Term
| What is a JND? Are they constant across stimulus intensity levels? |
|
Definition
| Just noticeable difference |
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Term
| According to Weber’s Law, what happens to the JND as stimulus intensity increases? |
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Definition
| When the intensity increases the jnd increases |
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Term
| At low stimulus intensities, observers sometimes detect a stimulus and sometimes fail to detect it. How did Fechner explain this phenomenon? |
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Definition
| Threshold, there’s an absolute threshold but that threshold changes from moment to moment |
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Term
| Briefly describe the method of limits. |
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Definition
| Intensity starts below threshold, increases until detection (this amount is recorded), decreases until no detection. Repeat. |
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Term
| Briefly describe the method of constant stimuli. |
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Definition
| Intensities below and above threshold, threshold defined as 50% detection |
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Term
| Briefly describe the method of adjustment. |
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Definition
| Just like the method of limits, except the observer is adjusting the intensity levels |
|
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Term
| What are these methods (limits, constant stimuli, adjustment) supposed to be measuring? |
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Definition
|
|
Term
| What is the unit of Fechner’s psychophysical scale? |
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Definition
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|
Term
| What assumption did Fechner make in order to make this unit sensible? |
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Definition
| That all JND’s are subjectively equal |
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Term
| According to signal detection theory (SDT), is there such a thing as an absolute threshold? |
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Definition
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Term
| What 2 factors determine performance in a detection experiment, according to SDT? |
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Definition
| Sensitivity and response bias |
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Term
| In any detection experiment, there are 2 things that might be true (a signal was present, or it was not), and 2 things that an observer might report: I detected a signal, or I did not detect anything. This makes for 4 possible outcomes. What are they? |
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Definition
| Correct rejection, false alarm, miss, hit |
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Term
| What determines how an observer places their criterion for detecting a signal, according to SDT? |
|
Definition
| the relative benefits and costs |
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Term
| What 2 things make an observer more conservative? |
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Definition
| costs for false alarms, reward for correct rejections |
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|
Term
| What 2 things make an observer more liberal? |
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Definition
| costs for miss, reward for hits |
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|
Term
| What SDT statistic describes an observer’s sensitivity, independent of their bias? |
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Definition
|
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Term
|
Definition
| proportions of hits as a function of proportion of false alarms |
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Term
| What happens to an ROC curve as a signal becomes more detectable (i.e,. as an observer’s sensitivity to that signal increases)? |
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Definition
| they bow up and to the left |
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Term
| Briefly name and describe the family of methods developed by S.S. Stevens to measure psychophysical functions for intensity perception. |
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Definition
| Direct magnitude estimation, the observer assigns a number based on the intensity |
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Term
| Using these methods, what kind of function results? |
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Definition
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Term
| On discrimination tasks (i.e,. 2AFC), a characteristic curve relating performance to the physical difference between stimuli usually results. What is the shape of this curve? |
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Definition
|
|
Term
| What are the two most popular functions for fitting this curve? |
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Definition
| Cumulative Gaussian, weibol |
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|
Term
| What do we mean by a 2AFC task? |
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Definition
| Choose which of the two things that it was, can’t say I didn’t see it or I don’t know, have to pick A or B |
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Term
| In general, judging from psychophysical functions, is perception veridical (i.e., do you see things as they really are)? |
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Definition
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Term
| Again judging from psychophysical functions, can we say that perception is adaptive? |
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Definition
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|
Term
| Why do we have greater acuity in our central vision? |
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Definition
| this is where the fovea is. there are lots of cones which have 1 to 1 connectivity with bipolar cells |
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Term
| Why do we have greater sensitivity in our peripheral vision? |
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Definition
| Because convergent connectivity between rods and their bipolar cells |
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|
Term
| Why don’t we have great sensitivity and acuity throughout the visual field? |
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Definition
| Because there is a trade off relationship between acuity and sensitivity |
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Term
