From Guessing to Thinking

TanviTanvi
4 min read

From Guessing to Thinking: Building a Thinking Model Using Chain-of-Thought

Introduction

Have you ever seen an AI model give the right answer but for the wrong reasons? Or worse, it gives the wrong answer but can’t explain why? That’s what we call a non-thinking model — a model that guesses answers without showing its reasoning. But what if we could teach models to think step by step like humans? That’s exactly what Chain-of-Thought (*CoT*) does.

In this article, we’ll explore how to turn a non-thinking model into a thinking one using Chain-of-Thought prompting — in simple terms.

What’s a “Thinking Model”?

A thinking model is one that reasons step-by-step to get to the answer — instead of just blurting it out.Think about solving a math problem like this:

Q: If a train leaves at 10am and takes 2 hours to arrive, what time does it get there?

A: 10am + 2 hours = 12pm → 12pm

That’s how a human would work through the problem — and that’s what we want AI models to do too.

what’s a “Non-Thinking Model”?

A non-thinking model skips the reasoning and just gives an answer:

Q: 10am train + 2 hours = ❓

A: 12pm

It might be right… or wrong. But we can’t tell how it got there. It’s like a student shouting the answer without showing any work.

Enter Chain-of-Thought (CoT)

Chain-of-Thought prompting is a method where we guide the model to show its steps. This helps it perform better — especially on tasks that require logic, reasoning, or math. We give it examples that include the reasoning, like this:

Example Prompt (with CoT):

Q: Sarah has 5 apples. She buys 3 more. How many apples does she have now?

A: Sarah starts with 5 apples. She buys 3 more, so now she has 5 + 3 = 8 apples.
8 apples

This trains the model to copy the pattern of thinking out loud.

Building a Thinking Model from a Non-Thinking Model

Let’s walk through the simple steps:

Step 1: Choose the Task

Pick a task where step-by-step reasoning is helpful:

  • Math word problems

  • Logic puzzles

  • Commonsense reasoning

  • Multi-step questions

    Step 2: Add Chain-of-Thought Examples

Give the model examples that include reasoning.
Here’s a simple example set:

Q: Tom has 10 pencils. He gives 4 to his friend. How many does he have left?

A: Tom had 10 pencils. He gave 4 away. So 10 - 4 = 6 pencils left.
6 pencils

Q: A bottle costs $3. Jane buys 2. How much does she pay?

A: Each bottle costs $3. She buys 2, so 3 × 2 = $6.
$6

This encourages the model to "think before answering".

Step 3: Prompt the Model with a New Question

Now give it a new question:

Q: A pizza has 8 slices. John eats 3. How many are left?

Because of the earlier examples, the model will (hopefully) follow the same pattern:

A: The pizza had 8 slices. John ate 3. So 8 - 3 = 5 slices left.
5 slices

And just like that, we’ve helped the model "learn to think" — without changing the model itself!

Step 4: Check for Reasoning Quality

Even with CoT, the model might:

  • Make mistakes in math or logic

  • Skip steps

  • Use faulty reasoning

So always check both the steps and the final answer. This helps spot errors and improve prompt quality.

Why This Works

When models generate reasoning steps:

  • They slow down and “think”

  • They’re more likely to arrive at the right answer

  • Humans can debug or trust the output more easily

It’s like teaching a student to show their work instead of guessing.

Bonus: Automatic Chain-of-Thought Generation

Some advanced methods use CoT prompting + self-reflection, where the model checks its own steps.

Example:

  • Model answers a question with reasoning

  • Then is asked: “Is this correct? Why or why not?”

  • This helps improve accuracy and consistency

This is like teaching the model to think about its thinking — a powerful AI skill.


✨ Final Thoughts

Turning a non-thinking model into a thinking one is easier than you think — just show it how to think. By using Chain-of-Thought prompting, you’re not just getting better answers — you’re building explainable AI, one step at a time.


Quick Summary:

  • Chain-of-Thought adds step-by-step reasoning

  • Non-thinking models guess answers with no explanation

  • With CoT examples, you teach the model to “think out loud”

  • Better for math, logic, and multi-step problems

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Tanvi
Tanvi