How we organize and interpret sensory information Perception How we organize and interpret sensory information

Selective attention - we can only focus awareness on a limited part of what we are sensing. Cocktail party effect – type of selective attention in which you can attend to only one voice at a time Cell phones and driving? Listening to music and studying?

Visual Capture The tendency for vision to dominate your senses. At an IMAX movie, it feels like you are moving because it looks like you are moving. Your vision dominates over your vestibular system.

Parallel processing – processing many things at once

Perceiving Images The first step in perceiving an image is determining the figure and ground.

FIGURE Figure and Ground Figure–ground organization is a type of perceptual grouping which is a vital necessity for recognizing objects through vision. In Gestalt psychology it is known as identifying a figure from the background. For example, you see words on a printed paper as the "figure" and the white sheet as the "background". FIGURE

Do you see the arrow?

Gestalt and the Urge to Organize

Other Gestalt principles Simplicity- Gestalt is also known as the "Law of Simplicity" or the "Law of Pragnanz" (the entire figure or configuration), which states that every stimulus is perceived in its most simple form. Gestalt theorists followed the basic principle that the whole is greater than the sum of its parts.

Gestalt Principles: Closure Law of Closure—The law of closure states that individuals perceive objects such as shapes, letters, pictures, etc., as being whole when they are not complete. Specifically, when parts of a whole picture are missing, our perception fills in the visual gap.

Gestalt Principles: Continuity This Gestalt law states that learners "tend to continue shapes beyond their ending points". The edge of one shape will continue into the space and meet up with other shapes or the edge of the picture plane. The example below illustrates that learners are more apt to follow the direction of an established pattern rather than deviate from it.  We perceive the figure as two crossed lines instead of 4 lines meeting at the center.

Gestalt Principles: Proximity We tend to group things together by closeness.

Gestalt Principles: Similarity We tend to group things together by likeness

Gestalt, Subliminal Messages, and Films Subliminal Messages in popular Films Subliminal Messages in Disney Films Dangers of Disney Films

Motion Perception How does the brain recognize an object is moving Motion Perception How does the brain recognize an object is moving? How does it interpret the direction of movement? Brain interprets shrinking objects as receding and enlarging objects as approaching

Stroboscopic Effect the perception of motion produced by a rapid succession of slightly varying images (animation, movies) Stroboscopic effect

Phi phenomenon an illusion created when two or more adjacent lights blink on and off in succession, creating the perception of movement (lighted signs, illusions)

Perceptual Constancy the ability to perceive an object is the same even as the illumination and retinal image changes. Shape Constancy- perception that shape of an object doesn’t change just because image on the retina does.

How many right angles do you see?

Perceptual Constancy Size constancy (King Koch or the incredibly shrinking teacher) – perception that an object’s size remain the same even as the retinal image changes.

Perceptual Constancy Color constancy- an example of subjectiveconstancy and a feature of the human color perception system which ensures that the perceived color of objects remains relatively constant under varying illumination conditions.

Perceptual Constancy Lightness constancy – the perception that familiar objects have a constant lightness, even while illumination varies.

Visual Cliff – used to check for depth perception.

Depth Perception Monocular Depth Cues Linear perspective (parallel lines appears to converge on a vanishing point) Relative height (more distant objects are higher) Relative size (more distant objects are smaller)

Depth Perception Monocular Depth Cues Relative clarity (objects in the distance appear hazy) Overlap/interposition (continuous outlines appear closer)

Depth Perception Monocular Depth Cues Texture gradient (texture details, like roughness, diminish with distance)

Depth Perception Monocular Depth Cues Light and shadow

Depth Perception Monocular Depth Cue Motion parallax (or relative motion) – Distant objects will appear slow in comparison with close objects even when the two are moving at the same speed Think of an airplane traveling overhead. http://www.youtube.com/watch?v=-OmK3rGk__I&NR=1

Depth Perception Binocular depth cues – require two eyes Retinal disparity – the greater the difference between the images on your two retina, the closer the object (“camera 1, camera 2”, “finger sausage”, hole in the hand) Convergence – the greater your eye muscles must strain (or converge) to focus on an object, the closer the object (notice how hard your eyes strain when you focus on the tip of your nose).

Size-distance relationship Size-distance relationship When other monocular cues tell us an image is further away, it actually appears larger.

Horizon Moon

High moon on a clear night.

Muller-Lyon Illusion Which is longer?

Muller-Lyon Illusion

Extrasensory Perception Telepathy – mind reading Clairvoyance – perceiving remote events Precognition – Knowing things before they happen Telekinesis (psychokinesis) – moving objects with one’s mind (not technically ESP)