Psych 1101 Chapter 6 Sensation and Perception Basic Principles of Sensation and Perception sensation is the process by which our sensory receptors and nervous system receive and represent stimulus information from our environment Bottom up processing is analysis that begins with the sense receptors and works up to the brain s integration of sensory information Rods and cones afferent neurons retinas hair cells luner ears olfactory receptors nasal passages taste buds tongue touch receptors skin perception is the process of organizing and interpreting sensory information enabling us to recognize meaningful objects and events Top down processing is information processing guided by our experience and expectations breaking down into component parts sensory neurons are also known as afferent neurons they arrive at the central nervous system motor neurons are also known as efferent neurons they exit the central nervous system Sensory Systems all of our senses perform three basic steps they receive sensory stimulation transform that stimulation into neural impulses deliver the neural information to our brain the process of converting one form of energy into another that our brain can use is called transduction Sensory adaptation sensory adaptation refers to diminished sensitivity as a consequence of constant stimulation The phenomenon of sensory adaptation enables us to focus our attention on information changes in our environment without being distracted by uninformative background stimulation Perception perception is influenced by our experiences our learned assumptions and beliefs as well as by sensory input through experience we form concepts i e schemas which organize and interpret unfamiliar information a given stimulus may trigger radically different perceptions partly because of our different schemas but also because of the immediate context Absolute and Difference Thresholds absolute threshold the minimum stimulation needed to detect a particular stimulus 50 percent of the time priming effect we can process some stimuli too weak to recognize indicating that much of our information processing occurs automatically and unconsciously subliminal messages difference threshold the minimum difference between two stimuli that a person can detect 50 percent of the time weber s law just noticeable difference difference thresholds increase in proportion to the size of the stimulus Sensation and Perception Notes Sensory receptors are specialized neuron cells transform one sort of information to another translation to a different language perception is something you get unconsciously and judgment is a conscious perception offaction is a sensory labeling system bottom up processing is when you put individual components together and they form as a whole virtual reality is exposing an individual to virtual Color Perception Young Helmholtz Trichromatic three color Theory retina has three types of color receptors red green and blue Various combinations of these three result in different colors for example when both red and green sensitive cones are stimulated we see yellow Hering s Opponent Process Theory color perception is controlled by the activity of two opponent systems blue yellow and red green