Test 3 Review Chapter 6 Thresholds o Absolute thresholds are the minimum stimulation necessary to detect a stimuli 50 percent of the time o Subliminal stimuli occur when information processing occurs automatically and off the screen of our conscious mind These can have noticeable effects on our conscious o Difference threshold is the minimum difference a person can detect between any two stimuli half the time Depends on the size or strength of the stimuli Weber s law says that two stimuli must differ in a constant proportion not a constant amount Sensory Adaptation diminishing sensitivity to unchanging stimulus o Nerve cells fire less frequently after constant exposure to stimulus o Allows us to focus on informative changes in our environment The eye o Process of vision Light enters eye through cornea which bends light It then passes through the pupil which is controlled by the iris muscle Behind the pupil a lens focuses incoming light rays on the retina The retina consists of rods and cones o Cones are for details and rods are on peripherals The optic nerve carries information to brain Visual Information Processing o Different parts of the brain respond to different types of object viewed o Parallel processing the brain divides a visual scene among sub dimensions such as color movement form and depth Color Vision o Cones are responsible for color vision o Color resident in our brains light waves don t emit color o Retina has three types of color receptors Red green and blue o Opponent processes opposing retinal processes red green yellow blue white black enable color vision o Color vision occurs in two stages The retina s cones for red green and blue respond in varying degrees to different color stimuli The cones signals are then processed by the nervous system s opponent process cells Hearing o The brain interprets loudness from the number of activated hair cells Touch o Only pressure has identifiable receptors o Other skin sensations are variations of the basic four pressure warmth cold and pain o Important sensors in joints tendons bones and ears enable sense of the position and movement of body parts o Vestibular sense is the sense of body movement and position including balance Pain o There are different nociceptors sensory receptors that detect hurtful temperatures pressure or chemicals that trigger pain o Pain can be effected by physiological and biological influences Pain can often be ignored People overlook a pain s duration People remember pain at its peak and at its end o Pain can be perceived when others are feeling pain o Being given fake pain killers cause the brain to produce real ones Taste o Five sensations sweet salty sour bitter and umami o Taste receptors reproduce every two weeks o As you grow older the number of taste buds decrease o Expectations influence brain s response Smell o Olfactory receptor cells allow us to smell o Preferences for smells are often learned Perceptual Organization o When given a cluster of sensations people typically organize them into a gestalt whole or form o Figure and ground When we see things we see them as a figure against a background o Grouping Proximity we group nearby figures together Similarity we group similar figures together Continuity we perceive smooth continuous patterns Connectedness We see things that are uniform and linked Closure We fill in gaps to create a complete whole object o Depth perception Depth perception is an innate ability People perceive vertical dimensions as longer than identical horizontal dimensions o Perceptual Constancy Shape constancy we perceive the form of familiar object as constant even while our retinal image of it changes moving door Size constancy we perceive objects as having a constant size even while our distance from them varies Lightness constancy We perceive an object as having a constant lightness even while its illumination varies Color constancy as light changes we still perceive the same color Surroundings determine the color we see o Perceptual Interpretation Experience allows us to recognize faces and objects Vision is a partly acquired sense There is a critical period during infancy for normal sensory and perceptual development o Perceptual Adaptation Senses adapt quickly when disoriented especially vision o Perceptual Set Mental predispositions that greatly influences what we perceive Perception is both innate and learned Chapter 7 How we learn o Successful adaptation requires both nature and nurture o Conditioning is the process of learning associations In classical conditioning we learn to associate two stimuli and thus to anticipate events Watson and Pavlov were proponents of this It is a basic form of learning by which all organisms adapt to their environment In operant conditioning we learn to associate a behavior and its consequence and thus to repeat acts followed by good results o Conditioning Conditioned learned unconditioned unlearned Acquisition When one links a neutral stimulus and an unconditioned stimulus so that the neutral stimulus begins triggering the conditioned response Higher order conditioning occurs when pairing a neutral stimulus with a conditioned stimulus Extinction and Spontaneous Recovery Extinction is the diminished response that occurs when the conditioned stimulus no longer signals an impending unconditioned stimulus Spontaneous recovery is the reappearance of a weakened conditioned response after a pause after the pause the conditioned response can come back Generalization the tendency for stimuli similar to a conditioned stimulus to elicit similar responses Discrimination is the learned ability to distinguish between a conditioned stimulus and other irrelevant stimuli Biological predispositions Organisms can be conditioned mainly to things that contribute to their survival o They are predisposed to learn associations that help them adapt o Operant Conditioning Shaping behavior think of petting a dog after it does a trick Successive approximations reward responses that are ever closer to the final desired behavior and ignore all other responses Reinforcer any event that strengthens a preceding response o Negative reinforcement strengthens a response by reducing or removing something undesirable such as pressing snooze on an alarm clock It removes a punishing event o Primary reinforcers are unlearned o Conditioned reinforcers are learned Reinforcement Schedules o Intermittent reinforcement produces greater resistance to extinction that