Here's an article illustrating what goes into high-profile journal publications, and why you should always read past the title and the abstract. Björn Brembs noticed this paper coming out in Current Biology on fruit fly receptors and behavior, whose abstract claims that "blocking synaptic output from octopamine neurons inverts the valence assigned to CO2 and elicits an aversive response in flight". As Brembs puts it:
We currently have a few projects in our lab that target these octopamine neurons, so this was a potentially very important finding. It was my postdoc, Julien Colomb, who spotted the problem with this statement first. In fact, if it wasn't for Julien, I might have never looked at the data myself, as I know the technique and I know and trust the lab the paper was from. I probably would just have laid the contents of the abstract to my memory and cited the paper where appropriate, as the results confirmed our data and those in the literature (a clear case of confirmation bias on my part).
When you look harder, you find that yes, the genetically manipulated flied do seem averse to carbon dioxide plumes. But when you check the control experiments, you find that the two transgenes added to the flies (independent of the change to the octopamine system that's the subject of the paper) both decrease the tropism for CO2. So there's really no way of knowing what the effect of both of them might be, octopamine signaling or not, and you might well suspect that the two of them together could hose up the carbon dioxide response without invoking the receptor pathways at all.
As Brembs says, though, the authors aren't trying to hide this. It's in the body of their paper. Abstract be damned, the paper itself states:
"We note that the Tdc2-GAL4/+ driver line does not spend a significantly greater amount of time in the CO2 plume by comparison to air, but this line, as well as the UAS-TNT/+ parent line, spends significantly more time in the CO2 plume in comparison to their progeny. Therefore, this experimental result cannot be fully attributable to the genetic background."
No, not fully attributable at all, especially if the progeny show some sort of additive effect of the two transgenes. Of course, if you water down your conclusions too much, you might not get the paper into as good a journal as you'd like. I'll let Brembs sum up:
To make this unambiguously clear: I can't find any misconduct whatsoever in this paper, only clever marketing of the sort that occurs in almost every 'top-journal' paper these days and is definitely common practice. On the contrary, this is exactly the behavior incentivized by the current system, it's what the system demands, so this is what we get. It's precisely this kind of marketing we refer to in our manuscript, that is selected for in the current evolution of the scientific community. If you don't do it, you'll end up unemployed. It's what we do to stay alive.
If there's anyone out there who thinks that this doesn't go on in the chemistry literature, my advice is to please look around you a bit. This sort of thing goes on all the time, and I'd guess that most of us automatically dial down the statements in paper titles and abstracts as we read them, without even realizing any more that we're doing so. But in a case like this (and there are many others), even that process will still let erroneous conclusions into your head. And we all have enough of those already.