There are many interesting comparisons between the way the human brain processes information and the way a computer does it. By looking at the similarities and differences between the two I believe it is possible to understand each much better. The table below introduces a few of these comparisons, and the rest of this post will expound on these and others:
Computer Components Listed Next to Their Corresponding
Brain Components
Computer
|
Brain
|
Type
|
Hard Drive
|
Cortical Structure & Connections
|
Long-term Memory
|
Cache
|
Working Memory
|
Short-term Memory
|
CPU Cache
|
Sustained Firing
|
Focus of Attention
|
RAM
|
Synaptic Potentiation
|
Short Term Store
|
CPU
|
Prefrontal Cortex
|
Instruction Processing
|
Programmed Code
|
Associations / Cortical Search
|
Instruction Selection
|
Operating System
|
Personality
|
Interface
|
Motherboard
|
Peripheral Nervous System
|
Connecting Structure
|
BIOS / Firmware
|
Instincts and Reflexes
|
Predispositions
|
Hardware
|
Anatomy, Wetware
|
Physical Structures
|
Software
|
Associations, Schemas, Beliefs
|
Mental Structures
|
Microphone, Camera, Keyboard, Mouse
|
Ears, Eyes, Touch, Smell, Taste
|
Input
|
Monitor, Speakers
|
Voice, Muscles
|
Output
|
GPU
|
Visuospatial Sketchpad
|
Internal Video
|
Sound Card
|
Phonological Loop
|
Internal Audio
|
Virtualization
|
Empathy
|
|
Clock Cycles in hz
|
Oscillations in hz
|
Cycles per Second
|
Capacitor
|
Neuron
|
Memory Unit
|
Transistor
|
Neuron
|
Fundamental Processing Unit
|
Logic Gate
|
Neural Circuit
|
Secondary Processing Unit
|
Humans were designed over 100s of millions of years of
evolution. Computers were designed over the last 100 years.
Brains learn from every experience they have. Most
computers (outside of machine learning) do not learn from experience, although
they can save data from operations if you ask them to. Bytes in a program
remain unaltered after every use. However, every time a brain’s memory is used
it is at least slightly altered.
Brains can never do the same thing, or have the exact
same state twice. Asked to perform the same operation a computer will perform
each step in an identical manner over and over again with no variation.
A brain is a piece of biology. A computer is a piece
of technology. Brains are electrochemical. Computers are electronic and electromechanical.
Brains are analog, and computers are digital. Brains are flexible, computers
are inflexible.
A computer can be rendered useless if a single
microscopic part is damaged. A brain shows graceful degradation and can work
near flawlessly in many tasks even after severe damage. For example, cutting
one wire in a CPU or motherboard can completely incapacitate a computer. But
humans can often still think, move, and speak even after extensive traumatic
brain injury.
Humans search for novelty, food, sex, resources, and
are driven by curiosity. Computers simply process exactly what we ask them to.
They have no choice, no discretion at all. They are incapable of altering their
own processing stream.
Both brains and computers are designed to retrieve and
activate (recall) specific information on command.
They both store information in long-term memory. They
both also retrieve information from long-term memory when it is needed by
placing it into short-term memory. When this happens, the information goes from
dormant to active and can be used in processing.
Both brains and computers transition from state to
state as a function of time. Their present state is based on what long-term
information is currently active in short-term memory. The very next state is determined
by how the currently active information interacts with preset rules. In
computers, these rules come from programmed lines of code. In brains, they come
from associative memories.
Both take inputs, combine them with short-term memory,
and use this to determine the output. When computers do this they take user
input (mouse and keyboard) and reference them against instructions, coded by
programmers, to create output (sound and video). Humans, on the other hand,
take environmental input and use their memories, encoded by experience, to
create behavior.
Humans and computers can both complete tasks. How to
complete the task is often described by an algorithm held memory. To go about
the task they transition from one state to the next in a serial manner, where
each state prompts the next state. This causes them to progress through the
algorithm until the task is complete.
A computer employs algorithms created by a programmer.
