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Loop Polarity Tracer

Run the Loop Polarity Tracer MicroSim Fullscreen

About This MicroSim

This causal loop diagram holds the two learner loops from Chapter 8 on one canvas. They touch at Mastery, the stock both loops share:

  • Learning loop: Mastery raises Confidence, Confidence raises Practice time, and Practice time raises Mastery. All three links are positive.
  • Goal loop: a larger Gap between goal and mastery raises Study effort, Study effort raises Mastery, and Mastery lowers the Gap. Two links are positive and one is negative.

Each link carries a green plus or a red minus, the generator's causal loop convention. The loop markers start as grey question marks. To reveal a marker you trace its loop: the Trace next link button highlights one link at a time while a counter tallies the negative links so far. Before the final link, the MicroSim asks you to decide whether the loop is reinforcing or balancing, then reports the full count and the rule: an even number of negative links (including zero) makes a reinforcing loop, and an odd number makes a balancing loop.

Flip a sign mode turns the diagram into an experiment. Click any link to reverse its polarity (flipped links are drawn dashed) and watch the loop marker switch between R and B. Flipping two links in the same loop shows why the rule is about the parity of the count, not about any single link.

The diagram is stored as a JSON document in the causal loop schema (metadata, nodes, edges with polarity, and loops with type and path) at the top of loop-polarity-tracer.js. As the chapter notes, these loops are a plausible hypothesis about a learner, not a measured result.

Learning objective: The learner will examine a causal loop diagram, trace its polarity links, and determine whether the loop is reinforcing or balancing.

Bloom's taxonomy level: Analyze (verb: examine)

How to Use

  1. Hover over or click a variable to read its one-sentence description in the details panel.
  2. Click a link to see its polarity and the reason for it, such as "More practice, more mastery."
  3. Choose a loop in the Loop menu and press Trace next link. Watch the highlighted link and the "Negative links so far" counter.
  4. When one link remains, look at its sign and choose Reinforcing or Balancing. The feedback names the total count and reveals the loop marker.
  5. Check Flip a sign, click a link, and watch the loop marker change. Press Restore signs to return to the original diagram.
  6. Use the +, − and Fit buttons to zoom; the mouse wheel scrolls the page, not the diagram. You can also drag the diagram or a variable.

Iframe Embed Code

You can add this MicroSim to any web page by adding this to your HTML:

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<iframe src="https://dmccreary.github.io/microsims/sims/loop-polarity-tracer/main.html"
        height="514px"
        width="100%"
        scrolling="no"></iframe>

Lesson Plan

Audience

Teachers, instructional designers, learning-technology developers and learning-analytics practitioners (college undergraduate and professional development).

Duration

15 minutes

Prerequisites

  • Definitions of a feedback loop, a polarity link and a causal loop diagram (Chapter 8, "Systems and Feedback")
  • Reading arrows in a network diagram (Chapter 8, "Networks with vis-network")

Activities

  1. Read the links (3 min): Click each of the six links and restate its reason in your own words, using "if the source goes up, the target goes ..." for each.
  2. Trace both loops (5 min): Trace the Learning loop and then the Goal loop. Before the final link of each, commit to Reinforcing or Balancing and write down the count that justifies your choice.
  3. Flip experiment (4 min): Turn on Flip a sign. Predict what happens to the Goal loop if you flip Mastery → Gap, then flip it. Next flip two links in the Learning loop and explain why its label does not change.
  4. Discuss (3 min): The two loops share Mastery. Describe in two sentences what the combined system might do over time when both loops act at once.

Assessment

  • Given a new three- or four-link loop, the learner counts the negative links and classifies the loop correctly.
  • The learner explains why flipping one link changes a loop's type but flipping two links in the same loop does not.
  • The learner can state the polarity of a link as a causal "if the source rises" sentence.

References

  1. Causal loop diagram - Wikipedia. Polarity links, reinforcing and balancing loops, and the negative-link counting rule.
  2. Feedback - Wikipedia. Positive (reinforcing) and negative (balancing) feedback in natural and engineered systems.
  3. System dynamics - Wikipedia. The field that uses causal loop diagrams to reason about behavior over time.
  4. vis-network documentation - vis.js. The network library used to draw the diagram, with physics disabled and fixed positions.