1. Intro Flashcards
How are human senses different from other species?
Humans: 400-700nm, small sound frequency range. Bees: UV Dogs and cats: high freq sounds Rattlesnakes: IR Elephants: low freq sounds
What is the evolutionary reason for perception?
Important types of energy in the environment govern which senses have developed through survival of the fittest mechanisms.
Define sensation
The input from sensory organs from our environment
Define perception
The interpretation of sensory information
Similarities between the eye and a camera
Pinhole and pupil
Imaged inverted on screen and retina
Differences between eye and a camera
Perception is more than the retinal image for example adaptation, illusions, experience-dependent perception and heuristics.
What is the moon illusion?
The moon remains the same size at a 0.52 degree visual angle however when it is low on the horizon it appears to be bigger.
Why are illusions useful?
They tell us about the choices or rules that the system uses to construct a visual representation from a retinal image.
What is a physiological illusion?
One with a physical cause such as tiring out or providing excessive stimulation.
What is a perceptual illusion?
Misapplied knowledge in interpreting or reading sensory information. A 2d retinal image is ambiguous with an infinite number of configurations which could have created it. The perceptual system constructs the most likely explanation.
What is the MAE illusion?
The motion after-effect illusion is due to fatigue of direction-selective motion channels. It results in static images appearing to move in the opposite direction.
How does the Hermann or Scintillating grid work?
An excited neurone in the fovea decreases activity of surrounding neurones in the receptive field - lateral inhibition. Therefore the increased luminance in the fovea representation excites the ganglion cell which inhibits cells in the surroundings resulting in the intersections appearing darker.
What is the Thatcher illusion?
Can’t detect changes in features in an upside-down face but you can when the face is the right way up.
