PSY350: WEEK 4 The Senses: Vision

Vision What’s up this week? How we see  Parts of the eye  Functions of the parts of the eye Interpreting what we see 1. Brain parts that interpret messages from the eye 2. Remembering 3. Selecting 4. Illusions and Tricks of the Mind

How We See: Physiology Structure (the parts) Sequence (the process) Visual pathways (crossed!)  Optic nerves  Optic chasm  Lateral geniculate nucleus (part of the thalmus)  Optic radiation  Visual cortex... And on via dorsal and ventral routes

Interpreting What We See: Visual Pathways Dorsal (“Where”)  Motion + Timing + Depth  From visual cortex to parietal cortex  No need for conscious thought Ventral (“What”)  Shape, colour, depth...  Matched to previous memories in temporal lobe (identify)  Moves on to frontal lobes for meaning and significance – conscious perception  See also: ‘Recognizing Faces’ (p. 82)  face recognition area and amygdala

Interpreting What We See Illusion: Depth Illusory motion Illusory depth (the “where” pathway)

How We See – Visual Perception “Bottom up”  Pre-sets the brain with information about the whole field of vision “Top down”  Selects which parts of the scene to make conscious Colour and shade are influenced by context (and expectations) More illusions: brightness, form, colour

Interpreting What We See 2. Remembering  Iconic memory

Interpreting What We See 3. Selecting Paying attention Simons Lab: Selective Attention UBS Visual Cognition Lab areas/demonstrations/

Interpreting What We See 4. Illusions and other cool stuff “Rules” govern how we see, and how we understand what we see  Motion Parallax:  Gestalt Laws of Form Perception

Interpreting What We See “Binocular Rivalry”

Interpreting What We See Afterimage - confuse your photoreception: Stare at the central point (plus sign) of the black and white picture for at least 30 seconds and then look at a wall near you, you will see a bright spot, twinkle a few times, what do you see? or even who do you see?

Interpreting What We See Stare at the eye of the red parrot while you slowly count to 20, then immediately look at one spot in the empty birdcage. The faint, ghostly image of a blue-green bird should appear in the cage. Try the same thing with the green cardinal, and a faint magenta bird should appear.

Interpreting What We See

Illusion: Perceptual Drift

Illusion: Count the Dots

Illusion: Are These Lines Slanted?

Interpreting What We See Contextual cues are important! The Ebbinghaus Illusion

Interpreting What We See Contextual cues are important! !