1  Introduction

1.1  The nature of creativity ......................................... 1 

1.2  Aspects of creativity .............................................. 2 

1.3  Social aspects of creative behaviour ........................ 6

1.4  Some definitions ................................................... 7

1.5  The art and the science .......................................... 8

2  Theories of creativity 

2.1  Poincaré and the four-stage model .......................... 10

2.2  Weisberg's criticism of the four-stage model ............. 11

2.3  A critique of Weisberg's view .................................. 15

2.4  The cortical-arousal theory of creativity ................... 18 

2.5  Some characteristics of creativity ............................ 21 

3  Computational modelling

3.1  The computational modelling approach .................... 24

3.2  The benefits and drawbacks ................................... 26

3.3  Previous computational models .............................. 28

3.3.1  Randomness and rigidity .............................. 29

3.3.2  Generative grammars .................................. 30

3.3.3  Discovery programs .................................... 33

3.3.4  Meta-rules ................................................. 42 

3.3.5  Analogical mechanisms ................................ 44 

3.3.6  Towards flexible representations .................... 46

3.3.7  Decentralised systems .................................. 49

3.3.8  The neural-network issue .............................. 52 

4  Emergent-memory models 

4.1  A characteristic of computational modelling .............. 56 

4.2  A theory of emergent memory ................................ 58

4.3  A formal definition ................................................. 59

4.3.1  Builders ....................................................... 60

4.3.2  K-lines ......................................................... 61 

4.3.3  Censors and suppression ................................ 65 

4.3.4  Credit assignment ......................................... 68 

4.3.5  Task selection ............................................... 69 

5  A Computation Model: GENESIS 

5.1  Computational decisions ......................................... 74 

5.2  Micro-Eleusis as a domain ....................................... 76 

5.3  Domain-specific details ........................................... 79 

5.4  Implementation details ........................................... 87 

5.5  Alternative computational models ............................ 90

5.5.1  SPARC/μE .................................................... 91

5.5.2  A genetic representation ................................ 91

5.5.3  Two classifier systems ................................... 92

5.5.4  The NODDY algorithm ................................... 92

6  Empirical Studies 

6.1  The scope of the empirical study ............................. 94

6.2  The 24 sequences ................................................. 96

6.3  GENESIS at work ................................................. 100

6.3.1  Best-first behaviour ..................................... 100

6.3.2  Terraced-scan behaviour .............................. 113

6.4  Sequence analysis ............................................... 119 

6.4.1  GENESIS-BF .............................................. 119

6.4.2  GENESIS-TS .............................................. 121

6.4.3  The classifier systems ................................. 124 

6.4.4  SPARC/μE's analyses .................................. 125

6.5  Programs as dealers ............................................ 125 

6.6  Programs as players ............................................ 129 

6.7  Playing with people ............................................. 131     

7  Conclusions To Be Drawn 

7.1  Theoretical results .............................................. 140

7.2  Results from the Implementation Stage ................. 141

7.3  Experimental Results .......................................... 142 

7.4  Empirical Conclusions ......................................... 144

7.5  The "aha!" phenomenon: cause or effect? ............. 145

7.6  Chunking and magic numbers ............................. 146 

7.7  Controlled randomness ...................................... 147

7.8  Breaking out and going wrong ............................ 150

7.9  Conceptual spaces ............................................ 154 

7.10  Mere novelty real creativity .............................. 157 

7.11  Summary points ............................................. 160 

A  The Twenty-four Test Sequences                                    169