ChatGPT 5.1 - New personalities put to the test

OpenAI just launched ChatGPT-5.1 Instant and ChatGPT 5.1 Thinking.

ChatGPT 5.1 now lets you choose from eight personalities.

We tested them so you don’t have to - here’s the quickest way to find the one that fits you.

Why it matters

The more you chat with a model, the more you come to rely on and expect a certain way of talking - just as you do with a human friend.

OpenAI received negative feedback when ChatGPT-5 came out from a segment of very loyal ChatGPT-4o users who felt ChatGPT-5 didn't have the same soul, the same depth as the previous model.

With the new and upgraded options you will be able to find a style that fits the AI co-worker you're looking for.

What are the styles and how do you select them?

There are eight styles, including the default. You select them by heading to your setting menu (bottom left if you are on desktop) and clicking "personalisation"

The names are self-explanatory, but the best way to see the impact is to ask the same question to each of them in turn.

To put it in an enterprise context I've asked ChatGPT to help me prepare for a 121 with a direct report where I need to have a challenging conversation.

Default

Professional

Friendly

Candid

Quirky

Efficient

Nerdy

Cynical

Which should you choose?

My advice is to test them all out for one day each, so you have time to get a feel for their style, how they interact with you, and how they deal with different scenarios.

1. Pick one personality today
2. Use it for a full workday
3. Notice: clarity, push-back, speed, confidence
4. Switch tomorrow and compare

At work I want a creative and effective mentor that can push back and challenge me. I'm not looking for a sycophantic supporter of every mad idea.

So for me I'll be tending towards Candid - but I'll update this post after a week!

Go Deeper

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• OpenAI ChatGPT-5.1 release blog post
• Kowalah Wednesday Webinars - learn one ChatGPT feature and ask your questions
• Kowalah Templates and Guides - AI policies, job descriptions and more - all free and un-gated