A brain’s algorithms derive from guesswork, memes, trial and error, process of
elimination and insight.
They can both multitask. Humans can switch between
tasks several times per minute. Computers often switch between tasks thousands
of times per second. In both brains and computers, separate tasks can be called
“streams.” When you run a program on your computer it looks like its only
running one thing at a time, but it is actually running dozens of programs,
applications, and services simultaneously. The simultaneity is an illusion,
however. Because it can only focus on one task at a time, the CPU actually
switches between tasks rapidly, in an effort to keep them all up to speed.
During this switching it often stays with a single program for just a few
millionths of a second at a time. Your serial conscious mind is much slower,
spending at least a few seconds on each thought.
Some computer processors have multiple CPU cores
making it possible for them to have several separate information streams
running at the same time. However, each core in a CPU (even multithreaded
cores) must process information in a strict serial or linear manner. Similarly,
thoughts can only involve one serial stream of information at a time. But the
brain accomplishes its serial stream of consciousness through massive parallel
processing. Your massively parallel unconscious mind performs thousands to
millions of operations in a second, and they truly occur simultaneously.
The brain is decentralized. Every memory is
distributed over many neurons. One isolated neuron cannot hold a memory all by
itself. It holds a tiny fragment of a memory. These fragments combine with
other fragments from other neurons to form words, concepts, and ideas. The
computer on the other hand stores bits in definite physical locations that
either contain a certain amount of electrical charge, designating a 1, or does
not contain that charge, designating a 0. Groups of 8 bits create binary words
that have meanings that include letters, numbers, and mathematical and logical
operations for the CPU to perform.
Because each memory is distributed over many neurons,
each neuron must play a role in many completely separate memories. Not so in a
computer. A computer’s bits are stored in microscopic capacitors. Each capacitor can only
hold one bit each. Its memory is not distributed, it is localized.
A bit can only have one of two states (0 or 1). This
is because a transistor can either be on or off. Similarly, a neuron is either
firing or not firing.
The brain uses neurons to hold memories. Computers use
registers to hold their memories. Each register is made up of capacitors, and
each capacitors can hold a bit. There are 8 bits in a byte (e.g. 01101100), and
bytes are shuttled from register to register.
The brain uses circuits of neurons to process
memories. Computers use transistors and logic gates to process bytes.
Neurons and the information that they encode do not
move around, they remain stationary. Despite being set in a fixed point in
space, they do send signals to each other, but the informational content held
by one neuron is unique to it, and cannot be transferred to another. The
registers (made of capacitors) in a computer also do not move, but the bits and
bytes of information they hold are constantly and rapidly copied, and
transferred from register to register.
The average computer today has billions of capacitors,
and around 4 billion transistors. The brain wins in sheer number of processing
units. The average human brain has 100 billion neurons. Each of these neurons
makes many, many connections (synapses) with other neurons, and typical estimates
for the number of synapses in the brain vary between 100 trillion, and a
quadrillion.
Neurons and transistors both integrate an input to
create an output. The neuron, has many more inputs and outputs than the
transistor though. Neurons can have thousands of inputs, and tens of outputs,
whereas transistors have two inputs and one output. The elementary logic of a
transistor can be made much more complex when transistors are used together to
construct logic gates, but even logic gates (AND, NOT, XOR, NAND etc.) do not
even have tens of inputs or outputs. However. despite their low connectivity,
transistors are much faster.
Transistors can switch billions of times per second,
whereas neurons generally fire less than 400 times per second. Even logic gates
(made of several transistors) are much faster than neurons.
Information is also carried through space far more
quickly in computers. The buses, wires, and channels on a circuit board can
move electrons a large fraction of the speed of light (299,792,458 meters per
second). An axon can only propagate an action potential as fast as 150 meters
per second.
A brain uses “content addressable memory, and spreads
activation from active neurons to inactive neurons to search for associated
concepts. A computer uses “byte addressable memory” to locate the next byte
called upon by the CPU in the database using rows and columns.
