Neuroscience based machine intelligence models by Gary Gaulin

Tuesday, November 18, 2008



Source code (but not compiled .EXE program found here that Visual Basic programmers do not need to run) is available on Planet Source Code here:

http://www.planetsourcecode.com/vb/scripts/ShowCode.asp?txtCodeId=71381&lngWId=1

If you do not have a Visual Basic compiler then here is a zip file with the IntelligenceGenerator5.EXE file.

IntelligenceGenerator5

In the above download, save the zip file to your hard drive in a new folder with a name like IntelligenceGenerator5 then locate and open folder to unzip then run. There should not be a problem or do I expect one but if you worry about viruses getting into it then before running you can check to make sure this is the program I uploaded. Here are the "Properties" (right click on program icon) I have here of the IntelligenceGenerator5.EXE file to look for that should match what you received.

Modified: November 14, 2008, 8:24:42 AM
Size: 108 KB (110,592 bytes)


AUTONOMOUS BEHAVIOR

Autonomous behavior does what it wants to do. In some cases can be trained but wanting to be trained has to be in its behavior. For this reason fully autonomous robots are unpredictable and may accidentally or on purpose charge then attack what it sees or hears.

A robot born with no memories at all that is left to its own to explore and learn would have to bump into things the different ways it can bump into them before learning how not to bump into things. We did the same. Very early on we bumped into a solid object to find out that hurts, so had to learn how not to do that. Then we learned how to stand by trying to stand then falling down every time until we finally made it all the way and were standing, then fell right back down again. Therefore a ten horsepower robot to scurry around the living room, is a very bad idea. It might even learn to avoid stalling out when it hits a wall by going fast enough to go clear through, then soon be down the street visiting neighbors houses.

Autonomous behavior might make a very bad housekeeper but it will here be studied because it is found in molecular machines, cells, insects on up to humans where this behavior is sometimes called "free-will".


SELF-LEARNING

Searching for answers and striving to be increasingly better is inherent to the learning mechanism itself, in the simple yet effective way that it works. Therefore the human brain is much more complex than the computer model but the fundamental interaction is the same. We have a memory that responds to what is being sensed, with action signals sent to muscles, where feedback circuits wire back success or failure and includes pain receptors to add a more automatic "don’t do that" reflex that more suddenly puts what muscles are doing into reverse.

Human intelligence is electrochemically produced by neurons that also control muscles and other processes. In addition to intelligence human intelligence also possesses consciousness. Although consciousness has been traced to a relatively small region deep inside the brain, how this awareness works is not yet known.


ASSOCIATIVE MEMORY

Associative Memory stores an Action to be taken in response to environmental Sensors.

We have the following sensors, called the "Senses"[23]:

1 Sight
2 Hearing
3 Taste
4 Smell
5 Balance and acceleration
6 Temperature
7 Kinesthetic sense
8 Pain
9 Other internal senses

In computer programming an associative memory is easily implemented with an Associative Array. The memory system is represented by name it was given when created, we will simply call it "Memory" which in turn gives us the array called "Memory()" where inside parenthesis is specified where in memory to read or write action data.

To read/recall a Memory Action:

Action = Memory(Sensors)

To write/store a Memory Action:

Memory(Sensors) = Action

The "Sensors" variable is an integer (whole) number that addresses one of the Actions in memory for reading or writing. Value will range from 0 to the last location which is determined by how many sensors of any kind the robot has in total.

In an electronic system size of memory exactly doubles for each on/off condition (bit) that is added to be sensed. Where there is only one bit memory has two Action data locations 0 and 1. Where there are two bits there are four locations 0 to 3. Where there are three bits there are eight locations 0 to 7.

Where there is more information than can be all at the same time wired into a single memory system as in the retina of our eye many sensors are summed together to extract only the information the rest of the brain needs from the overwhelming number of photoreceptors that the retina contains.


CONFIDENCE DRIVEN

When you encounter a new problem you never saw before, you know when you have no solution in memory. Your confidence in having the correct response is 0, because you have no response at all for that yet. The best you can do is guess. If that didn’t work then you guess again. While growing up we had to try holding cups upside down and other angles to figure out that unless it stays "upright" the contents spill all over the floor. And coordinating muscle movement to walk then run involves a lot of falling down.

In the computer model all locations in memory likewise start off with Confidence = 0. Confidence is incremented up to a maximum of 3. When a guess leads to what it instinctually wants, it’s stored with Confidence = 1. If it works again, then it’s incremented to 2. Then finally to 3. The confidence range of 0-3 is all that’s needed. Going beyond that range is not necessary.

How confidence is incremented leads to various behaviors. All at once going from 0 to the max of 3 leads to overconfidence. If its confidence is easily brought back to 0 then it will have little confidence in any of its responses but that can lead to trying new things.

Seeing food and hungry while motor direction is moving it closer, is here a successful response. But if it is hungry and what it's doing is not getting it any closer, it’s failing, so the intelligence must take a guess. Random motor settings are tried. If settings work then they remain in memory, else it takes another guess what to do.

