Humans and incentives

“People respond to incentives.” So says the cornerstone of economics. But there’s nothing unusual about people in this regard.
I realized this when I finally got Lucius to use his catflap by applying basic economics. First, I reduced the cost of using it by wedging it open. Then, I raised the opportunity cost of his preferred alternative to using the catflap - meowing at me to open a door - by going out for several hours on a visit to Cromford. And - most importantly I suspect - I gave him a high-powered incentive to use the flap, in the form of a bowl of tuna on the other side of it.
And this worked. I returned from Cromford to an empty bowl.
Lucius, then, responds to incentives.
In truth, though, such responses are common in the animal kingdom. This paper shows that

Standard price theory does a remarkably good job of describing capuchin purchasing behavior; capuchin monkeys react rationally to both price and wealth shocks.

Another demonstrates (pdf) that the income-leisure trade-offs of pigeons are in many respects similar to those of humans. There’s evidence (pdf) that squirrels respond to the risk of theft of food by hiding their food stores better. And Leonard Green and colleagues have found that rats and pigeons discount (pdf) the future in a similar way to humans.
In terms of responses to incentives, there is, therefore, nothing unique about humans. From an economist’s point of view, Gulshan Khan seems correct to say that “there is no separate object, entity, or being called ‘man’”.
This raises some tricky philosophical issues, such as:
1. Response to incentives is no evidence of high intelligence. It can be seen not just in primates and cats but in supposedly “lower“ animals too. 
2. What’s the link between response to incentives and conscious agency? If the two are linked, then the fact that animals respond to incentives is evidence that they are conscious beings like us - in which case the argument for animal rights is surely strengthened.
However, the two might not be linked. Sunflowers turn themselves towards the sun, apparently responding to incentives, but no-one attributes consciousness to them. If we take this line, though, human economic behaviour is no evidence that humans have free will.
3. Given that economic behaviour is common in the animal kingdom, what - if anything - makes humans unique? It’s too glib to say that humans have a sense of morality that sometimes can over-ride incentives - as, for example, when people choose to behave well even when incentives dictate otherwise. If we define morality as other-regarding behaviour, we would have to say that social creatures such as ants and bees display more of it than humans.
Instead, here’s a possibility. What makes humans unique is that we are an admixture. We are neither wholly pro-social like ants or bees, nor wholly selfishly amoral. And we are neither herd animals nor solitary ones such as cats. In other words, the distinctiveness of humans lies in the fact that our behaviour is to some (large?) degree unpredictable. 

Comments

[jameshigham]

Response to incentives is no evidence of high intelligence.

In fact, it can indicate the opposite. If a job which is too good to be true comes into your inbox [current situation] then my instinct is not to respond. Whether this is a sign of intelligence or not is debatable.

[McDuff]

It's not *very* unpredictable. On an individual level there's a degree of chaos that makes it difficult to chart out a lifespan, but if you know certain key facts about a person you can predict with some accuracy how they will respond to a certain immediate stimulus. Further, once we aggregate to populations it becomes even easier to model.

[Harmonious Jim]

Incentives are not the only thing that shapes behaviour, animal or human. I am about to get our puppy neutered, in large part to control his aggression. I'll bet that cutting off his 'nads does a better job in making him placid than trying to bribe him with treats.

[Churm Rincewind]

As far as I'm aware, there's only one activity which marks out mankind from the rest of the animal kingdom, and it happens to be an economic one - trading. All known human societies engage in trade, even if there's no benefit involved. There are no animals in the world of business, apart from (insert your own joke here).

[chris]

@ Churm - chimpanzees trade services (eg grooming). Quite why they don't trade goods is, though, an interesting issue:
http://www.sciencedaily.com/releases/2008/01/080130092136.htm

[Churm Rincewind]

@Chris - fascinating stuff. But I don't think that reciprocal grooming counts as trade, because there's no "debt" or "bargain" involved. If chimpanzee A grooms chimpanzee B, there's no forward obligation on chimpanzee B to return the favour, and experimental studies show this to be so. This may simply be because debts and bargains can only exist when they're enforceable, which is true of human societies but not of animal communities, which kind of makes my point self-fulfilling.

Oh, and incidentally, of course animals are conscious. But that doesn't strengthen the argument for animal rights, it simply complicates it. Another topic for another day...

[CahalMoran]

Really interesting post, Chris.

[Tom Addison]

Got to say that I'm disappointed that you didn't name your cat after an Arsenal player. Thierry would be a great name for a cat!

[chris]

@ Tom - he was named Lucius when I got him.
Given his stamina, speed and intelligence, he could be named Squillaci.

[BT]

Complex language is what makes humans different from other animals. Language enables meme-based evolution.

Our commonality with other animals reflects our gene-based social behaviour - including morality.