Research Methods: Variables, Controls, Placebo, Therapeutic Touch and Ethics
Independent and Dependent Variables
Independent variable (IV): what the researcher deliberately changes or manipulates in an experiment.
Example: chocolate amount given to participants. The act of giving chocolate is the manipulation.
Formal view: the IV is the condition or treatment level applied to participants.
Dependent variable (DV): what is measured to assess the effect of the IV.
Example: acne (in the chocolate-and-acne scenario).
The DV is the outcome variable you collect data on to see if it changes with different IV levels.
Other classic developmental psychology example:
IV: feeding method (breastfed vs bottle-fed).
DV: intelligence (measured later by an intelligence test).
Design goal: determine if being breastfed makes a difference in intelligence later in life.
Additional scenario for practice:
Doctor Anderson conducts an experiment to see whether exposure to helpful models leads to helping behavior in young children.
IV: exposure to helpful models vs exposure to non-helpful models.
DV: whether the children exhibit helping behavior.
Common Experimental Design and Controls
Confounding variables are factors that could interfere with the study if not controlled.
Chocolate-acne example confounds to consider:
Amount of chocolate should be the same across participants.
Brand, type (dark, white, milk), and flavor should be the same.
Skin type should be as similar as possible across participants.
Age should be similar (to account for differences in skin, oil production, etc.).
Diet overall can influence skin oiliness and acne.
The experimental group receives the treatment/manipulation; the other group serves as a baseline for comparison (control).
Example of an exposure study: exposing participants to public television and then measuring reading skills.
Examples of Variables in Action
Behavioral psychology study: reinforcing comments and work effort
IV: presence or absence of reinforcing comments.
DV: level of work or effort displayed by participants.
Clinical psychology study: psychotherapy and future problems
IV: receipt of psychotherapy.
DV: likelihood or extent of problems in the future.
Placebo Effect and Experimental Controls
When testing medications, a double-blind design is often used to reduce expectancy effects:
If participants know they are receiving a treatment, they may feel or report benefits regardless of the actual treatment.
A placebo is a fake treatment (e.g., a sugar pill) used to control for expectancy effects.
Placebo effect: improvements that occur because a person believes they are receiving treatment, not because the treatment itself has a therapeutic effect.
Formal idea: in a placebo-controlled experiment,
Double-blind design helps ensure neither participants nor researchers know who is receiving the real treatment, reducing bias.
Therapeutic Touch and Scientific Scrutiny
Therapeutic touch: a claimed energy-based healing practice.
Claimed process: practitioner feels or channels healing energy from the heart center without touching the patient.
Widely practiced (reported in the transcript: hundreds of medical centers; ~80,000 practitioners, many nurses).
Scientific status: no robust scientific proof that it works; critics argue effects are due to belief or placebo.
Public test of therapeutic touch (Rose’s test):
Procedure: practitioners asked to feel the energy from her hand while it was hidden from their view (hands behind towel/cardboard).
Outcome: practitioners guessed the correct hand only 3 times out of 10.
Participant numbers: more than a dozen practitioners were tested; none passed at a level above chance.
Publication history: the test gained publicity and was published in the Journal of the American Medical Association (JAMA).
Broader implication: despite lack of objective proof, therapeutic touch continued to be practiced widely; belief and faith in the method contributed to patient experience and perceived benefit.
The placebo explanation: belief in a therapy can produce a perceived or real improvement even when the treatment has no active ingredient.
Public Perception, Media, and the Placebo Concept
The transcript emphasizes that belief can influence perceived outcomes, even if the underlying intervention has no pharmacological effect.
The same placebo logic applies across various interventions (e.g., stimulants vs placebos affecting sleep patterns in students).
Example: a group is told they will receive a stimulant or sleeping pill and then all receive a placebo; many report sleep differences or side effects due to expectations rather than pharmacology.
Ethical Guidelines in Research (Informed Consent, Anonymity, Debriefing)
Informed consent: participants should be given information about the study and agree to participate.
There is an argument that in some naturalistic public-observation scenarios, informed consent may be waived because obtaining consent could alter behavior (e.g., people returning a dropped dollar in a store).
Anonymity: researchers should protect participant identities; if anonymity cannot be guaranteed, studies should stop collecting identifying information.
Debriefing: after participation, researchers should explain the study, procedures, and results to participants.
The exception highlighted in the transcript: naturalistic observation in public settings may not require consent, but ethical guidelines typically require careful consideration and institutional approval.
The closing questions often focus on:
What is debriefing?
Which item is not a guideline for research ethics?
Quick Practice Points and Takeaways
Identify the IV and DV in common scenarios:
Chocolate vs acne: IV = amount/type of chocolate; DV = acne outcomes.
Breastfed vs bottle-fed: IV = feeding method; DV = later intelligence scores.
Exposure to helpful models: IV = exposure condition; DV = helping behavior.
Consider confounding variables and how to control them:
Keep chocolate amount, brand, type, and diet consistent.
Match participant characteristics (age, skin type) as much as possible.
Placebo and double-blind are crucial for reducing bias in experimental results:
Placebo effect occurs when expectations influence outcomes.
Double-blind designs help separate actual treatment effects from expectancy effects.
Therapeutic touch illustrates how belief can shape perceived outcomes, but rigorous scientific testing (e.g., controlled, blinded studies) is needed to establish efficacy.
Ethics matter: always consider consent, anonymity, and the need to debrief participants after a study.
Key numerical references from the transcript:
Sample size in the therapeutic touch test: 12+ practitioners tested; 3/10 correct in Rose’s test.
Exposed vs. non-exposed group in the model-behavior study: 40 participants; half exposed (n=20) to helpful models, half exposed to non-helpful models (n=20).
Public practice scale: ~80,000 practitioners of therapeutic touch.
Connections to Foundational Principles
Operational definitions: IVs and DVs must be clearly defined to enable replication.
Randomization and control groups: essential for attributing observed effects to the manipulation rather than to confounds.
Concepts of reliability and validity emerge in the discussion of how certain practices (therapeutic touch) may appear effective in practice but fail controlled testing.
Ethical conduct in research: informed consent, minimizing harm, maintaining confidentiality, and providing debriefing are core to responsible study design.
Quick Reference: Key Terms
Independent Variable (IV): The manipulated variable in an experiment.
Dependent Variable (DV): The measured outcome that depends on the IV.
Placebo: An inert treatment used to control for expectancy effects.
Placebo Effect: Improvement due to belief in treatment rather than the treatment itself.
Double-Blind: A study design in which neither participants nor researchers know who receives the active treatment.
Debriefing: Post-study explanation of methods, procedures, and results to participants.
Naturalistic Observation: Studying behavior in natural environments, often with minimal intrusion; may involve consent considerations.
Confounding Variable: An uncontrolled factor that can influence the outcome.
Therapeutic Touch: A contested practice claimed to manipulate a patient’s energy field; lacks robust scientific validation in controlled studies.
Practice Question Refresher
Doctor Anderson experiment: IV = exposure to helpful vs non-helpful models; DV = helping behavior.
Chocolate and acne: IV = amount/type of chocolate; DV = acne outcomes.
Breastfed vs bottle-fed: IV = feeding method; DV = intelligence scores later in life.
Reading skills study: IV = exposure to public television; DV = reading skills.
Behavioral psychology study: IV = reinforcing comments; DV = work level.
Clinical psychology study: IV = psychotherapy; DV = future problems.
Ethics: debriefing definition, consent requirements, and anonymity considerations.