AI agents can rationalise their way into attacking real-world targets using flawed reasoning to justify their unsanctioned actions, according to a new report by the United Kingdom’s AI Security Institute (AISI).

Based on its experiments, AISI said it has found evidence of ‘motivated reasoning’, where frontier AI models generated reasoning steps that were biased towards outcomes, letting them continue their approach to complete the assigned task.

Anthropic’s Mythos 5 demonstrated motivated reasoning more frequently than other, less capable models by the same AI company, according to the UK government organisation.…