For our investigation we have restricted the world to a stage

= Starting point for the research: a sys= tems perspective

In the introducti= on we differentiated between public (measurable) and private (introspective) information, and looked at 4 types of information: action, spatial info, ti= ming info, and planning. For actio= n and perception we also looked at 3 layers of private information – using = an analogy of peeling an onion.

In the second and= third chapters we introduced the stage and the skeleton that represent the interf= ace between public and private information, and that form the basis for action = in the world.

In the fourth thr= ough sixth chapters we looked at the setting for the research, ‘the world’ where public information is available. We discussed the 2 interfaces with= the actor, optical and mechanical. The optical interface leads to visual perception by the actor. The mechanical interface involves = moving the actor’s bones with electrical (neural) information. (For our analysis, the bones, join= ts, and muscles are visible and public and therefore belong into the world. The electric nerve impulses that t= ell the muscles what to do are part of the interface with the private brain-dom= ain.

In this chapter we explore the private side of the public and private interface from a systems perspective. To continue with= the pictures of the introduction, we shall discuss action, visual perception, planning, and timing. We shal= l also discuss briefly the nature of our knowledge about these systems, differentiating between public (measurable) knowledge and private (introspe= ctive) knowledge.

= ‘The brain’ and its optical and neural interfaces with ‘the world= 217;

In our simplified= model, there are two sub-systems that interface with ‘the world’. The first is one of the senses, bu= t I am not aware of a class-name for the second, the physical action subsystem. (Speech and singing might be illustrations of the output of an acoustic output subsystem, which should b= e a distinct member of this class.)

The first, managi= ng the input from the world, is the optical subsystem that manages the view through the eyes. We shall simplify by as= suming a Cyclops, i.e. one-eyed visual perception. We shall also assume brain-driven perception, or perception by request, where the eye ‘requests’ = the information that becomes the optical input by focusing on the view, so that= the eye is the client and the world is the server of the optical information. In other words, the eye ‘pulls’ the information from the world.

This model can be implemented in a client - server arrangement, (e.g. browser – SVG (http) - server).

The second subsys= tem manages the output from the brain to result in mechanical action through the bones of the skeleton. This i= s the neural connection from the brain to the muscles that move the bones. In this case the muscles need to b= e told what to do next and the brain through the neural network supplies the requi= red information, even if no change in relative joint angles is requested. Traditionally this is seen as a ‘push’ situation, where the brain pushes out the information ov= er the neural connections to the muscles.

This model can be implemented in a browser – http-server arrangement, (i.e= . client - server), where the browser representing the brain requests a form listing= the bones and enters the requested change in joint angles. The information on this form is th= en uploaded to the server, and the bone positions are modified as per request (assuming the changes do not violate constraints).

Note 1: To further simplify the mechanical model, we have split off control over the hands into a separate subsystem t= hat is not included in this model. Only the rough orientation of the hands relative to the wrists is included.=

= The problem of time for ‘the world’ interfaces

In the world subs= ystems discussed in a chapter above we assume that there is no memory of the past = and no plan for the future, but only the present. The optical subsystem bears a resemblance to video, where time is handled as a stepwise sequence of frames. We can use the same approach for the mechanical subsystem model of the world. This allows us to synchronize opti= cs and mechanics by assuming that we go from state to state in the bone positions which corresponding to a frame to frame sequence in the optical domain. In other words, the bone positions remain constant within the frame and are reflected in the views. At the same time, position-change information is received for each bone, which then results in modified bone positions for the next frame.

The ‘brain&= #8217; model, while it has and can use memory, it must respect the memory-free asp= ect of its interface with the world.

= Subsystems for ‘the brain’

Above we discussed interfaces for brain subsystems without specifying these subsystems. It should be noted that we treat t= he optical input as well as the neural output to the limbs as brain subsystems, but we could have called them optical and spinal subsystems – by the major connecting routes. The = main point is that we need to define the other boundaries for information processing, where they interface with yet other brain subsystems. We have alluded to the conjecture = that there such other subsystems by mentioning other senses and proprioception on the input side, and by mentioning plans and purposive (goal-driven) action.= We mentioned hand-action as a sepa= rate subsystem. We also mentioned = speech as an example of yet further actions, possibly with their own subsystems.

= Language and action

Our main focus fo= r this investigation is the relationship between language and action. We are therefore willing to lump o= ther functionality together into large and amorphous subsystems, while separating out language-related functions into smaller subsystems so that we can investigate and speculate on their interfaces.