There are many I can think of.
First of all the issue is not the homo economicus it self but how it is interpreted.
Humans are homo economicus (rational selfish), in a sense that stones are stonyeconomicus with the additive inverse of potential function as utility function.
The theory that stones want to minimize it’s potential energy correctly predict stones behavior on free fall and slippery slopes. The problem is that it’s simply not true. Stones do not have a will, let alone rational. If you interview Mr. stones, do you really rationally want to lower your potential energy, the stones don’t know. “Potential what?”
The same ways, humans are actually just automaton with little creativity. That rational creativity is actually a small part of humans behavior. Yes the idea that we have a utility function that we want to maximize correctly predict our behaviors (mostly under typical capitalistic settings). However, most humans do that by following their instincts and emotion rather than by being rational. Most humans are not aware why they do things.
Try reason with a hot girl on why she should sleep with you and see how far you go. Now just tell her how rich you are and throw money away for her buy buying expensive useless objects like flowers, chocolate, and lobsters. See if it works better.
Remember, if what you give is useless, then it’s romance. If what you give is useful, then it’s prostitution. Both works. The latter works too well that it’s illegal. Uhmmm… I am ahead of my self.
The same way try reason with voters and see how far you go. Now tell her how an almighty God died for their sins and want everyone to go to heaven unless they watch porn or have sex outside your pimphood’s terms and you’ll get your point across more.
Remember, if what you say doesn’t make sense, then it’s sacred religion. If what you say makes sense, then it’s force. Both works. The latter works too well that it’s politically incorrect.
Another flawed interpretation of homo economicus is the idea that we max out what we buy under the constraint of our wealth and income. A better model is that we max out what we buy under the constrain of our capability and power as in political power.
Hence, dictators and corrupt officials, that own nothing but control everything, will live happily. Their people that, in theory, own the country but control nothing will live miserably. Most economic class simply presume that ownership is controlship and treat deviation as special exception.
Another corollary is if we want to know what typical humans’ utility function is, we need to look at what people do when they have power, not when they’re rich. Under normal buy stuff under income constraint theory, we would think that happiness come from expensive hotel, traveling overseas, etc because that’s what rich people do. However the rich are often not politically powerful nowadays and hence not the one that can truly achieve happiness.
A better way to see what makes humans’ happy is to see what powerful persons, emperors, local thugs, or terrorists head get. That is. Own a harem. Prevent others from pursuing the same path. So huge part of happiness is in how well others are not happy.
If we want to incorporate that to homo economicus we would have to deduct others’ utility function out of ours. In a sense, we either see the obvious that we’re not just selfish but also bigotic. Another way is we simply incorporate bigotry into our definition of selfish, which is quite unintuitive. The last one is Milton’ Friedman’s approach.
Another obvious corollary is that humans tend to max out their power rather than simply wealth. Libertarians among us are rare. The higher the value of an object, the more humans want to control it. We can predict that prostitution and drugs will be “controlled” irrelevant of whether they are actually dangerous or consensual. They are just valuable and that’s enough to motivate voters and politicians to control or prohibit it.
We will also predict that those controlled are those most valued rather than those actually dangerous. Last time I check paracetamol is not a schedule 1 drug despite many death due to overdoses. It’s also not illegal for kids to earn money by rope walking across tall building. No body cry it’s dangerous for minor.
Another deviation from homo economicus is that we are not selfish. Our genes are. That one is biological fact. All those genes can reproduce mainly if we reproduce. However, our genes can also reproduce well if those similar to us or our family successfully reproduce.
So huge part of our utility function is in committing altruism in favor of our family and those similar to us. Again, we can be like Friedman, redefining selfish interests to include such factors. Another way is to simply see that we’re not selfish.
If we take into account this, then suicide bombing is not very strange.
I really think the real important true alternative to homo economicus is evolutionary psychology. The shift from selfishness from individuals to genes or even memes, are significant difference that do more correctly predict humans behavior. After all, the memes and genes have simpler utility function, namely reproduce, and hence much more easily analyzed. Humans, are simply mind controlled by those genes or memes.
Again, we can still shoehorn all those aspects into homo economicus. We can say, mother loves her children because her children are her tools to produce grandchildren. That sounds funny but it’s an accurate points of view nevertheless. However, we need to redefine selfish like Friedman, namely those incorporating the outcome and reproductive success of our genes, our memes as well as others.