| The muscles that control pupil size are called what? |
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Definition
|
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Term
|
Definition
| The opening in the iris that allows light in |
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Term
| If a bright light is shone suddenly at the eye, the pupil closes quickly. This is ___________ reflex. |
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Definition
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|
Term
| What do we call the process of focusing at a particular distance? |
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Definition
|
|
Term
| What is the function of the lens? |
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Definition
| To focus light on the retina |
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Term
| How does the lens fulfill this function for both near and far objects? |
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Definition
| Cilliary muscles bend the lens |
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Term
| What is the 3-layer sheet of cells that transduces light on the back of the eyeball? |
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Definition
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|
Term
| What is the center of this sheet of cells called (i.e., the part that is in a small pit)? |
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Definition
|
|
Term
| What are the 2 types of cells that actually transduce light? |
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Definition
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|
Term
| Which one of these cell types is more numerous in the fovea? |
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Definition
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|
Term
| Which is more numerous in the periphery? |
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Definition
|
|
Term
| Which type of transducer is responsible for high-acuity vision? |
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Definition
|
|
Term
| Which type is responsible for high-sensitivity vision? |
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Definition
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|
Term
| These photosensitive cells are connected to __________ cells, which are connected to ____________ cells. |
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Definition
| Bipolar cells, ganglion cells |
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|
Term
| The axons of ____________ cells make up the _____________ nerve. |
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Definition
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Term
| Information from the visual fields is split, so that all information from a visual field goes to the contralateral (i.e,. opposite side) hemisphere, at what structure? |
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Definition
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Term
| The structure in thalamus that receives most of the projections from the eye, and sends most of its projections to visual area V1, is the _______________? |
|
Definition
| LGN, lateral geniculit nucleus |
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Term
| The process by which the eye focuses near and far objects is called what? |
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Definition
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|
Term
| This process is caused partly by vergence movements of the eye. What also happens to the lens? |
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Definition
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Term
| If the eyeball is too short, so that the plane of focus for the image is behind the retina, _______________ results. |
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Definition
| Far-sightedness, hyperopia |
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|
Term
| If the eyeball is too long, so that the plane of focus for the image is in front of the retina, ______________ results. |
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Definition
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|
Term
| When the lens loses its flexibility, either normally with age or abnormally early in life, _________________ results. |
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Definition
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Term
| From V1, information about object identity is fed forward along the ____________ pathway while information about motion and location is fed forward along the _______________ pathway. |
|
Definition
| Parvo-cellular, magno-cellular |
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Term
| True or false: the pathway from eye to LGN to V1 describes the only pathway from retina to brain. |
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Definition
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Term
| People with brain damage who cannot consciously detect lights in part of their visual field, but nevertheless can point to those lights, all the while insisting that they are guessing, have a condition known as ________________. |
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Definition
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|
Term
| The part of the visual field that causes a neuron in the visual system to change its firing rate is called the _________________________ of that cell. |
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Definition
|
|
Term
| What are the two types of ganglion cells? |
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Definition
| The M-cells and the P-cells |
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|
Term
| A spatial arrangement of receptive fields such that nearby parts of the visual field are represented by nearby neurons is called a ____________________. |
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Definition
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|
Term
| This type of architecture is present in the retina, and also in ______________ and _____. |
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Definition
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|
Term
| What is an on-center, off-surround receptive field? |
|
Definition
| Stimulation on center: cells firing rate increases (turn on), stimulation on periphery of the receptive field causes the cells firing to decrease (turn off) |
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|
Term
| What is an off-center, on-surround receptive field? |
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Definition
| Stimulation on center causes cells firing rate to DECREASE, stimulation on periphery of the receptive field causes the cells firing to INCREASE |
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|
Term
