Recap: How People learnRecap: How People learn

Classical conditioningClassical conditioning Natural responsesNatural responses

Operant conditioningOperant conditioning Reward based (non-natural)Reward based (non-natural)

Cognitive PsychologyCognitive Psychology What’s going on in the brainWhat’s going on in the brain Eg. learning to read (observable, recognition, Eg. learning to read (observable, recognition,

autonomousautonomous

How people learn cont.:How people learn cont.:

ConstructivismConstructivism How individuals develop new knowledgeHow individuals develop new knowledge Previous exp. Previous exp. ExplanationsExplanations ExpectationsExpectations ExperimentExperiment ConclusionsConclusions

≈≈ ObservationsObservations

≈≈ HypothesisHypothesis

≈ ≈ PredictionsPredictions

Scientific MethodScientific MethodWhat is the scientific methodWhat is the scientific method ObservationObservation Compare to other experimental resultsCompare to other experimental results If both do not agree?If both do not agree? Consistent with predictions Consistent with predictions

No; reject hypothesis and formulate a new hypothesisNo; reject hypothesis and formulate a new hypothesis

Similarities with learning?Similarities with learning? New informationNew information Compare to previous knowledgeCompare to previous knowledge Different from prior knowledge?Different from prior knowledge?

Reject prior or current information; seek out more informationReject prior or current information; seek out more information

Hypothesis

Hypothesis: A potential explanation.Hypothesis: A potential explanation.

Observation

Experiment

Conclusion

Prediction

Question

Prediction: An expected outcome based on the hypothesis.Prediction: An expected outcome based on the hypothesis.

Scientific Process:Scientific Process:fact or fiction?fact or fiction?

Idealized methodIdealized method

Start anywhereStart anywhere

Not all learning needs experiments, but Not all learning needs experiments, but experiments are a powerful way of experiments are a powerful way of supporting or refuting hypotheses.supporting or refuting hypotheses.

Hypothesis:Hypothesis:a proposal intended to explain certain a proposal intended to explain certain facts or observations.facts or observations. The hypothesis should describe the expected The hypothesis should describe the expected

relationship between the observation and the relationship between the observation and the independent variable: but not the actual independent variable: but not the actual experiment (cause and effect approach). experiment (cause and effect approach).

What is the independent variable?What is the independent variable?

Some examples….Some examples….

Do you “prove” hypotheses?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 Shifts in “What is Known” to be scientifically truescientifically true

Greek shepherd observing sun movement, Greek shepherd observing sun movement, moon and stars.moon and stars. The cosmos is moving around us and earth is the The cosmos is moving around us and earth is the

center of it allcenter of it all This hypothesis was undeniable based upon the This hypothesis was undeniable based upon the

evidence available at the timeevidence available at the time But, other stars moved rather strangelyBut, other stars moved rather strangely

Claudius Ptolemy (greek philosopher) proposed Claudius Ptolemy (greek philosopher) proposed another hypothesis (very similar to first) in which another hypothesis (very similar to first) in which these “objects” could move in the patterns these “objects” could move in the patterns noted….this thinking lasted, unfalsefied, for 1500 noted….this thinking lasted, unfalsefied, for 1500 years. years.

Nicholas CopernicusNicholas Copernicus

The earth was not the center of everything! The earth was not the center of everything!

He hypothesized that the Earth was just a planet He hypothesized that the Earth was just a planet orbiting the sun and spinning on its own axis.orbiting the sun and spinning on its own axis.

Now we have two hypotheses! Which is correct?Now we have two hypotheses! Which is correct?

More refined observations, experiments, etc. More refined observations, experiments, etc. were conducted and we now have been living were conducted and we now have been living with the Copernican model for the last 500 with the Copernican model for the last 500 years.years.

Let’s see what the future brings.Let’s see what the future brings.

Experiment DesignExperiment Design (KISS Principle) (KISS Principle)

Keep it simple ……Keep it simple ……

Experimental terminologyExperimental terminology

Prediction: Prediction: The prediction is based upon the experiment The prediction is based upon the experiment designed to test the hypothesisdesigned to test the hypothesis

IfIf two almond groves are under different two almond groves are under different watering regimes (schedules) watering regimes (schedules) thenthen I would I would predict that the greater watered grove has a predict that the greater watered grove has a higher almond yield than the less watered grove. higher almond yield than the less watered grove.

The prediction includes the independent variable The prediction includes the independent variable and the dependent variable of the experiment.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.

Data representation : Comparison of Data representation : Comparison of meansmeans

Time for ball to travel 1 m (seconds)

Heavy Light Heavy Light

A. Supports hypothesis 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.

Time for ball to travel 1 m (seconds)

ObservingObserving

ClassifyingClassifying

CommunicatingCommunicating

MeasuringMeasuring

Formulating HypothesisFormulating Hypothesis

PredictingPredicting

Identifying and controlling variablesIdentifying and controlling variables

Testing hypothesis (a.k.a. experimenting)Testing hypothesis (a.k.a. experimenting)

Interpreting dataInterpreting data

Science Process SkillsScience Process Skills