For the second time in two weeks, a study has been published that suggests that people who use AI may display less cognitive ability than those who don’t rely on it. The studies have bolstered critics’ accusations that AI makes you stupid.

The most recent study was conducted by the University of Pennsylvania’s Wharton School and looked at a sample size of over 4,500 participants. The study, which looked at the cognitive differences between people who used LLMs like ChatGPT to do research and those who used Google Search, found that the people who used chatbots tended “to develop shallower knowledge” of the subjects they were researching. Both groups were asked to research how to start a vegetable garden, with some participants randomly selected to use AI, while others were asked to use a search engine. According to the study’s findings, those who used ChatGPT gave much worse advice about how to plant a vegetable garden than those who used the search engine. Researchers write:

The shallower knowledge accrues from an inherent feature of LLMs—the presentation of results as syntheses of information rather than individual search links—which makes learning more passive than in standard web search, where users actively discover and synthesize information sources themselves. In turn, when subsequently forming advice on the topic based on what they learned, those who learned from LLM syntheses (vs. standard search results) feel less invested in forming their advice and, more importantly, create advice that is sparser, less original—and ultimately less likely to be adopted by recipients.

The study concludes that this occurred ironically because of ChatGPT’s advertised benefit—”sparing users the need to browse through results and synthesize information themselves.” Because researchers did not have to hunt for information themselves, their “depth of knowledge” was markedly lower than those who did. “In this sense, one might view learning through LLMs rather than web search as analogous to being shown the solution to a math problem rather than trying to solve it oneself,” the research concludes.

The UPenn study follows on the heels of research produced by MIT, published earlier this month, that showed a similarly problematic cognitive impact produced by AI. That study, which observed the neural activity of college students who were using ChatGPT to study, found that increased AI use resulted in reduced brain activity, or what the researchers termed “cognitive debt.” The study used an EEG machine to measure the neural activity of three different groups of students—one that used ChatGPT to study, one that used Google Search, and one that used neither. The study showed that ChatGPT users displayed markedly less cognitive activity than even those who were using Google Search to find information.

The methodology of the MIT article has since been called into question by AI enthusiasts. Critics have noted that the study in question was not peer reviewed and that a small sample size of participants makes it hardly exhaustive. Similarly, critics have argued that while the EEG measurements show certain decreases in specific forms of brain activity, that doesn’t necessarily mean that participants are “dumber” as a result. Indeed, less mental exertion (and, thus, less activity) can be a sign that a person is actually more competent at a task and doesn’t have to expend as much energy as a result. From a certain perspective, these recent assessments of AI’s cerebral impact reek of a moral panic about a new and not altogether well-understood phenomenon.

On the other hand, the conclusion that using an app to complete a homework assignment makes you less capable of thinking for yourself would appear to be self-evident. Outsourcing mental duties to a software program means you’re not performing those duties yourself, and, as is pretty well established, doing something yourself is often the best way to learn. Of course, the internet has been curtailing human mental activity since it first went online. When was the last time you had to remember how to get somewhere? It really seems like Google Maps collectively robbed us of that ability over a decade ago.

Other evidence for AI’s stupidification effect is even more obvious: the maelstrom of cheating that’s been happening in America’s educational system means that students are making their way through high school and college with limited to no understanding of the subjects they’re studying. While there is still much to learn about how AI impacts us, we shouldn’t forego common sense when it comes to interpreting what we’re seeing with our eyes. If a student can’t write an essay without ChatGPT, it may be a sign that they don’t have a particularly bright academic future ahead of them.