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Lab in Human Cognition
Todd Gureckis
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Tuesday, January 26, 2010
Agenda for Today
Follow up lecture: What makes a good experiment?
Alignments between data and theory.
Discuss reading
What makes a good experiment?
Experiment 1 - collect data/begin analysis
Assign reading for Experiment 1
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Third
What makes a good
experiment?
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Where does life come from?
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Since 4th century B.C. the theory of
spontaneous generation dominated
thinking about this question
Nile River floods -> enriching soil, etc.. ->
frogs appear -> frog must come out of the
mud
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Francesco Redi (1668) Experiment
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John Needham (1745) Experiment
Boiled broth (thought to kill any
microorganisms), then let it sit out.
Still found evidence of microorganisms.
Revived the spontaneous generation
experiments
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Pasteur solved it
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What went wrong and why?
A failure to detect confounding
variables. Was it sloppy science?
Hard to say. The relevant variables
themselves were poorly understood.
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What went wrong and why?
A failure to detect confounding
variables. Was it sloppy science?
Hard to say. The relevant variables
themselves were poorly understood.
Big challenge in cognitive science...
What information in the environment
are people use and how? Difficult to
control, must proceed with extreme
caution.
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2, 4, 6
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Confirmation Bias - tendencies of humans
(scientists included) to seeks positive examples of
a theory rather than things that would refute it.
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Falsification
Karl Popper (1935) philosopher of science
“The Logic of Scientific
Discovery”
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Popper argued strongly against the latter, holding that scientific
theories are abstract in nature, and can be tested only indirectly, by
reference to their implications. He also held that scientific theory, and
human knowledge generally, is irreducibly conjectural or hypothetical,
and is generated by the creative imagination in order to solve
problems that have arisen in specific historico-cultural settings.
Logically, no number of positive outcomes at the level of
experimental testing can confirm a scientific theory, but a single
counterexample is logically decisive: it shows the theory, from which
the implication is derived, to be false. Popper's account of the logical
asymmetry between verification and falsifiability lies at the heart of
his philosophy of science. It also inspired him to take falsifiability as
his criterion of demarcation between what is and is not genuinely
scientific: a theory should be considered scientific if and only if it is
falsifiable.
-Wikipedia Karl Popper entry
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Falsifiable theories can in principal be ruled
out by performing a critical experiment.
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Alignments beween theory
and data
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Fourth
What do theories in
cognitive science really look
like?
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The Ideal Gas Law
PV = nRT
http://www.phy.ntnu.edu.tw/ntnujava/index.php?
topic=25
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Levels of Analysis
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Marr’s Three Levels
Marr, David (1982) Vision
Computational Level
What is the goal of the process and why is it
appropriate/adapted to the environment
Representational Level
How can the computational level be realized?
How is information represented?
What algorithms/processes are used?
Implementation Level
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Simon, H.A. (1998) “What is an ‘explanation’ of
behavior” in Mind Readings: Introductory
Selections on Cognitive Science
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Break
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