Interesting, thank you!
Thanks for your comment, adamShimi! Do you have a sense of the profile of people that find eating snails disgusting? I wonder if it's a generational issue, for example. In Spain, eating snails now seems to be much more prevalent among older generations than among the youngest population.
Hey Julia! I partially address that point in the section that Linch indicated. As you say, whether snails have a capacity for valenced experience is still uncertain. When compared to bivalves, snails have more diverse and specialized sensory organs. As snails are motile and active foragers, they display a wider range of behaviors, and that is reflected in greater neural complexity. For instance, snails show nociceptive responses, like avoidance behavior in response to high temperatures (not surprisingly, several sources that provide instructions for cooking snails mention the attempts of snails to escape boiling water). However, relatively little is known about the anatomical organization and actual functions of most neurons in their ganglionic regions.I must admit that I haven't investigated any bivalves in detail. Still, for what I know, the case for snail sentience is much better than the evidence for bivalve sentience.
Although the possession of nociceptors is perhaps some evidence of a capacity to feel pain, it is certainly not by itself "a good indicator" of that capacity. If nociceptors are not connected to centralized information-processing structures, these neurons could trigger reflexive reactions (i.e., similar to spinally mediated responses in mammals), but that would not imply that the nociceptive input is consciously perceived (in humans, see Becker et al., 2012; Dubin & Patapoutian, 2010). If we understand consciousness as suitably integrated information (Oizumi et al., 2014), the projections of nociceptors to integrative information-processing structures is a crucial aspect to examine when judging the probability that a nonhuman individual is conscious.
In the case of C. elegans, unlike other invertebrates, they do not seem to have a specific neural region for the processing of spatial information and organization of movement. In other words, movement and stimuli discrimination do not appear to be integrated in a manner sufficiently similar to the vertebrate midbrain (see Altun & Hall, 2011; Kato et al., 2015).
However, it should be noted that some noxious stimuli reactions have been identified in C. elegans, specifically, physiological responses to nociception and moving away from a noxious stimulus. However, heat-evoked escape responses in these animals, for example, are considered highly stereotypical, and a reflexive reaction (Leung et al., 2016).
Finally, when I used the term "simple" [nociceptive behaviors] here I specifically meant: (i) nociceptive responses can be identified, but they do not necessarily account for noxious stimulus intensity and direction, (ii) absence or insufficient indicators of 'long-term' learning and memory, and (iii) absence or insufficient indicators of motivational tradeoffs. Given our findings (summarized here), C. elegans seem to mostly display simple nociceptive responses.
I applied to RP when I decided to make an important change in my career. If RP hadn't hired me, I'd have kept trying it at different EA organizations, maybe as an intern. Yet, I would likely have ended up working in a management position at a local NGO.
Yes, now I'm more careful while walking outside.After our research on invertebrates, I also placed a net in some windows at home, and I purposefully keep them closed as long as possible to prevent any flying insects from visiting us and being "welcomed" by my cats.
I do think that the chances of bivalves being sentient are quite low. However, I do not eat them because I'm already used to a plant-based diet, and given our uncertainty, I adhere to the precautionary principle in this case.
In general, I would not recommend consuming marine invertebrates produced in countries where trawling is not banned, given its impact on other aquatic animals for whom there is a high probability that they are sentient (i.e., fish and other vertebrates).
Still, I'm unsure about the consequences of promoting bivalve consumption, even if they are farmed. I'm concerned about how some people might interpret such a message –e.g., they may assume, without much thought, that consuming other more complex invertebrates (e.g., shrimps) is equivalent.
I agree with Jason. Additionally, I probably wouldn't be a researcher if I didn't work for an organization like RP because of operational costs, security/risk, and well-being reasons. But more importantly, since I'm at an early stage of my career as a researcher, if I worked independently, I wouldn't count on the support of my team and researchers with more experience. That would make it very difficult for me to improve and develop professionally as a researcher.
¡Gracias por tu interés y tu colaboración, Mati!
Thank you for your interest and collaboration, Mati!
Good question about repellants. Indeed, if food were the limiting factor, repellants would be much more effective. But in agricultural lands, crops constitute a superabundant source of potential food. In these landscapes, invertebrates like some insects or snails do not seem to be mainly limited by the amount of available food –instead, access to quality feed appears to be a matter of greater importance.
Therefore, deterring insects typically move off on to a new crop, where they do not necessarily compete for food, and their populations can thrive. So it is unclear whether repellants will actually reduce populations of target invertebrates. That is why repellents are only used occasionally in crops. They work better as a part of a strategy that incorporates other forms of population control.