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Chapter 4

PSYC 235 Chapter 4: PSYC235 Chapter 4

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PSYC 235
Christopher Bowie

WEEK 5 – Chapter 4: Research Methods Important Concepts - Before we discuss specific strategies we must consider several general ways of evaluating research Basic Concepts of a Research Study - Hypothesis: an educated or statement to be tested by data - Research Design: how you want to test for the hypothesis including aspects like: o Dependent Variable: some aspect of the phenomenon that is measured and is expected to be changed or influenced by the independent variable (ex. How much alcohol research participants choose to drink) o Independent Variable: the aspect manipulated or thought to influence the change in the dependent variable (ex. Effects of anxiety induction) - Internal Validity: the extent to which the results of the study can be attributed to the independent variable - External Validity: the extent to which the results can be generalized or applied outside the immediate study Hypothesis - Once a researcher decides what they want to study, the next step is to put it into words that are unambiguous and in a testable form - Concept of testability, using example of low self-esteem and depression, allows us to: o Say either lower self esteem signals depression later – may be able to implement preventative efforts o Say there is no relationship between self-esteem and depression – look for other signs that may predict - When possible, the independent variable is manipulated by the researcher to provide a better test of its influence on the dependent variable Internal and External Validity - Relating to internal validity, we have to remember confounding variables, defined as any factor in a study that makes results uninterpretable o A variable other than independent may be affecting dependent o Ex. In self-esteem study, people who agree to participate may have higher self- esteem than others - To ensure internal validity, may have control groups where these participants are not exposed to independent variable - Randomization: assigning people to different research groups so that each person has an equal chance of being placed in any group o Improves internal validity - Analogue Models create controlled conditions of lab aspects that are comparable to the phenomenon under study - Also want to ensure external validity, including generalizability, relating to the extent that results can apply to all people with a disorder WEEK 5 – Chapter 4: Research Methods o If we try to control all variables because of internal validity, such as age, gender, etc., then we eliminate external validity Statistical vs. Clinical Significance - Statistical significance usually means probability of obtaining the observed effect by chance is small o Ex. Study found that medication and psychological treatment helped people stay sober for 77 days and those with placebo for 75 days ▪ This is statistically significant, but not clinically ▪ Because such a large population, 1383 volunteers, even small difference is statistically significant - Clinical significance describes whether or not the difference was meaningful for those affected o Led researchers to develop statistical methods that address not just that groups are different but also how large those differences are – effect size o Ex. Few of us would say that’s staying sober for 2 more days was worth taking the medication for The Average Client - Patient uniformity myth – seeing all participants as one homogenous group o Ex. Group A improved over 50% over group B hides important individual differences o Inaccurate generalizations about disorders and their treatments o Ex. For the person whose drinking increased with the experimental treatment, it would make little difference that “on average” people improved o Gender, group etc. comparison may be misleading Studying Individual Cases - Best way to analyze an unknown disorder is by case study method – intensively investigating one or more individuals who display the behavioral and physical patterns - Does not use the scientific method - Few efforts made to ensure validity and many confounding variables present - Rely on clinician’s observations of differences among one person or group w/ disorder o Ex. Interviewing individual - Sometimes coincidences happen that are irrelevant to the condition under study and may lead to mistaken conclusions about what causes certain conditions and what treatments would be best - Public and researchers often more highly influenced by dramatic accounts than by scientific evidence o Ex. Man who was romantically attracted to horses WEEK 5 – Chapter 4: Research Methods Research by Correlation - Important to know if two variables are related to each other - Correlation: a statistical relationship between two variables o ex. Is schizophrenia related to size of ventricles - Correlation does not imply causation o Ex. Occurrence of marital problems in families is correlated with bad behavior of children – you will see a correlation between these two o May be that problems in a marriage can cause disruptive behavior in children o Genetic influences – more inclined to argue - We don’t know if A causes B, if B causes A, or if there is a third variable C that causes both - Positive Correlation: higher scores in one variable is associated with higher scores in the other variable; lower scores in one will cause lower scores in other - Negative Correlation: relationship between two variables is reversed; higher scores on one will cause lower scores on the other - Correlation Coefficient: can vary from -1.0 (a perfect negative correlation) to +1.0 (a perfect positive correlation) o Ex. Negative correlation between social supports and illnesses could be represented by a number such as -0.40 Epidemiological Research - The study of incidence, distribution and consequences of a particular problem