Copyright, 2005, Prentice Hall, Sarafino CHAPTER 11 Intrasubject Research: Small-N Designs

Copyright, 2005, Prentice Hall, Sarafino What is an Intrasubject Design? An intrasubject, sometimes called a small-N design, design refers to research: –That manipulates an independent variable –That is carried out on only one, or at the most, a few participants. –Where the participant is measured over time. –Where individual data for each participant is presented – usually in a graphical form.

Copyright, 2005, Prentice Hall, Sarafino Overt Behavior Overt behaviors are those that can be viewed or directly assessed. There are 2 types of overt behavior: –Verbal (use of language, e.g., words) –Motor (body movement, e.g., running speed). Common measures associated with overt behavior include: –Performance speed –Trials –Reaction time

Copyright, 2005, Prentice Hall, Sarafino Covert Behavior Covert behaviors are those that are not directly observable. –Some examples include feelings, current physical states, and attitudes. –If we can’t directly observe covert behavior then how do we measure it? We can measure covert behaviors directly with machines (e.g., heart rate monitor) or indirectly (e.g., self-reports).

Copyright, 2005, Prentice Hall, Sarafino Direct and Indirect Measures of Covert Behavior Direct techniques can include: –EEG (cortical brain activity) –GSR (skin conductivity) –PET and MRI (brain imaging). Indirect techniques can include: –Surveys –Questionnaires

Copyright, 2005, Prentice Hall, Sarafino Surveys and Questionnaires Surveys and questionnaires are important methods psychologists use to gather information about covert behavior. They generally include some of the following characteristics: –Closed-ended items (participants are restricted to a set of fixed responses, e.g., true/false, multiple choice questions.) –Open-ended items (participants are free from response restriction, e.g., What do you think about serial killers?).

Copyright, 2005, Prentice Hall, Sarafino Closed-ended items are generally superior to open-ended items because they are much easier to score (remember this when you do your Honors Thesis). There are many useful ways to present close- ended items to participants each with their own set of pros and cons: –Point scales –Likert scales –Segmented rating scales –Numerical rating scales Types of Closed-Ended Items

Copyright, 2005, Prentice Hall, Sarafino Before you start, check the thousands of published psychological survey and tests to see if one already exists on your topic. –If not, then you need to create one. The following steps will help you: Composing a Survey

Copyright, 2005, Prentice Hall, Sarafino Composing a Survey 1.Describe, in detail, your measure and refer to this description often. 2.Decide on who you will measure. Why? 3.Design items to gather demographic data. 4.Design numerous items only on the topic you are interested in – do not try to measure everything. 5.Rework your items – e.g., make them as simple and straightforward as possible. Avoid jargon, technical terms, negative wording, and double- barreled items. 6.If using closed-ended items, be sure your response sets cover the complete range of possible answers in equal increments. Why? And be sure you response sets match the question. Why? 7.Decide on the statistics you are likely to use. 8.Pretest the survey on a group of people who will not be in your actual study. Tell them you want constructive criticism. 9.Revise the test and make it look professional. 10.Now the fun part begins – giving the survey and deciding if your survey is reliable and valid. This comes in later chapters.

Copyright, 2005, Prentice Hall, Sarafino Other Types of Data: Remnant Remnant data refers to the use of existing remains, products, or evidence of behavior to infer or explain past events. Some examples include: –Physical Traces E.g., Graffiti, garbage. –Archival Data E.g., birth weights and rates, weather reports and crime.

Copyright, 2005, Prentice Hall, Sarafino How to Identify Pseudoscience? The “Trappings” of Science –Pseudoscience tries to be like real science. –Pseudoscience makes predictions about phenomenon, but rarely tests them. Data is Often Based on Testimonials –Data like this can be easily manipulated. Evasion of Disproof –Explanations given by the pseudoscience to account for data that disprove the pseudoscience are difficult/impossible to test (e.g., the phenomenon can’t be measure by conventional means)

Copyright, 2005, Prentice Hall, Sarafino Naturally Occurring Behavior Sometimes psychologists want to study ongoing or naturally occurring behavior. This is unique because researchers not only have to be concerned about what they are observing, but also when and where the behavioral observations will be made. To deal with this, psychologists often employ: –Time sampling technique Taking samples of behavior only at certain times. –Event or Situation sampling technique Taking samples only in a predetermined situation.

Copyright, 2005, Prentice Hall, Sarafino Types of Data The are two main categories of data: 1.Quantitative Is numerical or can easily be converted to numerical form. 2. Qualitative Usually narrative in nature and difficult if not impossible to convert to numerical.

Copyright, 2005, Prentice Hall, Sarafino Scales of Measurement Once you have determined the type of data you will generate, you now need to coordinate this with statistics procedures. The first step in doing this is to determine your data’s “scale of measurement”. –There are 4 Different Scales of Measurement 1.Nominal 2.Ordinal 3.Interval 4.Ratio Let’s consider each one.

Copyright, 2005, Prentice Hall, Sarafino Nominal Scale Most basic level of measurement. Numbers represent simple qualitative differences in your variables. –E.g., 1 = group_1; 2 = group_2, etc. Numbers are not intended for numerical calculations, but to classify data. General rule: Similar objects or events are assigned similar numbers, and different objects get different numbers. Statistical procedures: –Frequency counts; Chi-Square.

Copyright, 2005, Prentice Hall, Sarafino Goals of Scientific Research There are 4 main goals of scientific research: 1.Description 2.Prediction 3.Understanding 4.Application

Copyright, 2005, Prentice Hall, Sarafino Research Strategies There are 4 main research strategies used in psychological research and covered in detail in the remainder of the text: 1.The Experimental Strategy 2.The Quasi-experimental Strategy 3.The Correlation Strategy 4.The Descriptive Strategy