Perception Flashcards
Sensation
Physical stimulation of the sensory receptors is processed by sense receptors.
Our brain interprets the information from our five senses which leads to perception.
Perception
Organisation and interpretation of sensory information by the brain.
Information received from sense receptors is combined with the brain’s interpretation of what that information means.
Difference between sensation and perception
Sensation is the detection of a stimulus in the environment, such as light or sound waves.
Perception is the brain interpreting and understanding these sensations.
Theories of perception
- Gregory’s constructivist theory sees a difference between sensation and perception.
- Gibson’s direct theory sees them as being the same thing.
Ponzo Illusion
Misinterpreted depth cue.
Two separate horizontal lines of the same length, surrounded by two lines converging into the distance.
People perceive the higher horizontal line as longer than the one below.
Müller–Lyer illusion
Misinterpreted depth cue.
Two separate vertical lines of the same length, one with ingoing fins and the other with outgoing fins.
People perceive the vertical line with outgoing fins as longer than the vertical line with ingoing fins.
Rubin’s vase
An ambiguous figure.
Image of two faces and a vase in the same picture.
Both are correct so your brain can’t decide which one it is.
Ames Room
Misinterpreted depth cue.
Invented by Ames (1934).
Room looks normal but is actually the shape of a trapezoid.
When two people stand on either side on the back wall, one appears to be much bigger than the other even though they are both the same size.
Visual Cues
Features of the environment that give us information about movement, distance, etc.
Visual Constancies
seeing objects as the same despite seeing them from different angles and distances.
Monocular depth cue
A way of detecting depth or distance, which will work with just one eye.
Monocular depth cue (Height in plane)
Objects higher up in the visual field appear further away
Monocular depth cue (Relative size)
Smaller objects in the visual field appear further away.
Monocular depth cue (Occlusion)
Objects that obscure (hide) or are in front of others appear to be closer whilst objects behind other objects seem further away
Monocular depth cue (Linear perspective)
When parallel lines converge the point at which they come together, the vanishing point, is perceived to be further away.
Binocular depth cue
A way of detecting depth or distance, which requires two eyes in order to work.
Binocular depth cue (Convergence)
The eyes converge closer together when objects are close to us. Muscles round our eyes work harder when objects are close. This information is sent to the brain to give information about depth and distance.
Binocular depth cue (Retinal disparity)
Each eye sees things differently as they are positioned on the face about 6 cm apart. Retinal disparity is the difference between the left and right eye’s view which the brain receives to give information about depth and distance.
Misinterpreted depth cues
Objects in the distance that appear smaller are scaled up by our brain so they look normal size.
Sometimes the brain perceives distance when there isn’t any which creates a visual illusion.
Size constancy
The brain perceives familiar objects as a constant size despite the size of the image they produce on our retina changing with distance.
Ambiguous figures
A type of visual illusion where there are two possible interpretations of the same image, and the brain cannot decide which one to choose.
Fiction
A type of visual illusion that causes the brain to perceive something that is not there.
Gibson’s Direct Theory of Perception (Direct perception)
Sensation and perception are the same thing. The eyes detect everything we need to judge depth, distance and movement. We don’t need past experience.
Gibson’s Direct Theory of Perception (Optic flow patterns)
Everything in our optic array gives us all the information we need to be able to judge depth, distance and movement. When moving, the point we are moving towards stays stationary and everything else rushes away from it which let our brains know we are moving.
Gibson’s Direct Theory of Perception (Motion parallax)
He thought binocular and monocular cues were needed so that we are able to judge depth and distance accurately. One cue is motion parallax (monocular depth cue) where objects that are closer to us in our visual field are moving further away. objects closer in our visual field appear to move faster than objects further away.
Gibson’s Direct Theory of Perception (The influence of nature)
Perception is innate, we are born with the ability to perceive, rather than it being a skill we learn through experience.
The eyes detect fine changes in light, texture, movement and depth so we can understand distance and depth.
Gibson’s Direct Theory of Perception (Evaluation)
- A strength of Gibson’s theory is that it has real-world meaning.
Research was based on the experience of pilots from the Second World War.
This makes it more relevant to explain how we perceive the world on a daily basis. - A weakness of Gibson’s theory is that it struggles to explain visual illusions.
Gibson proposed that we will always perceive accurately whereas illusions trick the brain into misperception.
This suggests there is more to perception than his theory suggested.
Gregory’s Constructivist theory of Perception
