Slideshow 2 - Psychology as a Science

What is science?

1. the universe operates according to certain natural laws

• things happen in an orderly way and we can determine cause and effect 

2. these laws are discoverable and testable

• we can use these laws to make predictions and then experiment to see if we were right 

Scientific Method

1. idenfity questions of interest + consult literature 

2. develop testable hypothesis (must be operationally defined) 

3. select research method, choose participants, collect data

4. analyze data and accept or reject the hypothesis 

5. seek scientific review, publish, replicate study 

6. build a theory 

Theory

a set of statements that describes general principles about how variables relate to one another 

• several different theories can exist at once

Hypothesis 

a prediction that is stated in terms of the study design, and is derived by the theory being tested

• hypothesis testing - use a sample and look at difference between control and experimental groups

• null hypothesis - no difference between the groups tested

• alternative hypothesis - there is a difference between the average performance of individuals

Data

the observations that are collected

Variable

• any characteristic, number of quantity that can be measured or counted

• condition, event, or situation being studied 

• types

  • quantitative vs qualitative 

  • dependent vs independent

Conceptual vs operational definition

e.g.  bullying

• conceptual: Bullying is an ongoing and deliberate misuse of
  power in relationships through repeated verbal,
  physical and/or social behaviour that intends to
  cause physical, social and/or psychological harm. It can involve an individual or a group misusing their power, or perceived power, over one or more persons who feel unable to stop it from happening.

• operational: we could measure bullying using observations of number of times someone calls another person a name, self reports, surveys, etc.

Population

the entire group that is of interest to researchers 

• e.g. all first year students at SJU

Sample

a portion of the population that is selected for the study; must represent the population 

• e.g. students who sign up for a particular study

Descriptive research

• case studies, naturalistic observation, surveys

• purpose: observe, collect, record data → meets descriptive goal of psychology 

• pros:

  • good for developing early ideas

  • more reflective of actual behaviour than other methods

  • easier to collect data

• cons:

  • little or no control ove variables

  • researcher and participant biases

  • cannot explain cause and effect

Experimental research

• manipulation and control of variables

• purpose: identify cause and effect → meets explanation goal of psychology

• pros: 

  • allows researchers precise control over variables and to identify cause and effect 

• cons

  • ethical concerns

  • practical limits

  • artificiality of lab conditions

  • confounding variables

  • participant and researcher biases

Descriptive statistics

describing features of a data set by generating summaries about data samples

Measures of central tendency

• mean: average 

• median: middle number 

• mode: number that occurs most often (may be mroe than one) 

• on a perfect normal distribution, all three central tendency measures are the same 

Measuring variability

• range

• variance 

• standard deviation - approximate average deviation around the mean 

Scatter diagram/plot

• visual depiction of a relationship between two variables

• bivariate 

• individual scores on both x and y 

Interpreting relationships

• correlation coefficients may range b/w -1 and +1

• the closer to +-1, the stronger the relationship; the closer to 0, the weaker the relationship

• correlations have limitations but they help us make predictions

Inferential statistics

• allows you to make predictions (inferences) from data

• take data from samples and make generalizations about a population

• get data from experiments

P-value

• number describing how likely it is your data could have occured by random change 

• p < 0.05 is statistically significant 

• tells us how sure we can be that one thing is related to another or how sure we can be that two groups are different (the results are from group differences and not just random chance) 

Effect size and r

• how strong is the relationship between two variables? 

• how big is the difference 

Effect size and r

• for correlations

• this is the +-1 value that indicates the linear relationship between two variables

• pearson correlation coefficient

Effect size and cohen’s d

• for group differences

• asses effect size when comparing the means of two experimental groups

• the difference between the peaks of two normal distribution curves

• the bigger the d the bigger the effect hehe

Nutrition studies on residential school children

• used baseline of malnutrition and hunger experienced by indigenous children in schools 

• tested different interventions (starving them vs giving them proper nutrition)

The Montreal Experiments

• supposed purpose was to find a cure for schizophrenia, but it was really just illegal human experimentation using drugs and psychological treatments

• high voltage shock therapy, drug induced sleeps, LSD megadoses, psychic driving (repeated audiomessages to alter their behaviour)

The Nuremberg Code

1. voluntary consent of subject is essential

2. experiment should yield fruitful results for the good of society

3. experiment shoudl be designed and ased on results of animal experimentation and knowledge of natrual history of the disease or other problem 

4. experiment should be conducted as to avoid all unecessary physical and mental suffering

5. do not conduct experiment if you think someone could die or be seriously injured because of it

6. degree of risk should never exceed the importance of the problem being solved

7. proper preparations shuould be made to prevent even remote possibilities of death or serious injury

8. experiment should be conducted only by scientifically qualified people 

9. during experimentation subject should be allowed to stop it if they think they’re gonna be harmed a lot

10. scientists must be prepared to stop the experiment for the same reasons 

Ethical research

1. respect for persons 

2. concern for welfare 

3. justice 

• tricouncil policy statement