L11 - Colour vision Flashcards
(15 cards)
What is sensation?
Conversion of external stimuli into electrochemical signals in our brain
What is perception?
How these electrochemical signals are interpreted and represented
What is the definition of hue?
The property we normally use to describe colour, like blue, green and red
What is saturation?
How intensely the hue is expressed
What is brightness?
The perceived amount of light reaching your eye
What did Palmer (1777) find?
3 diff types of light sensory, each processing a specific wavelength
What did Young (1802) and von Helmholtz (1852) find?
3 sensors but each are sensitive over a range of wavelengths, but maximally for red, green and violet. These are the L-cones, M-cones and S-cones
What did Ewald Hering (1892) propose??
The opponent-process theory - to explain that colour perception is not simply a matter of cone receptors summating their responses, but that there are in fact three opponent dimensions that come together to produce colour vision
What did Isaac Newton conclude about colour mixing??
- White light was a combination of all colours
- Colours can be combined to generate new ones
This is called additive mixing
What theory did Chevreuil (1839)
The theory of simultaneous colour contrast
- noticed that colours appeared different depending on what colours surrounded them
What is subtractive colour mixing
Light energy is reduced when two sources are combined
What did Wallach (1948) find about colour consistencies?
Found that colours (including brightness) is perceived in relation to their surroundings
What did Nascimento and Foster (1997) and Foster (2011) suggest about theories for colour constancy?
That the differences and ratios in excitation between cone types enable us to perceive colours as being stable despite lighting conditions
What does Dael, et al. (2016) show about colours to express emotions??
That we associate certain colours with certain emotions - showed participants videos of an actor expressing happiness or panic.
- Colours along the red-yellow spectrum were deemed more appropriate for joy expressions
- Colours along the cyan-bluish hues were deemed more appropriate for fear expressions
What did Babin et al. (2003) find about colour and consumer behaviour?
They examined the effects of cool (blue) vs. warm (orange) interiors on shopping behaviour
- For a blue store: bright lights resulted in higher price fairness perceptions
- For orange store: soft lights resulted in higher price fairness perceptions
