Psychology of Thinking:
Embedding Artifice in Nature
Perceived Complexity
• Many things that appear complex are result of simple
mechanism acting on a complex environment
• Consider the path of ant
on seashore or skier on
mountain slope
– Path might be mistaken
for a student’s path
through problem/solution
space when solving a complex problem
• Complexity largely due to not being able to
anticipate obstacles
Perceived Complexity
• “An ant, viewed as a behaving
system, is quite simple.”
• Controversial hypothesis?
– “Human beings [minus emotions
and memories], viewed as
behaving systems, are quite simple.”
• Do you believe Simon?
• Why does Simon believe this?
• How does it relate to theory of computing?
Understanding Thinking
• Examine results from cognitive psychology
– What do they tell us about capabilities?
– What do they tell us about limits?
• Look at
– Problem solving
– Concept attainment
– Memory skills
– Natural language processing
Problem Solving as Search
• Generalizing search
(e.g. cryptoarithmetic problems)
– Brute force solutions
– Pruning tree based on
contradictions
– Algebraic solution based on design constraints
• “the more sophisticated the search strategy,
the less search was required”
Problem Solving as Search
• My take: the more domain knowledge
applied, the less search is required
– Is search the right word?
– Generate and test vs. compute value
• People change strategies – is this just
searching for a search strategy?
• Lesson: watching people solve problems can
provide information about cognitive processes
Concept Attainment
• Example with cards
– Determining which cards show things in a class of items
and which are not in the class
– Experiments show
• People do not always discover strategies that could be taught
• People do not have sufficient memory unless process is slowed
down
• 7 +/- 2 elements in
short-term memory
• 5-10 seconds to move
chunk to long-term
Patterns in Experimental Results
• Problem in reporting experimental results in variety of
metrics
– # of trials, # of errors, time to criterion
• Learn unrelated nonsense syllables (Task A)
– 10-15 seconds each
• Learn unrelated words or related nonsense syllables
– 1/3 time of Task A
• Learn continuous prose
– 1/10 time of Task A
• Modeling experience with EPAM
– Approximately predicts times found in studies
• Simon suggests 2 chunks of short-term memory
– Only 7 to 10 if no interruptions to task
Organization of Memory
• Recall of randomized characters show chunking (at
multiple levels)
– Three to four at each level?
– Simon hypothesizes list structure (LISP)
• Recall of chess boards
– All are slow on randomly placed chess
pieces
– Experts faster on boards that made
sense
• In practice, problem solving occurs
in a combinations of verbal,
mathematical, and diagramatic reasoning
• Potential issues with Simon’s interpretation
– Simple problems -> simple solutions
– What about perception?
Natural Language Processing
• Connection between transformational
linguistics and information-processing
psychology
• I saw the man on the hill
with the telescope
– SAW ((I, WITH (telescope)),
(man, ON (hill)))
• Only the expressible
thinkable? (vice versa?)
What does it mean to know?
• Searle’s Chinese Room
Lessons / Summary
• “the system is basically serial in its operation”
– Do you agree?
– Where is this true? Where might it be false?
• Experimental work can provide insight into
cognitive processes
• “we should not expect it [cognition] to
become essentially more complex”
– Why not? Should we expect for it to remain
simple?