Quite simple: We, the people. Our "proper" genus and species.

Now, there are two different ways to look at this nomenclature. There's the economics thoughts on what H. economicus is and then there's my thoughts. Let's begin with the official version:

H. economicus is the human species in its capability to rationally decide, that is, essentially that people will act in their own best interest when making decisions.

This is one of the basic assumptions of economics. (see: "economics is just a tool") When provided with a choice, H. economicus will take that which leads to the most personal gain.

Such a perspective of course misses things like the benefits of society, altruism, ethics, etc. and in general, that is why Adam Smith would be very upset with us today: we forgot that he said we needed an ethical basis on which to run his economy.

On my own, before I had learned about H. economicus from economists, I had heard the term and came up with a few thoughts:

In the past, we have always separated the Homo-genus with major changes to the members of the population. A large brain-size or the use of tools, for example, would lead to a new species. What then is the most striking difference in today's species?

I think the major change came along when we developed the concept of worth. And, I'm not speaking about inherent worth here. A tree has a "worth" to us in that it provides shade; a river with its fish. But, we only think about things in terms of worth because we are completely included in the system. Were we still in an earlier species, would we think like that?

I think not. I believe that somewhere along the lines we began to assign a tanglible and personal worth to objects. Now, notice I'm not using the term "money". That, of course, is a result of this thinking, but not originally.

Worth is related to bartering and trading (not to mention stealing and manipulating) which were the founding concepts of civilization. In fact, when first thinking about what our species should be called instead of Homo sapien (sapien), I came on the idea of cilivization. This might have worked, but what about bees? Ok, their civilization is different than ours, naturally, but civilization nevertheless came across as effect rather than cause.

Worth, on the other hand, seems to explain quite a lot about who and what we are. We define everything in these terms; we seek profit and optimization. We want more.

Now, speaking in terms of changes of genus means that an evolutionary process is implied. And, how it is that evolution instilled in us the concept of worth, well, I'm still working on that.

Did it have something to do with language? Was it that an ancestor said in some gruntal language, "My kill", and with that assigned a worth, a personal desire to maintain the kill.

Perhaps, it lies more closely to the economists point-of-view: reasoning is key. When we could say, "ah, if I give her that, I need to at least get that much in return". That assigns a certain worth, as opposed to the animal kingdom which uses more direct methods: biggest lion gets the kill. And, since reasoning is related to brain-size perhaps we are back to our answer. More to come, evolution-lovers...

Anyway, since I didn't know that the term H. economics had positive connotations, I've always used it somewhat as an insult. Only later did I discover that it was used quasi-proudly by economists, as a sign for how "reasonable" humans are.

Somehow, this shouldn't surprise me. When opinions on worth are so fundamentally different as between me and economists, I should only assume that we would see the human species in two completely different ways.