Spiders are intelligent

I'm not entirely sure I agree with this. It might be simply a problem of to concise an answer. There appear to be a number of difficulties with the way you've put things. A bit of amplification may be in order. Behavior most assuredly does change, except for genetically determined, hard-wired, instinctive and inherited behaviors (such as the spider web pattern). However, even here, we are likely discussing "no change over an individual lifespan" rather than "no change period". Given long-term environmental changes, etc, or changes in other selection pressures, such inherited behaviors can also "evolve" even in a relatively short (a few generations in some cases with short-lived fast-reproducing organisms) time span.I think I know what you meant, but you may be opening up a can of worms by the way you went about it.

I know I’m coming a bit late to this thread. I’d like to offer perhaps a different way of looking at the subject of “intelligence” - without attempting to rigorously define what that is. Someone upthread suggested that “intelligence” and “instinct” were two opposite poles on a continuum of capability. I’m not sure they’re necessarily diametrically opposite, but certainly could represent two distant points on the line. One possible way of defining the continuum would be the degree of “rules-based” (i.e., instinct) vs. “adaptive” (i.e., intelligence) behavior exhibited by the individual taxon in question. I am so totally NOT a neurobiologist that I may be talking out my fundament, but it would seem to me that all organisms exhibit a mixture of the two types, and their relative position on our putative continuum would depend on what proportion of their overall behavioral repertoire is composed of the one or the other.As an example, consider the behavioral repertoire of a relatively simple organism like the neotropical chigger (family Trombiculidae), the absolute bane of every tropical ecologist’s existence. These tiny organisms lie in wait atop vegetation, then drop or jump onto passing warm-blooded animals (especially, it appears, ecologists), and either burrow under the skin or bite, causing incredibly itchy welts. From my close, personal (and often miserable) observation, it appears these organisms have an extremely limited, almost entirely rules-based set of behaviors: they can only move in one direction (forward), they wait for weeks or even months for a passing large mammal, etc. Although they may have unsuspected abilities, the vast majority of their behavior can be encompassed by a few, extremely simple rules. For instance, we can characterize their “hunting” thusly:1. go forward until obstacle => up
2. go up until “up” = “down” => stop
3. when detect urea => drop
4. if drop = skin => bite/burrow
5. if drop /= skin AND urea = “yes” => go up until skin => bite
6. if drop /= skin AND urea = “no” => 1And that’s about all. Obviously there are reproductive rules, and possibly predator avoidance rules, but they can all be reduced the same way. This would tend to put chiggers toward the bottom end of the scale (which at least gives me the satisfaction of knowing I'm smarter than they are while I'm furiously scratching the results of their programming). Primates and cetaceans, for instance, because of their extremely complex and adaptive behaviors, would cluster toward the “intelligence” end of the scale. I don’t know where a spider would fit in this, but my guess is that neurobiological complexity has a lot to do with where the specific organism would land on the scale. I have no idea whether there have been any studies that would verify this, but it would seem to be consistent with the robotics references molbiogirl has posted.Does this make any sense to anyone?

I'm not sure this follows from what I said. I noted that I thought that behavioral complexity could be correlated with neurobiological complexity. Spiders, with all the best will in the world, simply don't have the latter to sufficient extent to be positioned very far along the line towards the "intelligence" end. One example would be the observation that orb weavers and other web-spinning spiders seem to be highly constrained in their behaviors. You never see an orb weaver turning active hunter - regardless of relative prey abundance or optimimum strategy. In addition, web-spinners seem to be highly conservative in their designs, with nearly every species "specialized" in a particular exact type of web (which is only modified by the physical constraints imposed by the substrate). This kind of highly conserved behavior would seem to be indicative of "rules-based" rather than "adaptive". MBG's spider-bots demonstrate this kind of behavior - and I'm sure you'll admit that these devices are purely "programmed". Spider behavior may be pretty complex programming, but is none the less "rules-based". I have absolutely no clue what you're on about, here. Sorry.