Introduction to Psychology Study Guide 2 Sensation is the stimulation of sensory receptor cells that relay to higher centers in the brain for processing The firing neurons usually travel through the thalamus to higher For example pot roast may stimulate your taste and smell brain sections sensation another Perception is the interpretation of that sensory information so that it has meaning We can use sensory information in combination Synesthesia is using one sense to interpret information from o One example is people who can smell red which is very o fMRI saw that when a person eats you can see the visual part rare of their brain stimulated These are your following senses Hearing is stimulated by sound waves Vision is stimulated by light waves Touch is stimulated by pressure on the skin Pain is stimulated by a wide variety of potentially harmful stimuli Taste is another sense Smell is a sense as well There are two sensation thresholds Absolute threshold is the minimum threshold for stimuli that have to be there for you to detect something It s like the human standards o There is individual difference in which some are more sensitive than others in all or some senses Difference threshold has to do with just noticeable difference JND and whether you perceive a change o It can very individually as it would like in hearing tests o It involves strong contrast effects such that if you move from one extreme state to another extreme state you ll notice a huge change An example of this could be moving your hand from extremely cold water immediately to extremely hot water 1 Other examples of this are hearing tests and an eye doctor changing lenses Signal detection theory occurs when we are trying to sense something accurately It talks about the way you can be right or wrong in sensation perception We want accuracy in sensation perception but we can be wrong Says Yes Hit False Alarm Says No Miss The stimulus is on Correct rejection The stimulus is off Yes sayers tend to say yes and makes more hits No sayers tend to say no and make more correct rejections An example would be a weatherman We wouldn t want him to be biased You can also think about the empty hollow thud when all got admitted to asylums and stayed for an average of 11 days Asylums were yes sayers but Ronald Regan cut their funding and the asylums went from false alarm to miss Some people think that this led to an increase of homeless people however some disagree similar to the chicken or egg dilemma Within the visual system light waves reflect different colors which stimulate sensors The light waves pass through your cornea which focuses through your pupil Your pupil can be dilated under dark light and constricted under bright light Your visual system is the most complex of all 60 70 of sensory The visual system takes in information in the most complex way There are several components of your visual system cells are found in your retina 1 Cornea 2 Pupil 3 Iris 4 Lens helps dilates and constricts the pupil focuses light waves onto the retina very flexible when you are young but less flexible as you age because it becomes harder to constrict when needed a You can correct your vision when your lens isn t perfect with glasses or contacts 5 Fovea dipped in area similar to a cave involves focused vision your peripheral vision tends to be less focused you see color much more brightly when you re focusing than in the peripheral vision 6 Optic nerve there are no sensory receptor cells here it creates a blind spot in each eye 2 7 Retina consists of a thick sheet of neurons of sensory receptors cell located at the back of your eye There are two types of visual receptor cells One is called rods and you have about 120 million They used more for your periphery vision which means you don t see colors well They focus on black and white primarily This can be though of in terms of night vision The other is called cones and you have about 6 million There are used for color vision and they are more cones near the fovea They need color waves to function well and thus do not deal with darkness well They respond immediately to changes in the focal vision and light stimuli Certain cones correspond to certain light waves It might be helpful to remember the optic nerve demonstration Your blind spot is different for both eyes Each eye compensates for the other eyes blind spot When it comes to dark adaptation rods take longer to adapt There are two theories of color vision which are both correct and work together Trichromatic theory states that there are three types of cones that respond to different wavelengths cones that fire to red blue and green o This theory cannot explain blindness and color contrast Opponent process theory involves bi polar cells that are found in the middle layer The bi polar cells are connected to many different cones and maybe even rods o This involves a maximized firing to one color and a minimized firing to another color o This explains after images o This also explains color blindness which tends to occur in pairs of the bi polar cells When it comes to visual perception there are two rules In terms of size constancy the object size remains constant regardless of distance or the size of the image on retina o This is affected and influenced by previous experience with an object the presence of the surrounding objects and the distance between the object and person o A person looks smaller when they are far away and as they move closer we know that they are moving closer to us not getting bigger 3 In terms on shape constancy we are able to recognize shape regardless of changes in angle or position When it comes to depth perception think about monocular cues and binocular cues Monocular cues only take one eye Binocular cues needs both eyes o There is a motion parallax in which things that are closer to us go by much more quickly while things that are farther away go by much more slowly o Occlusion occurs when one object blocks another and you are able to tell which is object is closer o In terms of relative size larger objects seem closer o During convergence your eyes move closer together as the o Binocular cues also have to do with moving objects o Retinal disparity is when the objects that are moving are object gets closer hitting your retina at different positions which helps you track things across the field Object perception theories have to do with how we learn to visually label an object Feature detection theory means