Perception- Part 2

Change Blindness

What does this say?

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Top-Down vs. Bottom Up

Re-Cap of Perspective: Perceptual Constancy Perceptual Constancy- Tendency for perceptions of objects to remain relatively unchanged in spite of changes in raw sensations Brightness Constancy: piece of white paper does not change when it moves from am dimly lit room to a brightly lit room Color constancy: colors do not seem to change much in spite of different conditions of light Size constancy: dollar bill from 1 foot and 10 feet with seem different in size, however we do not perceive it as different because familiar objects do not change in perceived size as different distances Shape constancy- a penny seen straight on is circular, from an angle it’s oval however we continue to perceive it as circular

Perceptual Organization: Gestalt Visual Capture tendency for vision to dominate the other senses Gestalt--an organized whole tendency to integrate pieces of information into meaningful wholes

Perceptual Organization: Gestalt Grouping the perceptual tendency to organize stimuli into coherent groups Grouping Principles proximity--group nearby figures together similarity--group figures that are similar continuity--perceive continuous patterns closure--fill in gaps connectedness--spots, lines, and areas are seen as unit when connected

Re-Cap: Depth Perception Texture Gradient- texture of objects more severe up close Linear Perspective- images cast smaller images on retina when they are more distant, parallel lines appear to grow closer further away Superposition- Closer objects tend to be partially in front of distant objects Shadowing- shadow suggest depth of object Speed of movement- objects further away move across the field vision slower Aerial Perspective- distant objects look hazy Accommodation- shape of lens of eye changes to focus on visual images

Philosophers have debated the origin of our perceptual abilities: Is it nature or nurture? What do you think?

Beliefs German philosopher Immanuel Kant- knowledge comes from our inborn ways of organizing sensory experience British philosopher John Locke- through our experiences we also learn to perceive the world

Could a person who is blind from birth distinguish this visually if they gained sight as an adult?

Critical Period Critical period of vision is at birth through infancy of humans, cats, monkeys

Cataracts Definition: an eye disease in which the lens becomes covered in an opaque film that affects sight, eventually causing total loss of sight.

Perceptual Adaption With vision, the ability to adjust to an artificially displaced or even inverted visual field Example: wearing a new pair of glasses (may be fuzzy at first, a few hours or days, eyes will adjust)

Perception and the Human Factor Human Factors Psychology explores how people and machines interact explores how machine and physical environments can be adapted to human behaviors

Perceptual Set: Human Factors Actual descent path Pilot’s perceived descent path Altitude looks this much higher 20 18 16 14 12 10 8 6 4 2 Distance from runway (miles) 10 8 6 4 2 Altitude (thousands of feet)

Is it really possible?

Is There Extrasensory Perception? controversial claim that perception can occur apart from sensory input telepathy clairvoyance precognition Parapsychology the study of paranormal phenomena ESP psychokinesis

Claims of paranormal phenomena include astrological predictions, psychic healing, communication with the dead, and out-of-body experiences

ESP Three types of ESP: Telepathy- mind to mind communication Clairvoyance- perceiving events as they are taking place Precognition- perceiving future events Also associated with ESP, psychokinesis (“mind over matter”

http://viscog.beckman.illinois.edu/djs_lab/demos.html www.grand-illusions.com http://www.mindhacks.com/ http://psych.hanover.edu/Krantz/tutor.html http://users.skynet.be/J.Beever/pave.htm

http://philomel.com/musical_illusions/ http://www.audiodesignline.com/204300429

Activity Take out a piece of paper and something to write with On that piece of paper you are going to write a paragraph about someone you know -You may not choose a family member - You may not use their name or how you know them - Identify how they have helped you learn a life lesson