AIToday
Large Language ModelsAI Safety & AlignmentZenn AI/MLPublished: Oct 29, 2026, 01:00 JST

GPT-5.4 Thinking era means old hallucination image is outdated

Send on LINE
GPT-5.4 Thinking era means old hallucination image is outdated

3 Key Points

  1. What happened

    The 2023 pattern of models inventing facts has been largely curbed by reasoning models, retrieval and better answer-withholding, with GPT-5.4 Thinking scoring 82.7% on BrowseComp versus GPT-5.2's 65.8%.

  2. Why it matters

    If the classic fabrication is largely suppressed, remaining errors shift to bad sources, misread documents and flawed reasoning, so quality judgments should cover the whole search-and-verify system, not the model alone.

Not sure about something? Ask the AI

Questions and answers are published on this page.

Summaries like this, every morning.

Context & Analysis

The debate is framed around a distinction between defining the phenomenon and tracking the stage of the technology. It notes that around 2023, large language models tended to answer even when they lacked knowledge, producing plausible authors, years and definitions for things that did not exist. It traces part of that behavior to an evaluation incentive: scoring that gives credit for correct answers while treating wrong answers and abstentions as equal makes guessing rational, a structure it says was discussed in a 2026 Nature paper and remains an evaluation-design issue. The author cautions, however, that the existence of that incentive does not prove every current model prioritizes guessing.

The shift the piece centers on is the ability to look things up before answering. Web search, document search and retrieval-augmented generation are described as different implementations of the same idea: grounding answers in external information rather than stored knowledge alone. Combined with improved reasoning and uncertainty handling, this widens the options beyond guessing or declining to a third path of retrieving first. The author stresses that benchmark gains show better search and information integration, not that search automatically precedes every answer.

On the economic side, experience with AI is separated from the ability to use it well. It contrasts the 58.8% usage experience rate with the 39.5% who missed all five questions in a separate ICT literacy survey, noting the latter did not directly measure hallucination detection. It also cites a 2025 Quarterly Journal of Economics study of customer-support work in which AI assistance raised average productivity by about 15%, with larger gains for less experienced staff, as evidence that AI can narrow gaps even as it may widen them for those who can set problems and evaluate outputs.

FAQ
What evidence is given that hallucination has decreased?
It cites GPT-5.4 Thinking scoring 82.7% on the search-based BrowseComp benchmark, compared with 65.8% for GPT-5.2, as reported by OpenAI, and says Anthropic has published similar retrieval and reasoning improvements for Claude Opus 4.6.
Is hallucination solved?
No. It says errors remain from incorrect retrieved information, misreading sources, mismatches between evidence and conclusions, and mistakes in multi-step reasoning that self-verification may not correct.
How common is generative AI use in Japan?
It cites the 2026 edition of the Ministry of Internal Affairs and Communications' information and communications white paper, which put the generative AI usage experience rate at 58.8% in the FY2025 survey.
Send on LINE

AI news that matters for your work, delivered every morning.

Pick your industry and the AI tools you use, and get news related to your work every day.

Free · 30 seconds with Google · unsubscribe anytimeWhat is AIToday? →

Ask AI

Ask AI anything about this article. The AI reads this article, earlier AIToday articles, and Wikipedia, and cites its sources. Q&As are published on this page for other readers too.

Questions and answers are published on this page.

Related Articles

Next articleAI agent pricing as of 2026年10月: from a few thousand yen to millions