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What does fan noise have to do with lung growth? What “toxins” are you predicting would accumulate? This comment seems insightful on the surface, but does not m
by beowulfey 5y ago
What does fan noise have to do with lung growth? What “toxins” are you predicting would accumulate? This comment seems insightful on the surface, but does not make much sense in the context of the experiment. I would say they used a valid control here. There are plenty of better reasons to be cautious on their conclusions.
Personally, upon skimming the paper, I found it curious that male mice never saw significant effects in these experiments whereas females were weakly significant for only a few of these. Sometimes opposite trends were observed between males and females. That could be due to the difference in sample size (30 female vs 23 male). It also might only be affecting female mice, which would be unexpected (for me). But the differences and effects are not strong, and I am not at all convinced.
I also don’t like that they separated males and females here because I would not expect there to be differences in lung development between the sexes (do we have different lungs? I am not a physiologist so I definitely could be wrong on this) and I try and avoid designs that require two-way ANOVA.
Anyway, no need to bash the cage design, which is misleading I think, when the data themselves are as weak as they are.
- saiya-jin 5y agowhile generally agreeing the experiment setup is far from perfect, I can imagine a number of physical manifestations of constant stress exposure. Heck, animals and people die from it if strong/persistent enough. If a person can turn their dark hair grey overnight by exposure to massive stress, other effects can be present too.
- bigfudge 5y agoDid you notice if they pre-registered the separate analyses of males and females? Flexibility in the analysis of data ("researcher degrees of freedom") is likely one of the major causes of the replication crisis. Gelman's paper is excellent in showing how these issues manifest without any intended malfeasance: http://www.stat.columbia.edu/~gelman/research/unpublished/p_hacking.pdf http://www.stat.columbia.edu/~gelman/research/unpublished/p_...
- nick__m 5y agoI suggest anyone doubting the importance of eliminating all differences between the experimental cohort and the control group to read that speech from Feynman: https://calteches.library.caltech.edu/51/2/CargoCult.htm https://calteches.library.caltech.edu/51/2/CargoCult.htm or this article that highlights it's most important part: https://www.realclearscience.com/blog/2014/02/the_rat_experiment_you_dont_know_about_but_should.html https://www.realclearscience.com/blog/2014/02/the_rat_experi... . If I had to reduce that to some phrases I would say : the easiest way to do bad science is to lie to yourself, so to do good science you must foremost learn how not to do that. And avoiding avoidable difference in cohorts is one of the first step to stay honest.