Chapter 4: Perception for Test 2 Flashcards
Oldest color theory
Trichromatic Theory of Color vision.
the trichromatic theory is based on experiments of ___ ____ and types of ___ ___
color matching and types of color blindness
our color vision is made of ____ broad ranges of color
3 broadranges of color
what happens to a person’s range of color when they are colour blind?
people with color blindness cannot see 1 of the 3 broad ranges of color.
explain what was determined by the color matching experiments
scientists determined that as long as you ahad 3 lights of 420, 560 and 640 nm wavelengths, you could match the color to any other color of light.
If you took away one of the lights, you now have a “restricted range’ of a spectrum and couldn’t match all the colors.
T/F: physical energy in the environment doesn’t have perceptual qualities
Tire. Light waves are NOT COLORED; but their wavelength determines the perception of color, cause thats just what our bodies do with the perception of EMR.
which colors are needed in order to make all other colors
red blue yellow
which color of light are we more sensitive to? whY?
we are very sensitive to changes in yellow, but not as senstivie to blue light. This is due to our CONE DENSITY TYPE. we have more long (red) and medium (yellow) wavelength cones that short wavelength cones.
Red cones = ____ wavelenght cones
Green cones = ____ wavelength cones
Blue cones= ____ wavelength cones.
Red cones : Longer wavelength
Green cones = middle wavelength
Blue cones = shorts wavelength cones.
What is dichromatism and what is the most common form?
dichromatism: a two-color deficiency. Typically lacks the long wavelength cone, resulting in red-green color blindness, the most common type of dichromatism.
why does a dichromat have trouble seeing the vibrancy of color in addition to certain colors themselves?
if a person is only color blind to lets say red, other colors may appear drab because even red is still prominent in creating other colors. Ex/ even though they should supposedly be able to see purple, it won’t look as vibrant because it is missing the perception of its red component.
if you have red green color blindness, red appears ___
grey
you need all 3 ___ ___ for vibrancy, even if you have the cone for that color.
you still need all 3 CONE TYPES.
What is a tetrachromat?
an animal that contains cones that can detect wavelengths out side of visible light range. Ex/ insects have cones that can detect UV light.
how can bees detect flower types?
they are tetrachromats. they see flowers in a different way than we do because they can detect changes in UV radiation. This gives them an entirely new set of colors, and allows them to recognize polarized light and alternative flower pattersn that we cannot see.
Explain the receptors of a Mantis Shrimp
the mantis shrimp has 12 color receptors. it is the largest number of receptor types of any animal. The shrimp’s cones span both UV and IR detection. Can see heat waves.
Explain the results of the Mantis Shrimp color discrimination task.
The task involved showing ranges of different lights, and the shrimp would need to be able to recognize specific colors in order to get a food reward.
the color discrimination tasks tested FINE-COLOR discrimination to see if the shrimp could see alternative “colors”, considering it had 12 different receptors and humans only had 3. The shrimp couldn’t detect any more colors than humans could despite having more cone types.
Showed that although he had many cone types, the shrimp was lacking a color-recognition mechanism that prevented him from distinguishing fine colors.
explain the mechanism behind the opponent process throy
when you stare at a color, you lose sensitivity to that color and the opposing color is seen later on after you EXHAUSTED the cones of the original color.
Opponent process theory can be used to explian the ___ ___
after images
cells in opponent cells take into account the ___ ___ ___ a type of cone is being strimulated in the retina
NUMBER OF TIMES.
Difference between trichromatic and opponent process theories in terms of receptors and localization
the trichromatic theory involves how light is perceived at the retinal level.
the opponent process theory keeps track of which cones are activated and maintains opponent neuron processes BEYOND the retina.
the ratio of cone activity is received and processed by ___ ___ further in the brain. This allows for ___ detection
opponent neurons further in the brain. this allows for the detection of HUES.
explain how opponent process cells determine which cones are activated.
different shades of color/eex red elicit different number of long wavelength cones being strimulated. the opponent process cells process which cones are activated by each hue and allows us to see FINE COLOR in detail. We have fine color discrimination because of opponent process cells.
Trichromatic and opponent process theories are ____ theories. The trichromatic theory discusses color detection, and the opponent theory discusses HUE detection
complementing theories. We need both.
Why can’t the Mantis shrimp discern different hues despite having so many different types of cone receptors
the mantis shrimp does not have opponent cells. He cannot process the color he is seeing.
What is the effect of color constancy
allows us to maintain the same color understanding even we are in different lighting situation. Ex/ we know an object is the same color if its in the light or in the shade. If we see an object in the light, and then it goes under a tree, we do not think the object changed color.
how can color constancy be used as a visual illusion
some colors “light up” at times when in different lighting, but there is actually no difference in color.
In a visual illusion, the color may not be getting darker in the shade like we expect it to, so we think that the color is just completely different.
Our brain makes automatic corrections when we change lighting conditions.
Penumbra
the fuzzy border at the edges of a shadow.
___ ___ allows us to distinguish shadows from something that is TRULY just darker colored.
lightness constancy
reflectance edge
appearing dark because it is actually a DIFFERENT SHADE.
illumanence edge
appearing darker because it is in the shadow.
T/F: our brain can discriminate between reflectance and illuminence edges
true
Which area in the brain is involved in strictly perceiving faces?
the fusiform gyrus/fusiform face area.
T/F: the FFA can light up when seeing things that aren’t a human face, but may resemble a face.
true. it also lights up when we see cars because their lights resemble faces.
Explain the greeble study. what did they find in terms of the Fusiform gyrus activation?
trained people to look at greebles and tell one greeble from another. Pre training people had no response in the fusiform face area when trying to distinguish greebles. after training them (allowing them to study the greebles so they could tell them apart), people’s fusiform gyrus lit up when looking at the greebles.
therefore, the FFA also lights up when you’re trying to discriminate between DETAILS OF AN OBJECT, not just faces. Any image where we need to look at fine differences will result in activation of the FFA.
T/F: Any image where we need to look at fine differences will result in activation of the FFA.
TRUE. FFA does not just light up with only faces. They light up in pictures that resembly faces, or with objects that have fine detail.
