Lecture 6: Sensation & Perception i. ii. iii. iv. v. vi. vii. viii. Sensation & Perception a. How do we construct our representations of the external world? b. Sensation i. Detection of physical energy (stimulus) from the environment and conversion into neural signals c. Perception i. How we select, organize, and interpret our sensations Information Processing a. Perception requires two types of processing i. Bottom-up processing 1. Begin with sensory processing 2. Works up to the brain’s integration of sensory information ii. Top-down processing 1. Begin with knowledge, expectations 2. Guide interpretations of sensory information Psychophysics a. A study of the relationship between physical characteristics and of stimuli and our psychological experience of them Sensory Adaptation a. Diminished sensitivity because of constant stimulation Attention a. The world contains more information than we can fully interpret or process all at once b. The ability to deal with some stimuli and not others is selective attention c. Part of attention seems to be due to mental effort on your part d. Part of attention seems a natural side effect of mental effort e. Part of attention seems effortless f. But how does it work? Example a. Mental effort either is or requires attention Attention is a Powerful Force a. When you are busy doing something else, you can fail to observe even very significant things b. That’s why is not a good idea to talk on a cell phone while driving a car Attention (pt. 2) a. Another way to interpret these results is that attention is necessary to detect stimulus changes b. Explains how people can “look” but not “see” c. Selective attention allows us to process information that is important to us i. Focus on limited part of our environment d. Can lead to inattentional/ change blindness i. Failing to detect visible objects when attention directed elsewhere