Research Circle – PHD – 2016By, Amr Kamel Ahmed

Supervised by, Dr. Alaa Hamdi

Cognitive Architectures

Cognitive architecture is an engineering approach for modeling cognitive systems.

Cognitive systems could be bug, bird, animal or human

But in most cases it is human

It doesn’t model static structure only

It models cognitive behavior also

Cognitive Architectures (CA)

A single set of mechanisms that account for all of cognition (using the term broadly to include perception and motor control). For example,LanguageProblem solvingDreaming.

Some of the things a UTC must explain are:How intelligent organisms respond flexibly to the environmentHow they exhibit goal-directed behavior and choose goals

rationally (and in response to interrupts: see previous point)How they use symbolsHow they learn from experience

Unified Theories of Cognition (UTC)

PsychologyEvaluating cognitive modelsStudying learning techniques and methodsUnderstanding cognition models of specific tasks i.e.

Vehicle drivingComputer Programming

RoboticsTransformation from systems that do limited low level

tasks extremely well to systems that perform wide range of tasks with acceptable results

Artificial Brain Projects

Motivation

ClassificationSymbolic

ArchitecturesSoarACR-R

Sub-Symbolic ArchitecturesLEABRA

Hybrid ArchitecturesLIDA

Biologically Inspired Architectures• 4CAPS• ACR-R• LIDA

Emotional & Motivational ArchitecturesEmotion Machine

Cognitive Memory TypesCognitive Architectures

The roots of the distinction of human memory returns to Atkinson-Shiffrin model proposed in 1968

They assert that human memory has three separate components:- Sensory register, where sensory information enters memory. Short-Term store, also called working memory or short-term

memory, which holds inputs from sensory register and long-term store.

Long-Term store, where information which has been rehearsed in the short-term store is held indefinitely.

Memory Types

Each sensor has its own sensory registerDo not process information carried by stimulusDetect and hold information for use by Short-Term memory Information only transferred to short-term memory when

attention is given to it, otherwise decays rapidly and forgotten Iconic Memory:-

Sensory memory associated with visual system. It was experimentally shown that it is separated to short-term

and long-term memory Decays after 0.5 – 1.0 seconds

Echoic Memory Associated with auditory system Holds superficial aspects of sound (e.g. pitch, temp or rhythm) Having duration between 1.5 and 5 seconds

Sensory Registers / Memory

Attended information is transferred to Short-Term Memory (STM)

Information that enters STM decays and lost as well as sensory memory

However it usually stays longer than sensory memory (18 – 20 seconds)

Information can stay at STM for much longer time through rehearsal

Information in STM doesn’t have to be of the same modality Example, written text enters as visual can be held as auditory and vise

versa

There is limit to the amount of information that can be held in STM to 7 +/- 2 chuncks

Short-Term Store / Memory

It is a process involves repeating information over and over in order to get the information processed and stored in memory

There are two types of rehearsalMaintenance rehearsal

It is useful in maintaining information in STM. However; it is not an effective way of having information processed and transferred into Long-Term Memory

Example, repeating a phone number out loud until put the number onto the phone to make the call.

Elaborative RehearsalThis type of rehearsal if more effective in transfering

information from STM to Long-Term MemoryIt involves thinking about the meaning of the information and

connecting it to other information already stored in memory

Memory Rehearsal

Is the memory stage where information can be stored for long periods of time.

Information can be maintained in Long-Term Memory (LTM) indefinitely

Two types:- Explicit Memory (Declarative) refers to all memories that are

consciously available, includes:- Episodic Memory:-

Refers to memory for specific events in time as well as supporting their formation and retreival

Semantic Memory Refers to memory of factual information such as meaning of word

Autobiographical Memory Refers to knowledge about events and personal experience from an individual’s

own life. Similar to episodic but it is related to individual lifespan

Implicit Memory (Procedural Memory) Refers to the use of objects or movements of the body Such as how to use a pencil, drive a car or ride a bicycle

Long-Term Store / Memory

Examples Cognitive Architectures

SoarSoar is a general cognitive

architecture for developing systems that exhibit intelligent behavior

It has been in use since 1983

evolving through many different versions to where it is now Soar, Version 9

http://soar.eecs.umich.edu/

ACT - RAdaptive Control of

Thought – Rational (ACT-R)

The ACT theory has origins in the Human Associative Memory (HAM) theory of human memory

A production system was proposed that procedural knowledge was implemented by production rules

Leabrea Architecture includes three major brain

systems: Posterior cortex

Perceptual and semantic processing

Using slow, integrative learning Hippocampus

Specialized for rapid encoding of novel information

Using fast, arbitrary learning Frontal cortex / basal ganglia

complex Active and flexible maintenance

of goals and other context information,

Serves to control or bias processing throughout the system

CLARION Architecture Action-Centered Subsystem (ACS)

Control actions i.e., to maintain and apply

procedural knowledge Non-Action-Centered Subsystem

(NACS) to maintain general knowledge i.e., declarative knowledge

Motivational Subsystem (MS) to provide underlying motivations

for perception, action, and cognition, in terms of providing impetus and feedback

Meta-Cognitive Subsystem (MCS) to monitor, direct, and modify the

operations of the other subsystems for better performance

LIDA Architecture

Based primarily on Global Workspace TheoryLIDA simplified cognitive cycle constitutes a unit of

sensing, attending and actingLIDA cognitive cycle divided into three phases:-

Understanding phaseAttention / conscious phaseAction selection phase

LIDA Architecture

Cognitive computing aims to develop a coherent, unified, universal mechanism inspired by the mind’s capabilities

it seeks to implement a unified computational theory of the mind

2007, IBM developed C2 mammalian scale near real-time cortical simulator

A notable C2 innovation is the memory efficient representation of synaptic state significantly increasing model scale.

In 2013, IBM introduced the TrueNorth neuromorphic CMOS chip. It consists of 4096 HW coresEach one simulating 256 programmable neuronsEach neuron has 256 programmable synapses

Cognitive Computing

Cognitive Computing

Although there are hybrid cognitive architectures which includes both symbolic and sub-symbolic subsystems however they are separated islands

There are no integration between symbolic and sub-symbolic subsystems that enables the usage of symbolic representations based on sub-symblic platform.

All symbolic representations relies only on Von Neumann architecture

There is no sub-symbolic architecture that allow causality

Issues

How to create symbolic cognitive architecture relies on neural-based platform

How to build neural-based hardware platform suitable for cognitive architectures:-Nano scale neuronsVery low power consumptionLow cost of implementationScalable to include massive number of neurons (10^8 neurons

scale)

How to integrate both paradigms into single cognitive architecture that realizes Allen Newell aspects for Unified Theory of Cognition

Open Points of Research

Thank You