Week 5 Flashcards
(22 cards)
What are the three approaches to perception?
Bottom up - perception is built using feature detectors increasing in complexity; Gestalt - a more holistic approach; Direct - perception is from the environment
What is the Gestalt approach to perception?
It is more than the sum of the part; step 1 = figure/ground (determine what is the background and then what is an object); step 2 = principles of grouping (NS innately predisposed to organise sensory input along certain principles of group)
What are the principles of grouping?
Proximity, similarity/simplicity, good continuation, good form,
Serial vs parallel processing.
Serial - slow, involves conjunctions of primitive features; parallel - fast, involves early analysis of primitive features
What is involved when recognising objects?
Code features, taking context into account, recognise object.
What is the geon theory of recognising objects?
Everyday objects are made up of a series of basic geons or shapes.
What is perceptual constancy?
Ability to perceive an object is the same even as the illumination and retinal image changes.
What are the difference types of perceptual constancy?
Lightness, shape, size, colour, orientation.
What is lightness (brightness) constancy?
The perception that familiar objects have a constant lightness, even while illumination varies.
What is shape constancy?
Perception that shape of an object doesn’t change just because image on the retina does.
What is size constancy?
Perception that an objects size remain the same even as the retinal image changes.
What is colour constancy?
Perception that familiar objects have a consistent colour, even if changing illuminations alter the wavelength reflected.
What are the three factors that colour has?
Physics, physiology, perception.
Tri-chromatic theory vs. Hering’s Opponent-Process theory.
Tri-chromatic - perceived colour of an object is determined by the ratios of the responses of the three cones types in the retina of the eye. Hering - Visual system (cones) responds differently to opponent colour pairs. One colour will excite a cone while the opponent colour will inhibit that cone.
What evidence is there for Hering’s Opponent Process of colour perception?
Categorial perception of colours - international grouping of basic colours; simultaneous colour contrast, colour afterimages, colour blindness occurs in combinations of red/green and blue/yellow.
Which theory of colour perception is correct; Hering or Tri-chromatic?
Both; there are three cones and your sensation of colour is based on the relative activity of the three. Your perception of colour is based on the relative colour in the opponent pairs.
The opponent-process theory argues that…
All colours are derived from three antagonistic colour systems black-white, blue-yellow and red-green.
For the perception of light waves, 700 nanometers is to __ as 400 nanometers is to __.
Red; violet.
Even though the image of your dog on your retina changes as your dog runs to fetch a stick, you do not perceive your dog as getting smaller, Which process of perception explains this phenomenon?
Perceptual constancy
My ability to read a page by altering the position of my eyes is due to what?
Superior colliculus.
The recognition-by-components theory asserts that we categorise objects by breaking them down into their component parts and then what?
Matching the components against stored ‘sketches’ in memory.
You are in a museum. A statue is in the middle of the room. You walk around it and examine it from many places in the room. The retinal images of the statue change, but you do not perceive the statue as changing. This process is known as?
Perceptual constancy.
