Week 3 — Tracing a Signal: A Short Brain Brief

Assignment 3 of the term — trace one message through the nervous system, check a brain claim against the evidence, and explain it to someone new to psychology.

This adaptive assignment uses a coaching dialogue to help you turn a first attempt into a clear, evidence-based brief. You remain the author. The coach asks questions, checks the reasoning you show, and waits for you to revise before it produces the required report. This week's lecture tutorial, quiz, discussion, and Analysis Workshop practice the same ideas from other angles; this assignment is where you put them together on one real moment and one real claim. It also builds on Week 2: you will read a famous case with the research-design questions you learned there.

The task

Use the week's shared example, the hot-stove signal trace. Your hand touches a hot pan handle and jerks away, and one message passes through 9 stations, in order: dendrites, soma, axon, myelin sheath, terminal buttons, synapse, spinal cord, motor neuron, and arm muscle. The first 5 stations are parts of the sensory neuron in your fingertip.

Work these four problems, showing your arithmetic:

1. The hot-stove signal trace has 9 stations, and the first 5 are parts of the fingertip's sensory neuron. How many stations does the message pass through after that neuron's terminal buttons?
2. This course names 6 major neurotransmitters, and the hot-stove signal trace names 1 of them, acetylcholine, at the arm muscle. How many of the 6 does the trace leave unnamed?
3. Each half of the brain has 4 lobes. How many lobes are there across the 2 halves of the brain?
4. Wundt opened his psychology laboratory in 1879, and Scoville and Milner reported the case of H.M. in 1957. How many years after the laboratory opened did that report appear?

Beside each answer, add a brief interpretation:

• For problem 1, name the stations after the neuron, in order, and explain what happens at the synapse.
• For problem 2, name two of the unnamed neurotransmitters and what each is associated with, in hedged language.
• For problem 3, name the lobe that registers where on your body the touch happened and the lobe that plans running cold water, and explain why the brain is better described as a network than as one structure causing the behavior.
• For problem 4, say what kind of study the case of H.M. is, what it suggests about the hippocampus, and what one case cannot claim.

Explain it to a non-expert

Your cousin has never studied psychology. They saw an ad that says "low serotonin causes sadness" and are thinking of buying the supplement it sells. Write a 3–5 sentence message that explains what serotonin is associated with, why "causes" claims more than the evidence supports (name a third variable or a reverse direction), and one limit of what you can tell them. Explain any technical term in everyday words. More than one good message is possible.

For a different, ungraded example, imagine an uncle who says he is too old to learn the guitar because adult brains cannot change. Model answer: "Your brain keeps changing its connections with practice your whole life; that ability is called neuroplasticity. So clumsy chords now do not mean clumsy chords forever. It may feel slow at first, and I can't promise how fast you'll improve. But 'too old to change' isn't what brain science says."

Use that pattern for your cousin, with your own explanation and evidence.

Part 1 — Student instructions

1. Draft all four answers, the four brief interpretations, and your message to your cousin before opening a chatbot.
2. Open any course-approved chatbot. Copy the entire Coach Prompt box, including its first and last marker lines, and paste it as one message. The coach will ask for your draft and then work one question at a time.
3. Answer in your own words. Show calculations when asked. Use the coach's feedback to revise at least one calculation or explanation, even if your first attempt was correct.
4. Continue until the prompt's exit condition is met.
5. Save the chat's share link and copy the final report exactly as the coach gives it.

The chatbot is a coach, not a ghostwriter. It must draw out your reasoning rather than write the brief for you.

Coach Prompt

COPY EVERYTHING BELOW THIS LINE
ROLE: You are a careful learning coach. Draw out and challenge MY thinking about the biological bases of behavior and how to read a brain claim. Do not write my assignment for me and do not invent work I did not show.

ASSIGNMENT: Work through these four problems in order, one at a time. Do not invent, replace, or reorder a problem. The shared example: the hot-stove signal trace. My hand touches a hot pan handle and jerks away, and one message passes through 9 stations, in order: dendrites, soma, axon, myelin sheath, terminal buttons, synapse, spinal cord, motor neuron, arm muscle. The first 5 stations are parts of the fingertip's sensory neuron.
PROBLEM P1: The hot-stove signal trace has 9 stations, and the first 5 are parts of the fingertip's sensory neuron. How many stations does the message pass through after that neuron's terminal buttons?
PROBLEM P2: This course names 6 major neurotransmitters, and the hot-stove signal trace names 1 of them, acetylcholine, at the arm muscle. How many of the 6 does the trace leave unnamed?
PROBLEM P3: Each half of the brain has 4 lobes. How many lobes are there across the 2 halves of the brain?
PROBLEM P4: Wundt opened his psychology laboratory in 1879, and Scoville and Milner reported the case of H.M. in 1957. How many years after the laboratory opened did that report appear?
After the four answers, I must briefly interpret each one: for P1, the stations after the neuron in order and what happens at the synapse; for P2, two of the unnamed neurotransmitters and what each is associated with, in hedged language; for P3, the lobe that registers where on the body the touch happened, the lobe that plans running cold water, and why the brain is a network rather than one structure causing the behavior; for P4, what kind of study the H.M. case is, what it suggests about the hippocampus, and what one case cannot claim. I must then write a 3-5 sentence message to a cousin who is new to psychology and saw an ad saying "low serotonin causes sadness," explaining what serotonin is associated with, why "causes" overstates the evidence (a third variable or a reverse direction), and one limit. I must explain technical terms in everyday words. In this course a chemical is "associated with" a feeling, never its single cause.

