Lecture 3 Sept. 23 Cognitive
• Pattern Recognition: We recognize patterns by only selecting certain information for
I. Template Models
i. Match stimulus to a mental template stored in memory. Support/examples
for this idea are barcodes (Every time the code is read the same product
a) Inefficient: generally, it is not possible to have enough templates for
b) Irregular world: A lot of the objects we process are irregular.
c) Strict match: they need a very strict match in order to work.
II. Feature Models
i. Feature more regular than patterns: Features are easier to recognize
than complex objects. We can recognize more complex things by first
recognizing their features.
ii. Complex objects composed of simple features: even people are
composed of simple objects.
iii. Gibson 1969: Studied Features of letters. Said that we actually perceive
letters as a breakdown of lines and curves.
iv. Neisser 1964: Had people look for letters amongst a whole bunch of
other letters. He found that it was harder to pick out the letter if it had
similar lines to the others. Ex. Easier to find the letter z in the following:
OUQZG than in these: KWYZX.
v. Hubel & Wiesel: there are different cells in the eye. He found this by
1. Simple Cells: Location specific
a) Simple patterns of light
b) Location specific c) Edge, slit, line
2. Complex: Same as simple but NOT location specific
i. Hypercomplex: Moving lines
a) Speed of transmition
b) Y (movement speed)
vi. Word Superiority Effect:
i. Subject is shown the letter D, then a mask, then asked if they saw
a D or a G.
ii. Subject is shown the letter WIND, then a mask, then asked if they
saw the word WIND or WING.
iii. Subjects are better remembering the word WIND than the letter D.
This is due to top down processing.
vii. Repetition Blindness: we fail to see something when it happens a
second time or is repeated.
i. RSVP: Rapid Serial Visual Presentation. Says that people fail to
respond to/see stimulus the second time.
viii. Avant & Lydall: Masking of BOY vs YOB. Found a shorter interval is
required to erase BOY than YOB. In other words, the interval between the
letters and the mask needed to be shorter for a real world. This is
because real words are processed much more quickly.
ix. Top Down: knowledge we already have is used to process information
vii. Object Recognition
i. RBC Theory: All objects are made up of features, and all features are
common forms called Geons (fundamental geometric forms). Our system
breaks objects down onto these geons, and we note where the geons
connect. These geometric combos are remembered. Bottom up model.
ii. Agnosia: Failure/difficulty in recognizing objects. Causes by specific
a) Apperceptive Agnosia: disruption in perceiving patterns. Can see
lines, colour, etc. but cannot process into a whole. Located in the right
parietal lobe. b) Associative Agnosia: Can form gestalt, can copy a drawing, but
cannot associate with meaning. Temporal lobes of both hemispheres.
iii. Prosopagnosia: disruption of face recognition. Can be visual or auditory
• Selective Attention
I. Filter Theory (Broadbent):