Sensation Sensation: detecting stimuli from the body or surroundings. Perception: interpreting and organizing sensations into meaningful patterns.

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

Top-Down Processing We perceive by filling in the gaps in what we sense. I _ant ch_co_ate ic_ cr_am. 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).

More Top-Down Processing Aoccdrnig to rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Our experience and expectations enable us to immediately perceive the scrambled letters as meaningful words and sentences. Face Blindness Videos (Parts 1 & 2) http://www.youtube.com/watch?v=dxqsBk7Wn-Y http://www.youtube.com/watch?v=q8cXus7SNQY

What if we could sense everything? Life would hurt. So we can only take in a window of what is out there. Psychophysics: studies the relationship between physical stimuli and our psychological experiences to them.

Absolute Threshold The minimum amount of stimulation one can detect through a given sense 50% of the time.

Absolute Thresholds Taste: 1 teaspoon of sugar dissolved in two gallons of water Smell: 1 drop of perfume diffused throughout a three-room apartment Touch: the wing of a bee falling on your cheek from a height of 1 centimeter (.39 inch) Hearing: the tick of a watch from 20 feet in very quiet conditions Vision: a candle flame seen from 30 miles on a clear, dark night

Difference Threshold (Just Noticeable Difference) The minimum amount of change in stimulation that can be detected.

Weber’s Law Computes the Just Noticeable Difference. It’s always a constant %, NOT a constant amount. Two lights must differ by 8% Two weights by 2% Two sounds by 0.3%

Signal Detection Theory Absolute thresholds are not really absolute. Things like motivation or physical state can effect what we sense. Many moms could sleep through a war, but if one of their kids even whimpers, they’re up!!!

Subliminal Stimulation Below one’s absolute threshold for conscious awareness. Do subliminal messages work? Most evidence suggests it’s not effective.

Subliminal Messages: The Early Years James Vicary claimed to have flashed the words “eat popcorn” and “Drink Coca-Cola” on a movie screen for 1/200th of a second, every 5 seconds during the movie Picnic. He claimed popcorn sales increased 58% and Coke sales increased 18%. Vicary’s experiment was never successfully replicated He later acknowledged the study was a fraud.

The Middle Years: Embedded images and text Embedded images and text are subliminal messages This ad for Tanqueray allegedly contains a phallic symbol.

Recent Years: Product placement Product placement is a form of supraliminal persuasion Subtle, perhaps, but not subliminal

Embedded images in Disney movies The Little Mermaid “Is that a sandcastle in the background, or are you just glad to see me?” The artist who painted this scene claimed the resemblance to a phallic symbol was unintentional.

More Disney embedding That’s a new constellation to me… Can you find Mickey Mouse?

Are there hidden messages in song lyrics? Can the mind detect lyrics that might be played in reverse? http://jeffmilner.com/ba ckmasking/index.html

Sensory Adaptation Tendency of sensory receptors to respond less and less to constant stimulation. This is also why you get assaulted by A perfume cloud when walking by an Old lady. 1 spritz is enough guys.

Energy vs. Chemical Senses Energy Senses Chemical Senses

Transduction Transforming signals into neural impulses. Information goes from the senses to the thalamus, then to the various areas in the brain. Remember Ethan in Sky High? He changes his body to slime. Solid form to liquid form. Change from one form of energy to another.