Tag Archives: evolution

Cialdini’s Principles of Persuasion and the Importance of Recognising “Enforced Compliance”

Influence: The Psychology of Persuasion is Robert Cialdini’s 1984 book discussing what he calls the six fundamental psychological principles of compliance: consistency, reciprocation, social proof, authority, liking and scarcity.

The conclusion to Cialdini’s book points out why, in this increasingly complex world, resisting attempts at “enforced compliance” (deception) through these key principles is as important as recognising and responding to truthful instances of their implementation:

Because technology can evolve much faster than we can, our natural capacity to process information is likely to be increasingly inadequate to handle the surfeit of change, choice, and challenge that is characteristic of modern life. More and more frequently, we will find ourselves in the position of the lower animals—with a mental apparatus that is unequipped to deal thoroughly with the intricacy and richness of the outside environment. Unlike the animals, whose cognitive powers have always been relatively deficient, we have created our own deficiency by constructing a radically more complex world. But the consequence of our new deficiency is the same as that of the animals’ long-standing one. When making a decision, we will less frequently enjoy the luxury of a fully considered analysis of the total situation but will revert increasingly to a focus on a single, usually reliable feature of it.

When those single features are truly reliable, there is nothing inherently wrong with the shortcut approach of narrowed attention and automatic response to a particular piece of information. The problem comes when something causes the normally trustworthy cues to counsel us poorly, to lead us to erroneous actions and wrongheaded decisions.

Together, Unconscious: We All Sleep

One constant that connects us all in some way is that–at the end of our day–we lie down and slowly slip into a state of reduced or absent consciousness and become at the mercy of our fellow man. Every day we fall asleep: we have done so for millions of years and will continue to do so.

This humbling thought was inspired by David Cain’s short disquisition on how the act of sleeping is something that unites us together, all around the world. David’s post didn’t quite take the route I was expecting after reading the (wonderful) excerpt below1, but is still definitely worth a read.

It’s an interesting quirk of Mother Nature — that she insists on taking us down to the ground like that, every day, no matter who we are. For all of us, the act of leaving consciousness is the same, it’s just our settings and situations — which bookend that unconsciousness — where we differ.

via Link Banana

1 I was expecting the post to concentrate on the first sentence (leaving consciousness), rather than the second sentence (sleep as a connector).

Size and Complexity: Why Animals Are the Way They Are

From bone strength and oxygen absorption in larger animals, to the perils of surface tension and poor eye design in smaller ones: just some ideas to consider when studying comparative anatomy and why animals are the way they are.

A perfect take on the topic is J. B. S. Haldane‘s 1928 On Being the Right Size. In this absorbing short essay, Haldane looks at why rhinos have short, thick legs; why the smallest mammal in Spitzbergen is the fox; and, primarily, how the size of an animal determines almost everything about its anatomy.

There is a force which is as formidable to an insect as gravitation to a mammal. This is surface tension. A man coming out of a bath carries with him a film of water of about one-fiftieth of an inch in thickness. This weighs roughly a pound. A wet mouse has to carry about its own weight of water. A wet fly has to lift many times its own weight and, as everyone knows, a fly once wetted by water or any other liquid is in a very serious position indeed. An insect going for a drink is in as great danger as a man leaning out over a precipice in search of food. If it once falls into the grip of the surface tension of the water—that is to say, gets wet—it is likely to remain so until it drowns. […]

The higher animals are not larger than the lower because they are more complicated. They are more complicated because they are larger. Just the same is true of plants.

As is typical of Haldane, he finishes with something a bit more political than anatomical, stating that “just as there is a best size for every animal, so the same is true for every human institution”. Something to consider.

via The Browser

The Evolutionary History of the Brain

The development of the human brain is intricately linked with almost every moment of our evolution from sea-dwelling animals to advanced, social primates. That is the the overwhelming theme from New Scientist‘s brief history of the brain.

The engaging article ends with a look at the continued evolution of the human brain (“the visual cortex has grown larger in people who migrated from Africa to northern latitudes, perhaps to help make up for the dimmer light”), and this on why our brains have stopped growing:

So why didn’t our brains get ever bigger? It may be because we reached a point at which the advantages of bigger brains started to be outweighed by the dangers of giving birth to children with big heads. Or it might have been a case of diminishing returns.

Our brains are pretty hungry, burning 20 per cent of our food at a rate of about 15 watts, and any further improvements would be increasingly demanding. […]

One way to speed up our brain, for instance, would be to evolve neurons that can fire more times per second. But to support a 10-fold increase in the “clock speed” of our neurons, our brain would need to burn energy at the same rate as Usain Bolt’s legs during a 100-metre sprint. The 10,000-calorie-a-day diet of Olympic swimmer Michael Phelps would pale in comparison.

Not only did the growth in the size of our brains cease around 200,000 years ago, in the past 10,000 to 15,000 years the average size of the human brain compared with our body has shrunk by 3 or 4 per cent. Some see this as no cause for concern. Size, after all, isn’t everything, and it’s perfectly possible that the brain has simply evolved to make better use of less grey and white matter. That would seem to fit with some genetic studies, which suggest that our brain’s wiring is more efficient now than it was in the past.

Others, however, think this shrinkage is a sign of a slight decline in our general mental abilities.

via @mocost

In Evolution, Adaptability Beats Fitness

The longest continuous evolution experiment was started in 1988 and is still ongoing. The study, examining the “evolvability” of Escherichia coli (E. coli), has recently surpassed 52,000 generations and has had a sample of the population frozen and saved every 75 days (every 500 generations). The wealth of data obtained is fantastic and these frozen ancestors have been the focus of a recent study that set out to find whether the eventual “evolutionary winners” displayed signs of their genetic superiority hundreds of generations earlier.

To the researcher’s surprise, the bacterial winners in fact showed the absolute opposite: they were far inferior to the strains of bacteria that died out in later generations. To explain this they discovered that while these ancestors were conventionally less evolutionarily fit (they reproduced at a much slower rate), these “evolutionary winners” were much better at adapting to circumstances and at taking advantage of beneficial mutations. Adaptability trumped fitness.

“[The idea of] selection for evolvability has been in the air for a long time, but this is one of the first real systematic and explicit demonstrations of this actually happening,” said evolutionary biologist and population geneticist Michael Desai of Harvard University […]

The first surprise came when the team compared the fitness of four strains — two EWs [eventual winners] and two ELs [eventual losers] — and found that while all four strains had significantly higher fitness than the ancestral strain, the ELs appeared more fit than the EWs. Comparing the four strains directly confirmed the result: The two EW strains were at a significant disadvantage to the ELs. If these strains had not accumulated any more mutations, the researchers estimated the EWs would have gone extinct in just 350 additional generations. […]

The results suggested that the EWs, while initially at a disadvantage, prevailed in the long-term because they were more likely to acquire more beneficial mutations. In other words, the EWs had greater evolvability.

This seems like evolutionary evidence for the premise of Tim Harford’s latest book, Adapt.