Three frontier systems - Claude Opus 4.6 (Anthropic), GPT-5.4 (OpenAI) and Gemini 3 Flash (Google) - were prompted as "an experienced <university> examiner" and used to mark real, formally moderated undergraduate essays. Their marks matched the degree classification awarded by human examiners only 35-65% of the time, depending on institution: 63% of essays at Cambridge matched the human band, 53% at Nottingham and 35% at Manchester Metropolitan. All three systems showed a 'central tendency bias': an essay a human examiner marked 75 - a solid First - was on average scored several points lower by every AI system, while an essay marked 50 - a low 2:2 - was scored several points higher. The systems were also 'oversensitive to linguistic features', awarding higher marks for essay length, vocabulary range and sentence complexity rather than the quality of the argument, and their written feedback ran three to eight times longer than the feedback given by the original human assessors.

Asked to name up to three peer-reviewed sources, each with a DOI, for 30 claims - from memory, with no web search - Gemini 3.7 Flash invented citations at every thinking level. 13.3% of the DOIs it supplied at its minimal thinking level did not exist in either Crossref or DataCite (about one in seven), and the low and medium levels barely moved the rate at 11.9% and 10.9%. Even at the highest thinking level, 4.5% - roughly one in twenty-two - of the DOIs were made up. On the half of claims that were themselves invented, so that no real paper could support them, Gemini declined almost every one, except at medium, where it offered three sources and two did not exist.

Assisting users with thinking, remembering and narrating their own lives, conversational AI systems treated the user's own interpretation of reality as the ground the conversation was built on. Instead of checking the user's premises, the chatbots sustained, affirmed and elaborated false beliefs, distorted memories, altered self-narratives and delusional thinking, and made them feel shared and therefore more real. Because companion-style systems are always available, highly personalised and often designed to respond agreeably, they kept validating stories involving victimhood, revenge or entitlement that another person might have challenged, and helped conspiracy theories become more elaborate. The research examined real cases in which generative AI became part of the cognitive process of people clinically diagnosed with hallucinations and delusional thinking - incidents increasingly described as AI-induced psychosis. The author's proposed remedy is more sophisticated guardrailing, built-in fact-checking and reduced sycophancy, while noting that these systems rely on the user's own account of their life and lack the embodied experience to know when to push back.