Lecturer's Précis - Smith (1993)

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First published online 10:41 GMT 11th March 2002, Copyright Derek J. Smith (Chartered Engineer). This version [HT.1 - transfer of copyright] dated 12:00 13th January 2010


Smith's (1993/1996) "Five-Plus-One Cognitive Hierarchy"

The problem with the older A-shaped cognitive hierarchies is that each processing box presents its précis of what it believes happens to information passing through that box with little distinction between the short term and the long term nature of the memory resources involved. Information in transit - a wholly short-term phenomenon - is shown by the arrows on these diagrams, but little is said about what happens to it when it arrives at its destination (where, if the organism in question is to benefit from prior learning, it needs to have the current and the prior interact in some way). The conventional explanation for neural information processing is that ongoing neural depolarisation events are "switched" in some way by past structural changes. To show this happening, however, requires more powerful flow diagrams, so in Smith (1993) we took the classical five-module diagram and placed it under a more powerful microscope. Instead of considering only two levels of analytical expansion (showing only the modules within the overall system), we went to four levels of analysis (showing subprocess within process within module within system). We also added the data stores accessed within each module, together with a sixth module, to take care of consciousness. We then simplified this for teaching purposes as a three level diagram (Smith, 1996). Here are the 1993 and 1996 versions. A detailed commentary is given only for the 1996 diagram. The "nested circles" diagram is one of several optional flow diagramming techniques, and was pioneered by the Yourdon School (see, for example, Edward Yourdon and Larry Constantine, 1979). Here are the two diagrams in reverse date order, so as to put the introductory version first:

Smith (1996): Here is the teaching version of the 1993 diagram (second figure below), complete with introductory explanation. When reading the notes, it may help to place your finger on flowline (1) on the diagram (bottom left), and then follow the argument as it develops. 

Sensory-Motor Systems: The sensory module is where information (a lot of it) is received from the outside world along pathway (1). Fortunately, most of it (2b/2c/2d) gets dealt with subconsciously, being used to monitor and correct skilled motor acts, to trigger automatic reflexes, or to provide feedback to a variety of homeostatic behaviours being controlled by the autonomic nervous system. The motor module can likewise look after itself to a large extent, that is to say, it can locally control many activities once it has had time to develop the necessary motor skills: it simply accesses its prior knowledge of the muscle patterns required (12) and then issues the appropriate instructions to the muscles involved (13a). The logic here is highly complex, however. One particular need is for a continuous flow of sensory feedback along pathway (1-2b), and another is for the senses to be told in advance what the muscles are up to, so that they know better what inputs to expect. This latter stream of information passes along pathway (13b). Meanwhile, information which is going to be consciously attended to is passed along pathway (2a) to .....

Cognition (1) - Perception: This module is where sensory input is analysed in the light of past experience, that is to say, perceived. As we have already seen elsewhere, perception takes place in two main phases. The first phase is for incoming information to be organised into its most likely natural clusters, and the second is for these clusters to be recognised. The organising phase (3) is best described as applying the various gestalt laws, and ensures that the pattern recognition phase is given as good a start as possible. Each successful recognition is called a percept, and the individual percepts - or, more usually, scenes made up from many percepts - are passed along pathway (4) to the awareness system (next). For pattern recognition to work, of course, the process needs access to previous experience with the stimuli in question. This type of memory is called perceptual memory, and it follows that whenever external objects are encountered for the first time, new perceptual memories need to be created (5b). There is also an element of perceptual expectancy set up along pathway (6). This allows the pattern recognition process to be speeded up, by enabling it to take educated guesses at what it is likely to be presented with next.

Cognition (2/3) - Awareness/Memory: This module is where the stream of images provided by the perceptual system is analysed, and judgements made as to what is going on in the outside world. This creates a short term awareness of that outside world, and requires both short term continuity of consciousness and significant reference to long-term memory. In other words, awareness per se adds little value to an organism: for an experience to be worth having, it needs to be remembered. It also needs to be tagged in some way as "nice" (and therefore to be repeated whenever possible) or "nasty" (and therefore to be avoided), and this information is provided along pathway (2e). The current best guess is that there are two types of long term storage available to assist the decision making process. [The] first type of storage is episodic memory - your memory of your past personal life, and the second type of storage is semantic memory - your general knowledge. Past "frames" of awareness move into episodic memory along pathway (5a), and, over time, the episodic traces are analysed (7) to provide semantic memory with new general knowledge. When using memory to make decisions, either the episodic or the semantic store can be referred to (8a/8b). If additional resources are required (that is to say, if you have a problem to solve before you can make your decision), then a temporary "problem space" is set up in working memory and accessed as needed (two-way pathway 9). The end result of all this is that some sort of willed behaviour is decided upon, and the necessary instructions are now passed down pathway (10) to initiate it .....

