Recap: How People learn Classical conditioning Natural responses Natural responses Operant conditioning Reward based (non-natural) Reward based (non-natural) Cognitive Psychology What’s going on in the brain What’s going on in the brain Eg. learning to read (observable, recognition, autonomous Eg. learning to read (observable, recognition, autonomous

How people learn cont.: Constructivism How individuals develop new knowledge How individuals develop new knowledge Previous exp. Previous exp. Explanations Explanations Expectations Expectations Experiment Experiment Conclusions Conclusions ≈ Observations ≈ Hypothesis ≈ Predictions

Scientific Method What is the scientific method 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? New information Compare to previous knowledge Different from prior knowledge? Reject prior or current information; seek out more information

Hypothesis Hypothesis: A potential explanation. Observation Experiment Conclusion Prediction Question 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. 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. The cosmos is moving around us and earth is the center of it all 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 This hypothesis was undeniable based upon the evidence available at the time But, other stars moved rather strangely 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.

Data representation : Comparison of means Time for ball to travel 1 m (seconds) 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)

ObservingClassifyingCommunicatingMeasuring Formulating Hypothesis Predicting Identifying and controlling variables Testing hypothesis (a.k.a. experimenting) Interpreting data Science Process Skills