Inner World

This section presents a model of the "inner world" of a subject, the objects and data-structures that make up this space and how operations on these data-structures can be implemented using the available Screen Based Reasoning subsystems. The model is highly speculative in nature, as little experimental data are available. The only indications for "correctness" of the model can be found in it's capacity to explain certain structures and phenomena.

Approach and Summary

In the sections below we will list a number of items of the Inner World - objects, operations and phenomena - and explain each of them in terms of the Screen Based Reasoning model, data-structures and subsystems. The model has been inspired by Thomas Metzinger's "Self-Model Theory of Subjectivity".

Objects of the Inner World

There are two types of objects in the "inner world":

• Perceptions and
• Thoughts

Perceptions represent states of the "outer world" in the "here" and "now", while "thoughts" refer to a number of different phenomena of the "inner world". Several types of "thoughts" can be distinguished:

• Word Thought:
  The subject "hears" a short phrase or sentence with the "inner ear". This may be accompanied by "silently" pronouncing the phrase.
• Picture Though:
  The subject "sees" a 2D image, a 3D scene or a short sequence of images with the "inner eye".
• Plan Thought:
  A "plan thought" forms unconsciously as a response to an "urge" or "goal". Simple plans may remain below the consciousness threshold if they consist of one or few actions with well known decompositions and high confidence scores. Plans with multiple options that require "decisions" give rise to "scenarios" (the actual paths though the plan) that will attract the "attention focus". The "attention focus" will then initiate a conscious simulation of the scenarios as plan execution in order to determine further details, to discover additional decision points and to calculate time and costs etc.
• Train of Thought:
  Refers to a state of day dreaming where the mind follows a "scenario" without a specific goal similar to scenarios simulation in plans above. The mind will unconsciously select a continuation after the current scenario has finished.
• Reasoning Thought:
  SBR views "conscious reasoning" (as opposed to subconscious Description Logic reasoning as part of Scenes) as a variant of "plan thought".

Mental Events

All of the above thoughts may appear as "events" in the mind generated by a number of subsystems.

• Event:
  Events interrupt the ongoing mental process and immediately attract the focus of attention, if the intensity of the event exceeds the "event threshold". Events are generated from body sensations, from the external world or from "thoughts" that have formed subconsciously and that suddenly enter the conscious mind.
• Urge:
  A simple but intensive event typically originated from body sensations like hunger, pain, itching, sexual desire, aggression etc. The characteristic of an urge is that it appears in the realm of "primitive" desires, as opposed to compound goals and desires on the social or higher levels of the "goal hierarchy". An "urge" usually allows for a simple and fast action to satisfy the urge, such as scratching, ingesting food etc.

Events above a certain threshold capture the "attention focus". This threshold depends on the foreground activity of the subject, the event threshold may be increased considerably when the subject "is concentrated". Then the "impulse control" mechanism of the attention focus becomes active and may discard the event after short consideration with previously analyzed utility/costs, or lead to a longer consideration in order to calculate or update utility/cost. Finally (or in parallel to the above calculations) the event is passed on to the planner in order to develop an execution strategy. The resulting plan is may or may not be checked for side-effects and is passed on to the Persistent Goals subsystem for execution. The persistent goals subsystem subconsciously includes the new plan in the persistent plan hierarchy and starts to execute the plan if it has obtained the highest priority.

Possible sources of events include:

• 3D Reconstruction and Object Configurator:
  After the identification of a previously unknown object
• Plan Recognition:<brAfter identifying a thread, an opportunity or the previously unrecognized plan of an agent
• Planner:
  After finishing a previously unfinished plan or when learning a new task decomposition
• Episodic Memory:
  "Associations" may pop up related to the current sensor input directed by the Attention Subsystem.
• Plan Reasoning:
  After discovering new characteristics of plans.
• Social Reasoning:After identifying threads or opportunities, after concluding a new inference that explains previously unknown behavior of agents.

Mental Self-Model of the Subject

The mental self-model refers to the subject's awareness of it's own thoughts and mental activities and the abstractions constructed on top of them. Scene Based Reasoning proposes to implement this self-model using a short-term Episodic Memory that maintains a trace of the subject's conscious thoughts of the last minute or so. This model predicts that a subject is not capable to observe it's own thoughts directly, but only their trace. "Conscious" thoughts are defined as those thoughts that are reflected in the "thought trace".

The normal object-level processing capabilities of Scene Based Reasoning can be employed to create abstractions of the reflected thoughts, to observe co-occurrence between thoughts and other internal objects and analyze the factors leading to certain thoughts just like they were happening in the outer world.