PSY 100: 9/11/25

Course Logistics and Updates

• Review the transcript for the most up-to-date class/version of the syllabus, since it changes over time.

• New class location noted: Pearson Hall.

• Supplemental Instruction (SI) is a separate enrolled class providing extra practice (quizzes, class activities, repeated material) to help with engagement in large classes.

• If you think SI would help, attend the SI session (the materials are reinforced there before returning to the main class).

• Schedule guidance: the schedule is on the last page of the syllabus. Scroll to the end to see deadlines; the instructor may forget to remind you at times.

• Example deadline given: application paper due on October 12.

• The instructor plans to finish the current topic (scientific method of psychology) and then move to biology.

Supplemental Instruction and Scheduling

• SI programs exist to help with material repetition and activities before/after the main class.

• Check your schedule page regularly to avoid missing deadlines.

Assignment Policies and Communication

• If you have questions about assignments, refer to the contract (between you and the instructor) for details.

• There are extra resources: an extra example, extra class activity, and extra quizzes.

• Policy on absences and makeups:

  • Emailing the instructor does not automatically change the class policy.

  • If you have a really good reason for missing class activities/quizzes, your grade may still be impacted but can be discussed.

  • Missing class more than twice a month without a compelling reason will likely affect your grade.

• Formatting requirements: if an assignment specifies an exact format (e.g., APA, double-spaced), those requirements must be followed; points will not be deducted for not meeting unspecified criteria beyond the stated format.

• The class will cover the scientific method of psychology and then transition to biology.

Experimental Method in Psychology: Key Concepts

• A variable is something that can be manipulated to study its effect on another variable.

  • Example manipulations discussed: sleep duration, nap length (e.g., 30 minutes vs 2 hours).

• Controlling extraneous variables is crucial to internal validity (ensuring observed effects are due to the manipulation).

• Challenges in real experiments: bringing participants from home into a lab can introduce uncontrolled variables (mood, environment).

• Demand characteristics and expectations can influence outcomes (e.g., researchers telling rats are stupid vs intelligent affecting performance).

• Not all studies are perfectly controlled; sometimes a naturalistic setting has higher external validity but lower internal validity.

• Internal validity vs. external validity:

  • Internal validity focuses on whether the manipulation caused the observed effect.

  • External validity concerns how well the results generalize to real-world settings. Internal validity vs. external validity: - **Internal validity** focuses on whether the manipulation caused the observed effect. It is the extent to which a study establishes a trustworthy cause-and-effect relationship between an independent variable and a dependent variable. High internal validity means that the observed changes in the dependent variable are indeed due to the manipulation of the independent variable, rather than extraneous factors or confounds. This is largely achieved through strict control of all other variables, randomization of participants to groups, and careful experimental procedures. Threats to internal validity include confounding variables, demand characteristics, experimenter bias, and maturation effects. - **External validity** concerns how well the results generalize to real-world settings. It refers to the extent to which the findings of a study can be applied to other situations, people, or populations outside of the research setting. A study with high external validity means its results are generalizable; for example, findings from a lab experiment on a specific sample could realistically reflect what happens in the broader population or in a natural environment. Factors influencing external validity include the representativeness of the sample, the realism of the experimental setting, and the ecological validity of the tasks or procedures used. There is often a trade-off between internal and external validity: highly

• Example illustrating bias: researchers’ expectations can bias results if the experimenters’ beliefs influence measurements (the “not” group effect).

• Brain-behavior link: intended to isolate manipulated variable (nap duration) to see its effect on memory or other outcomes, while keeping other factors constant.

• Real-world example from a video: observations during an interrogation measured by physiological indicators (heart rate, breathing, skin resistance) to infer stress or cognitive load.

• Thought-provoking historical note: Ted Kaczynski (Unabomber). Mentioned in the transcript as part of a broader discussion; history and psychology intersect in understanding motives, profiling, and the ethics of research into dangerous individuals.

Consent, Deception, and Debriefing in Research

• Informed consent forms (IRB-approved) are essential when participants sign up.

• Debriefing is required after deception or misleading procedures to explain the study’s true purpose and reduce potential harm.

• Deception may be used in some studies, but participants must be debriefed afterward to restore trust and understanding.

• For any study, maintain consistent experimental protocol across participants to avoid confounds.

Experimental Design Exercise: Classroom Protocols

• In a simplified class experiment, you form two groups (experimental and control) with a small sample (e.g., five participants per group).

• Procedure basics:

  • All participants undergo the same initial task (e.g., a word recall exercise).

  • One group performs an additional task (e.g., count backwards by a constant step for 60 seconds) to create a cognitive load.

  • The control group remains at rest during that period.

  • Afterward, participants are asked to recall as many words as possible; responses are scored by counting correctly recalled words.

• Reporting: write a short report (1–2 pages) including:

  • Hypothesis: one group will perform better than the other.

  • Methods: exactly what was done, including timing and instructions.

  • Results: numerical outcomes (e.g., counts of correct words per group).

  • A short discussion linking results to potential confounds (e.g., age, gender, prior experience).

  • A figure presenting the average scores for the two groups:

  • Compute the average for each group: ext{Average}= rac{ extstyle \sum{i=1}^{n} xi}{n} where the sum runs over participants in the group.

• Data collection sheets and worksheets:

  • You should have two worksheets (one per group) and a table capturing scores.

  • The worksheet includes the words recalled and the corresponding score for each participant.

  • A figure illustrating group averages should be included in the report.

• Script for participant instruction to ensure consistency:

  • A standard script (e.g., reading a list of words aloud at a fixed pace, then counting backwards) to minimize variation across participants.

