Perception Psychology 1106 3112021 Introduction n n When

Perception Psychology 1106 3/11/2021

Introduction n n When we talked about sensation we were concerned with moving from one for of energy or another to neural energy Bottom up processing Perception is top down Imposing organization on sensation 3/11/2021

Attention n Basically the allocation of perceptual resources to sensation Selective attention means that we can only focus these resources in a limited way The Cocktail Party Effect Lots of stuff going on, you hear lots of stuff, but only listen to the conversation you are in n Tested with dichotic listening n 3/11/2021

Dichotic Listening n n n Different messages in each ear Shadow one ear Can’t even tell the language spoken in the unattended ear! If story moves from one ear to another, you cannot help but follow it Same with vision! (Becklen and Cervane, 1985) 3/11/2021

Dichotic stuff n Even if not perceived, stimuli can affect behaviour n Wilson (1979) Preferred previously herd tunes! n Could NOT identify them n n Szostalo (1998) n 3/11/2021 Learned contingency they could not identify

Form Perception n n How do we tell the difference between an object and the background Gestalt psychologists thought we use various rules n n n Proximity -> group nearby things together Similarity -> similar figures are grouped together Continuity -> smooth continuous patterns Closure -> we fill in gaps Connectedness -> perceive spots, lines, areas as a single unit when connected 3/11/2021

Examples n Proximity n Similarity n Closure n connectedness n Continuity 3/11/2021

Depth Perception n A two dimensional image is projected on your retina Yet, you see in 3 D What’s up with that? n n Somewhat built in Visual cliff experiments (Gibson and Walk, 1960 3/11/2021

Binocular cues n n Your eyes receive subtly different information because they are in different locations This retinal disparity provides a cue as to how far awy an object is This is how 3 D movies work Convergence too, how far in your eyes are turned, the angle 3/11/2021

Monocular Cues n n Many other cues rely on one eye Relative size n Bigger is closer 3/11/2021

Monocular Cues n Interposition n n Something blocking something else is closer Relative clarity n Clearer is closer 3/11/2021

More Monocular Cues n Texture gradient n n More detail closer Relative height n High = far, unless there is an horizon 3/11/2021

More Monocular Depth Cues n Motion parallax n n Faster moving stuff is closer Relative brightness n Brighter is closer 3/11/2021

n n So, even though I have no true threedimensional vision, I can see in ‘#D’ Solely based on monocular cues 3/11/2021

Motion perception n Looming effect Things seem to be coming at you when they get bigger Things seem to be going away from you when they get smaller n n n Even in babies A rapid series of slightly different images conveys movement Oddly enough bobbing your head doesn’t convey motion 3/11/2021

Motion perception n The phi phenomenon illusion does a nice job of illustrating how motion perception works 3/11/2021

Perceptual Constancy n n A book is perceived as a book, even when the retinal image is radically different The proximal stimulus is, in fact very different 3/11/2021

Size Distance relationships n n Small is far away Probably explains some illusions Importance of edges Experience plays a role 3/11/2021

Lightness Constancy n n n Black paper reflects 100 times more light than white paper, if the black paper is in sunlight and the white is in your room But, you see the black paper as darker Context is everything 3/11/2021

Perceptual constancy n n n These sort of things happen with other systems too Clocks seem to make a tick tock sound We don’t only organize, we interpret 3/11/2021

EAT THEDOGATEM (Mc. Burney and Collings, 1984) 3/11/2021

Interpretation n People born blind that gain sight, what can they do? Figure ground n Colours n Can’t tell a sphere from a cube! n n Most of this work had poor control, so monkeys and cats have been used too 3/11/2021

Interpretation and Experience n n n Same results with cats and monkeys Perceptually restricted kittens Horizontal or vertical bars Can’t see what they haven’t experienced! Probably a critical period 3/11/2021

Perceptual adaptation n n n When you put prisms on people that shift the world say 45 degrees to the right, people adapt pretty quickly Even upside down! Stratton (1896) Got sick Got confused B day 8 he was riding a bike! 3/11/2021

adaptation n n Once he went back to normal he had to re adapt! Different depending on species Cats people, monkeys, no probs Fish, amphibians, not a chance 3/11/2021

Perceptual Set n n n When we perceive something we are, in essence, organizing it People only notice backwards messages when you tell them what they are looking for! Schemas are important Kids see faces as the key Adults add the importance of the body May even explain some stereotypes 3/11/2021

Perception without sensation or ESP!!! n n Remember, science is skeptical Burden of proof is on the claimer Keep in mind the idea of chance Psychics missed the following: n n n WWII 9/11 OJ Kennedy assassination Shuttle disaster 3/11/2021

What psychics did predict… n n n Satan would be discovered working in a homeless shelter, reading to the blind and delivering Meals on Wheels The Super Bowl would be cancelled after the first half because team owners would refuse to cough up an extra $10, 000 for each player. A time tunnel would be created to allow people to make a one-way trip back into time. (A way to make the return trip is supposed to be discovered in 2006. ) Source, Jan 8, 2002 issue of ‘The Star’ By definition you CANNOT have ESP 3/11/2021