Week 1 — Measuring a Mental Process: A Short Lab Report — Traditional alternative (no AI)

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Assignment 1 of the term — summarize what a reaction-time laboratory measured and explain it to someone new to psychology.

This week you learned that psychology studies mental processes through behavior, and that it tests its ideas instead of trusting them. In this assignment you work four short problems on a small laboratory measurement, interpret each one, and explain the measurement to someone who has never studied psychology. This week's lecture tutorial, quiz, discussion, and Analysis Workshop practise the same ideas from other angles.

The task

A small laboratory, built the way Wundt's 1879 Leipzig laboratory was, timed one simple behavior: a light flashes and the participant presses a key as fast as possible. The reaction-time sample is an illustrative set of nine trials constructed for this course (not real data). The times, in milliseconds (ms), are 312, 289, 401, 356, 298, 275, 388, 342, and 310. The mean of the nine trials is 330.1111 ms and the median is 312 ms.

Work these four problems, showing your arithmetic:

1. Add the nine reaction-time trials (312, 289, 401, 356, 298, 275, 388, 342, and 310 ms). What is the total, in milliseconds?
2. The slowest trial took 401 ms and the fastest took 275 ms. What is the range of the nine trials, in milliseconds?
3. The median trial took 312 ms. How many milliseconds longer than the median trial did the slowest trial (401 ms) take?
4. One second is 1,000 ms. How many seconds did the median trial (312 ms) take?

Beside each answer, add one brief interpretation:

• Problem 1: name the behavior each trial records and the mental process a researcher infers from it, and say what the total is for.
• Problem 2: say what the range shows about how much the trials varied, and explain why a timed number, which anyone can check, outlasted introspection as a method.
• Problem 3: explain why a few slow trials pull the mean above the median, then offer an explanation for the slow trials from each of two of the six perspectives (biological, psychodynamic, behavioral, cognitive, humanistic, sociocultural). Name each perspective and keep the language hedged: "may," "might," "is associated with."
• Problem 4: write one falsifiable hypothesis about reaction time that a laboratory like this one could test, name a result that would show it to be wrong, and say why it is a hypothesis rather than a theory.

Explain it to a non-expert

A family member who has never studied psychology sees your report and asks, "Why would anyone time how fast people press a button?" Write a 3–5 sentence message that explains what the timing measures (the key press you can see, and the mental process behind it you cannot), reports how long a typical trial took in everyday words, and names one limit, including that this sample is illustrative and has only nine trials. Explain any technical term in everyday words. More than one good answer is possible.

For a different, ungraded example, imagine a grocery store that times how long shoppers stand at a new self-checkout screen before tapping "Pay." Model answer: "We timed the pause before people tap Pay because the pause is something we can see, and it hints at something we can't: how long people spend figuring out the screen. Most shoppers paused only a few seconds, but a few took much longer, so we look at the middle shopper, not the average. One week at one store is too little to say why the slow shoppers paused; we'd need to test an idea, such as whether bigger buttons shorten the pause."

Use that pattern for the reaction-time sample, with your own wording and evidence.

Show your arithmetic. A reader should be able to reproduce every number you report from the nine trial times without guessing which values or steps you used.

Deliverables

Submit a single lab report containing:

• the four answers, each with the arithmetic shown and the brief interpretation the task names for that problem;
• your message to the family member, explaining what the timing measures, how long a typical trial took, and one limit; and
• a one-line restatement of the trial times you used, so your results are reproducible.

Keep it to roughly one page. Clear and correct beats long.

Choose how you show it. Present your report as written text, or as a recorded audio or video explanation of about three minutes with a transcript, or as a labelled sketch of the nine trials with a short note. Every form is graded by the same scoring criteria. 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.

How you'll be graded

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

Academic integrity and AI use

This version is designed to be completed without AI: do the computations, the interpretations, and the writing yourself, without a chatbot or other AI tool. You may use a calculator or a spreadsheet for the arithmetic. Submitting AI-generated work as your own, or copying another student's work, is an integrity violation under the course policy.

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