| Describe the 3 types of edge detectors in V1 and the types of stimuli they respond to. |
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Definition
1. Simple-cells (respond to straight edge at a particular orientation)
2. complex-cells (respond to straight edge in a larger receptive field)
3. hyper-complex cells (an edge at a particular orientation only of a particular length) |
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|
Term
| These cells (simple, complex) are arranged into columns, termed __________ columns. Adjacent columns respond to what kind of stimuli relative to each other? |
|
Definition
| Orientation-columns, nearby orientations |
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Term
| True or false: cells in V1 are stimulated by input from only 1 eye. |
|
Definition
|
|
Term
| What are ocular dominance columns? |
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Definition
| Stimulated more strongly by one eye than the other |
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|
Term
| What is an arrangement of 2 rows of orientation columns, one for each type of ocular dominance, called? |
|
Definition
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|
Term
| The fovea, although covering only a tiny part of the visual field, is represented by the majority of V1, a phenomenon called ____________________________. |
|
Definition
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|
Term
| When it is dark, visual information is handled by what kind of vision? |
|
Definition
|
|
Term
| What kind of photoreceptor is most associated with this kind of vision? |
|
Definition
|
|
Term
| What is consequence of this fact for color perception in low light? |
|
Definition
| We have poor color perception in low light |
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|
Term
| In bright lighting, visual information is handled by what kind of vision? |
|
Definition
|
|
Term
| What photoreceptor is most associated with this kind of vision? |
|
Definition
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|
Term
| The process by which sensitivity increases with time in darkness is called what? |
|
Definition
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|
Term
| Experiments indicate that under the right conditions (and what are those conditions?), as little as ______ photons of light may cause a conscious sensation of light. |
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Definition
|
|
Term
| What are the 5 influences on sensitivity discussed in class? |
|
Definition
1. State of the photoreceptor’s transduction molecule population (i.e., how many are available to transducer light into electrical potential)
2. Wavelength of light
3. Size of the stimulated area
4. Part of the retina that is stimulated
5. Duration of stimulation |
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|
Term
| What do we call the point at which perception of 2 sequential flashes of light cannot be distinguished from a single flash of light? |
|
Definition
| CFF- critical flicker frequency |
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|
Term
| What is detection acuity? |
|
Definition
| The smallest stimulus that can be detected |
|
|
Term
|
Definition
| The smallest offset between two lines that can be detected |
|
|
Term
| What is resolution acuity? |
|
Definition
| Smallest gap in an object that can be correctly detected |
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|
Term
| What is recognition acuity? |
|
Definition
| The smallest that familiar objects can be recognized |
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|
Term
|
Definition
| Smallest moving object that can be detected as moving |
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|
Term
| What is the technical term for far-sightedness? |
|
Definition
|
|
Term
| What is the technical term for near-sightedness? |
|
Definition
|
|
Term
| What causes near-sightedness, genes or environment? |
|
Definition
|
|
Term
| A sudden, ballistic movement of the eye is what? |
|
Definition
|
|
Term
| The periods between these movements, when the visual system takes in information, are called what? |
|
Definition
|
|
Term
| In order for slow movements of the eye to be smooth, there must be an external moving stimulus. These movements are called what? |
|
Definition
|
|
Term
| The system that allows us to stay focused on a stationary target while our head moves is called what? |
|
Definition
|
|
Term
| The reflex that causes our eyes to move when there is a sudden movement in the visual field is called what? |
|
Definition
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|
Term
| When our eyes move centrally toward each other to focus on a nearby object, this is what kind of eye movement? |
|
Definition
|
|
Term
| The tiny eye movements that keep our retina from getting fatigued with repetitive stimulation are called what? |
|
Definition
|
|
Term
| What happens to our vision during a saccade? |
|
Definition
|
|
Term
|
Definition
| Suppression of reception caused by stimuli occurring right before or right after the masked stimulus |
|
|
Term
|
Definition
| Stimuli occurs right before the masked stimulus |
|
|
Term
| What is backward masking? |
|
Definition
| Stimuli occurs right after the masked stimulus |
|
|
Term
| What are the 3 components of color? |
|
Definition
| Hue, brightness, saturation |
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|
Term
| What physical property of light is most related to perception of hue? |
|
Definition
|
|
Term
| What type of photoreceptor cell mediates color vision? |
|
Definition
|
|
Term
| How many types of color-sensitive photoreceptor are there? |
|
Definition
|
|
Term
| What theory of color vision does this number provide support for? |
|
Definition
|
|
Term
| What phenomenon of color vision does this number explain? |
|
Definition
| Additive color mixing: The fact that all visible colors can be made as mixtures of three colors as long as no two colors can be mixed to make the third color |
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|
Term
| What is the other main theory of color vision? |
|
Definition
|
|
Term
| What phenomenon of color vision was this theory meant to explain? |
|
Definition
|
|
Term
| Is there any physiological evidence for this theory? |
|
Definition
|
|
Term
| What phenomenon does the term color constancy refer to? |
|
Definition
| Color stays the same under a wide range of luminance |
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|
Term
| The condition of insensitivity to the color red is _______________. |
|
Definition
|
|
Term
| The condition of insensitivity to the color green is _______________. |
|
Definition
|
|
Term
| The condition of blindness to the color red is _______________. |
|
Definition
|
|
Term
| The condition of blindness to the color green is _______________. |
|
Definition
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