Tuesday, 1 December 2009

Where were you this morning at 5 AM?

Well officer....

I was writing a pre-proposal for research funding, because the deadline was today and planning is on one of those pages in my dictionary which was accidentally removed by brute force.

Since chances are slim I will be invited to send in a full proposal (because my #@XX%&@ is not finished yet) there will probably be about three people who will ever read it. So, for the effort, I'll post it here as well :)

Here's a part of my alibi (including spelling errors and general awkwardness :) ):

On the origins of the discrete contents of the mind

How and why do we translate our continuous external environment into an internal environment, which consists of matters predominantly discrete, bounded and categorical? Even our actions in the external world can be described as discrete movements or movement patterns. These discrete contents of our internal world are often the objects of study in Psychology. Examples are speech-sound categories extracted from a continuous acoustic signal, the individual words they are compiled into and the categorical semantic information the word conveys. Colour labels attributed to specific ranges of a continuous distribution of electromagnetic radiation are another example. Attitudes towards a minority population and gender stereotypes may be viewed as the outcomes of a categorization process as well. Many streams of information from different sources need to be combined and evaluated to designate a category label like “us” or “them” or “Masculine” or “Feminine”. It is evident that the process of transforming the continuous flow of information from different sources into distinct categories requires a mechanism operating across different spatial and temporal scales. It is also evident that an answer to the question might benefit from an interdisciplinary approach.

Stored and static or emergent and dynamic?

The dominant theory used for the scientific description of the discrete cognitive world is one in which cognitive processes may be understood as algorithmic operations on abstract symbol-like mental representations of stored information. The mental representation of a speech sound would consist of information about the range of frequencies that would trigger the activation of the representation if they were to be detected.

Many objections can and have been made against this machine-metaphor of cognition. One objection is that it is not clear how these discrete representations are created from the continuous stream of perceptual information. It often appears psychologists assume the external world to be as discrete and sequential as the representations and the algorithms. Moreover, many categorical boundaries and algorithms are assumed present at birth and thus coded in our genes. More important is the fact that abstract mental representations of categories are static. Their boundaries should be at certain critical values of a feature variable. Several studies have shown however that perception of category boundaries on a continuum of an acoustic parameter is subject to well-known nonlinear phenomena as hysteresis. This means that the boundary between the categories is not perceived at one critical value, but changes to other values dependant on the direction the continuum is sequentially traversed. [1,2]. These results were successfully modelled by a potential model describing the categorisation performance: The speech sound categories were conceived of as the discrete attractor states whose relative strength was influenced by the value of the continuous acoustic parameter, but also by previously perceived trials.

If we generalize this dynamic account of categorical speech perception to the broader question of the apparent discreteness of the contents of mind, we may arrive at the following conjectures:

1. The apparent discrete nature of the contents of the mind can be understood as the emergence of discrete attractor states at the macro-level of cognition from the continuous interactions between system components at the micro-levels.

2. The emergence of a discrete attractor state occurs as a consequence of the strength and the nature of the coupling between system components at the micro-levels

3. As the system self-organises its way through an ever changing landscape of attractor states this may appear as a sequential succession of discrete cognitive content. The changes are however driven by the continuous interactions of processes at the micro-levels.

4. The coupling of two previously independent systems will create discrete attractor states in a shared phase space depending on the strength and nature of the coupling

It is the main goal of this project to investigate whether these conjectures are universally applicable to all phenomena characterised by discretization of a continuous variable. A sub goal is to evaluate whether it can serve as a plausible alternative ontology to the machine-metaphor. Plausible in this case would mean not only by scientific standards like empirical support and evidence from simulation studies but also relating to the strong intuitive validity of the machine metaphor.


No comments:

Post a Comment