Single Subject designs

Studying people as they are vs. changing something Two general types of research designs:  People are studied and observed as they are  Something is done, and the effects of that something on people are measured Today: will talk about one specific type of the second of these – single subject- designs

Single-subject designs Just what they sound like: just one person is a participant  Why would this be done? Advantages? Disadvantages?

The something being done… Generally, goal = stop some sort of problematic behavior, or encourage some sort of positive behavior Basic ingredients:  How much of the behavior was engaged in initially (baseline – or referred to with letter A)  How much of the behavior is engaged in after some kind of intervention (referred to with letter B) Why is the A part needed?

Adding a bit of a twist What if something else was going on in the world, and *that* was responsible for the change? In other words, how can we be sure the intervention was responsible for the change? Take it away…  Referred to as ABA design

Thinking about the context of the study What if the behavior doesn’t go back to baseline, when the intervention is taken away? What if the behavior that’s been altered is something that *shouldn’t* (ethically) go back to baseline?

What else to do? Multiple baseline  Insert intervention at different time-points, in different situations (e.g., at home, at school)

What if you want to compare different interventions? Can measure baseline, introduce one intervention, go back to baseline, and then introduce the other (assuming that the behavior can, or should, go back to baseline)  A-B-A-C-A

What if you think two interventions might work best when given at the same time? First, establish effect of one of the interventions  A-B Then, add in the other intervention  A-B-BC Then, take away the second intervention, to see if you can go back to the baseline of the first  A-B-BC-B Then, re-establish the baseline with both interventions, together  A-B-BC-B-BC Then, add just the second intervention, for comparison  A-B-BC-B-BC-C Then, see if the baseline of both interventions is reverted to  A-B-BC-B-BC-C-BC Then, see if the same level, with just the second intervention, can be achieved  A-B-BC-B-BC-C-BC-C Finally, go back to the original baseline  A-B-BC-B-BC-C-BC-C-A

Two interventions vs. one alone Interaction: effect of one intervention is greater (or different) when coupled with a second intervention  E.g., maybe a monetary reward is more effective if it’s coupled with the ability to buy candy

Applying all of this What sorts of others’ behaviors could be changed in this fashion? What sorts of interventions might be effective  Maybe it would depend on the person?

Examples Professor looking at one side of the room M&M’s and use of particular words

Swain & Jones article What was the goal of the study – which behavior did they want to change, and how did they want to change it? Which type of design was used? What was found?

For homework… Think of a behavior of a friend’s that you could try to change Think of an intervention that you could use to change that behavior Ask a friend if he or she would mind being a part of a study Let that friend know what he or she can expect (remember informed consent!)  But don’t give away what it is that you’re testing – why not? Institute one of the designs we’ve talked about (at minimum ABA, but feel free to try multiple baseline, or multiple intervention)

For homework, cont’d Explain to your friend what behavior you were measuring, and what intervention you used As your friend if he or she thinks that that intervention would work, or did work Show your friend your results, and ask if he or she is surprised

For homework, cont’d Write a short paper on the experience  Be sure to address all of the questions on the website for this assignment