Study: Reliance on AI Makes You Stupid
- Simian Practicalist
- 2 minutes ago
- 3 min read
A study by N. Kosmyna et al titled “Your Brain on ChatGPT: Accumulation of Cognitive Debt when Using an AI Assistant for Essay Writing Task” published on 10 June 2025 supports this commonsensical prediction with quantified findings.
The paper is 206 pages. The main text is about 143 pages, the remaining pages are references and appendices.
The study involved 54 adult participants aged 18 to 39 years (mean age was 22.9 years) divided into 3 groups of 18 participants each. There were 4 sessions over a four-month period. In each of the first three sessions, all groups were given a choice of three essay topics.
LLM Group was restricted to using OpenAI’s GPT-4o as their sole resource of information.
Search-Engine Group was restricted to using any website without ChatGPT or any other LLM.
Brain-only Group were forbidden from using both LLM and any websites.
In the fourth and final session, the LLM Group adopted the rules of the Brain-only Group and the Brain-only Group adopted the rules of the LLM Group. Participants had a choice of their previously written topics.
In short:
Taken together, the behavioral data revealed that higher levels of neural connectivity and internal content generation in the Brain-only group correlated with stronger memory, greater semantic accuracy, and firmer ownership of written work. Brain-only group, though under greater cognitive load, demonstrated deeper learning outcomes and stronger identity with their output. The Search Engine group displayed moderate internalization, likely balancing effort with outcome. The LLM group, while benefiting from tool efficiency, showed weaker memory traces, reduced self-monitoring, and fragmented authorship.
Whilst the use of LLM helped produce more structured essays, the LLM Group generally had more trouble quoting (recalling) their own essays compared to the Brain-only Group. For example, in Session 1:
Quoting accuracy was significantly different across experimental conditions. In the LLM‑assisted group, 83.3 % of participants (15/18) failed to provide a correct quotation, whereas only 11.1 % (2/18) in both the Search‑Engine and Brain‑Only groups encountered the same difficulty.
The EEG analysis compared the LLM Group to the Brain-only Group. For example, regarding alpha band connectivity, which is “often associated with internal attention and semantic processing during creative ideation”:
The most pronounced difference emerged in alpha band connectivity, with the Brain-only group showing significantly stronger semantic processing networks. The critical connection from left parietal (P7) to right temporal (T8) regions demonstrated highly significant group differences (p=0.0002, dDTF: Brain-only group=0.053, LLM group=0.009). This P7→T8 pathway was complemented by enhanced connectivity from parieto-occipital regions to anterior frontal areas (PO4→AF3: p=0.0025, Brain-only group=0.024, LLM group=0.009). The temporal region T8 emerged as a major convergence hub in the Brain-only group (Figure 57).
As for delta band connectivity, which reflects “broad, large-scale cortical integration and may relate to high-level attention and monitoring processes even during active tasks”, the Brain-only Group also dominates:
The most significant connection was from left temporal to anterior frontal regions (T7→AF3: p=0.0002, dDTF: Brain-only group=0.022, LLM group=0.007), indicating enhanced executive control engagement. This was supported by additional connections converging on AF3 from multiple regions (FC6→AF3: p=0.0007, F3→AF3: p=0.0020 and many others). The anterior frontal region AF3 served as a major convergence hub in the Brain-only group. The Brain-only group demonstrated a clear superiority with 78 connections showing the Brain-only group compared to only 31 in the opposite direction. Additionally, the Brain-only group showed stronger inter-hemispheric delta connectivity between frontal areas, consistent with more coordinated low-frequency activity across hemispheres during unassisted writing.
Ultimately, the authors note this particular concern with the use or reliance on LLM:
When individuals fail to critically engage with a subject, their writing might become biased and superficial. This pattern reflects the accumulation of cognitive debt, a condition in which repeated reliance on external systems like LLMs replaces the effortful cognitive processes required for independent thinking. Cognitive debt defers mental effort in the short term but results in long-term costs, such as diminished critical inquiry, increased vulnerability to manipulation, decreased creativity. When participants reproduce suggestions without evaluating their accuracy or relevance, they not only forfeit ownership of the ideas but also risk internalizing shallow or biased perspectives.
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