The computer model has a ring circuit that adds a sense of what is around itself, and with it comes a significant increase in confidence. With this simple circuit the intelligence will right away know where something out of its field of vision is located. There are here six memory location where one is set to act as a pointer to one of six angles.

When you click the "Circuit" checkbox you see what is in essence a ring of six neurons, numbered from 0 to 5. The state of what it sees ahead at Angle 0 shifts from neuron to neuron around the ring. The reference angle for body position could come from the sun, magnetic field, nearby landmark, balance circuit, or other source of rotational feedback.



Direction of food is shown as blue pointer. In this example the food angle just switched from being to the left out of field of view, to being straight ahead. The right motor is running forward (green) while the left is stopped (gray). So it's here Spinning Left (SpL) and Spinning Towards (SpT) what it "sees" to the left of it.

Sensing direction like this adds another level of intuition. Will now learn how to turn in the right direction to follow what when out of its field of vision. Like when something goes fast in front of you, turning the right direction is automatic. You don't look left then right back and forth until you by chance see it again. It's possible to grab the last feeder with your mouse so it has to chase after it. Will notice that it learns to turn in the right direction towards it.

What this adds is shown below, where the chart with Angle and SpT bit added to the Address is shown above the graph of the same age without it. The Food Supply slider control was set to 1 (lowest amount) so it has to work hard to keep itself fed.

In the graph you can also see how well it keeps itself fed, the red line No intelligence at all would have the graph showing a battery level that flat-lines at 0, which in essence, is dead. But notice the red line here. See how it very quickly learns to find food so it doesn't go to zero full, starved, like it would be if stuck in a circle never bumping into food.



We can see from the lower red line of second graph that it had more trouble staying fed. Confidence is also noticeably lower due to it being a slower learner. Shown below, is the graph when its ability to see food is entirely taken away.



In the above three examples, the only thing that has changed is the amount of environmental sensory information. And this intelligence is not at all fussy. Adding any kind of sensor, that does almost anything, can greatly increase its awareness.

Sensory information such as this does not require detail. So even though the typical ring neuron structure is another simple common six sided hexagonal geometry, with large numbers of them a biological brain can store angles representing complex sights and sounds.

It is not necessary to connect every single pixel of eye information directly to memory. In human vision many photoreceptor pixels are combined into a single signal before being sent to the brain via optic nerves. The visual information is not all at once processed, it is processed in "layers" of neural circuits.


INTELLIGENCE SYSTEM

To form an Intelligence System with a RAM chip type memory system we Address memory with input sensory information from photosensor eye pixels, microphone ear, battery charger (taste of its food), battery low (hungry), bumper or other sensors useful. This gives each unique environmental situation a unique memory location where a unique Action response to it controls motors, speaker, light or other device it might at some time find helpful.

Whatever is there for a photoreceptor, will work just fine. Even an eye-spot made of a centriole crystal is better than nothing. On up from there are telephoto eyes of birds of prey. Whatever there is developing for an eye gets wired into.



The basic mechanism that produces the phenomena of intelligence can be modeled with a simple loop. We will here give the intelligence control of tank-like 2 motor drive system. Motor Forward and Motor Reverse is controlled with two bits where motor is off when 00 or 11 while motor is moving one way or the other when 01 or 10 with it not mattering which order the control bits are connected to memory. Intelligence inherently self-organizes all inputs and outputs then “learns”.

In the first line of program code we have what the intelligence is to control and could be real motors. With molecules this could be the Krebs Cycle. The "Call" instruction causes top to bottom program flow to jump to where another routine generates a virtual environment containing the robot then jumps back when finished. Where real motors are used the four motor control bits are only sent to motor controller circuit, then returns.

The second line adjusts a Confidence level in response to the condition of the "Stall" environmental input sensor that is 1 (true) when eiter wheel stop turning as it would when wall stops it. We here combined Left and Right Stall shown in above electronic circuit diagram into one, which does not have to be done but is here used that way. Other sensors such as eye pixel, battery low sensor and another for having found charger is added with another If..Then.. statement. Conf(Addr) is a one bit memory array location that stores Confidence level from 0 to 3 at address specified by the "Addr" variable. Due to the way electronic counters operate (but not synapse) the program assumes that Conf(Addr) will not go below zero or above limit, in this case three. The RunMotors subroutine would here change -1 to 0 and 4 to 3 so it stays in range.

The third line uses binary powers of two so that there is a unique Memory Address location for each possible input sensor combination. Networks of neurons already connect in a way that forms a unique branching paths so do not require a numerical address like this, but a computer memory here simulating them requires a number be given. Other inputs can be included in this addressing with the next power of two such as adding "+(EyePixel*32)" to include photosensor to see light from a battery charger. Memory size doubles for each bit added which is at first not a problem but can become unnecessarily complex. Not all sensory information need be included in addressing, just what is needed to make an efficient addressing system to sort visual experiences into unique locations in the memory. When there are a large number of inputs they are first summed in different layers of detail.

