The Computer Metaphor l The brain is a computer (an information processing device) l The mind is a (collection of) programmes l Our perceptions and cognitions are constructed out of the collective activity of these programmes

The Hard Problem Why does (some of) the brains activity generate subjective experience? Having explained everything physical about the brain, there is something still left over – experience e.g. Childbirth See David Chalmers (1996) book, The Conscious Mind & your 1st year Consciousness course notes

Cognitive Models l Cognitive models fractionate the mind l Initial questions for any cognitive model »How many mechanisms? »What does each mechanism do? »How do the mechanisms work together? - functional architecture l How do you find answers to these questions?

Inspiration l Brain anatomy and function? »What happens to cognition after brain damage? »How are cognitive functions carried out by the brain? l Man-made computing devices? »How do computers represent, store and process information? l Introspection?

Look Within? l Generates descriptions of memory phenomena »Memories pop into mind. »It helps to have a cue to jog the memory. »Sometimes they come back involuntarily l But how? »How does information become conscious? »Where did it come from, where does it go? »How is the target memory found? »How can you be sure you have the right memory? »How do you know the memory contents are accurate

It may depend upon your span of attention

It may depend upon the fidelity of episodic encoding Low fidelity Hi-fidelity

Proprioception

Size Constancy and After Images l After images have a constant retinal size l After images change size if their perceived distance changes (Emmerts Law). l The visual system somehow combines the constant retinal signal along with distance information to generate the apparent size of the after imge.

A Visual and Proprioceptive Illusion l Subjects were dark adapted for 5 minutes l After image of hand produced by a flash gun positioned above subjects head l Now in total darkness, hand is moved either towards or away from face l Subject reports any change in size of afterimage, relative to initial size at start point.

What do the Illusions Reveal? l Hidden visual and proprioceptive mechanisms that underlie conscious perception l The constructive nature of our perceptions l The tip of the iceberg?

Summary l A host of processing mechanisms generate our conscious experiences l The nature (i.e. how they work) of these mechanisms is hidden from us l We dont realise the extent to which our percepts and thoughts are constructed