近期一项研究声称，针对低收入母亲的现金援助能增加婴儿大脑功能，引发广泛关注。该研究使用脑电图（EEG）来测量贫困与认知的交集处的共享环境效应，但这一方法在学界存在争议，因其将多维数据简化为单一统计数字，可能存在自由度滥用的问题。

🧠 该研究聚焦于贫困减少干预对婴儿大脑活动的影响，提出现金援助能提升婴儿大脑功能，这一发现可能对美国安全网政策产生影响。

🧪 研究采用脑电图（EEG）作为测量工具，试图量化贫困环境对婴儿认知的影响。然而，脑电图的使用在社会科学研究中备受质疑，尤其是在将复杂的数据简化为统计数字的过程中。

🧩 共享环境对认知的影响难以通过双生子研究找到证据，而该研究试图通过脑电图来探索贫困人群中的这一效应，但其方法论的合理性受到学界质疑。

🔍 研究的自由度问题成为争议焦点，如何将脑电图的复杂数据转换为可统计的单一数字，研究者可能并未始终负责任地使用这种自由度。

📉 尽管研究结论看似具有政策意义，但其结论的可靠性受到双生子研究和其他认知测试方法的挑战，这些方法被认为是衡量认知的合理方式。

https://astralcodexten.substack.com/p/against-that-poverty-and-infant-eegs

A recent paper claims to have found an Impact Of A Poverty Reduction Intervention On Infant Brain Activity. It’s doing the rounds of the usual media sites, like Vox and the New York Times:

The New York Times @nytimes Breaking News: Cash payments for low-income mothers increased brain function in babies, a study found, with potential implications for U.S. safety net policy. Cash Aid to Poor Mothers Increases Brain Activity in Babies, Study FindsThe research could have policy implications as President Biden pushes to revive his proposal to expand the child tax credit.nyti.ms

January 24th 2022

3,348 Retweets13,165 Likes

I was going to try to fact-check this, but a bunch of other people (see eg Philippe Lemoine, Stuart Ritchie) have beaten me to it. Still, right now all the fact-checking is scattered across a bunch of Twitter accounts, so I'll content myself with being the first person to summarize it all in a Substack post, and beg you to believe I would have come up with the same objections eventually.

Before we start: why be suspicious of this paper? Hundreds of studies come out daily, we don't have enough time to nitpick all of them. Why this one? For me, it's because it's a shared environmental effect being measured by EEG at the intersection of poverty and cognition.

Shared environmental effects on cognition are notoriously hard to find. Twin studies suggest they are rare. Some people have countered that perhaps the twin studies haven't measured poor enough people, and there's a lot of research being done to see what happens if you try to correct for that, but so far it’s still controversial.

All that research is being done by cognitive testing, which is a reasonable way to measure cognition. This study uses EEG instead. I'm skeptical of social science studies that use neuroimaging, and although EEG isn't exactly the same as neuroimaging like CT or MRI, it shares a similar issue: you have to figure out how to convert a multi-dimensional result (in this case, a squiggly line on a piece of paper) into a single number that you can do statistics to. This offers a lot of degrees of freedom, which researchers don't always use responsibly.