or set of problems in a population - By tracking a disorder among many people they will find important clues as to why it exists - Incidence: the estimated number of new cases during a specific period - Prevalence: number of people with a disorder at any one time o Study both of these variables among different groups of people o Ex. Data indicate prevalence of alcohol dependence is lower in women - Extent of medical problems mostly, also useful for psychological - Joseph Goldberger found correlations between disorder and small amounts of B vitamin; deficiency caused symptoms like paranoid schizophrenia and catatonic periods - Effects of 9/11 attacks caused much greater rates of anxiety and PTSD in New York students o Combined with other results from Canada, suggests that geographical location correlates with level of distress o Correlational study bc did not manipulate independent variable - Cant tell us what causes phenomenon Research By Experiment - An experiment involves the manipulation of an independent variable and the observation of its effects WEEK 5 – Chapter 4: Research Methods - Never 100% confident that our experiments are internally valid (that no other explanations are possible) we are cautious about interpreting our results Experimental Designs - Researchers observe groups to see how different variables are associated - Group experimental designs – more active researchers by changing independent variable to see how behavior is affected o Ex. Design study to reduce insomnia in adults, follow for 10 years; independent would be treatment that would not have naturally occurred - Clinical Trials can be used to determine the effectiveness and safety of treatment o Level of formality regarding how it’s conducted o Method of evaluation that follows rules (ex. How you should select participants, how many individuals, how to assign groups etc.) o Everyone treated the same - Within this, have randomized clinical trials that employ randomization of participants into each group - Controlled clinical trials describe experiments that rely on control conditions to be used for comparison purposes - Randomized controlled clinical trials uses both concepts; important in treatment outcome research Control Groups - Not exposed to independent variable - Allows researchers to see that their treatment did help the treated participants - Nearly identical to treatment - Would do same assessments to both groups - People in treatment group often expect to get better - Placebo effect is when behaviour changes as a result of a person’s expectation of change, rather than manipulation by an experimenter - Frusto effect is when people in control group are disappointed that they are not receiving treatment o ex. In depression, this would make symptoms worse - Placebo Control Groups: placebo given to members of control group to make them think they are getting treatment o Easy in medical studies (Ex. Sugar pill) but difficult in psychological studies - Must distinguish between positive expectations and results of actual treatment - Double blind experiment: participants are “blind” as well as researchers and therapists o Ex. Researcher knowing that one treatment is more effective may “try harder” for that one compared to other one o Allegiance effect is when treatment that wasn’t meant to work, they may not try hard o Less change of bias - As an alternative of giving no treatment (sugar pill) researchers may compare different treatments called comparative treatment research WEEK 5 – Chapter 4: Research Methods Process and Outcome of Treatment - Process research focuses on the mechanisms responsible for behavior change or “why does it work” o Ex. How does the medication work? (ex. Does it lower serotonin levels? o In psychological interventions, we determine what is “causing” the observed changes ▪ Understand active ingredients of our treatment ▪ Eliminate aspects that are not important ▪ Create more powerful, newer versions that may be more effective - Outcome research focuses more on positive and negative effects of treatments or “does it work?” o Treatment process involves finding out why or why not it works o Treatment outcome involves finding out what changes occur after treatment Single-Case Experimental Designs - Systematic study of individuals under a variety of experimental conditions - Skinner thought it was better to make many observations about one individual as opposed to few about many individuals - Differ from case studies in their use of various strategies to improve internal validity - Can still help explain abnormal behavior and how to treat it Repeated Measurements - A behaviour is measured several times instead of only once before you change the independent variable and once after - Learn how variable behaviour is and if it shows any trends - Instead of measuring anxiety once when they come in (initial) and once after treatment, measure often during to see if her feelings of anxiety have actually reduced or if she was just having a good day o May have just been a part of daily variations - Helps identify how a person is doing before and after intervention - Parts of repeated measurements: 1. Level or degree of behaviour change within different interventions (top) 2. Variability over time (middle) 3. Trend or direction of change (bottom) Withdrawal Designs - Researcher tries to determine whether the independent variable is responsible for changes in behaviour - First, condition is evaluated to establish a baseline - Then, change in independent variable (ex. Beginning treatment) WEEK 5 – Chapter 4: Research Methods - Last, treatment is withdrawn and researcher sees if anxiety changes again o If anxiety lessens compared to baseline, can say treatment is working - Gives researchers a better sense of whether or not the treatment itself caused behavioural change - Researcher would have to decide if it was worth the risk to make
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