(Drivebycuriosity) - How did intelligence develop? Max Bennett gives in "A "Brief History Of Intelligence" a plausible answer (amazon ). According to him the long and winding row to intelligence went with 5 breakthroughs:Breakthrough #1: Steering: the breakthrough of navigating by categorizing stimuli into good and bad, and turning into good things and away from bad things.
Breakthrough #2: Reinforcing: the breakthrough of learning to repeat behaviors that historically have led to positive valence and inhibit behaviors that have led to negative valence.
Breakthrough #3: Stimulating: the breakthrough of mentally simulating stimuli and actions.
Breakthrough #4: Mentalizing: the breakthrough of modeling one`s own mind.
Breakthrough #5: Speaking
Each breakthrough was possible only because of the building blocks that came prior. Each
breakthrough emerged from new sets of brain modifications and equipped
animals with a new portfolio of intellectual abilities.
The book is densely filled with valuable information and elegantly written. It´s quite impossible to condense the huge material appropriately so I present here just some tidbits:
Evolving From Chaos
The human brain evolved from the unthinking
chaotic process of evolution, small random variations in traits were
selected for or pruned away depending on whether they supported the
further reproduction of the life-form.
After
countless random nucleotide chains were constructed and destroyed, a
lucky sequence survived. This new DNA-like molecule wasn`t alive per se,
but it performed the most fundamental process by which life would later
emerged: it duplicated itself. These molecules didn`t have to survive individually
to survive collectively - as long as they endured long enough to create
their own copies, they would, in essence, persist. Any new lucky circumstances that facilitated more successful duplication would lead to more duplicates.
In
the eyes of evolution, the hierarchy has only two rungs: on one, there
are those that survived, and on the other, those that did not.
Beating Entropy
By self-replicating, DNA finds respite from the
second law of thermodynamics. The unbreakable law of physics declares that entropy - the amount of disorder in system - always and
unavoidably increases; the universe cannot help but tend toward decay. Life persisted not in matter but in information.
In
evolution, systems starts simple, and complexity emerges over time. The
first brain - the first collection of neurons in the head of an animal -
appeared six hundred million years ago in a worm the size of a grain of
rice. This worm was the ancestor of all modern brain-endowed animals.
Our
ancestors from around five hundred million years ago transitioned from
simple worm-like bilaterals to fishlike vertebrates. Many new brain
structures and abilities emerged in these early vertebrate brains, most
of which can be understood as enabling and emerging from breakthough #2:
reinforcement learning.
Common Roots
The
reason why brains across the animal kingdom are so similar is that they
all derive from common roots in shared ancestors. Every brain in the
animal kingdom is a little clue as to what the brains of our ancestors
looked like. The difference between our brain and a rat`s brain is only a handful of brain differences. The brain of a fish has almost all the same structures a our brain.
Our ancestors were the first fish to evolve the ability to survive out of water.
Outwitting Predators
We cannot understand the breakthroughs in brain evolution without also understanding the trials and triumphs of our ancestors: the predators they outwitted, the environment calamities they endured, and the desperate niches they turned for survival.
The innovation of wings independently evolved in insects, bats, and birds; the common ancestors of these creatures did not have wings. Eyes are also believed to have independently evolved many times.
An octopus has an independent brain in each of its tentacles and can blow a human away at multitasking. Pigeons, chipmunks, tuna, and even iguanas can process visual information faster than a human.
A gene is simply the section of DNA that codes for the construction of a specific and singular protein.
DNA is relatively inert, effective for self-duplication but otherwise limited in its ability to manipulate the microscopic word around it. Proteins, however, are far more flexible and powerful. In many ways, proteins are more machine than molecule.
Blueprint Of Life
Armed with proteins for movement and perception, early life could monitor and respond to the outside world. Bacteria can swim away from environments that lower the probability of successful replication, environments that have, for example, temperatures that are too hold or cold or chemicals that are destructive to DNA or cell membranes. Bacteria can also swim toward environments that are amenable to reproduction. And in this way, these ancient cells indeed had a primitive version of intelligence, implemented not in neurons but in complex network of chemical cascades and proteins.
DNA was transformed into the informational foundation from which the stuff of live is constructed. DNA had officially become life`s blueprint, ribosomes its factory, and proteins its product.
The most impressive biological system in these early cyanobacteria was not their protein factories but their photosynthetic power plants - the structure that converted sunlight and carbon dioxide into sugar,which could then be stored and converted into cellular systems for extracting and storing energy. It provided cyanobacteria with abundance of fuel with which to finance their duplication.
