Dung beetles - evolving

One of the lies frequently used to refute evolution is that it can’t be seen happening. That argument is, of course, both irrelevant and untrue.

Evolution is routinely observed in action and a recently published paper (reported in The Economist) has illustrated yet another case. What I like about this case is that it illustrates speciation.

Speciation is more than an animal evolving a trait (like a longer tail, or bigger teeth) but rather a single species evolving into two different species. The resulting species are unable to interbreed and will go on to evolve completely separately - just has humans and chimps have evolved separately since their own ancient split.

The object of the study was the humble dung beetle, or rather a specific species of dung beetle which has recently split into four species. The beetles in question were introduced into eastern Australia, western Australia and North Carolina within the last 50 years.

Since then (through a fascinating mechanism that has to do with the relationships between horn, penis and vagina sizes - read the article for more detail) the different populations have developed to the point where they are (or very nearly are) completely different species.

Well within a human lifetime. Take that.

New Scientist has this article about a study showing that a woman’s voice becomes more attractive when she is most fertile. The researchers made recordings of women during four different phases of their menstrual cycles. The recordings were played in random order to both men and women, who consistently rated recordings made during fertile stages as more attractive. It seems that using voice alone both men and women are able to subconsciously detect fertility.

I’ve previously blogged about another experiment showing that fertile lap dancers earn more tips - this is just another example of the fact that we can subconsciously detect fertile women.

I explain the evolutionary reasoning behind these interesting effects in that article. In short, it pays women to conceal when they are fertile - so men will stick around all the time to be sure. It pays men to know when women are fertile so that they can focus energy when it counts.

This post is loosely based on the superb article by Steven Pinker: The Moral Instinct

Humans are afraid of heights. Around the world humans of all cultures have an in-built fear of heights. Have you ever wondered why people have that fear? It’s to prevent injury and death as a result of falling. Right?

If proximity to heights induces fear then people will feel an urge to get away from the heights. Humans who are afraid of heights are therefore less likely to die by falling (even if they aren’t conscious of why they fear heights). Evolution has made fearing heights part of what it is to be human. It is an instinct wired into our brains.

Pretty simple. But did you ever think that morality - our sense of right and wrong - is also an evolved instinct? It’s a little less obvious but true.

The basic moral principles
By studying people’s moral judgments around the world anthropologists have realized that there are basic moral principles which appear to be universal to almost all people and across all cultures (they are instinctive, not cultural). A list of these basic moral principles has been suggested by Jonathan Haidt:

• Harm: Don’t harm innocent people
• Fairness: Reciprocate favors and punish cheaters
• Community: Loyalty, sharing, and solidarity among group members. Conforming to group norms
• Authority: Follow authority and respect people with high status
• Purity: Aim for cleanliness and and avoid defilement and contamination

These moral heuristics (rules-of-thumb) are instincts that have evolved for very good reasons - they helped our ancestors. Violating these principles makes people uncomfortable so in general the principles are obeyed. Pinker gives details on the evolution of the moral heuristics and he points out that the same moral principles have even been observed in monkeys (I have blogged about monkeys having a sense of fairness).

As an illustration I’ll go into more detail on the evolution of fairness and it’s associated emotions.

The evolution of morality - fairness
Humans benefit by working together in groups: we are all better off working together than any of us would be working alone. If I share my extra mammoth meat with you today when I have too much anyway, then you share with me later when I really need it. It pays both of us to work together.

However, as I have noted in the past, if people can cheat they will cheat - that complicates things.

Axelrod (and Dawkins among others) has shown that cooperation can and does evolve. Axelrod showed that evolutionary agents (for our discussion these are people) do naturally evolve toward a basic cooperative strategy (known as tit-for-tat). This strategy basically specifies:

1. Cooperation by default. This means that you get the benefit of cooperating with other ‘friendly’ people.
2. Punishment of cheating. Don’t let the ‘bad’ people get away with it.
   
3. Forgiveness. Once the cheat has been punished try to cooperate again.

If you think about it, this kind of strategy makes excellent sense - cooperate as much as possible, but don’t tolerate cheats. Robert Trivers suggested that humans unconsciously implement a kind of tit-for-tat strategy through their moral emotions. Steven Pinker has given us the following examples:

• Sympathy prompts a person to offer the first favor, particularly to someone in need for whom it would go the furthest.
• Anger protects a person against cheaters who accept a favor without reciprocating, by impelling him to punish the cheat or sever the relationship.
• Gratitude impels a beneficiary to reward those who helped him in the past.
• Guilt prompts a cheater in danger of being found out to repair the relationship by redressing the misdeed and advertising that he will behave better in the future.

So, we can see how several emotions and the moral sense of fairness have evolved in order to help humans implement a strategy for cooperation. Evolution is brilliant!

So what?
All this is fascinating, but it also has some interesting and powerful implications:

1. There is no absolute right and wrong - it’s all in our heads
Our sense of right-and-wrong is actually just an evolved instinct. There is no universal right-and-wrong or good-and-evil. There is just the moral judgment that each person makes using their instincts.

If my moral judgment in a situation is different to yours then who is right? There is no universal morality to appeal to for an answer. We are both just letting our moral instinct make a judgment – so we are both right… If there is no universal morality then what can we use to compare moral judgments?

Humans have a pragmatic way of dealing with this: we agree on moral judgments and then expect everyone in our society to abide by those judgments. It’s a real cop-out and, as we will see below, sometimes those judgments don’t make all that much sense.

2. Our moral ’sense’ is as fallible as other senses - moral illusions
Our moral sense is evolved just like our sense of sight. There are countless examples of optical illusions illustrating that even something as trusted as our sense of sight regularly gets things wrong. Similarly, our sense of morality can get things “wrong” quite easily.

