EPFL researchers unveiled a language model called MiCRo (Mixture of Cognitive Reasoners) that divides processing across four expert modules modeled on the brain's functional organization, EPFL announced on June 26, 2026. MiCRo routes each word of a sentence to one of four experts — language, logic, social reasoning, and world knowledge — letting users see which module handles which content and adjust its influence. The work was led by PhD candidate Badr AlKhamissi at EPFL's NLP Lab and NeuroAI Lab, in collaboration with neuroscientist Greta Tuckute of Harvard and MIT, and was presented at the International Conference on Learning Representations (ICLR). This article organizes the key facts on the basis of EPFL's official announcement.

What the Research Is

EPFL researchers designed the language model MiCRo to mirror the functional specialization of the human brain. The name MiCRo stands for Mixture of Cognitive Reasoners, denoting a structure that mixes role-specific expert modules instead of one monolithic neural network. The work was led by PhD candidate Badr AlKhamissi at the NLP Lab and NeuroAI Lab in EPFL's School of Computer and Communication Sciences (IC), in collaboration with neuroscientist Greta Tuckute of Harvard and MIT. Making the model's inner workings legible to people is the central goal of the research.

The Four Expert Modules

EPFL's MiCRo is split across four expert modules: language, logic, social reasoning, and world knowledge. When a sentence comes in, each word is routed to a different expert, a structure modeled on how the human brain splits processing by function. The four modules are separated by role to handle linguistic form, logical computation, relational and social context, and background knowledge respectively. Because the active expert is revealed word by word, the model's reasoning path can be traced.

Why the Reasoning Is Visible

MiCRo's interpretability is clearest in EPFL's example of splitting a dinner bill among friends. EPFL explained that, when splitting the bill, the social reasoning module identifies relational nuances while the logic module handles the arithmetic, so different reasoning types activate word by word. Users can observe which module handles which content, and adjust its influence, without any additional prompting. Rather than a black box that only emits an answer, it shows what kind of thinking happened where.

Limits and Significance

MiCRo's modular structure is a design modeled on brain regions, and it does not claim a one-to-one equivalence with human cognition. EPFL's announcement focuses on the structural strengths of interpretability and per-module routing rather than on quantitative benchmark numbers. How splitting experts balances performance and cost against a large monolithic model is an area that needs follow-up validation. The ability for people to check and intervene in why the model answered as it did is meaningful for safety.

Summary

EPFL researchers unveiled MiCRo, a language model that divides processing across four modules — language, logic, social reasoning, and world knowledge — modeled on the brain's functional specialization. It was led by PhD candidate Badr AlKhamissi at the NLP Lab and NeuroAI Lab, with Greta Tuckute of Harvard and MIT, and was presented at ICLR. ASAP organized the modular structure and interpretability on the basis of EPFL's official announcement, without speculating about quantitative performance numbers not in the announcement.

Sources: EPFL