lecture 2 PSYCH
Key Concepts: Validity, Reliability, and Test Design
If you don’t know the answer in reality, don’t answer; leave blank. This is about avoiding guessing on uncertainty.
In tests, in doubt: pick the middle option. Tests are designed with patterns that can be exploited to improve scores (e.g., private schools or academies practice the test repeatedly).
Validity vs Reliability:
Validity: tests measure what they intend to measure; often the most critical quality of a test.
Reliability: consistency of scores across trials or raters; depends on context.
Example: If a math test is given at the beginning and end of a quarter with the same questions, high reliability (same score) can imply you didn’t learn anything new.
Practical stance: Validity is usually the priority; reliability is important but context-dependent.
Inter-test reliability (a form of reliability): when different tests (e.g., SAT, ACT, LSAT, MCAT) yield similar results, credibility increases.
In clinical psychology, multiple tests for the same person can be used; if all tests converge on the same conclusion, credibility rises.
Important caution: tests can be reliable but invalid; e.g., an IQ test might consistently measure something, but not necessarily what it claims (not a definitive predictor of life outcomes).
Overview of test concepts helps in evaluating psychological assessments and their applicability in real-world settings.
The Scientific Method in Psychology: Hypotheses, Variables, and Experiments
Experiment flow: start with a hypothesis, test it, and compare results with the original hypothesis.
Concrete vs abstract reasoning differences:
A 10-year-old may stick with a hypothesis despite conflicting evidence (concrete reasoning).
A teenager is more likely to abandon a hypothesis when results conflict (abstract reasoning).
Core experimental elements:
Groups: control vs. experimental
Independent variable (IV): what you manipulate (e.g., Crest toothpaste vs. regular toothpaste)
Dependent variable (DV): your results (e.g., cavities after the study)
Example: Crest toothpaste (IV) vs regular toothpaste; DV: number of cavities; control group uses regular toothpaste; experimental group uses Crest.
Placebo: a sugar pill or inert treatment used to control for placebo effects in drug trials.
Purpose of a control group: provides a baseline to compare with the experimental condition to determine if the IV caused a difference.
Replication: the beauty of a good experiment lies in replicability; studies should yield the same results when repeated.
Mundane realism: the extent to which experiment results generalize to real-life settings; lab settings may strip away extraneous variables that exist in daily life.
Life as a series of everyday experiments: people constantly test hypotheses and adjust behaviors in response to outcomes.
Research Methods: Surveys, Case Studies, and Observational Methods
Surveys and polls:
Pros: quick access to information from thousands of people.
Cons: response rates and sampling biases; nonparticipation can undermine results; sample must be representative (city vs. suburbs; geographic and demographic coverage).
Polling pitfalls: early Clinton-Trump polls may have biased samples if they overrepresented urban or suburban populations.
Case studies:
In-depth studies of individuals (e.g., forensic psychology, serial killers like Edmund Kemper, Ted Bundy) to gain rich qualitative insights.
Strengths: provide detailed, contextual information.
Limitations: limited generalizability; interviews can be manipulated or misled (even the best interview can be deceptive).
Ethics and media literacy in research reporting: beware of “science-coded journalism” and sensationalism; repeated misinformation can create an echo chamber.
Observational and interview methods complement one another by providing different kinds of evidence about behavior.
Experimental Psychology: Design, Variables, and Replicability (Detailed)
Independent variables (IV): what the experimenter actively changes or manipulates (e.g., brand of toothpaste, Crest vs regular).
Dependent variables (DV): what is measured as the outcome (e.g., cavities, test scores).
Control groups: participants that do not receive the experimental manipulation to establish a baseline.
Experimental groups: participants that receive the manipulation.
Placebo and placebo effect: a non-active treatment that helps control for expectations influencing results.
Replication and refinement: if results don’t align with the original study, researchers may alter the independent variable or design and re-test to refine conclusions.
Mundane realism and ecological validity:
The more closely a lab study mirrors real-world conditions, the more applicable the results are to daily life.
However, high control reduces extraneous variables, which enhances internal validity but may reduce external validity.
Projective Tests and Mental Health Assessments
Projective tests:
Rorschach inkblot test: patients describe what they see in inkblots; no right or wrong answers. Used as quick assessments in counseling to gauge potential concerns (e.g., depression, suicidality).
Thematic Apperception Test (TAT): patients tell stories about ambiguous pictures; used to elicit themes about inner motives and conflicts.
Use: rapid, low-cost mental health screening, especially when time or resources are limited.
Considerations: projective tests are interpretive and rely on clinician judgment; results should be integrated with other data sources.
Alternatives: MMPI and other standardized inventories for more structured assessment (not expounded here but contrasted with projective tests).
Practical application: in child interviews, keep questions simple and concrete to avoid misinterpretation and ensure consistency of responses.
Psychometrics and Nonverbal Communication: Levels of Analysis
Projective tests in practice: quick tools to flag potential issues for further evaluation.
Multi-level analysis in psychology:
Micro level: brain-level processes (e.g., P300 ERP waves) and neural activity; fast, moment-to-moment brain responses.
Molecular level: observable, mid-range behaviors (e.g., reaction times to stimuli).
Molar level: large-scale behaviors in social and cultural contexts (e.g., violence, attraction, morale, prejudices).
The P300 wave (ERP):
An event-related potential occurring around 300 milliseconds after a surprising or relevant event.
Donchin’s work: used EEG to study how the brain processes unexpected name cues and other stimuli.
Micro level focus: what happens in the brain during rapid cognitive processing.
Nonverbal communication (Rosenthal):
Nonverbal channels include facial expressions, body language, tone of voice.