  • Example pacing: read words at a rate of one word every two seconds; count backwards from 100 by seven for 60 seconds; do not reveal the study’s true purpose beforehand to avoid bias (and then proceed to recall).

Foundations of the Brain: Self, Neurons, and Neural Communication

• Big philosophical question: What is self or identity? Self can be seen as a narrative of how we present ourselves and how we are perceived in different contexts (family, friends, colleagues).

• Approach to understanding how the self works: start with the body and neural basis, because complex experiences emerge from neural interactions.

• The brain as a network of cells: organized layers and connections allow perception, memory, decision-making, and action.

• A useful metaphor: a tree to illustrate neuronal structure and information flow:

  • Dendrites: parts of the neuron that receive information from other neurons.

  • Nucleus: stores and processes genetic and regulatory information.

  • Axon: a long cable-like projection that transmits signals to other neurons.

  • Myelin sheath: insulating layer around the axon that speeds transmission.

  • Nodes of Ranvier: gaps in the myelin sheath that enable saltatory conduction.

  • Schwann cells: cells that form the myelin sheath in the peripheral nervous system.

  • Axon terminals: release neurotransmitters to communicate with the next neuron.

• How signals travel: electrical impulses travel along the axon as action potentials, carried by ions across membranes; myelin speeds this process, while gaps (Nodes of Ranvier) enable rapid jumping of signals.

• Basic neuron components and roles:

  • Dendrites: receive input from other neurons; highly branched structures.

  • Nucleus: regulates neuronal activity and contains genetic information.

  • Axon: conducts electrical impulses away from the cell body.

  • Axon terminals: release neurotransmitters to influence the next neuron.

  • Myelin sheath: insulation; speeds up transmission.

  • Nodes of Ranvier: gaps in myelin that facilitate saltatory conduction.

  • Schwann cells: form the myelin sheath in the peripheral nervous system (PNS).

• Action potentials and membrane dynamics:

  • Resting state: the inside of the neuron is relatively negative compared to the outside.

  • Threshold: the critical level of membrane potential required to trigger an action potential (commonly around
    V_{ ext{threshold}} \,\approx\,-55\ \text{mV}).

  • Depolarization: triggered when the threshold is reached; influx of positive ions (e.g., Na extsuperscript{+}) makes the inside more positive.

  • Repolarization: following peak, the membrane potential returns toward the negative resting state, driven by ion efflux (e.g., K extsuperscript{+}).

  • Absolute and relative refractory periods: brief times when neurons cannot fire again or require stronger stimulation to fire again.

  • Resting potential: typically around V_{ ext{rest}} \,\approx\,-70\ \text{mV}.

  • Summary of phases: Resting state → Depolarization (inward Na extsuperscript{+}) → Peak of the action potential → Repolarization (outward K extsuperscript{+}) → Refractory period → Return to resting state.

• Synapses: the junctions where neurons communicate using neurotransmitters

  • Presynaptic neuron: the neuron that sends the signal; releases neurotransmitters into the synaptic cleft.

  • Postsynaptic neuron: the neuron that receives the signal.

  • Synaptic transmission involves chemical signaling across the synaptic gap, with various excitatory and inhibitory neurotransmitters.

• Excitation vs Inhibition in neural circuits:

  • Excitatory signals promote firing in the postsynaptic neuron.

  • Inhibitory signals decrease the likelihood of firing; balance between excitation and inhibition shapes information processing and behavior.

• Practical implication: dysfunctional signaling or loss of neurons can lead to cognitive or motor impairments; aging and diseases can impact myelin, synapses, and neural connectivity.

Real-World and Ethical Contexts in Psychology

• IRB-approved consent forms ensure participants understand risks and their rights.

• If deception is used, debriefing afterward is essential to explain the true purpose and address any potential harm.

• The classroom emphasis on standardized procedures aims to reduce confounds and improve replicability.

• The discussion of historical cases (e.g., Ted Kaczynski) highlights the breadth of psychology’s interface with ethics, motives, and societal impact.

• The transcript underscores the importance of keeping experimental protocols the same across participants to avoid biases and ensure interpretability of results.

Key Formulas and Numerical References (to memorize)

• Average score for a group:
  ext{Average}= rac{ extstyle \sum{i=1}^{n} xi}{n}

• Resting membrane potential (typical):
  V_{ ext{rest}} \approx -70\ \text{mV}

• Action potential threshold:
  V_{ ext{threshold}} \approx -55\ \text{mV}

• Conceptual reminder: the brain-to-body communication relies on passing signals via axons and synapses, with myelin speeding transmission and nodes enabling rapid conduction.

Quick Connections to Foundational Principles

• Reductionism: complex behaviors (self, decision-making) can be traced to neural activity and network dynamics.

• Experimental control vs. ecological validity: laboratory control improves causal inference; real-world relevance improves when tasks resemble everyday activities.

• Ethics in research: consent, deception, debriefing, and IRB oversight protect participants and maintain public trust in science.

• Learning and memory: working memory is engaged by tasks that require maintaining and manipulating information (e.g., word lists) under distraction (e.g., performing a secondary task like counting).

Summary of What to Take Away

• Understand the purpose of supplemental instruction and how it complements large lectures.

• Recognize key components of experimental design: independent/dependent variables, control groups, randomization, standard procedures, and ethical considerations.

• Distinguish internal vs external validity and how experimental settings influence each.

• grasps the basics of neuronal structure and signaling, including dendrites, axons, myelin, nodes of Ranvier, and synapses.

• Know the basics of action potentials, membrane potentials, and the phases of neural signaling.

• Appreciate the ethical and real-world contexts in which psychology research is conducted.

• Be able to compute simple averages and interpret basic data representations in reports.