New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

PSY 456: Week 7 Notes

by: Brianna

PSY 456: Week 7 Notes PSY 456

GPA 4.0

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

Notes from lectures on 3/22-3/24
Sensation & Perception
Class Notes
25 ?




Popular in Sensation & Perception

Popular in Psychlogy

This 6 page Class Notes was uploaded by Brianna on Saturday March 26, 2016. The Class Notes belongs to PSY 456 at Colorado State University taught by Amberg in Spring 2016. Since its upload, it has received 14 views. For similar materials see Sensation & Perception in Psychlogy at Colorado State University.

Similar to PSY 456 at CSU


Reviews for PSY 456: Week 7 Notes


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 03/26/16
Ch 9: Color Vision Function of Color ● classify and identify objects ● organize elements into objects ● foraging What colors do we see? ● 250 Colors ● Primary ○ red, yellow, blue ● Secondary ○ created by combining 2 primaries ● Intermediate or Tertiary ○ created by combining primary with secondary ● Achromatic Colors: contain no hue ○ white, gray, black ● Why is there variety? ○ colors are changed by ■ Intensity: changed perceived brightness ■ Saturation: adding white to a color results in less  saturated color Color and Wavelength ● Color perception is related to wavelength of light ○ 400­450 nm violet ○ 450­490 nm blue ○ 500­575 nm green ○ 575­590 nm yellow ○ 590­620 nm orange ○ 620­700 nm red ● Wavelengths ○ short ­ blue ○ medium ­ green ○ long & medium ­ yellow ○ long ­ red ○ long, medium & short ­ white ● Selective Transmission ○ transparent objects selectively allow wavelengths to pass through ● Simultaneous Color Contrast ○ background of object can affect color perception ● Colors of Objects ○ color of objects is determined by the wavelengths that are  reflected ○ Reflective Curves: percentage of light reflected for specific  wavelengths to perceive color ■ Selective Reflection: certain colors are selected to  be reflected back ● Additive Color Mixture ○ mixing lights of different wavelengths ○ all wavelength available to observer ○ superimposing blue and yellow lights leads to white ● Subtractive Color Mixture ○ mixing paints with different pigments ○ additional pigments reflect fewer wavelengths ○ mixing blue and yellow leads to green ■ blue and yellow have green wavelength, red and  blue wv cancels out Trichromatic Theory of Color Vision ● three different receptor mechanisms responsible for color vision ● Behavioral Evidence (Young & Helmholtz) ○ Color­Matching Experiments ■ observers adjusted amounts of 3 wavelengths in a  comparison field to match a test field of one wavelength ■ Results ● “normal” color vision: three  wavelengths ● color deficient: two wavelengths ● Physiological Evidence ○ measured absorption spectra of visual pigments in receptors ○ found receptors that responded maximally to ■ short wavelengths (419 nm) ■ medium wavelengths (531 nm) ■ long wavelengths (558 nm) ● Summary ○ color perception is based on response of three different cone  types ■ responses vary depending on wavelengths  available ● Are three receptors necessary for color vision? ○ one receptor type (monochromat) cannot lead to accurate color  vision ■ absorption of a photon causes the same effect no  matter the wavelength ■ any 2 wavelengths can cause the same response  by changing the intensity ○ two receptor types (dichromats) solve this problem ○ three receptor types (trichromats) allow for perception of more  colors Color Deficiencies ● Trichromatic Color Vision: 3 wavelengths ● Anomalous Trichromat: 3 wavelengths in different proportions than normal  trichromat ● Dichromatic Color Vision: 2 wavelengths  ○ Three Types ■ Protanopia (red­green) ● affects 1% of maes and .02% of  females ● individuals see short wavelengths as blue ● neutral point occurs at 492 nm ● above neutral point, see yellow ● missing the long wavelength  pigment (red) ■ Deuteranopia (red­green) ● affects 1% of males and .01% of  females ● see short wavelengths as blue ● neural point occurs at 498 nm ● above neutral point, see yellow ● missing medium wavelength  pigment (green) ■ Tritanopia (blue­yellow) ● affects .002% of males and .001 of  females ● see short wavelengths as blue  ● neutral point occurs at 570 nm ● above neutral point, see red ● missing short wavelength pigment  (blue) ● Unilateral Dichromat: trichromatic vision in one eye and dichromatic in the other ● Monochromatic Color Vision: 1 wavelength (truly color blind) ○ 4 types ○ very rare hereditary condition ○ only rods, no functioning cones ○ only perceive white, gray, and black tones ○ poor visual acuity ○ very sensitive to bright light ● Test with Ishihara Test Opponent­Process Theory of Color Vision ● Proposed