Of course intelligence is going to have some relative or "perspectivistic" properties. For a crude and extreme example, some extremely advanced species from another galaxy might find us too primitive to contact. Now, as far as a "motivation for specifically identifiable behaviors", I don't know exactly what you might be referring to.
I was contrasting "specifically identifiable behaviors" among individuals - so, very detailed descriptions of different behaviors between, say, upper-class people and lower-class people - with intelligence as a more general substrate that has little bearing on individually distinct behaviors.
In other words, between intelligence as a specific and quantifiable variant among individual human beings and intelligence as a general substrate that has minimal impact on individual behaviors, respectively. In the latter formalization, intelligence is less something that bears immediately on how individuals behave and more of a species-wide isomorphic pattern. From this perspective, I'd also propose that IQ tests don't actually measure intelligence at all, but something more like the ability to maintain logical consistency within a given set of axioms. IQ texts don't necessarily provide you with these axioms, but they expect you to already be familiar with them. I'm not sure this qualifies as "intelligence."
If we define intelligence as the extent to which an organism's approach to interacting with its environment serves its interests, does that make man the dumbest ever animal?
That would be an interesting argument to make.
According to Peter Watts, consciousness is an evolutionary mistake. But consciousness also isn't intelligence, and I think the two often get unconsciously and unintentionally conflated when we consider intelligence to manifest in rational action.
Also, I think you'd have to specify whether or not it serves an organism's
best interests, and this is a difficult value to qualify.
I'm not inclined to say that humans are the dumbest animals since we've managed to consciously alter our own relationship to the external world via a mediating set of tools and instruments. I think intelligence lies not in how individual humans are able to manipulate tools or solve certain problems, but in the more complex pattern that occurs between human existence and its environment. This is a recursive relationship, and invites some contradiction since human bodies are part of the environment from which they attempt to distinguish themselves, and in which they must survive. Intelligence isn't a quality of human beings, in this model, but rather a complex pattern that forms between a human organism and its environment. To some extent, I think we misidentify intelligence when we restrict it to an individual organism.
To take this one more step, I think that what we perceive as intelligence in individual humans is not a pure attribute of the human brain but an emergent pattern between organic subsystems, most obviously cognition.