Transcript Document 7873378

Recap: How People learn
Classical conditioning
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Natural responses
Operant conditioning
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Reward based (non-natural)
Cognitive Psychology
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What’s going on in the brain
Eg. learning to read (observable, recognition,
autonomous
How people learn cont.:
Constructivism
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How individuals develop new knowledge
Previous exp. ≈ Observations
Explanations ≈ Hypothesis
Expectations ≈ Predictions
Experiment
Conclusions
Scientific Method
What is the scientific method
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Observation
Compare to other experimental results
If both do not agree?
Consistent with predictions
No; reject hypothesis and formulate a new hypothesis
Similarities with learning?
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New information
Compare to previous knowledge
Different from prior knowledge?
Reject prior or current information; seek out more information
Observation
Question
Hypothesis
Conclusion
Prediction
Experiment
Hypothesis: A potential explanation.
Prediction: An expected outcome based on the hypothesis.
Scientific Process:
fact or fiction?
Idealized method
Start anywhere
Not all learning needs experiments, but
experiments are a powerful way of
supporting or refuting hypotheses.
Hypothesis:
a proposal intended to explain certain
facts or observations.
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The hypothesis should describe the expected
relationship between the observation and the
independent variable: but not the actual
experiment (cause and effect approach).
What is the independent variable?
Some examples….
Do you “prove” hypotheses?
An experiment NEVER proves a hypothesis
- A hypothesis that successfully predicts something is a good
hypothesis – it is supported.
Why is this? because you can never rule out that another
hypothesis exists that makes the same predictions.
If two hypothesis make the same predictions, but for different
reasons, how can you tell which is right? More experimentation
is the answer.
Theory: A hypothesis that has withstood many attempts to falsify it.
Law: A well established theory with broad explanatory power.
Shifts in “What is Known” to be
scientifically true
Greek shepherd observing sun movement,
moon and stars.
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The cosmos is moving around us and earth is the
center of it all
This hypothesis was undeniable based upon the
evidence available at the time
But, other stars moved rather strangely
Claudius Ptolemy (greek philosopher) proposed
another hypothesis (very similar to first) in which
these “objects” could move in the patterns
noted….this thinking lasted, unfalsefied, for 1500
years.
Nicholas Copernicus
The earth was not the center of everything!
He hypothesized that the Earth was just a planet
orbiting the sun and spinning on its own axis.
Now we have two hypotheses! Which is correct?
More refined observations, experiments, etc.
were conducted and we now have been living
with the Copernican model for the last 500
years.
Let’s see what the future brings.
Experiment Design
(KISS Principle)
Keep it simple ……
Experimental terminology
Prediction:
The prediction is based upon the experiment
designed to test the hypothesis
If two almond groves are under different
watering regimes (schedules) then I would
predict that the greater watered grove has a
higher almond yield than the less watered grove.
The prediction includes the independent variable
and the dependent variable of the experiment.
•Independent Variable: The variable the experimenter
manipulates. (eg. amount of water) (almond study)
•Dependent Variable: The variable the experimenter
measures to describe the response. (eg. weight of
almonds harvested)
•Control Group: A group in which the experimental
treatment is not applied. Used as a standard for
comparison.
2 main types
“No treatment”
“Natural”
•Factors to be held constant: Any factors that might
affect the results other than the independent variable
•Observation: A cannon ball falls faster than a feather,
and cannon balls are heavier than feathers.
•The question: Does mass affect how fast an object falls?
•Hypothesis: Heavier objects fall faster because the force
of gravity acts more strongly on larger masses.
•Hypothesis-based Prediction: If the above hypothesis is
correct, then if we compare the rate of movement of two
objects that differ only in mass and are accelerated solely
by gravity, the heavier object should move faster.
Now we can set up an experiment where only mass varies;
then if the different masses move at the same speed, the
hypothesis is falsified, but if they move at a different speed, it
is supported.
•Experiment:
–Method: Balls that weigh either 10 grams or 50 grams, but with the same
diameter, are rolled down the same ramp with a 1 meter distance marked
on it. Each ball will be placed behind a wooden barrier at the top of the
ramp. This barrier will be removed to allow the ball to roll down the ramp
without being pushed. The time it takes each ball to travel the 1 meter will
be measured in seconds.
–Sample size: 20 balls of each mass will be used. The experiment is
relatively easy to conduct, and the only limitation is availability of balls, so
there is no good reason to do less. 20 samples per group is generally
considered an adequate sample size for a comparison of means.
–Independent variable: The independent variable is the mass, in grams, of
each ball.
–Dependent variable: The dependent variable is the time, in seconds,
each ball takes to travel 1m.
–Factors to be held constant: The following variables will be held constant
across treatments: the diameter of all balls; the slope of the ramp; the
distance each ball travels during measurement (1 m); the way the balls are
released.
–Control group: There is no control group in this experiment. A control
group would consist of balls with no mass – a physical impossibility.
Heavy
Light
A. Supports hypothesis
(seconds)
Time for ball to travel 1 m
(seconds)
Time for ball to travel 1 m
Data representation : Comparison of
means
Heavy
Light
B. Falsifies hypothesis
Figure 1. Potential relationships between the mass of the ball and
the time for it to roll 1 m. A: If hypothesis is correct and B: if
hypothesis is incorrect.
Science Process Skills
Observing
Classifying
Communicating
Measuring
Formulating Hypothesis
Predicting
Identifying and controlling variables
Testing hypothesis (a.k.a. experimenting)
Interpreting data