8C - Visual Perception Flashcards
what factors influence visual perception
the biopsychosocial model
what are biological factors
internal genetic and/or physiologically based factors
how is the eye involved in visual perception
the retina contains photoreceptors which are the sensory receptors of the eye. they receive light and convert it into sensory info into a form that can be sent to the brain.
what are the 2 types of photoreceptors
rods and cones
what are rods
photoreceptors that allow someone to see in low levels of light (black and white)
it allows peripheral vision
what are cones
photoreceptors that allow someone to see colour and fine details in well-lit conditions (a rainbow)
name 2 biological abnormalities
color blindness and short-sightedness
what is colour blindness
when people struggle to differentiate between certain colours as a result of defective photoreceptors. (usually a genetic cause)
3 types of colour blindness: red-green, blue-yellow, and complete colour blindness (monochromacy)
what is short sightedness
only causes far away objects to appear blurry (myopia) due to a refractory error. this means the focal point of one or both eyes is located in front of, instead of on, the retina
can be corrected with prescription glasses or contact lenses
what are depth cues
depth cues are a source of info which help perceive how far away objects are, using internal and external cues (allows to see things in 3D)
binocular vs monocular depth cues
binocular - requires the use of both eyes to determine the depth of objects that are close
monocular - requires the use of one eye, as most depth cues are monocular
types of monocular depth cues
accomodation, motion parallax and pictoral depth cues
what is accomodation
involves our lens bulging and flattening according to how far away an object is
nearby objects - lens bulges
distant objects - lens flattens
what is motion parallax
uses our perception of movement to tell how far away things are
objects closer - appear faster
objects further - appear still
what are pictoral depth cues
often manipulated by artists when painting or drawing
these include:
- relative size
- height in visual field
- linear perspective
- interposition
- texture gradient
what is relative size
the image larger on the retina is perceived as being closer, and the image that is smaller on the retina is perceived as being further away
what is height in visual field
the closer objects are to the horizon line, the further away they appear
what is linear perspective
the convergence of parallel lines: the closer the lines converge, the more distant the path
what is interposition
when objects overlap, we perceive the covered object as being further away than the one obscuring it.
what is texture gradient
the closer we are, the more detail of texture we can see
types of binocular depth cues
retinal disparity, convergence
what is retinal disparity
the amount of differences between each of the images received by the brain from each retina, indicates the distance of the object
the more differences, the closer the object
what is convergence
the level of tension experienced in the muscles responsible for turning the eyes, thus giving us info about the distance of the object.
the more tension, the closer the object
what are psychological factors
internal factors pertaining to one’s mental processes (cognition, attitude, beliefs and thoughts)
