Chapter 6 Sensation perception PDF

Preview

Summary

Download Chapter 6 Sensation perception PDF

Description

Chapter 6 Sensation perception Chapter 6: Sensation and Perception  Sensing the World: Some Basic Principles o Sensation: the experience of having your sense organs stimulated o Perception: interpreting the sensations that are experienced, to recognize

meaningful objects and events o Sensation and Perception  Prosopagnosia: inability to perceive faces even though vision is fine o Bottom-up processing: analysis beginning with sensory receptors and

works up to brain’s integration of sensory info o Top-down processing: info processing guided by higher-level mental

processes (experience, expectations) o Thresholds  Psychophysics: study of relationship between physical characteristics of stimuli (e.g. intensity) and our psychological experiences of them  Absolute threshold  Minimum stimulation needed to detect particular stimulus 50% of the time  Signal Detection  Signal vs. background noise  Experience, expectation, motivation, fatigue

Thresholds Difference thresholds- minimum difference a person can detect between 2 stimuli half the time  It's not the amount of change, it's the proportion of change Weber's law- to be detectable the stimuli must vary by constant proportion not constant amount  It's not the amount of change, it's the proportion of change

Psychophysics- study of relationship btwn physical characteristics of stimulus (intensity) and our psychological experiences of them. Absolute threshold- minimum stimulation needed to detect particular stimulus 50% of the time

Sensory Adaptation- diminishing sensitivity to an unchanging stimulus Vision

Stimulus input: Light energy Tranduction: transforming one form of energy to another  

Short wavelength : high frequency (purples blues) Long wavelength: low frequency (reds and oranges)

Amplitude indicates brightness

The Eye Pupil:    

Lets light in Dimmed lighting: dilated/ Bright lighting: constricting Something you like pupils will widen Fight or flight pupils will dilate

Iris: membrane behind cornea of eye Regulate the amount of light entering your eye Cornea:  clear layering on the outside of the eye  Keep bad particles out of eye but still allow light to enter  Start to focus the light  

Lens: majority of the focusing of the eye

Retina:   

Entire section on the back part of the eye Where the light lands and gets projected to in the back of the eye Contains Sensory neurons for vision (photoreceptors)

Photoreceptors  Rods o o o

Help you see shading Help you see Working in dimmed lighting (night time)

 Cones o o o

Help you see color Help you see with clarity (fine detail) Only work in bright illumination (daytime)

Fovea:     

Section of the retina Directly behind the pupil Thing that you are fixating on Point of central focus Thing you are fixating on goes to

Nearsightedness: visual image is focused in front of retina Farsightedness: visual image is focused behind the retina

Visual Information Processing  Optic chiasm o o

Crossover point the X-shaped structure formed at the point below the brain where the two optic nerves cross over each other.

 Feature Detectors o o

Kind of neuron Nerve cells that respond to specific features of the stimulus (e.g. shape,angle, movement)

 Supercell Clusters o

Receive information from feature detectors and respond to more complex patterns

 Parallel Processing o

Processing many aspects of a problem simultaneously (vs. serial processing)

Color Vision The wavelengths of the light waves that an object reflects determine the color that we see o Young-Helmholtz trichromatic theory  Retina contains 3 different color receptors (red, green, blue)  Opponent-Process Theory  Opposing retinal processes allow for color vision  Red-green  Yellow-blue  White-black o

Perceptual Organization o Gestalt  An organized whole  A school of thought emphasizing that the whole is different

than the sum of its parts

o

Form Perception  Figure-ground  Organization of visual field into its objects (figures) and

surroundings (ground)

Grouping  Tendency to organize stimuli into coherent groups

Proximity: Things that are physically close together, get grouped together 

We favor continuous or uninterrupted lines

Closure: We perceive lines and edges even when there are none physically present. Depth Perception: ability to perceive the world in 3-d even through the images that fall on the retina are in 2-d  Developed around time infant learns to crawl.

Binocular cues: depth cues that result from the use of both eyes 

Retinal disparity: compare image from retinas of both eyes. Greater disparity



Binocular convergence: information about how much eyes must rotate inward

means object is closer. (slightly dif. Images coming into your eyes) to look at an object. More rotation means object is closer

Monocular Cues: depth cues that are available to each eye separately Relative Motion: everything behind the fixation point moves with you, and everything in front of the fixation point moves behind you Vanishing point: Point on the horizon that all lines are converging on; objects that are closer to the vanishing point are at a greater distance to us

Aeriel Perspective: Things that are close to you are clearer and easier to see. Things that are further away from you are harder to see, foggy, unclear, and take on a bluish tint; as the light is reflecting off the dust and particles in the atmosphere, things look foggy and far away Perceptual Consistency: perceiving objects as unchanging even as the image on the retina changes Perceptual Constancy 

Lightness Constancy: objects seem to have the constant lightness even when illumination varies



Relative Luminance: Amount of light an object reflects relative to its surroundings



Color constancy: perceiving familiar objects as having constant color even when changing illumination alter perspective wave lengths



Social Thinking Role- set of expectations (norms) about social position, defining how those in the position ought to behave.



Person- situation interaction...