Scientific Thinking (Week 1)

Double Blind Design

Make sure that your subjects have no clues as to which group they are in or what they are supposed to have happen to them. But all, conceal the treatment from the experimenter. Neither the experimental subjects nor the experimenter know which treatment a subject is receiving. Helps get rid of any biases.

Making Observations

Note apparent patterns or possible cause and effect relationships.

Example of Scientific Thinking

Observation: It rains more on weekends than on Mondays Hypothesis: Particulate matter from car exhaust builds up all week when there is more driving. This enhances cloud formation and leads to rain. Experiment: Measure rain in the place of observation and a place where there is no car exhaust and there should be the same amount of rain everyday. Conclusions: Humans can change local weather patterns due to their activity

Elements of an Experiment

Treatment: an experimental condition applied to subjects Experimental Group: Group of subjects exposed to treatment Control Group: A group of subjects treated identically to the experimental group, but are not exposed to the treatment. Indep Variable: Can be observed / measured at the start of the process and changed as ness. Dep Variable: Can also be observed/measured but is the result of the indep variable

Randomize

To improve the quality of your experiment, randomize your subjects across control and experimental groups. Randomly assign your subjects to different groups.

Steps of the Scientific Method

1. Make Observations. We make these automatically. We see things and try to figure out why they are the way they are. 2. Formulate a hypothesis. Explanations for the things we see. 3. Make a testable prediction. If my hypothesis is true... What might be true based on our hypothesis. 4. Conduct a critical experiment. Keep all variables controlled except one. We test our hypotheses and discover alternatives 5. Draw Conclusions and make Revisions. We draw conclusions, modify our hypotheses, and continue the process of scientific thinking Note: These do not always occur in a nice orderly fashion. Often they might overlap

How you increase the validity of your experiment?

1. Randomize, Control, and Double Blind Design. The better controlled an experiment is, the more confidence we will have in its results. However, it is important to note that the better experiments are controlled, the more probable it is for them to become poorer models of the situation at interest.

Hypothesis v Theory

A hypothesis is a proposed explanation for an observed pattern that leads to testable predictions. A scientific theory, however, is a hypothesis that is exceptionally well supported by empirical data and has withstood the test of time and many experiments. Unlikely to be altered by any new evidence.

Critical Experiment

An experiment that makes it possible to determine decisively whether a hypothesis is correct. At the core of scientific thinking is the ability to develop and undertake a critical experiment.

Formulating Hypotheses

Based on observations we can develop hypotheses. A hypothesis is a proposed explanation for an observed pattern that must generate testable predictions. We can only determine whether a hypothesis is valid by putting it to the test.

Anecdotal Observations

Based on one or a few observations, people conclude that there is or is not a link between two things. Allows for superstitions to develop.

Control

Keep the differences between your groups minimal. If we want to attribute a difference between the two groups to experimental treatment, there must be no other underlying difference between the groups.

Eyewitness Testimony

Is eyewitness testimony infallible? If it is unfallible, then the percent of incorrect IDs should be zero. An experiment found that 30% of lineup IDs were wrong and 10% of sequential viewing was wrong.

Can a hypothesis ever be true?

It is impossible to prove that a hypothesis is absolutely and permanently true. New observations can always arise that may affect its truthfulness.

Predictions

Once we have a hypothesis, we want to predict an outcome that will occur if our hypothesis is correct.

Draw Conclusions and Revise

Once we have the results of an experiment, we examine and analyze them. We try to draw conclusions and see if they support the hypothesis. If it doesn't support, we revise the hypothesis and conduct more experiments.

Replication

Replication, the process of repeating a study, is an important part of scientific thinking. An experiment that an be done multiple times by different people and gives the same result is effective against bias, so our confidence in its results is increased

Null Hypothesis

Sometimes researchers will create null hypotheses, which basically just say that there is no relationship between two things and are easy to disprove.

What is the Scientific Method?

The Scientific Method is an empirical process that involves observations, hypotheses, predictions, experiments, and conclusions. It is a flexible, adaptable pathway to understanding the world (even beyond science) and it tells us situations when we must change our beliefs.

Scientific Thinking v Scientific Method

The scientific method is NOT a rigid set of rules that can only be applied to certain things. Rather, it is a highly flexible process that can be used to explain a bunch of things, not only in science. Better referred to as scientific thinking.

Pseudoscience

While scientific thinking is power, it can be costly, time consuming, and difficult, so cheating has its appeal. Nine out of ten blah recommend blah. This is pseudoscience. How many people were in the survey? What was asked? How were they selected? What was the alternative option? They want to persuade you of something but they may not have spent the resources discovering whether or not it is true. Should always be asking - how do you know?