Aim What is the difference between sensation and

Aim: What is the difference between sensation and perception? What role does nature and nurture play in our perception? What factors influence our perception? Do Now: • Which box feels heavier? (Shhh! Don’t talk about it yet!) Homework: • Read text pps. 202 – 209 & 220 – 229 • Sensation and Perception Test Tuesday 11/21 • Project Due Wed – Write up and Presentation

Context Effect • The context in which something is sensed impacts perception.

Sensation and Perception • sensation – the process of taking in energies from the environment and transforming those energies into neural energy (taking in info) transduction • perception – the process of interpreting sensory information so that it has meaning (interpreting info)

The Case of Kenge Page ___ • Define – nature, nurture. • What does the case reveal about the nature v. nurture debate? Mbutu Pygmy Tribe in Congo

Differing Views of Perception Empiricist: • start out as infants with a “blank slate”, everything comes from environment • Perception is influenced by values, expectations, experience and culture Nativists View: • believe we are born with a certain amount of knowledge, preprogrammed

Constancy • Objects change in our eyes constantly as we or they move…. but we are able to maintain content perception • Shape Constancy • Size Constancy • Brightness Constancy

Constancies

Constancies

Perception & Illusions are influenced by … • Biological Factors – sensory analysis • Psychological Influences (Gestalt, context, expectancies, mental sets/ schemas etc) • Socio Cultural Factors

Muller – Lyer Illusion Which line is longer?

Explaining the Muller – Lyer Illusion Our experience in a “carpentered” world shapes our perception of the lines in the Muller Lyer Illusion. Where would you expect people not to be fooled by this illusion?

Culture and Muller Lyer Illusion • Corners in our rectangular carpentered world teach us to interpret outward and inward arrowheads at the end of the line as a cue to the lines distance from us (it’s length). • The red line of the ticket booth looks shorter than the red line to the right. • But both are the same!

Which animal does the spear point to? It depends upon experience. Those who have never seen a 2 D drawing or photo’s of 3 D scenes have difficulty.

What is above the woman’s head? Answers depend upon the culture you come from. What will westerners say? East Africans?

Top-Down Processing • We construct reality using prior knowledge and experience • We fill in gaps based upon what makes • priming • I _ant ch_co_ate ic_ cr_am. • Considering the following sentence, (Wray & Medwell 1991; 98) • “If you aer a fluet reodur you wll hve no prblme reodng ths sntnce “ • Based on our experiences and schemas. • If you see many old men in glasses, you are more apt to process a picture of an old man (even when you may be in error). http: //www. simplypsychology. org/perception-theories. html

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Priming • Illustrates mental processing without awareness. • given info and then is later tested to see if it will affect performance • AKA subliminal suggestion • http: //www. youtube. com/watch? v=i 1 OV hl. Rpw. Jc&safety_mode=true&persist_safe ty_mode=1

In a study subjects were asked to unscramble words. Group A – sentences with polite words Group B – sentences with rude words Group C – neutral words At end of experiment. Experimenter was always talking to research assistant. How do they get his attention? • Only 10% of polite primed interrupt, 65%of rude primed interrupt, 35% of neutral interrupt! • •

Bottom-Up Processing • Also called feature analysis. • We use the features on the object itself to build a perception. • Takes longer that top-down but is more accurate.

Bottom-up vs. Top-down Processing • bottom-up processing – • top-down processing – the operation in sensation and perception in which and perception, launched sensory receptors register by cognitive processing at information about the brain’s higher levels, external environment and that allows the organisms send it up to the brain for to sense what is interpretation (part to happening and to apply whole) that framework to information from the – song for first time world (whole to part) – favorite song

Advantages / Disadvantages of Top Down Processing? • PRO - Allows us to identify sounds images quickly, even before full examination is done! • CON - Mistakes!! Bias!! • We use this 90% of the time!!!

Pro’s & Con’s of Bottom Up Processing • Opposite of Top Down • takes longer, but is more accurate • EX: Overheads

Read this out loud. What happened? Why?

AMES ROOM • http: //www. youtube. com/watch? v=h. CV 2 Ba 5 wrcs&safety_mode =true&persist_safety_mode=1&safe=active

Ames Illusion • Distorting rooms • Many judgments of size, shape or distance which may seem absolute are relative in the sense that they depend on other features in the visual field. • Objects of the same size and apparent distance will give different size retinal images

What do you see? Why? • We look for patterns, organize things, etc • Sometimes we see things that aren’t there or was not intended. • Helps us survive and make sense and organize world Base in California Face on mars

Gestalt Psychology

Gestalt Principles • a school of thought interested in how people naturally group/ organize their perceptions according to certain patterns • We innately look at things in groups and not as isolated elements and try to find patterns – main principle: the whole is different from the sum of its parts -computer screen image (sum) pixels (parts) – closure – proximity – similarity – continuity – Figure Ground – Phi Phenomena

Gestalt Principles: Proximity • proximity: object near each other see them as a unit (4 columns; not 16 squares)

Gestalt Principles: Similarity • similarity: objects that are similar seen as a unit/group (columns of circles and squares; rows of circle and squares)

Gestalt Psychology • Common Direction/ Continuity (objects that form a continuous form are perceived as same group)

Gestalt Principles: Closure • closure: disconnected or incomplete figures fill in the spaces and see them as complete figures Kanizsa triangle

Perceived Motion • Stroboscopic effect (flip book effect) • Phi phenomenon • Autokinetic Effect (if people stare at a white spotlight in a dark room, it appears to move. )

Gestalt Rules – Define each of the following. Page 13 of packet. • • • Figure/ Ground Simplicity Proximity Closure Similarity Continuity http: //www. usask. ca/education/coursework/skaalid/theory/gestalt. htm http: //graphicdesign. spokanefalls. edu/tutorials/process/gestaltprinciples/gestaltprinc. htm

Applying Gestalt to designing… • Which is more appealing? Why?

We have a tendency to organize things to better understand them…. • Concept maps help us organize and make sense of information • Use it when we study

• Think of an example (anything) that reflects or illustrates Gestalt Psychology…