Lecture 2 Sept. 16 Cognitive
• Multi-Store model of Memory: The idea that info flows through our system.
I. Environmental input: sound, vision, etc.
II. Sensory registers: Aka. Sensory memory. Visual, auditory, etc.
III. *Short term store: temporary working memory. Rehearsal, coding, decisions,
retrieval strategies. This can trigger a response output.
IV. *Long term store: Permanent memory
V. These memory stores can be differentiated based on
iv. Type of Code
• Basics of Visual Perception
i. Reception of stimulation from environment
ii. Initial encoding into nervous system.
i. Process of interpreting sensory information
III. Sensory Structure: Light waves project onto retina (p.77)
i. Rods, cones, bipolar cells, ganglion cells,
ii. Rods/cones, black layer of neurons
iii. First to be stimulated by light waves
iv. Neural firing pattern from rod/cones to bipolar cells, then to ganglion cells.
v. Axons of ganglion cells form bundle called optic nerve vi. Nerve projects back to send neural message to visual cortex in occipital
IV. Cones are for color vision; rods are for black and white.
V. Compression: Only fraction of light waves reaches the retina. Especially in
peripheral vision, because we don’t need detail.
• How is information gathered?
I. Series of fixation-saccade cycles: moving our eyes around in a certain way, rapid
i. Eyes move in jerky patterns
ii. Not smooth
iii. Variable: 25ms-175ms-
iv. Nothing “seen” during this
i. Eyes pause to foveate and take in info
ii. Fovea is where highest resolution in eye is
• Sensory Memory: Neural activation in the retina is brief and terminates with external
stimulation. The perception of the event persists after stimulus is terminated. This implies
that a memory system exists. There is a memory system for each sense.
i. Happens over time.
ii. Sensory memory is activated by stimuli from the environment. Sensory
memory gets into our minds over time. If we do not see something long
enough, we don’t perceive all of it. It has been shown that it takes about
20ms to get stimuli into out system.
ii. Erikson and Collins Superimposed dot patterns: showed random
patterns and varied the time between patterns. When two patterns are
shown closely enough together, the letters can still be perceived. If they are shown far enough apart, two separate patterns are seen and the
letters were not perceived
ii. Whole report technique: showed people a bunch of numbers and asked
them to report everything that they said. This would lead us to believe that
the sensory memory is very small.
iii. Partial report technique: showed the same numbers and asked them to