Tragedy of the Commons, Over-Population, Cheaters and Evolution


The production of public goods. 

  • Public goods are products manufactured by an individual that can then be utilized by the individual or its neighbors.
  • The public goods produced by the microbes can be used by all, even the individuals who are not themselves producers.
  • Since production comes at a metabolic cost, and thus a cost in fitness, it pays to be a cheater.A cheater is a kind of parasite, living off the public goods producing individuals, without contributing anything to the group.
  • Since the cheaters have higher fitness, the whole group would soon fall into the trap of the tragedy of the commons. The question then is how this is avoided.

The answer is that such a system is regulated by negative frequency-dependent selection. When one kind becomes rare, it gains a fitness advantage, and therefore rebounds to become more frequent again. When cheaters become frequent, the amount of public goods is decreased, and suddenly cheaters are at a disadvantage. This relies on some spatial structure that makes sure that the public goods are on average closer to the non-cheating microbes.

The attentive reader might already have seen the similarity to certain aspects of human society.

Criminals, for example, are cheaters who live off the production of the rest of society. However, society can tolerate some amount of crime, obviously, just as in the microbial world freeloaders can exist at low frequencies.

  • Where the tragedy of the commons in humans has yet to play out, is in the case of population growth, as discussed by Hardin. In many parts of the world, there is no incentive for the individual to be the one that does not have more children.
  • The result is population growth, and if that growth isn’t stopped sooner than later, the result is overexploitation of resources. This is turn leads, as is already all too evident, to the disappearance of many human resources (i.e., other species), and if we’re unlucky, to the eventual disappearance of humans, too.

Incentives needs to be created for all humans not to have many children, such that population growth can be reversed, and the ultimate result of the tragedy of the commons can be avoided.

Our Brain Structure Defines What We "See" and Experience


“…differences in the morphology, or shape, of our brains are mirrored in differences in the way we consciously experience and apprehend the world, including our own brains and bodies. “

excerpted from Scientific American article

In other words, the thicker the SPL cortex, the faster two interpretations switch back and forth. It is known from other imaging and clinical studies that the SPL in the back of the brain controls selective visual attention, but how the thickness and density of SPL gray matter should be important is anybody’s guess.

Ask people what they believe to be the defining feature of consciousness, and most will point to self-awareness. To be capable of being aware of your hopes, to worry about your spouse’s illness, to wonder why you feel despondent or why he provoked you is taken to be the pinnacle of sentience.

Self-awareness is, by and large, absent in nonprimates. Although my dog—as with many and, perhaps, all animals—experiences the sights, sounds and, in particular, the smells of life, she doesn’t worry why her tail isn’t wagging as it used to or whether tomorrow’s food will appear.

So can differences in this elusive higher-order aspect of consciousness be tied to differences in brain structures? Yes, as a just published third study by Rees and his colleagues concludes.

Thirty-two healthy volunteers carried out a difficult visual task in the scanner. They had to judge which one of a number of faint patches was a tad more salient than the other ones; this judgment was purposefully made demanding. Following each trial, subjects had to choose a number between one and six, indicating the confidence they had in their own judgment. A six indicated that they were very confident of their judgment, whereas a one implied a guess. That is, they were asked to introspect: Are you sure you just saw the bright patch here? Psychologists know this as meta-cognition: thinking about thinking.

Not surprisingly, subjects differed greatly in the accuracy of their judgments (independent of the level of their performance). Think of the game show Who Wants to Be a Millionaire, where contestants have to judge whether they want to use a lifeline before they know the answer, depending on their confidence.

Some people are astute, using the lifelines wisely; other people fritter them away. The cognitive scientists extracted a measure of variability of introspection and discovered that this measure correlated with variability in gray matter volume in the right anterior prefrontal cortex. The more neurons you have in this region in the front of the brain, the better your introspection. Not that your performance goes up, but the insight you have into your performance—whether you thought you did well or not—increased.  Patients with lesions in these regions typically lose the ability to introspect. And this part of the neocortex has expanded more than any other region in primates.  Again, the neuronal mechanisms underlying this correlation remain unknown for now.

Rees’s studies establish that differences in the morphology, or shape, of our brains are mirrored in differences in the way we consciously experience and apprehend the world, including our own brains and bodies. In this way, neuroscience maps the physical structure of the material brain onto the inner geometry of phenomenal and ineffable experience.