The brain has electrical oscillations that organize
and coordinate timing between its separate specialized modules (cortical
regions). Similarly, the computer uses electrical oscillations in the form of a
system clock to organize and coordinate its operations. The brain oscillates up
to around 150 times per second (150 hz). A modern computer’s system clock
oscillates at frequencies above 3 billion times per second.
Human brains live 79 years on average. Desktop
computers have a lifespan of 3 to 5 years.
The brain never shuts down until death. A computer is
regularly turned off. Brains and computers both sleep. Computers have a
hibernation setting and humans do not.
Brains don’t crash or hang like computers do. Both can
get viruses. Both can malfunction and take damage from overheating.
When one operating system simulates another operating
system within it, this is called virtualization. When one person simulates the
thoughts of another in their mind, this is called empathy.
Two brand new computers of the same make and model
will be identical, two members of the same species will be very different.
A new computer is much like a baby in that it has a
basic input/output system (BIOS) that will determine how it will
“instinctually” interact with its environment. Both new computers and babies
will come to acquire a lot of disparate information over their lifetime, making
each very unique.
In the case of trauma for instance, some human
memories that are unwanted cannot be forgotten. However, information can be selectively
and permanently erased from a computer.
Some things that we would like to remember (like an
old phone number) cannot be recalled. Other things (like a new phone number)
may be difficult to store at times. A computer doesn’t have this problem, if it
is asked to recall, or store a memory on the hard drive, it does it with no problems and no
mistakes.
Both brains and computers use instructions. In a sense
these come in the form of “if, then” instructions. Both can be thought to have
instruction sets made up of all the possible operations they can perform. A
computer’s instruction set is its alphabet containing operations like add,
divide, recall from RAM, and place in RAM.
Computers are often described as having a “memory
hierarchy,” expressed as a pyramid with different levels of memory storage.
This is also referred to as a caching hierarchy, because there are different
levels of short-term memory with different associated speeds.
The levels at the top are faster, smaller, and more
energetically expensive. The same could be said for human memory, because there
are several levels, the levels at the top are faster, and more metabolically
expensive. The following table is my attempt to compare the levels of these two
hierarchies:
Computer
|
Brain
|
Time Scale
|
CPU
Register
|
Cortical
Binding
|
Very
short-term working memory (millis.)
|
CPU
Cache (SRAM)
|
Sustained
Firing
|
Short-term
working memory (seconds)
|
RAM
|
Synaptic
Potentiation
|
Short-term
memory (seconds to hours)
|
Virtual
Memory
|
Short-term
Potentiation
|
Short-term
memory (minutes to hours)
|
SSD
|
Commonly
used LTM
|
Accessible
Long-term Memory
|
Hard
Drive
|
Long-term
Memory
|
Long-term
Storage (days to lifetime)
|
RAM and CPU cache memory, much like working memory,
are volatile. This means that the information in them decays rapidly and require
energy be maintained. RAM and cache, also like working memory, have a limited,
and fixed capacity.
Long-term memory holds everything a person knows, just
like the storage drive (HDD or SSD) holds everything the computer knows.
A person’s long-term memory takes longer to access
than short-term memory, but has a much larger capacity. Similarly, the storage
drive takes much longer to access than RAM or cache, but has a much larger
capacity.
Human short-term memory is thought to be able to
remember 3-7 items or concepts at a time. Computer short-term memory can hold
millions of bytes, but cannot hold any true concepts. Nothing in a computer can
hold concepts.
In order to feed more pertinent information into
limited-capacity short-term memory the least pertinent information must be
removed.
Both brains and computers get rid of the least
recently used information to make room for new, incoming information in their
short-term memory. This is an eviction policy known as LRU for “least recently
used.”
We can take notes when there is too much information
to hold in working memory. Similarly a computer can record information in a
swap or paging file if there is not enough room in RAM.
Computers and humans use limited resources to perform
tasks. They can both reach a processing limit where they are loaded by tasks so
much that their performance decreases. In humans this is called cognitive load.