Cognition (4) - Behaviour: Consciously initiated behaviour (10) can often conflict with behaviour initiated via the subconscious routes described above (2b/2c/2d), so somehow the best balance of willed and unwilled behaviours needs to be "authorised". We recommend the term scheduling to describe this operation, and what the subject ends up scheduling is usually a compromise of several often conflicting demands. This implies that some sort of pleasure-pain evaluation (see above) has been going on using pathway (2d-2e). This, in turn, implies that the primary function of "the will" is to adjust current sensory input, using behaviour, in the direction of the maximum net pleasure. The final selection - whatever it happens to be - is passed down pathway (11) to the motor system (see above) to "deliver the goods" .....


Redrawn from a black and white original in Smith (1996:10). This version Copyright © 2002, Derek J. Smith.


Smith (1993): Here is our original personal attempt (a) to add STM and consciousness to the classical five-module cognitive hierarchy, and (b) to take each module to two additional levels of analysis (thus addressing the problem of showing both functional and structural processing hierarchies in a single diagram). The sensory and motor systems (one module each) are shown at the bottom of the diagram, whilst the "cognitive system" (four modules) is shown at the top. Information flowlines connect the processing modules, and some attempt has been made to indicate relative flow by relative thickness. The general logic of the flow is as set out in the simplified 1996 version (above). The LTM stores are shown as blue boxes, the STM stores as pink boxes, and medium term memory as mustard yellow boxes. The principles of memory access in Cognition (3) have subsequently been discussed in Smith (1997a,b,c; 1998).


Redrawn from a black and white original in Smith (1993:84-85). This version Copyright © 2002, Derek J. Smith.



Subsequent Developments

The evolutionary pedigree of the A-shaped cognitive hierarchy diagram was discussed in Smith and Stringer (1997), and a computer animation of the 1996 diagram was presented at the ASSC4 Conference in Brussels. The latest developments will be presented at the "Tucson 5 - Towards a Science of Consciousness" Conference, at the Centre for Consciousness Studies, University of Arizona, in April 2002. 



Smith, D.J. (1993). The psychology of effective college governance. Part 2 - The cognitive skills. Journal of Further and Higher Education, 17(2):77-85.

Smith, D.J. (1996). Memory, Amnesia, and Modern Cognitive Theory. Cardiff: UWIC. [ISBN: 1900666006]

Smith, D.J. (1997a). The magical name Miller, plus or minus the umlaut. In Harris, D. (Ed.), Proceedings of the First International Conference on Engineering Psychology and Cognitive Ergonomics (Volume 2). Aldershot: Ashgate. [ISBN: 0291398472] [Being the transcript of a paper presented 24th October 1996 to the First International Conference on Engineering Psychology and Cognitive Ergonomics, Stratford-upon-Avon.]

Smith, D.J. (1997b). The IDMSX Set Currency and Biological Memory. Cardiff: UWIC. [ISBN: 1900666057] [Workbook to support poster presented 10th March 1997 at the Interdisciplinary Workshop on Robotics, Biology, and Psychology, Department of Artificial Intelligence, University of Edinburgh.]

Smith, D.J. (1997c). Chunking and Cognitive Efficiency: Some Lessons from the History of Military Signalling. Cardiff: UWIC. [ISBN: 1900666065] [Transcript of paper presented 27th March 1997 to the 11th Annual Conference of the History and Philosophy of Psychology Section of the BPS, York.]

Smith, D.J. & Stringer, C.B. (1997). Functional Periodicity in Biological Information Processing Architectures. Cardiff: UWIC. [ISBN: 1900666073]

Smith, D.J. (1998). Commentary on "Cortical Activity and the Explanatory Gap" by J.G. Taylor. Consciousness and Cognition, 7:214-215.

Smith, D.J. (2000). A slow-motion video analysis of the arrival and circulation of initially unbinded input within consciousness. Computer-animated poster presented 30th June 2000 at the Fourth Annual Meeting of the Association for the Scientific Study of Consciousness, Free University, Brussels, Belgium. [Need a transcript?]