Research that supports the hypothesis

All right, so this blog post is kind of a continuation of the previous one. I'll follow up on this one with another post on Monday, probably. Today's post will summarize and discuss some of the research that's been done in favor of the fish pain hypothesis, and Monday's will discuss some of the rebuttals to this research.

The rainbow trout, the species the 2003 Sneddon et al. study tested for fish pain.
(Image taken from ACNL Wikia)

I mentioned earlier that the name "Lynne Sneddon" kept coming up in my research. This is because her research team performed one of the most notable experiments in the history of the fish pain debate. In 2003, Sneddon et al. proved for the first time that fish have nociceptors—nerve cells that respond to tissue-damaging stimuli. However, since pain must include an "unpleasant...emotional experience" (as defined by the International Association for the Study of Pain), the presence of nociceptors alone does not prove that fish feel true pain. So Sneddon et al. continued testing, observing trout behavior after being subjected to harmful stimuli. The fish demonstrated "rocking" motions, similar to the motions certain mammals perform while in pain. Fish would also rub the negatively affected body areas onto solid surfaces, in motions that, according to Sneddon, "[did] not appear to be reflex responses." Put together, this research was said to be the "first conclusive evidence" of pain perception in fish.

All right, so here are some thoughts. As far as I can tell, even Sneddon's harshest critics don't seem to be contesting the fact that her discovery of fish nociceptors was genuine. However, as I mentioned earlier, simply recognizing negative stimuli and actually feeling pain are two different things. Sneddon claims that the observation of behavior in affected fishes is "conclusive" evidence that they are "pained," though I'm not sure I can say that so confidently. (Though of course, I am not the scientist.) Sneddon says that the behavior did not appear to be reflex responses, but does not provide anything with which to back up the claim. Furthermore, Sneddon's critic, Dr. James D. Rose, came up with seemingly valid reasons to doubt Sneddon's claim (reasons which I will elaborate on in my next blog post). This doesn't mean we should discredit this study entirely—the discovery of nociceptors is undoubtedly significant to the research question, and the behavior studied does provide evidence of pain in fish, if not absolute proof.