Terraforming The Earth
It was the cyanobacteria, with their new found photosynthesis, that constructed Earth`s oxygen-rich atmosphere and began terraform the planet from a gray volcanic rock to the oasis we know today.
Oxygen is an incredible reactive element, which makes it dangerous in the carefully orchestrated chemical reactions of a cell. Unless special intracellular protective measures are taken, oxygen compounds will interfere with cellular processes, including the maintenance of DNA. This is why antioxidants - compounds that remove highly reactive oxygen molecules from the bloodstream - are believed to offer protection from cancer.
Preys And Predators
Microbes began to actively eat other microbes. This fueled the engine of evolutionary progress; for every defensive innovation prey evolved to stave off being killed, predators evolved an offensive innovation to overcome the same defensive. Life became caught in an arms race, a perpetual feedback loop: offensive innovations led to defensive innovations that required further offensive innovations.
While plants survive by photosynthesis, animals and fungi survive by respiration. Animals and fungi both breath oxygen and eat sugar; both digest their food, breaking cells down using enzymes and absorbing their inner nutrients.
Sugar is produced only by life, and thus there are only two ways for large multicellular respiratory organism to feed. One is to wait for life to die, and the other is to catch and kill living life. Early in the fungi-animal divergence, they each settled into opposite feeding strategies. Fungi chose the strategy of waiting, and animals chose the strategy of killing.
What happens when you see something you want, like food when you´re hungry, a sexy mate. In all cases, your brain releases a burst of dopamine. What happens when you get something you want, like when you´re orgasming or eating delicious food, your brain releases serotonin.
Opioids are the relief-and-recover chemicals after experiencing stress.
The Gift Of Imagination
Vertrebrates get an extra boost of reinforcement when something is surprising. To make animals curious, we evolved to find surprising and novel things reinforcing, which drives us to pursue and to explore them. Even if the reward of an activity is negative, if it is novel, we might pursue it anyway.
The electric signalling of neurons is highly sensitive to temperature - at lower temperatures, neurons fire much slower than at warmer temperatures. A side effect of warm-bloodiness was that mammal brains could operate much faster than fish or reptile brains.
The gift the neurocortex gave to early mammals was imagination - the ability to render future possibilities and relive past events.
Abundance Of Calories
Habits are automated actions triggered by stimuli directly. They are the way mammalian brains save time and energy, avoiding unnecessarily engaging in simulation and planning. When such automation occurs at the right times, it enables us to complete complex behaviors easily; when it occurs at the wrong times, we make bad choices.
Early primates seemed to have had a unique diet of foraging fruit directly in treetops - they ware frugivores. They plucked fruit from trees right after it ripened but before it fell to the forest floor. This allowed primates to have easy access to fruit without much competition from other species. This unique ecological niche may have offered early primates two gifts that opened the door to their uniquely large brains and complex social groups. First, easy access to fruit gave early primates an abundance of calories, providing the evolutionary option to spend energy on bigger brains. And second, and perhaps more important, it gave early primates an abundance of time.
Rational Economic Behavior
Early primates had a unique diet: they were frugivores. Fruit-based diets come with several surprising cognitive challenges. There is only a small window of time when fruit is ripe and has not yet fallen to the forest floor. For many of the fruits these primates ate, this window is less than seventy-two hours. Some trees of offer ripe fruit for less than three weeks of the year. Some fruit trees has few animal competitors (such as bananas in their hard-to-open skin), while other fruit has many animal competitors (such as figs). These popular fruits are like to disappear quickly, as many different animals feed on them once their are ripen. Primates needed to keep track of all the fruit in a large area of forest and any given day know which fruit was likely to be ripe; and of the fruit that was ripe, which was likely the most popular and hence disappear first. It is interesting that this fact needed rational economic behavior which is denied by many modern so-called economists, like the behavioral economists.
85 Percent Meat
A frugivore must plan its trips in advance before its hungry. Setting up a
camp en route to a nearby popular fruit patch the night before require
anticipating the fact that you will be hungry tomorrow if you don`t take
preemptive steps tonight to get to food early.
All human invention, both technological and cultural, require an accumulation of basic building blocks before a single inventor can go "Aha", merge the preventing ideas into something new, and transfer this new invention to others.
Homo erectus became a hypercarnivore, consuming a diet that was almost absurd 85 percent meat. Homo erectus may have been so successful that the displaced their local competitors; around the time Home erectus appeared, many of the other carnivores in the African savanna began to go extinct.
There is much, much, more information in the book - read it!
