Artificial Intelligence - Do Larger Language Models Imply Better Reasoning? A Pretraining Scaling Law for Reasoning

Hey PaperLedge crew, Ernis here! Ready to dive into some brain-tickling research? Today, we're tackling a paper that looks at how those super-smart Large Language Models, or LLMs, think – specifically, when they're trying to figure things out based on a web of interconnected information.

Think of it like this: imagine you're trying to find out if your friend knows someone who can fix your vintage record player. You ask around, connect the dots between people, and eventually, hopefully, find the right person. That's multi-hop reasoning – connecting the dots through multiple steps.

This paper creates a kind of artificial world – a "knowledge graph" – that mimics the complex connections we see in the real world, like social networks or the internet. They then chop off some of the connections in that world, creating missing pieces.

Now, they train LLMs on this incomplete world. The LLMs have to learn all the connections they do see, and then try to infer the missing ones – essentially, filling in the blanks.

Here’s where it gets interesting. The researchers found that as they made the LLMs bigger and bigger, their ability to reason… didn't always get better! In fact, sometimes it got worse! It's like giving someone too much information – they get overwhelmed and can't see the forest for the trees.

The paper calls this a "U-shaped loss curve". It means performance goes down before it eventually goes up, as the model gets even bigger, but that initial dip is a puzzle.

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So, why does this happen? The researchers think it's because of something called "excessive memorization." Imagine you're trying to solve a riddle. If you just memorize a bunch of facts, you might not actually understand how they connect. You might just be spitting back information without truly reasoning.

The LLMs, when they get too big too fast, might be doing the same thing. They're memorizing the connections they see, but they're not actually learning to reason about the relationships.

"Overparameterization can impair reasoning performance due to excessive memorization."

The researchers then looked at different things that could affect this, like the structure of the knowledge graph (is it tightly connected or more spread out?), the size of the model, and how long they trained it.

And here’s a cool finding: they discovered a way to predict the ideal model size for a particular knowledge graph! They found that the complexity of the graph – how many possibilities there are to search through – can be used to estimate the optimal size of the LLM. Think of it like figuring out how big a toolbox you need based on how complicated the job is.

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So, why does this research matter?

• For AI developers: It gives us clues about how to build better, more efficient LLMs that can actually reason, not just memorize.
• For businesses: It can help optimize LLMs for tasks like knowledge discovery, customer service, and risk assessment, where connecting the dots is crucial.
• For everyone: It gives us a better understanding of how these powerful AI systems work, and how to make them more reliable and trustworthy.

This is a really interesting piece of research that suggests that bigger isn’t always better when it comes to AI reasoning. It also highlights the importance of understanding how these models learn, not just what they learn.

Here are a couple of things that popped into my head while reading this paper:

• If excessive memorization is a problem, could we design training methods that force LLMs to reason more and memorize less? Maybe by adding extra "noise" or uncertainty to the data?
• How can we better measure "reasoning" in LLMs, beyond just whether they get the right answer? Can we develop metrics that assess the process of reasoning, not just the outcome?

Let me know what you think, PaperLedge crew! Until next time, keep those neurons firing!

Credit to Paper authors: Xinyi Wang, Shawn Tan, Mingyu Jin, William Yang Wang, Rameswar Panda, Yikang Shen