These channels are often redundant (all telling the same story) but can also contradict each other.
In deception, tone of voice may be more informative than facial expressions.
Studies show tone can influence medical treatment outcomes in alcoholism treatment, where hostile tones predict poorer outcomes.
Implicit attitudes and bias:
Banaji (Yale) and the Implicit Association Test (IAT) measure automatic associations between concepts (e.g., race and positive/negative values).
IAT results can reveal unconscious biases that may not align with conscious beliefs.
fMRI studies (Phelps) link IAT results to amygdala activation, suggesting neural correlates of bias.
Research explores whether IAT scores predict real-world behavior; this remains a question for future decades.
The molar vs micro distinction also informs how researchers design interventions that consider cultural and social contexts.
History and Philosophy of Psychology: Paradigms, Founders, and Evolution
Kuhn’s Structure of Scientific Revolutions:
Science evolves through paradigm shifts; older schools eventually give way to new ones.
Revolutions occur when current theories can no longer explain emerging questions.
Terms: paradigm shift, revolutionary science, evolving truths.
Renaissance thinkers and the mind-body problem:
Descartes (mind-body dualism): proposed the mind controls the body; emphasized the mind as a seat of thought.
The mind-body problem: philosophical question about how mental states relate to physical states.
The Renaissance era catalyzed new ideas in science, mathematics, and instrumentation (telescopes, magnifying glasses, new number systems).
Early empiricism and positivism:
John Locke: tabula rasa (mind as a blank slate); knowledge from experience; challenged inherited or preordained traits (e.g., predestination).
Auguste Comte and positivism: knowledge should be derived from objective observation; emphasis on empirical data.
Early psychology’s split between more philosophical and more experimental traditions:
Wilhelm Wundt (Leipzig): founded the first experimental psychology lab, emphasizing measurement of reaction times, judgments, and associations.
G. Stanley Hall: introduced Freud to the American public; founded the American Psychological Association; early psychology in the U.S.
William James (principles of psychology, 1890): emphasized consciousness, emotions, the self, personal values, and religion; argued for psychology as a broad science of human experience.
Proponents like the Jamesians vs. the “soft” critics argued for a scientific approach focused on sensation, perception, and learning; Freud and psychoanalysis also gained traction with a different theoretical framework.
The evolution of methods and the role of science in psychology:
Early psychologists debated whether psychology should emulate physics and chemistry (precision, measurement) or include broader human experiences (consciousness, meaning).
The field requires multiple perspectives and diverse methods to understand the brain, mind, and behavior.
Foundational Concepts and Real-World Implications
Psychology as a science:
Defined as the scientific study of behavior and mental processes.
Psychologists aim to predict and sometimes control behavior; basic research can inform practical solutions in education, stress reduction, peace-building, and violence prevention.
Researchers study both humans and other animals to understand universal psychological processes.
Practical takeaways for everyday life and education:
Be mindful of how context, measurement, and bias influence judgments about behavior.
Recognize the limitations of self-report surveys and the value of converging evidence from multiple methods.
Understand the difference between statistical reliability and validity when evaluating tests and research findings.
Appreciate the role of replication and the potential for paradigm shifts in science; be open to new evidence and revised theories.
Key Names, Terms, and Concepts to Remember
Reliability vs Validity: reliability is consistency; validity is accuracy in what’s being measured.
Intertest Reliability: across different standardized tests that measure similar constructs.
Hypothesis testing and experimental design: control vs experimental groups; IV vs DV; replication; mundane realism.
Crest toothpaste experiment: IV = Crest vs regular toothpaste; DV = cavities; control group uses regular toothpaste.
Placebo effect and placebo-controlled trials.
Surveys and sampling biases; nonparticipation; sample representativeness.
Case studies: Edmund Kemper, Ted Bundy; limitations in generalizability.
Projective tests: Rorschach Inkblot, TAT; themes from responses used in clinical impression formation.
EEG and ERP: P300 wave; micro-level brain processes; timing around 250–350 ms after unexpected stimuli.
Nonverbal communication: channels (facial expressions, body language, tone of voice); redundancy and potential contradictions; deception cues.
Implicit attitudes: IAT; Banaji (Yale); amygdala (Phelps) as neural correlates; ongoing questions about predictive validity.
Levels of analysis: micro (neural), molecular (rapid behaviors), molar (cultural, social phenomena).
Foundational figures and ideas: Wundt, James, Hall, Freud; Descartes; Locke; Comte; Weber; Donchin; Flourens; phrenology critique; Kuhn; rise of psychology as a science.
Real-world considerations: media literacy, biased polls, and the ethics of psychological research and reporting.
Connection to Future Topics and Study Tips
Expect to see how researchers design experiments today, including advanced neuroimaging and behavioral analytics.
In upcoming programs, you’ll learn more about how psychologists conduct research and evaluate evidence, bridging theory with practical application.
Study tips: practice identifying IV vs DV in example studies; evaluate validity and reliability in given test descriptions; recognize when a result might generalize beyond the lab (mundane realism) and when it might not.
Quick Recap Formulas and Numeric References
Energy concept discussed: "Energy equals mass times velocity square" → E = m c^2 (contextual misstatement noted in transcript; presented here as the standard formula referenced).
Neural timing: P300 ERP response approximately t \approx 300 \,\text{ms} after an unexpected event.
Neural conduction speeds mentioned: fastest impulses around v \approx 2 \,\text{mph} (figurative example); other statements referenced speeds up to about 200 \,\text{mph} in neural impulse contexts (conceptual exaggeration for illustration).
Experimental consistency and replication emphasized throughout; importance of reproducing results to confirm findings.