We know that our sense of sight has got something “wrong” when we realize that what we thought we saw doesn’t match reality. As we have learned (implication 1 above) we have no similar way of judging our moral instincts. So when I say that our moral sense gets things wrong, I mean that if you think about some moral judgments rationally they don’t always make sense.

This is because morality is based on heuristics (the 5 moral principles from earlier) which don’t necessarily lead to rational and consistent judgments every time. The trolley problem (worth an entire posting itself) is an excellent example but here I will give a simpler example from Pinker.

A family’s dog is killed by a car in front of their house. They heard that dog meat was delicious, so they cut up the dog’s body, cook it and eat it for dinner.

What is so wrong with that? Seriously? It causes us to feel disgust because it hits the purity principle, but rationally there is actually nothing wrong with it. No one is harmed; the family is happy and had a cheap and delicious meal to remember their dog by. Be rational. We just feel that this is wrong but we don’t have good reasons for it. Perhaps this is a case of the purity instinct firing unnecessarily.

Disclaimer: As you will see if you read about the trolley problem, rationally examining moral judgments can make you feel very uncomfortable. I still don’t know what to think…

3. Sometimes what we perceive as immoral is just a different weighting on the basic moral principles
We now know that there is no universal moral code against which we can measure moral judgments. We also know that sometimes our moral judgments don’t even make rational sense. How can we judge others as wrong or immoral if their judgments differ from our own?

As Pinker points out, the other party is often also acting morally, he/she has just used different priorities on the 5 moral principles:

Many of the flabbergasting practices in faraway places become more intelligible when you recognize that the same moralizing impulse that Western elites channel toward violations of harm and fairness (our moral obsessions) is channeled elsewhere to violations in the other spheres. Think of the Japanese fear of nonconformity (community), the holy ablutions and dietary restrictions of Hindus and Orthodox Jews (purity), the outrage at insulting the Prophet among Muslims (authority). In the West, we believe that in business and government, fairness should trump community and try to root out nepotism and cronyism. In other parts of the world this is incomprehensible — what heartless creep would favor a perfect stranger over his own brother?

Where to from here?
In short: I don’t know.

For instance, I have previously attacked those Muslims who thought it just to execute a teacher for naming a teddy bear Muhammad. Now I realise that they were acting by their own moral judgments. I still disagree strongly with them, but I now know that I don’t have any moral high-ground.

I would like to appeal to rationality to show that I am right, but I’m not at all comfortable using rationality against all moral decisions so that would be cheating.

Knowing more about the true nature of morality hasn’t given me the answers - it has made me realise that I wasn’t even aware of the questions!

Richard Dawkins is a great author and evolutionary biologist - I have several of his books at home. Dawkins is also well known as a vociferous atheist which means many people blindly reject what he says. I recently read a letter that he apparently wrote to his 10 year old daughter back in 1995 about belief. It makes for excellent reading - very easy to understand which is important.

Basically, he is writing about why she (and people in general) should believe things. The GOOD reason for believing in things is evidence:

• Direct evidence. For instance astronauts have been out into space and seen that the earth is really round. That is a good reason to believe that it really is round.
• Indirect evidence. Where direct observation is not possible we can still find evidence that an idea is right. Dawkins gives the example of a detective at a murder scene. He can still work out who did it, even though nobody actually saw the crime.

Dawkins then goes on to describe BAD reasons for believing something:

• Tradition. Beliefs are often passed down through generations. Just because they are old beliefs doesn’t make them true. As Dawkins says “No matter how long ago a story was made up, it is still exactly as true or untrue as the original story was”. Tradition is a bad reason to believe something.
• Authority. Just because somebody tells you to believe something doesn’t make it true. Sometimes I do take somebody’s word on something - like the speed of sound. The difference is that there is evidence that I can look at if I wanted. I have taken a shortcut, but I can do that because there is evidence available.
• Revelation. Dawkins defines revelation as when people have a “feeling inside themselves that something must be true, even though there is no evidence that it is true”. Unless there is actually evidence (a good reason) which agrees with your gut feeling then it is a bad reason to believe something.

The last bit of the letter is what I am increasingly finding crucial. People need to learn to think a little:

Next time somebody tells you that something is true, why not say to them: “What kind of evidence is there for that?” And if they can’t give you a good answer, I hope you’ll think very carefully before you believe a word they say.

I’m frequently confronted by people who say something like: “Evolution is just a theory - it’s not fact.” This just proves that the person doesn’t actually understand what a “theory” is - I have already blogged on the issue.

Basically:

• “In science the word theory means an explanation of how the world works that has stood up to repeated, rigorous testing. It’s hardly a term of disparagement.”

Wired has an article on the subject which calls for a change in phrasing:

• For truly solid-gold, well-established science, let’s stop using the word theory entirely. Instead, let’s revive much more venerable language and refer to such knowledge as “law.”
• It performs a neat bit of linguistic jujitsu. If someone says, “I don’t believe in the theory of evolution,” they may sound fairly reasonable. But if someone announces, “I don’t believe in the law of evolution,” they sound insane. It’s tantamount to saying, “I don’t believe in the law of gravity.”

I’ve always felt that the best thing to do is improve people’s understanding. The problem is that getting the message across is really tricky (I blogged about the problem here). This guy reckons that:

• It’s time to realize that we’re simply never going to school enough of the public in the precise scientific meaning of particular words. We’re never going to fully communicate what’s beautiful and noble about scientific caution and rigor. Public discourse is inevitably political, so we need to talk about science in a way that wins the political battle — in no uncertain terms.