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| Question | Answer |
| how do we go from the distal stimulus to the proximal stimulus with visual perception? | light |
| what is light? | a form of electromagnetic energy & travels as a wave |
| what is a wavelength & intensity? | wavelength: peak to peak intensity: peak to trough |
| how do we psychologically experience wavelengths & intensity? | wavelength is perceived as colour, intensity is perceived as brightness |
| what is the measurement/units of the position of wavelengths we're sensitive to?? i.e. visible light | 400 nm - 700 nm |
| what are the colours for short, middle & long wavelengths? | short: violets & blues middle: greens & yellow long: reds |
| how does light help us perceive the distal stimulus? (proximal stimulus) | light that is emitted from a light source, scatters into the environment, is reflected from from objects |
| what is the function of the eye? | to produce in-focus images to the receptor cells |
| where are receptor cells located? what're they called? (specialisation) | in the retina -- photoreceptors |
| Which parts of the eye form an edjustable aperture? | Iris & pupil |
| what are the iris & pupil? | iris: coloured bit of eye pupil: black hole in the middle |
| what does the pupil allow for? | light to pass thru the eye to the receptor cells |
| what is an adjustable aperture? | where the iris & pupil work together to control & change the size of the pupil to change -- limiting or increasing -- the amount of light that ca pass thru |
| what role do the cornea and the lens have? Where are they located? | bending & focusing light to form an in-focus image onto the retina Cornea - front most layer Lens - right behind pupil |
| what is the focusing power of the cornea & lens? | cornea: 80% lens: 20% |
| which of the cornea & lens can change size? Why? | Lens -- controlled by the ciliary muscles |
| what is the process of the lens' changing shape due to the ciliary muscles? | accomodation |
| what are the effects of the lens being fatter & thinner? | fatter = close objects focused (focusing point reaches closer instead of beyond) thinner = far objects focused (focusing point reaches farther) |
| Name the two refractive errors & what they mean | myopia - nearsightedness, focus point is too short before it reaches the retina hyperopia - farsightedness, focus point is beyond retina |
| which glasses & lens' shape can fix myopia & hyperopia? | concave - myopia, bends light less, focus point travels further Convex - hyperopia, bends light more, focus points gets shorter & closer |
| how is light being not so properly bent with each refractive error? | myopia - light bent too much, doesn't reach retina hyperopia - light bent too little, goes beyond retina |
| what is the retina? what is it composed of? | photosensitive layer at the back of the eyeball, composed of multiple layers of diff. cells & neurons |
| what are photoreceptors? what do they contain? | light-sensitive receptors that carry out transduction, contain photopigments |
| the two types of photoreceptors | cone & rod |
| which photoreceptor is best at night? | rod |
| which photoreceptor perceives colour? | cones |
| which photoreceptor is responsible for the purkinje shift? what is it? | rod cells as they're monochromatic - red is a darker shade of grey than green |
| which wavelength are rod cells most sensitive to? | middle, green ones |
| what are the 3 types of cone cells? | red, green and blue |
| what is the fovea? | a small central area of the retina, right behind the pupil, which is densely packed with cone cells and has around 150k cells per millimetre squared |
| what is dark adaptaion? | where our eyes recover & regain their sensitivity to light when going into a dark place after being in a bright place |
| after 20-30mins in the dark, how much reater is our light sensitivity? | x100k |
| what effect does very bright light have on our photopigets? | bleaching effect |
| what is convergence? which photoreceptor has more of it? | where one neuron receives signals from many others -- rod cells |
| on average, one ganglion cell receives signals from... | 120 rods, 6 cones |
| what is acuity & what is it dependant on? | acuity is the ability to detect fine details of a stimulus -- and is determined by neural convergence |
| The greater the neural convergence.. | the lower the acuity |
| which photoreceptor has higher acuity? | cone cells -- as they have lower neural convergence |
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