Chain of Thought Prompting: Guiding LLMs Step-by-Step

Pankaj Pandey
5 min readDec 20, 2023

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Chain of Thought (CoT) prompting is a technique that helps Large Language Models (LLMs) perform complex reasoning tasks by breaking down the problem into a series of intermediate steps. Think of it as providing the LLM with a roadmap to follow instead of just the destination.

Photo by Chelsea shapouri on Unsplash

Imagine navigating a winding maze. Large Language Models (LLMs) often face similar challenges in complex reasoning tasks, lacking a clear pathway to the solution.

Chain of Thought (CoT) prompting emerges as a beacon, guiding LLMs step-by-step through the intellectual labyrinth.

Gone are the days of simply throwing a problem at an LLM and hoping for a hit. CoT empowers us to deconstruct complex tasks into a sequence of intermediate reasoning steps, akin to laying down steppingstones across the maze.

Here’s how it works:

Start with the question: You present the LLM with the actual question or task you want it to solve.

Break it down: Then, you provide a few-shot sequence of reasoning steps that demonstrate how to approach the problem. These steps are like mini explanations that show the LLM the thought process leading to the answer.

Follow the chain: The LLM uses this chain of thought as a guide to reason out its own answer. It analyzes the information, applies the intermediate steps and ultimately generates its own final response.

Benefits of CoT Prompting:

Improved accuracy: With clear reasoning steps, the LLM is less likely to make mistakes or jump to illogical conclusions. This is especially helpful for tasks with multi-step logic or complex reasoning requirements.

Transparency: CoT prompts make the reasoning process more transparent, allowing us to understand how the LLM arrived at its answer. This is crucial for building trust and identifying potential bias or errors.

Better performance on complex tasks: CoT is particularly effective for tasks that require multi-step reasoning, logical deduction or common-sense application. These are areas where past LLMs often struggled.

Adaptability: The technique can be used for various tasks, from solving math problems and interpreting data to summarizing text and even creative writing.

Precision-Guided Reasoning: By providing a clear path, CoT reduces the risk of LLMs stumbling into erroneous conclusions or leaps of illogical faith. Multi-step tasks and convoluted reasoning problems, once impenetrable to LLMs, become navigable landscapes with CoT at the helm.

Transparency in the Spotlight: CoT lifts the veil of mystery shrouding LLM decision-making. Witnessing the chain of thought reveals how the LLM arrived at its answer, fostering trust and allowing us to pinpoint potential biases or missteps.
Unlocking Complex Domains: Tasks that were once the exclusive domain of human reasoning, like solving intricate math problems or deciphering data-driven insights, become accessible to LLMs empowered by CoT. This expands the range of applications where LLMs can shine.

Versatility Unbound: CoT isn’t a one-trick pony. This technique adapts to various realms, from scientific analysis and creative writing to data summarization and textual interpretation. The possibilities are as diverse as the tasks themselves.

Limitations of CoT Prompting:

Manual effort: Creating effective CoT prompts requires understanding the problem and designing the reasoning steps yourself. This can be time-consuming and complex for intricate tasks.

Model size: CoT seems to be more effective for larger LLMs with stronger reasoning capabilities. Smaller models might struggle to follow the prompts or generate their own reasoning chains.

Prompt bias: Like any other prompting technique, CoT can be susceptible to biased prompts that lead the LLM to incorrect conclusions. Careful design and testing are crucial.

Bias Blind Spots: Just like any prompt, CoT is susceptible to biased information. Careful design and thorough testing are crucial to ensure the LLM doesn’t follow a misleading path.

Crafting the Path: Building effective CoT prompts requires understanding the problem’s intricacies and formulating a clear, logical chain of reasoning. This can be demanding, especially for complex tasks.

Examples

Let’s dive deeper into understanding CoT through some illustrative examples and code snippets:

Example 1: Solving a Basic Math Problem

Prompt without CoT: What is the sum of 5 and 3?

Prompt with CoT:
1. Let’s add the first number, 5.
2. Then, add the second number, 3, to the previously obtained sum.
3. The answer is the final sum.

A Sample Code Example (Python):

# Prompt without CoT
prompt = "What is the sum of 5 and 3?"
# Prompt with CoT
cot_steps = [
"Let's add the first number, 5.",
"Then, add the second number, 3, to the previously obtained sum.",
"The answer is the final sum.",
]
# Combine prompt and CoT steps
prompt_with_cot = "\n".join([prompt] + cot_steps)
# Use the prompt with/without CoT to generate the answer
# (the actual code for generating the answer will depend on the LLM platform)

This example demonstrates how CoT guides the LLM through a simple addition problem step-by-step, resulting in a more transparent and explainable solution.

Example: Answering a Factual Question

Prompt without CoT: Who was the first person to walk on the moon?

Prompt with CoT:
1. The moon landing happened in 1969.
2. We need to identify the astronaut who first stepped onto the moon during that mission.
3. Based on historical records, Neil Armstrong was the first person to walk on the moon.

A Sample Code Example (Python):

# Prompt without CoT
prompt = "Who was the first person to walk on the moon?"
# Prompt with CoT
cot_steps = [
"The moon landing happened in 1969.",
"We need to identify the astronaut who first stepped onto the moon during that mission.",
"Based on historical records, Neil Armstrong was the first person to walk on the moon.",
]
# Combine prompt and CoT steps
prompt_with_cot = "\n".join([prompt] + cot_steps)
# Use the prompt with/without CoT to generate the answer
# (the actual code for generating the answer will depend on the LLM platform)

This example showcases how CoT utilizes prior knowledge and reasoning steps to arrive at a factual answer, making the thought process behind the response more explicit.

Please Remember, these are just basic examples. The beauty of CoT lies in its versatility and adaptability to various task domains. As you gain experience with CoT, you can craft increasingly complex reasoning chains to empower LLMs to tackle even more intricate challenges.

Conclusion:

Overall, chain of thought prompting is a promising technique that opens new possibilities for LLMs to tackle complex tasks with greater accuracy and transparency. While challenges remain, it represents a significant step forward in improving the reasoning capabilities of these powerful language models.
CoT prompting stands as a groundbreaking advancement in LLM development. It equips these models with the tools to tackle complex tasks with greater accuracy, transparency and versatility. As we refine CoT techniques and overcome its limitations, we unlock a future where LLMs not only generate solutions but also illuminate the path they took to get there.

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Pankaj Pandey

Expert in software technologies with proficiency in multiple languages, experienced in Generative AI, NLP, Bigdata, and application development.