PSYC2900U Research Methods Lecture Notes PDF

11/18/2024 2 Lecture Overview...

11/18/2024 2 Lecture Overview Course reminders Setting up a factorial experiment Interpreting the results of a factorial experiment Ch. 9 – Factorial Designs PSYC 2900U – RESEARCH METHODS KARLA EMENO 1 1 2 Upcoming Dates 3 Reminder – Assignment #3: Method (20%) 4 Tuesday, Nov. 19th – Ch. 9 Factorial Designs – In-person lecture and tutorial Due Date Extension: Submit in Canvas by 11:59 pm on Tuesday, Nov. 26th Thursday, Nov. 21st – Ch. 10 Single-Subject Research – Recorded lecture You will begin Assignment 3 with a Current Study section (revised from posted in Canvas Assignment 2 based on TA feedback). Tuesday, Nov. 26th – Assignment 3 due in Canvas by 11:59 pm You will then write a Method section, which will explain – in detail – how Tuesday, Nov. 26th you would carry out your proposed study. This will include a detailed description of the participants, materials, and procedure. NO IN-PERSON LECTURE (slides only will be uploaded to Canvas on Ch. This assignment will end with a Study Limitations and Future Research 11 Presenting Your Research) Directions section where you discuss some limitations of your proposed NO IN-PERSON TUTORIAL – Optional exam Q&A sessions via Google research study and mention some future research that could follow from Meet instead from 1:10 to 2 pm and 4:10 to 5 pm: your proposed study. https://meet.google.com/rig-rpdo-eho Detailed instructions for Assignment 3 (including the grading rubric), an Monday, Dec. 9th, 12-2 pm (Regent Theatre) – Final Exam example template, and an example paper have been added to Canvas. 3 4 5 6 Reminder – Final Exam Factorial Designs – Just Extra Variables Date and Time: Monday, December 9, 12-2 pm Location: Regent Theatre at 50 King St E (DTR100) Complex experiments are the same as simple Exam will consist of multiple-choice and short-answer experiments, but they have two or more variables that questions. Approximately 90 marks in total on the exam. are manipulated (or measured, if it is an individual difference variable) Covers Chapters 1 through 10 (Ch. 11 is NOT on the exam). Variable A can have effects (or not) – main effect of A Exam is CLOSED-BOOK. Variable B can have effects (or not) – main effect of B Worth 35% of your final grade. The two variables can influence one another – Bring pencils, an eraser, and your student ID. interaction of A and B Request a deferred exam (for a valid reason) here. 5 6 1  11/18/2024 Factorial Designs 7 Factorial Designs (cont’d) 8 Experiments that include more than Can include any number of IVs with any one IV (i.e., factors) in which each number of levels. level of one IV is combined with Ex: 2 (therapy type: cognitive vs. each level of the others to produce behavioral) x 2 (therapy length: 2 weeks all possible combinations. vs. 2 months) x 2 (therapist gender: male Each combination becomes a vs. female); there are 8 conditions in total condition in the experiment. (2 x 2 x 2 = 8) Ex: 2 (cell phone use: yes vs. no) x 2 Usually only see 2-3 IVs with 2-3 levels (time of day: day vs. night) design each because: (1) the # of conditions with driving ability as the DV; there becomes unmanageable quickly and are 4 groups in total (2 x 2 = 4) (2) too many participants required. 7 8 Assigning Participants to Conditions 9 10 Non-Manipulated IVs All 3 designs involve two factors, but the difference is in how many times one factor is tested across the same individuals An IV that is measured but is non-manipulated. Between-Subjects Factorial Design: Ex: Gender, self-esteem, age All factors are between subjects They are usually individual difference (i.e., participant) No one person receives both conditions (levels) of a factor (IV) variables, which means they are between-subjects Within-Subject Factorial Design: factors. Each subject receives all conditions Still an experiment if at least one IV is manipulated. Mixed Factorial Design: Causal conclusions can only be made for the One Factor is between subjects, while the other is within subject manipulated IV. Must include counterbalancing 9 10 11 12 Non-Experimental Factorial Design Graphing the Results Factorial designs are non-experimental in nature if they include ONLY non-manipulated IVs. Must be cautious about inferring causation from non- experimental studies because of problems with: 1. Directionality 2. A potential third variable 11 12 2  11/18/2024 13 14 Main Effects Interactions When the effect of one IV depends on the level of The effect of one IV on the DV – averaging across another. the levels of any other IV(s). Everyday example: Your friend invites you to a This means that there is one main effect to movie and you say “it depends” on the movie and consider for each IV in the study. who else is coming. Main Effects are independent of each other. In many studies, the primary research question is about an interaction. 13 14 1 – Spreading Interaction 2 – Spreading Interaction 15 16 Types of Interactions Spreading Interaction: No effect for one group Weaker effect for one group There is an effect of one IV at one level of the other IV and there is either a weak effect or no effect of that IV at the other level of the other IV. Cross-Over Interaction: The IV has an effect at both levels, but the effects are in opposite directions. 3 – Cross-Over Interaction Effects are in opposite directions 15 16 17 Simple Effects An interaction means that the effects of at least one IV depend on the level of another IV. Simple effects are a way of breaking down the interaction to figure out precisely what is going on. They are only necessary when a significant interaction is found. If there is no interaction, then the main effects tell a complete and accurate story. 17 18 3  11/18/2024 20 Questions about Chapter 9? 19 20 4