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The
evolution of skills
an
introduction to some questions
Ques=
tion
1: What is a skill
•<=
/span>A
skill is the capability to perform a
How can data in the brain le=
ad to =
physical (mechanical) action
•I simplify physical action as rotary movement of l=
imbs about the joints
•I describe that movement in terms of polar coordin=
ates, capturing the rotation of the limbs about the joint
•I simplify by assuming one pair of muscles for eac=
h plane of rotation
•The brain sends neural information to muscles to c=
ontrol
their tension, which controls =
the
angle of rotation
•The neural information is frequently updated to co=
ntrol the speed of rotation
Information processing for =
converting a skill into action
•I see the brain as the information processing
hardware (the computer) that ‘executes’ programs (the
skill) that generate the neural information that controls
the muscle tension that leads to action
•Using this analogy, I need a programming language
to encode the skill
–Ballet choreography ‘programs’
repeatable physical action
Sample
skills to be programmed
<=
span
style=3D'font-size:75%'>•A simple w=
alk or
run
•A simple walk toward a visually perceived static o=
bject
– a simple food gat=
hering
•A simple walk or run to catch a visually perceived=
moving object – a simple hunt
<=
span
style=3D'font-size:75%'>•A simple
imitation of a visually perceived task
<=
span
style=3D'font-size:75%'>•A simple
exploratory walk (novelty, experimentation)
•Apprenticeship learning based on an imitation of a=
visually perceived task
•An optimized walk or run to catch a visually perce=
ived moving object (hunt a prey)
<=
span
style=3D'font-size:75%'>•An ambush =
to
catch a prey
<=
span
style=3D'font-size:75%;visibility:hidden'>•
Programming language:
action output requirements - 1<= /span>
action output requirements - 1<= /span>
•Specifying physical action in detail by specifying =
the trajectory of rotary motion at each joint
=
–Ballet does it by poses, but I need to break it do=
wn joint by joint, and up to three planes of rotation=
per joint
<=
span
style=3D'font-size:86%'>–For each p=
lane,
the current angle must be specified
–For each plane and angle, the current time must be=
specified
•From the above, and with simplifying =
assumptions, the neural inputs to control each =
muscle pair can be calculated
Programming language:
action output requirements - 2
action output requirements - 2
•<=
/span>The
angles for each plane for each of the joints are relative
–<=
/span>For
example, the elbow rotation have to be specified in terms of the
angle of the lower arm relative to the upper arm
•<=
/span>The
timing of angular rotation has to be coordinated to have
synchronized motion
Programming language:
eyeball action requirements
eyeball action requirements
•<=
/span>The
direction and focus of the eyes has to be known to allow
interpretation of the viewpoint
•<=
/span>I
see vision as sensory feedback from an action involving neck, he=
ad,
and eyeball rotations, where each of these is treated as a
joint
Programming language:
vision output requirements
vision output requirements
•Vision =
input
is the pixelated image on the retina
=
•<=
/span>I
am focused on the vision output that is part of the skill that le=
ads
to action
=
–<=
/span>I
need support for the geometry on which action is based, so that j=
oint
angles can be calculated by the brain
Wh=
at
is a (mechanical) action
•I only look at vertebrates, species where individuals have a skeleton
•I see physical (mechanical) action as rotary =
movement of limbs about the joints
•I describe that movement in terms of polar coordinates, capturing the rotation of the limbs <=
/span>about the joint.&=
nbsp;
The movement also happens in time,
so that a full description involves successive
joint angles over successive moments
in time
•I focus on physical (mechanical) action related to locomotion, such as walking and sitting down.
Action similarity whenever a skill =
is
applied
•<=
/span>If
the same skill is applied repeatedly by a single individual, all the
resultant actions should be similar
•<=
/span>Different
individuals might have the same skill, and all the resulta=
nt
actions should be similar from one individual to the next
<=
/span>
•<=
/span>
Skills as data objects in the brain
•<=
/span>An
innate skill is encoded both in DNA and the brain. The encoding might differ, but the
information should be the same.
•A learned skill is enc=
oded
only in the brain
Skill
persistence in the brain
•A
skill persists in the brain even when it is not used to produce
action
•<=
/span>An
innate skill starts at birth or some period of maturation and
persists more or less till death
•<=
/span>A
learned skill starts after learning and lasts until it is forgotte=
n
' + ENDSHOW_MESG + '
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