AI Quick Tips 221: How does GPT-5's reasoning compare to GPT-4o?

That’s led to a lot of beginners and casual users to question what the point of it is.  

I’m not going to resolve that in one “quick” post, but I can show you a specific example - directly from ChatGPT to illustrate how the reasoning works differently.  By the way, reasoning is one of the areas that has been harder to get right so these are welcomed improvements

Prompt

"You have three boxes. One contains only apples, one contains only oranges, and one contains both apples and oranges. All are mislabeled. You may pick one fruit from one box to determine what each box contains. Explain your reasoning and name the correct labels."

GPT-4o-style Response

If all the boxes are mislabeled, then the box labeled "Apples and Oranges" must contain only apples or only oranges.

If you pick one fruit from that box and it’s an apple, then that box contains only apples, and the box labeled "Apples" must be the mixed one, and the box labeled "Oranges" must contain only oranges.

If you pick an orange instead, then that box contains only oranges, the "Oranges" box is the mixed one, and the "Apples" box contains only apples.

Issues in GPT-4o’s reasoning:

• The final mapping is slightly vague and depends on you to mentally run both branches of logic.
  
  
• The explanation doesn’t fully eliminate ambiguity without mentally simulating both scenarios.
  
  
• It misses an explicit step-by-step mapping for both cases.

GPT-5-style Response

Since all labels are wrong, the box labeled “Apples and Oranges” cannot be mixed — it must contain only apples or only oranges.

1. 1. Take one fruit from the “Apples and Oranges” box.
      

• • • If it’s an apple → this box contains only apples.
      • The box labeled “Oranges” can’t be oranges (label is wrong), so it must be mixed.
      • The box labeled “Apples” must then contain only oranges.
        
        

• • • If it’s an orange → this box contains only oranges.
      • The box labeled “Apples” can’t be apples (label is wrong), so it must be mixed.
      • The box labeled “Oranges” must then contain only apples.
        
        

Final answer example (if you draw an apple):

• • ‘Apples and Oranges’ → Apples
  • ‘Oranges’ → Mixed
  • ‘Apples’ → Oranges

Improvements in GPT-5’s reasoning:

• Lays out a clear decision tree for both possible draws.
  
  
• Uses explicit elimination reasoning.
  
  
• Gives a concrete example outcome so you don’t have to mentally process the branches yourself.
  
  
• Clearer, step-by-step mapping makes the logic transparent.