9 Procedure for Conducting an Experiment

Institutional Approval Institutional Animal Care and Use Committee (IACUC) reviews research protocols for studies using nonhuman animals determines if proposed procedures are ethical e.g., avoid or minimize pain and discomfort Institutional Review Board (IRB) reviews research protocols for studies using human participants primary concern is participant welfare has informed consent been obtained? do potential benefits of study outweigh risks to participants?

Research Participants Chosen participants depends on research question obtaining animals albino variant of brown rat is most commonly used the Animal Welfare Act regulates care and housing the Guide for the Care and Use of Laboratory Animals (1996) provides a guide to using animals appropriately

Research Participants Obtaining human participants recruitment depends on type of participant needed examples research question dictates homeless participants then you would contact homeless shelters and visit areas frequented by homeless individuals research question dictates school children as participants then you would contact schools and possibly pediatricians’ offices convenience sample of college students often used in psychological research may not be representative of target population

Research Participants Obtaining human participants using the Internet to recruit research participants is becoming more common advantage providing access to a larger and more diverse sample than otherwise possible disadvantage select groups may not have access to Internet (e.g., disabled) sample may not be representative of target population No matter how participants are recruited important to report how participants were selected and assigned to research conditions (methods section)

Sample Size How many research participants should be included in the research? practicality must be balanced with the increased power that accompanies a large sample

Power The probability of correctly rejecting the null hypothesis Correctly saying the treatment conditioned produced an effect Power of at least .80 is desired i.e., we want to correctly reject a false null 80% of the time Factors that influence power sample size as sample size increases, power increases so does time and money required to complete research alpha level for now, all you need to know is that alpha is set at 0.05 effect size the magnitude of the relationship between two variables in a population can be estimated at small, medium, and large examine literature for approximate effect size estimation Should conduct Power Analysis to estimate sample size

Power Analysis

Apparatus and/or Instruments How will independent variable be manipulated and how will dependent variable be measured? depends on nature of research may involve active participation by researcher example – Langhinrichsen-Rohling and Turner (2012) a particular type of apparatus examples – computers, MRI, EEG Behavioral Research Methods is a good source to identify research instruments

Procedure and Scheduling detailed description of how experiment will be conducted important to allow for future replication Scheduling of research participants availability of the researcher and participants anticipate drop out rates with human participants

Consent to Participate Informed consent necessary unless waived by IRB Consent form should include the following elements: basic information about the study details about procedure of study including possible risks any potential benefits that might be derived the type of compensation provided and compensation penalty for early withdrawal for sensitive topics (e.g., depression, abuse) extra information for individuals who need assistance participants must be informed that they can withdraw from study at any time without penalty if using questionnaire, a statement indicating that participant can refuse to answer any question without penalty participants must be informed as to how the records and data obtained will be kept confidential

Instructions and Data Collection should be precise, but not overly complex refrain from certain phrases “pay attention”, “relax”, and “ignore distractions” language should be simple and on the level of the participant warm-up trials can assess understanding of instructions Data collection follow design

Debriefing Functions ethical educational methodological undo any deception involved in study decrease stress or risk if possible attempt to return participants to pre-experimental state particularly important if deception is used educational this mostly applies to students participating in research for class credit methodological to establish effectiveness of independent variable or deception to judge accuracy of participations’ suspicions and perceptions sense of satisfaction participant feeling as if they contributed to science and society

Debriefing How to debrief face to face generally preferred begin by asking if participant has questions question participant to determine if all aspects of study were clear if deception was used attempt to determine if participant discerned true nature of study explain the purpose of using deception ask participant not to reveal details of experiment to other participants

Pilot Study A brief run-through of the entire experiment with a few participants prior to the actual collection of data Serves several purposes: establishes clarity of instructions provides evidence that independent variable is being manipulated adequately familiarizes researcher with the procedure