Psych100 Exam 1 Review2Part 1: Sensation and Perception2Transduction, Sensation, Perception2Transduction: The process In which sensory information is converted into neural signals22Sensation: “The activation of the sense organs by a source of physical energy”22Perception: “The sorting out, interpretation, analysis, and integration of stimuli by the sense organs and the brain2ABSOLUTE THRESHOLD2 Absolute threshold: “the smallest intensity of a stimulus that must be present for it to be detected. Also, The point at which you are able to detect a stimulus on 50% of the trials.2 Difference Threshold: The measurement of how much of a difference there is between two stimuli that one is able to tell them apart22Weber’s Law2Book definition: In order for a difference between two stimuli to be perceptible, the stimuli must differ by at least a constant proportion.22• Or in other words: the change in a stimulus that will be just noticeable is a constant ratio of the original stimulus.22(Analogous to when you are in a noisy environment you must shout to be heard while a whisper works in a quiet room.)2Part 2: Sight 2Rods and Cones2Rods and cones are the two types of photoreceptors. Both are found in the back of the retina.2Horizontal, bipolar, and ganglion cells further refine the sensory input that is collected by the rods and cones before it travels to the brain2 2Rods see in black and white, and are found primarily in the periphery of retina2 2Cones see in color and are found in the fovea centralis. There are three kinds of cones: Blue, green red2The optic chiasm2The optic chiasm is the area in which the optic nerve from each eye crosses. An image on a person’s right eye is sent to the left side of the brain and the image on the person’s left eye is sent to the right side of the brain. 2COLOR VISION2• Two theories work in tandem to produce color vision:2 2• Trichromatic Theory of color vision: there are three kinds of cones, Each of which responds primarily to a specific range of wavelengths. 22• Opponent-process theory of color vision: receptors are linked in pairs, working in opposition to each other.2!Part 3: Smell and Taste2• Smell: evolved to assist with gestation(e.g. Don’t eat that it smells!) and to assist with communication (both social and sexual) by means of pheromones2• Smell is closely linked to memory 22• Taste: evolved to assist with recognizing possible poisons. Prompts expulsion from mouth22• Both utilize olfactory mechanisms.Part 4: PAIN 2• Gate-control theory of pain:2• “particular nerve receptors in the spinal cord lead to specific areas of the brain related to pain. When these receptors are activated, a “gate” is opened allowing the sensation of pain. 2Part 5: Hearing2The Basilar membrane runs through the center of the cochlea. The basilar membrane is covered with hair cells. When these hair cells are bent by vibrations (such as sound) entering the cochlea, the cells send a neural message to the brain.2Prolonged or frequent exposure to heavy vibrations causes damage to these hair cells and can lead to early hearing loss2The eardrum funnels vibrations through the middle ear into the inner ear where they are converted into neural signals and sent to the brain for interpretation.2The semicircular canals consist of three tubes containing fluid that sloshes through them when the head moves, this signals rotation or angular movement to the brain. (very much like a spirit level)2The inner ear houses structures known as the vestibular system, which are responsible for balance. The main structure of the vestibular system is formed by the semicircular canals2Part 4: Balance2Part 5: Perceptual processes2Illusions are physical stimuli that consistently produce errors in perception2Gestalt Psychology (“The whole is greater than the sum of its parts”)2!proximity! Objects!that!are!near!each!other!are!seen!as!a!group!!!!!!Closure! Objects!that!have!breaks!are!seen!as!whole!!!!!!!!similarity! Objects!that!are!similar!are!seen!as!grouped!together.!!!!simplicity! We!see!objects!in!the!simplest!and!most!straigh:orward!manner!possible!!!Gestalt Laws of Organization:2Ponzo illusion2Muller Lyer: Experience effects 2Individuals such as the Zulu tribe in Africa, are much less susceptible to the illusion than those who grow up in areas where structures are built using right angles and rectangles2Rules of Gestalt Psychology242Sometimes local features assist with the perception of global features 222 2 2BUT22 global features assist with local features.22Rules Cont.4 Perceptual Constancy:42The ability to recognize that physical objects are unvarying and consistent even though our sensory input about them varies22Size constancy: the size of an object remains constant despite the varying size of objects on the retina.244Types of constancy:42Shape consistency:4The shape of an object remains constant despite changes of the object’s shape on the retina 24Example! How!it!works! What!is!it!called?!!!!!!!Distant!objects!appear!closer!together!than!close!objects!!linear!perspec<ve!!! If!two!objects!are!the!same!size,!the!one!that!makes!a!smaller!image!on!the!re<na!is!farther!away!than!is!the!one!that!provides!a!larger!image!!Rela<ve!Size!!!An!object!blocking!another!object!will!be!seen!as!closer!to!you.!!interposi<on!!!! While!you!are!moving,!objects!that!are!closer!to!you!move!more!quickly!than!objects!that!are!farther!away!!mo<on!Parallax!!DEPTH PERCEPTION -MONOCLUAR CUES:2Depth perception:2Flower #12Flower #22In order to calulate the visucal angle= object size/distance4Retinal Disparity:2The Right and left eye view slightly different images, but blend into one continuous image when both eyes are open. Only major binocular cue.Questions, Comments,