I definitely don't eat any cephalopods either, I can't really stomach it, but admittedly it's mostly due to my own anthropomorphism of them.

I'm pretty much in agreement with you about intelligence barometers for non-human species, though I am not too well versed in the the parameters typically used.

I think the conversation abuts two different ideas that I always hold in opposition:

1) Complexity does not mean intelligence. This is especially a strong point to maintain for cephalopods, since many of them (I would say all, but I'm not quite sure) are not raised at all by their parents, so all their behavior is instinctual. Like I said before, not quite sure about the parameters used, so that may be neither here nor there for non-human species, especially ones whose nervous system is so goddamn divergent from our own. Octopuses are well known for their tool usage, but things like observational and conditioned learning are kind of up in the air, and they are some of the factors we highly attribute to intelligence.

2) EQ is a very good rough estimate, but efficiency of usage and differences in physiology can be somewhat un-accounted for (there is a body of work on nervous systems in cephaolopods, but I am somewhat ignorant of it, granted), particularly when we consider just how goddamn different cephalopod nervous systems and anatomy are to humans. A thing that could be trivial or telling that I can't find information about in 5 minutes on google is comparison of wet weight to dry weight accounted for in cephalopods EQ. Then again, just the fact that they have such minute control of chromatophores lends to the idea that "higher" functioning my be supplanted by just maintaining control of their complex anatomy. They are efficient information processors, regardless.

In all honesty, trying to determine intelligence is a very homo-centric thing in general, and I mostly trust my anthropomorphiz-ing more than anything else, since debates about pain, nociception, intelligence, and trying to quantify suffering just seem sort of pendantic as opposed to just focusing on the fact that we are some damn top-tier predators after all, things die so we may live, eat healthy, respect life, and just don't fuck up ecosystems in the process. This is all coming from an ex-vegan, long-term vegetarian who is having some cognitive dissonance about recently starting to eat some meat again.

Fun Fact: the brain of an octopus wraps around it's esophagus, so if they eat something too big they can cause brain damage. ,

Octopus vulgaris has an EQ of about 0.02. Sepia officinalis (the common cuttlefish) has an EQ of about 0.09.

By contrast, rabbits have an EQ of about 0.4. So octopuses are actually dumber than the dumbest mammals. They're also smarter than reptiles and probably about as smart as some birds.

Wikipedia:

Manta rays have the highest for a fish,[16] and either octopuses[9] or jumping spiders[17] have the highest for an invertebrate. Despite the jumping spider having a huge brain for its size, it is minuscule in absolute terms, and humans have a much higher EQ, despite having a lower raw brain-to-body weight ratio.[18][19][20] Mean EQ for reptiles are about one tenth of the EQ for mammals. EQ in birds (and estimated EQ in dinosaurs) generally also falls below that of mammals, possibly due to lower thermoregulation and/or motor control demands.[21] Estimation of brain size in the oldest known bird, Archaeopteryx, shows it had an EQ well above the reptilian range, and just below that of living birds.[22]

Cows and pigs don't have the equipment to use tools, manipulate the environment, or produce symbols we recognize. They're quadripedal and rely on all four legs for support. Are animals with hands automatically smarter than animals without them? Probably not. Sure, they don't have a large area of motor cortex devoted to doing things with their hands because they don't have any, but we haven't done enough studies on cows and pigs to say much about their minds.

A lot of the species we recognize as 'intelligent' are often predators, which I find interesting, but not surprising, as they have to be able to plan to catch their prey, whereas prey animals just have to not get caught.