – the process by which external stimuli is converted into electrical signals within neuronso Sense receptors – specific receptors for each of our five sense, transduces specific stimuli Ex: vision – light transduces into neural signals by specialized sense receptors called photoreceptorso 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 inputso 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 pasto Often we sacrifice small details, when we perceive, for the bigger pictureo 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 colorso 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 edgeso 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 conditionso 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 consistentlyacross 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
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