by Hering ○ color vision is caused by opposing responses ■ blue and yellow ■ green and red ○ result of chemical reaction in the retina ● Behavioral Evidence ○ color afterimages and simultaneous color contrast show the  opposing paring ○ types of color blindness are red/green and blue/yellow ● Physiological Evidence ○ researchers performing single­cell recordings found opponent  neurons ○ Opponent Neurons ■ in retina and LGN ■ excitatory response to one end of the spectrum ■ inhibitory response to other end Trichromatic and Opponent Process Theories combined ● each describes physiological mechanisms ○ trichromatic theory explains responses of cones in retina ○ opponent process theory explains neural response for cells further in the brain Color in the Cortex ● there is no single module for color perception ○ cortical cells in V1 and V4 respond to some wavelengths or have  opponent response cells usually also respond to forms and orientations ○ cortical cells that respond to color may also respond to white ● Types of Opponent Neurons in the Cortex ○ Single­Opponent Neurons ■ looking at larger scope, responds strongly to  specific wavelength and inhibits others ○ Double­Opponent Neurons ■ looking at boundaries, responds to more than one  specific wavelength Color Constancy ● perception of colors as relatively constant in spite of changing light sources ○ sunlight has approximately equal amounts of energy at all visible  wavelengths ○ tungsten lighting has more energy in the long wavelengths ○ objects reflect different wavelengths from these two sources ● Chromatic Adaptation: prolonged exposure to chromatic color leads to receptors ○ adapting when the stimulus color selectively bleaches a specific  cone pigment ○ decreasing in sensitivity to the color ○ adaptation occurs to light sources leading to color constancy ● Uchikawa ○ shown sheets of colored paper in three conditions ■ Baseline: paper and observer in white light ■ Observer not Adapted: paper illuminated by red  light; observer in white ■ Observer Adapted: paper and observer in red light ○ Results: ■ baseline: paper is green ■ not adapted: paper is slightly red ■ adapted: paper is yellowish ● Effect of Surroundings ○ color constancy works best when an object is surrounded by many colors ● Memory and Color ○ past knowledge of an object’s color can have an image on color  perception ● Hansen ○ saw photographs of fruits with characteristic colors against a gray  background ■ they adjusted the color of the fruit and a spot of  light ■ when the spot was adjusted to physically match the background, the spot appeared gray ■ but when the color of the fruits was changed to the  color of background, they were still perceived as being colored ● Achromatic Colors ○ perceived as remaining relatively constant ○ Perception of Lightness ■ is not related to the amount of light reflected by an  object ■ is related to the percentage of light reflected by an  object ○ The Ratio Principle: areas that reflect different amounts of light  look the same if the ratios of their intensities are the same ■ this works when objects are evenly illuminated ○ Lightness Perception under Uneven Illumination ■ source of information about illumination ● information in shadows: system  must determine that edge of a shadow is an illumination edge ○ system takes into  account object meaningfulness ○ penumbra of  shadows signals an illumination edge Color is a Construction of the Nervous System ● physical energy in the environment does not have perceptual qualities ○ light waves are not colored ● different nervous systems experience different perceptions ● honeybees perceive color outside of human perception Infant Color Vision ● difficult to know what an infant sees ○ chromatic color ○ brightness ● Bronstein et al ○ habituation ○ young infants have color vision ■ can perceive color and changes in brightness


Buy Material

Are you sure you want to buy this material for

25 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Bentley McCaw University of Florida

"I was shooting for a perfect 4.0 GPA this semester. Having StudySoup as a study aid was critical to helping me achieve my goal...and I nailed it!"

Janice Dongeun University of Washington

"I used the money I made selling my notes & study guides to pay for spring break in Olympia, Washington...which was Sweet!"

Jim McGreen Ohio University

"Knowing I can count on the Elite Notetaker in my class allows me to focus on what the professor is saying instead of just scribbling notes the whole time and falling behind."


"Their 'Elite Notetakers' are making over $1,200/month in sales by creating high quality content that helps their classmates in a time of need."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.