* Getting you thinking: Extension: Why does research need a hypothesis? Discuss with somebody else: What do you know of the term ‘hypothesis’ from science? How might it apply to Psychology?

* Aims and Hypotheses

By the end of this lesson you will be able: * To describe what is meant by the following: Aims, experimental/alternative hypothesis, one tailed/directional hypothesis, two tailed/non directional hypothesis, null hypothesis * To apply those terms to research examples.

* Aims Before carrying out a study to test a theory, you need to be clear about what your study (whether it is an experiment or non experiment) is intending to test. In order to generate an aim (or aims) a researcher needs to be clear about the purpose of the investigation. A research investigation always needs an aim to give it a clear focus. For example, the aim of an investigation into factors affecting children’s behaviour might be: ‘To investigate the relationship between food additives and hyperactive behaviour’.

* Hypotheses * Hypotheses are used by researchers to make predictions about what will happen in their experiment. Experimental/alternative hypothesis Experimental = if an experiment has been used Alternative = all other methods (we will come to these later) Null hypothesis Can be either: Directional (one tailed) Non directional (two tailed)

* The alternative / experimental hypothesis proposes the expected outcome in an experiment. * This hypothesis suggests that the IV will have an effect on the DV.

* Directional/One tailed experimental/alternative hypothesis * This refers to the prediction made about what you think will happen. * A directional/one tailed experimental hypothesis predicts which of the two conditions will result in a greater change in the DV. Thus it is predicting the outcome will fall in one direction. * This is based on previous research.

* Non directional/Two tailed experimental/alternative hypothesis * This refers to the prediction about what the experimenter thinks will happen. * However the direction is not predicted. The experimenter thinks the IV will affect the DV – but they are not sure in what direction. * Usually used when there is no previous research

* Check your understanding 1) Psychiatric patients are less likely to talk to themselves than psychologists are. 2) Eating chocolate affects memory. 3) It is more likely that people will obey a stranger in uniform than one wearing plain clothes. 4) Performance of students who listen to music whilst doing their homework differs from those who work in silence. Discuss whether each of the following experimental/alternative hypotheses are directional/one tailed or non directional/two tailed, and why. Extension: Write your own for someone else to decipher

* Research Hypothesis What is the operationalised IV and DV in this study? “20 participants were asked to complete a driving task that involved driving around a series of cones without hitting them. They had not consumed any alcohol in the previous 24 hours. Another group of participants were asked to complete the same task but after consuming 3 pints of beer. (The task was off road and permission had been granted). The number of cones hit was recorded in both groups.” To write a hypothesis always identify the IV and DV in the study first.

* The answer IV – Whether participants had drunk 3 pints of beer or had no alcohol DV – The number of cones knocked over Discuss how you think the IV and DV might be used to write a directional and non- directional hypothesis. Extension: How would a directional and non directional hypothesis differ when written?

* Writing a directional/one-tailed research hypothesis… This should be written using the following format: “There will be significantly more/less…(insert DV here) in the… (insert first condition of the IV - the one that will have the effect) compared to the…(insert second condition of the IV)” Now write a directional/one-tailed hypothesis for the alcohol experiment… Extension: Choose a study from the textbook and do the same thing.

* Answer “There will be significantly more cones knocked over (DV) by those who have drunk 3 pints of beer (IV) compared to those who had no alcohol (IV)”.

* Writing a non directional/two- tailed research hypothesis… This should be written using the following format: “There will be a significant difference in the…(insert DV here) between… (insert one condition of IV) compared to the…(insert second condition of IV)”. Now write a non-directional/two-tailed hypothesis for the alcohol experiment… Extension: Choose a study from the textbook and do the same thing.

* Answer “ There will be a significant difference in the amount of cones knocked over (DV) (between) by those who have drunk 3 pints of beer (IV) (compared to) and those who have had no alcohol (IV)”.

* Null hypothesis * In any study it must be possible to be able to contradict the experimental hypothesis from the findings. * When this is the case, the research hypothesis is rejected. * However, we still need a conclusion. Therefore, the null hypothesis refers to the probability that the results are due to chance. * This is accepted if the statistical test used tells us that our findings are not significant (more on this to come ).

* Null Hypothesis This should be written using the following format: “There will be no significant difference in the…(insert DV) between…(insert first condition of the IV) compared to…(insert second condition of the IV)” Now write a null hypothesis for the alcohol experiment… Extension: Choose a study from the textbook and do the same thing.

* Answer “There will be no significant difference in the number of cones knocked over (DV) by those who drank the 3 pints of beer (IV), compared to those who drank no alcohol (IV)”

* Hypotheses * Correlational hypotheses are written differently to experimental ones as you are not looking for cause and effect Alternative hypothesis Null hypothesis Can be either: Directional (one tailed) Non directional (two tailed)

* The alternative / experimental hypothesis proposes the expected outcome in an experiment. * This hypothesis suggests the direction of the relationship between the co variables

* Directional/One tailed alternative hypothesis This is a correlation, so the format is slightly different: * Directional/one-tailed hypothesis: Always use the following format: There will be a significant positive/negative correlation/relationship between variable one and variable two

* Non directional/Two tailed alternative hypothesis This is a correlation, so the format is slightly different: * Non directional hypothesis: Always use the following format: There will be a significant correlation/relationship between variable one and variable two

* Null Hypothesis This is a correlation, so the format is slightly different: * Null hypothesis: Always use the following format: There will be no significant relationship between first variable and second variable Read through and complete pages of your research methods booklet. Complete the activity in your activity booklet.

You are now able: * To describe what is meant by the following: Aims, experimental/alternative hypothesis, one tailed/directional hypothesis, two tailed/non directional hypothesis, null hypothesis * To apply those terms to research examples.

* Homework Due next lesson: 1) Read the information on ethics in your textbook. Preparation for next lesson: Choose a study from your textbook and explain the ethical issues involved with it.