Sensation

Sensation and Perception1Definition: the process by which stimulation of a sensory receptor gives rise to neural impulses (APs) that result in an experience, or awareness of, conditions inside or outside the bodySensation vs. PerceptionSensation = the process by which sensory organs in the eyes, ears, nose, mouth, skin, and other tissues receive and detect stimuli_______________________

Perception = the organization and interpretation of sensory stimuli by the brain_______________________You find that you have to add 1 teaspoon of sugar to a cup of coffee that already has 5 teaspoons of sugar in it to notice the difference in sweetness. If you have a cup of coffee with 10 teaspoons of sugar in it, how many teaspoons would you have to add to notice the difference in sweetness at least half the time?

1245

http://3.bp.blogspot.com/_vpzPBewsqWU/TPMrvnTvzoI/AAAAAAAAPnU/wUZD2mp1KJg/s1600/Kopi%2BDan%2Bgula.jpgSensation_______________ = the study of the relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them

________________ = the minimum stimulation needed to detect a particular stimulus 50% of the time

___________________________ = the minimum difference between two stimuli required for detection 50% of the timeAlso known as a ______________________________________: JNDs are proportional to the size of the original stimulus4Absolute threshold examplesSound: tick of a watch under quiet conditions at 20 feetTaste: one teaspoon of sugar in 2 gallons of waterExamples of Absolute Thresholds

You find that you have to add 1 teaspoon of sugar to a cup of coffee that already has 5 teaspoons of sugar in it to notice the difference in sweetness. If you have a cup of coffee with 10 teaspoons of sugar in it, how many teaspoons would you have to add to notice the difference in sweetness at least half the time?

1245

http://3.bp.blogspot.com/_vpzPBewsqWU/TPMrvnTvzoI/AAAAAAAAPnU/wUZD2mp1KJg/s1600/Kopi%2BDan%2Bgula.jpgHuman Sensory SystemsVisionHearing (Audition)Smell (Olfaction)Taste (Gustation)SomatosensesTouchVestibular senseKinesthesisReceptor CellsSpecific _______________ for each sense stimulate neurons in the CNS

Receptor cells _____________ sensory input from the environment (sights, sounds, smells)

Vision: The Electromagnetic Spectrum

The Human Eye

Receptor Cells for VisionRods concentrated in the periphery of the retinablack and white visionmost active in dim illumination

Conesconcentrated in the center of the retina (fovea)color visionmost active in bright illumination

Pathways in the Visual System

Its dark in your house and you are struggling to see what time it is without turning on the light. You notice that if you turn your gaze slightly to the side of your watch, you can make out the large numbers. The ability to see these large details in the dark is due to your:

presbyopiaoptic discconesrodsThe Auditory System

Comparing Vision and HearingSenseName of Receptor CellsLocation of Receptor CellsVisionHearingHair Cells in the Cochlea

Rods and cones are to vision as ___________ are to audition.eardrumspinnashair cellscochleasHearing_________ magnify sound from the ______________________________ in the _______ fire action potentials________________localizes sound in space__________ distributes frequency information__________________interprets soundPerception the organization and interpretation of sensory stimuli by the brain(knowledge-based processing)

19The processes that organize information in the sensory image and interpret it as having been produced by properties of objects or events in the external worldPerceptionIncludes the processing, organization, and interpretation of sensory signals

Results in an internal representation of environmental stimuliPerceptual organizationBottom-Up and Top-Down Processing___________________= analysis that begins with the sensory receptors and works up to the brains integration of sensory informationExample: reading (letters words)

___________________= information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations

Conscious perception of sensory information involves both types of processingExamples of Top-Down ProcessingPriming means that prior information will alter what we expect to perceive

The context in which we receive information also changes what we perceive

Priming

Priming: Duck or Rabbit?

Context

Context

Context

Context: A Young Beauty

Context: An Old Woman

Perceptual Organization: Figure & GroundOur visual system divides everything we see into components, a process called ___________________

The most important aspect of perceptual parsing is dividing what we see into the _______ and ________

Perceptual ambiguities demonstrate what happens when figure and ground are reversibleSometimes called ____________________Reversible Figures

Reversible Figures

Reversible Figures

Perceptual Organization: Gestalt PrinciplesLaw of Proximity

Law of Similarity

ClosureLaw of Proximity

Law of Similarity

Closure

Although a few keys on the piano were broken, Shana couldn't prevent herself from mentally filling the missing notes of the familiar melodies. This best illustrates the principle of:

proximitysimilaritycontinuityclosure

http://fineartamerica.com/images-medium/piano-keys-anthony-rapp.jpgDepth PerceptionDepth cues for the visual system can be divided into binocular depth cues and monocular depth cues

One important binocular depth cue is caused by the distance between the eyesThis cue is known as ______________________

Brain uses the disparity between the images of each eye to compute distances to nearby objectsBinocular Disparity

Binocular Disparity

Monocular Depth CuesInterpositionLinear perspectiveTexture gradientInterposition

Linear Perspective

Texture Gradient

Motion Cues for Depth PerceptionRelative Motion ParallaxDistance of objects from viewer determines their relative motionNearby objects appear to pass ___________Distant objects appear to pass more ___________

Perceptual ConstanciesRefers to the ability to retain an unchanging percept of an object despite variations in the retinal imageThree examples:Size constancyShape constancyLightness constancySize Constancy

Size Constancy

Shape Constancy

Lightness Constancy

Taking his first train ride, a child is amazed at how quickly the fence posts along the track are whizzing by, but the farm in the distance hardly seems to move. This best illustrates:Retinal disparityRelative motion parallaxSize constancyInterposition

Have a student read the slide.

Context affects our interpretation of stimuliHs and As.