The fourth line takes a guess when confidence in an action is below one (zero) by randomly setting the four motor control bits then confidence level to one to indicate low certainty. This part of the mechanism is also intuitive when one tries to imagine what would happen where we could not take a "guess" when necessary. We would forever get stuck right there, maybe repeating the same unsuccessful action like bumping into barrier over and over again until dropping from exhaustion. Flies sometimes do this for a while against a pane of glass to reach a light source on the other side. At some point it has to realize that it is not having any success then try something else, or perish. Even a dumb guess can still be a correct response to environment. This happens in the computer model when stuck against the wall being able to go no further. It has to be able to take a guess how to get out of that fatal (when starves there) situation as would happen to a simple organism in a changing environment with a genome that has 100% replication accuracy which would never try anything new. Or where guesses result in too many useless responses. The ability to take a "good guess" then stay with it must be present for either a genome or intelligence of the computer model to adapt and survive.

LoopStart:
1: Call RunMotors
2: If Stall=0 then Conf(Addr)=Conf(Addr)+1 Else Conf(Addr)=Conf(Addr)-1
3: Addr = LMF + (LMR*2) + (RMF*4) + (RMR*8) + (Stall*16)

This model is also analogous to finger muscle control that through training becomes coordinated in a way that they have the keyboard layout stored as motions to reach each key. In both cases intelligence successfully learns to navigate a 3D space without requiring a physical map. We are therefore able to type without consciously thinking about the level of intelligence that does the actual typing. There is in essence more than one intelligent mechanism at work in a brain. There are a number of them functioning at the same time.

We can sum up this mechanism by first needing something to control such as motors, muscles, inner cellular structure (stem cell migration) or the Krebs Cycle. Second there must be a way for success and failure of an action to be measured which can be from visual feedback to correct typing errors, molecular using chemical feedback, or in extreme cases not being able to endure the environment simply eliminates it. Third there must be a memory with a structure that saves actions in a unique location in memory for each combination of sensory input signals such as network addressing of a brain or genes located in a unique functional location in a chromosome in a unique chromosome territory inside the nucleus. Fourth there must be a way to take a guess in order to try a new action which at the genome level involves code changes where in somatic hypermutation (cells of the immune system) regions of the genome undergo recoding at some million times the normal rate to find a way to destroy an invader.


Classes Of Robotic Self-Learning

It is useful to define intelligence as in robotics according to David L. Heiserman 1979 in regards to the self-learning autonomous robot, for convenience here called "Rodney".[4] The Intelligence Generator/Detector described above is Beta class.


(1) ALPHA CLASS

While Alpha Rodney does exhibit some interesting behavioral characteristics, one really has to stretch the definition of intelligence to make it fit an Alpha-Class machine. The Intelligence is there, of course, but it operates on such a primitive level that little of significance comes from it. ....the essence of an Alpha-Class machine is its purely reflexive and, for the most part, random behavior. Alpha Rodney will behave much as a little one-cell creature that struggles to survive in its drop-of-water world. The machine will blunder around the room, working its way out of menacing tight spots, and hoping to stumble, quite accidentally, into the battery charger.

In summary, an Alpha-Class machine is highly adaptive to changes in its environment. It displays a rather flat and low learning curve, but there is virtually no change in the curve when the environment is altered.

(2) BETA CLASS

A Beta-Class machine uses the Alpha-Class mechanisms, but extends them to include some memory - memory of responses that worked successfully in the past.

The main-memory system is something quite different from the program memory you have been using. The program memory is the storage place for Rodney’s basic operating programs-programs that are somewhat analogous to intuition or the subconscious in higher-level animals. The main memory is the seat of Rodney’s knowledge and, in the case of Bete-Class machines, this means knowledge that is grained only by direct experience with the environment. A Beta-Class machine still relies on Alpha-like random responses in the early going but after experiencing some life and problem solving, knowledge in the main memory becomes dominant over the more primitive Alpha-Class reflex actions.

A Beta-Class machine demonstrates a rising learning curve that eventually passes the scoring level of the best Alpha-Class machine. If the environment is static, the score eventually rises toward perfection. Change the environment, however, and a Beta-Class machine suffers for a while, the learning curve drops down to the chance level. However, the learning curve gradually rises toward perfection as the Beta-Class machine establishes a new pattern of behavior. Its adaptive process requires some time and experience to show itself, but the end result is a more efficient machine.

(3) GAMMA CLASS

A Gamma-Class robot includes the reflex and memory features of the two lower-order machines, but it also has the ability to generalize whatever it learns through direct experience. Once a Gamma-Class robot meets and solves a particular problem, it not only remembers the solution, but generalizes that solution into a variety of similar situations not yet encountered. Such a robot need not encounter every possible situation before discovering what it is suppose to do; rather, it generalizes its first-hand responses, thereby making it possible to deal with the unexpected elements of its life more effectively.

A Gamma-Class machine is less upset by changes and recovers faster than the Beta-Class mechanism. This is due to its ability to anticipate changes.


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