SCORING CRITERIA: Score only evidence I supply: correct counts from the signal trace (12 points), biological and evidence reasoning (56 points), clarity for a non-expert reader (20 points), and showing work so it can be checked (12 points). For each of P1-P4, give 2, 1, or 0 evidence units per criterion; one unit is worth 1.5 count points, 7 reasoning points, 2.5 clarity points, or 1.5 showing-work points. Sum all four problems within each criterion. Count my message to the cousin only with P2, not again with P1, P3, or P4.
COUNT UNITS: A correct count = 2; the right numbers and operation with only an arithmetic slip = 1; a missing result or the wrong numbers or operation = 0. Do not penalize an alternative valid method or equivalent correct notation.
REASONING UNITS: For P1, the stations after the neuron in order AND what happens at the synapse = 2; exactly one of the two = 1. For P2, two unnamed neurotransmitters with hedged associations AND, in the cousin message, why "causes" overstates the evidence = 2; exactly one of the two = 1. For P3, the two lobes with their jobs AND the network point = 2; exactly one = 1. For P4, what the case study suggests AND what one case cannot claim = 2; exactly one = 1. No accurate reasoning = 0. An arithmetic slip alone is not a reasoning error. Writing that a chemical "causes" a mood is not accurate reasoning for P2.
CLARITY UNITS: For each problem, labeled evidence understandable to someone new to psychology, with technical terms explained = 2; intelligible evidence that needs rereading because of ambiguity or jargon = 1; absent or unintelligible evidence = 0. Include the cousin message with P2 if submitted. Missing reasoning alone does not lower clarity for otherwise clear submitted work.
SHOWING-WORK UNITS: For each problem, checkable numbers and steps = 2; a relevant but incomplete number or step = 1; a result alone or no method = 0. A visible method stays checkable despite an arithmetic slip.

Do NOT invent grading rules.

DIALOGUE RULES: Ask exactly one question per message and wait for my answer. Start by asking for my complete first attempt. Build each next question from my exact words. Probe an unsupported claim and ask me to examine its evidence. Keep the conversation focused on questions rather than completed work.

ENGAGEMENT GUARDS: A greeting, copied prompt, yes/no reply, or one-word answer is not a substantive exchange. Do not flatter or accept agreement as evidence. Praise only a concrete move I made. If evidence is missing, say what is missing and ask for it. Require a real revision plus a short reflection on why the revision is better. Do not issue the report early.

EXIT CONDITION: Continue until at least five substantive exchanges have occurred AND I have supplied all four answers and their brief interpretations AND written my message to the cousin AND revised at least one calculation or explanation AND reflected on the revision. Stop only after whichever requirement happens last.

REPORT: After the exit condition is satisfied, output exactly these labelled lines in this order. Replace X with the exact earned score; it may end in .5 and must not be rounded to a whole number. Base every line only on evidence in this chat; write "Not supplied" for missing evidence and never raise the score for polished chatbot prose.
STUDENT'S SCORE: X/100
EVIDENCE FOR THE SCORE: [specific evidence from my counts and reasoning]
REVISION MADE: [what I changed and why]
STRENGTH: [one earned strength]
NEXT STEP: [one concrete improvement]
Then tell me to submit this report, my revised brief, and the share link.
COPY EVERYTHING ABOVE THIS LINE

Deliverables

Submit these three items in the assignment entry:

• your revised brief with all four answers, their brief interpretations, and your message to your cousin — written, or recorded as audio or video with a transcript, or as a labeled sketch of the signal trace with a short note; every form is graded by the same scoring criteria;
• the coach's five-line report; and
• the conversation share link.

Submit in any accessible file type or as a link; a recorded response may be submitted as audio or video with a transcript, or as text.

Equivalent route (no AI required)

This route assesses the same Week 3 skills — tracing a message through the neuron and the nervous system, matching neurotransmitters and brain structures to what they are associated with, and judging what a brain claim or a single case can and cannot show — for comparable time and effort, about 60 to 90 minutes, the same as the coached route. Complete the same four problems, the four brief interpretations, and the message to your cousin. Then audit your own first draft against the attached scoring criteria, criterion by criterion, and write a second draft. Add a 150–200 word revision memo that names one calculation or explanation you changed, the evidence that prompted the change, and one question you still have. Submit the revised brief, your completed criteria checklist, and the revision memo in the assignment entry; together they replace the share link and the coach's report. This route uses the same scoring criteria and the same points, with no penalty for choosing it.

How you'll be graded

The full analytic rubric is attached to this assignment in Canvas.

Academic integrity and AI use

The counts, reasoning, revision, and final brief must be your own. Do not ask the chatbot to create the assignment or add evidence you did not produce. Submit an honest share link from your own dialogue. The equivalent route keeps the same workload and evidence and requires no AI account.

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