Perception Flashcards
What is sensation?
Physical stimulation of the five senses processed by sense receptors.
What is perception?
The brain’s interpretation of sensory information.
Which illusion is this?
The Ponzo illusion.
It works because of misinterpreted depth cue. You perceive the horizontal line higher up as longer.
Which illusion is this?
The Müller-Lyer illusion.
It works because of misinterpreted depth cue.
The two lines are the same length. The line with outgoing fins appears longer.
Which illusion is this?
Rubin’s vase.
This is ambiguous.
There is a vase and two faces but the brain alternates between which is perceived.
Which illusion is this?
The Ames room.
This works because of misinterpreted depth cues.
The room is the shape of a trapezoid and the floor painted to look like it is rectangular. People are seen as different sizes even though they are the same.
What are the two binocular depth cues?
Retinal density This is the difference between the view of the left and right ey which gives information on depth and distance.
Convergence Eyes point closer together when an object is close. Muscles work harder when they are converging which enables perception of distance and depth.
What are the 4 monocular depth cues?
Height in Plane Objects higher up look further away.
Relative size Smaller objects appear further away.
Occlusion An object obscured by another appears further away.
Linear Perspective Parallel lines e.g. the sides of straight tracks like railway lines, appear to get closer as they become more distant and eventually come to a point.
Optical illusions
What is size constancy?
Objects perceived as constant size despite size on retina changing with distance. This can be seen in the three man illusion.
(You can be reminded of this from the Father Ted clip - “small…. far away!”)
Optical Illusions
What are misinterpreted depth cues?
Objects apparently in the distance scaled up by brain to look normal size, causes visual illusions.
e.g. Ponzo illusion (converging lines give illusion of distance)
Muller Lyer illusion (outgoing arrowheds make line look like inside corner of the room, ingoing arrowheads look like outside of building)
Optical Illusions
What are ambiguous figures?
Two possible interpretations of images. Brain can’t decide which is correct.
e.g. duck/rabbit
Optical Illusions
What is fiction?
Seeing something that isn’t there.
e.g. Kanizsa triangle
What is Gibson’s direct theory of perception?
Perception doesn’t draw on past experience. Sensation and perception are the same.
The eyes detect everything we need without having to make inferences.
What are optic flow patterns?
When moving, things in the distance appear stationary (e.g. the moon) and everything else rushes past (e.g. trees)
Evidence for Gibson’s theory (eyes have all the information they need to see speed and distance)
What is motion parallax?
A monocular depth cue.
When we are moving past them, closer objects appear to move faster than objects that are futher away.
Evidence for Gibson’s theory.