Computers can quantify their processing resources and
tell you exactly how much of their resources are currently engaged by ongoing
tasks. Humans cannot do this precisely.
Computers can give you detailed up-to-date information
about the state of their components, the occupancy of their drives, heat of
CPU, memory usage, and others. Humans can make similar reports, though in the
form of unquantified sensations. Like people that can state their name and
birthday, a computer can display its make, model and manufacture date.
Like us computers have basic needs. They need energy
to run. They must be protected from the elements, and from physical harm.
Computers have no emotions, drive, curiosity, thought,
interests, imagination, opinions, creativity, philosophies, beliefs, fears,
wants, awareness, mental models, or sentience. A computer running AI software
can be considered an agent, but not a subjective entity.
Human information processing is much more energy
efficient. The largest supercomputers consume millions of watts of electricity,
and yet do not have the processing capacity of the human brain. An average home
desktop PC uses between 60 and 300 watts. The human brain uses merely 20 watts,
less than most incandescent light bulbs.
Computers are inherently adept at logic and
arithmetic, humans must learn it for years in school. Even the very first
computers from the mid 20th century were much faster at computing than humans.
This is how they got their name.
Most modern computers can multiply two 64 bit numbers
more than 4 billion times in a second. Can you do this calculation once in an
hour? Without a pen and paper humans cannot do this at all.
However, brains are inherently good at working
associatively, using abstractions, finding matches, completing patterns, and
using analogies. Computers struggle with this. Today even the most
sophisticated personal assistants (Siri, Alexa, Google Assistant) cannot hold a
conversation past one exchange. Every sentence you say to it is disconnected
from every other sentence.
Brains and computers are both adept at “networking,”
but only humans are good at socializing. AI chatbots are getting better, but
without any comprehension or consciousness, can their chatting really be
considered social?
Supercomputers are now approaching human brains in
terms of processing speed, and amount of memory. However, they cannot think,
even at the level of a two year old.
Even one year olds know things. A computer though does
not know anything, just like a thermostat doesn’t know anything. All it can
know is the locations of where bits are either 1s or 0s. In fact, any computer
in the world, even the most complicated AIs, could be replaced by wooden parts
and a hand crank (a mechanical Turing machine). It would amount to a tremendous
contraption, but in theory it would work exactly the same.
Computers are now better than humans at checkers,
chess, go, Jeopardy, object recognition, language translation, and much else.
Even the best computers and programs have trouble
understanding natural spoken language. Today they can transcribe and translate
language better than humans, but have zero comprehension. We have to admit
though that most humans have trouble understanding programming languages, and
very few people can read machine language (1s and 0s).
Computers appear to perform very complex tasks but
they are really performing very simple tasks extremely quickly. Because they
are exceptionally fast and accurate they can be made to chain together long
series of operations to produce useful software and applications. However, each
individual thing they do is very simple, the equivalent of elementary school
math.
Computers learn new programs immediately after
downloading and installing them. Humans can take years to learn new skills.
Computers can do things they were never programmed to
do explicitly, but only if that thing is implicit in their design. Humans can
do things that were never implicit in their design (like writing a poem).
Animal brains are embodied in the sense that they
interact with and live in the world. Desktop computers, phones and tablets are
disembodied.
Humans are made of carbon, oxygen and hydrogen.
Computers are made from silicon, metal and plastic. But very soon computer
semiconductors may be made from carbon nanotubes. This would make computers
carbon-based, just like us.
Computers have short-term memory, but it works in a
way that is fundamentally different from short-term memory in humans. Computers
have no equivalent of working memory. This is probably the most important
difference between humans and computers today. Until they are programmed to
simulate working memory they probably cannot be conscious.
If you found this
interesting, please visit aithought.com. The site delves into my model of
working memory and its application to AI, illustrating how human thought
patterns can be emulated to achieve machine consciousness and
superintelligence. Featuring over 50 detailed figures, the article provides a
visually engaging exploration of how bridging the gap between psychology and
neuroscience can unlock the future of intelligent machines.