CHAPTER LXVI 



Thinking, imagery and memory 



WARD C. HALSTEAD Unit m rity of Chicago, Chicago, Illinois 



CHAPTER CONTENTS 



Thinking Defined 



Thinking as Correlation and Integration 

 Neural and Humoral Forms of Information 

 Nature of Explanation 

 Canonical Form of Explanation 

 Model for Thinking about Thinking 

 Stages of Thinking Behavior 



Period of preliminary exploration 

 Presolution period of search 

 Period of vicarious testing of tentative solution 

 Act of closure- and registry of a memory trace 

 Appropriate action 

 The Necessary and Sufficient 

 Methods of Studying Thinking 

 Biological Intelligence 

 Nature of Images 



Figural Aftereffects 

 Nature nl Memory 



Maintenance of Homeostasis in the Central Nervous System 

 Summary 



THE STUDENT OF NEUROPHYSIOLOGY will sense in this 



chapter thai he is plunging directly into the 'thick 

 of thin things.' Yet he can, upon reflection, concede 

 that ever) word, sentence and idea of this volume 

 represents an interplay of thinking, imagery and 

 memory. If importance be assigned to its contents, 

 then the relevance of an attempt to understand these 

 aspects of the brain becomes clear. It is, of course, 

 impossible to give more than a selected contemporane- 

 ous view of our subject. Excellent historical and sup- 

 plementary discussions may be found in Fearing, 

 Reflex Action (ml; Boring, History of Experimental 

 Psychology (4); and Herrick, The Evolution oj Human 

 Nature {20). 



THINKING DEFINED 



Thinking is a form of problem-solving behavior 

 which invokes the correlation and integration of 



critical events in time and space. It is characterized 

 li\ a) a period of preliminary exploration, b) a pre- 

 solution period of search, c) a period of vicarious test- 

 ing of tentative solution, <h an act of closure and 

 registry of a memory trace, and 1 1 appropriate action. 

 The essential process of thinking is the bringing 

 together or grouping of critical events in time and 

 space. Ifwe analyze the kev terms in this proposition, 

 ii is apparent that the term 'critical events,' so far 

 .is the brain is involved, i^ synonymous with informa- 

 tion, with the technical restraints of information 

 theory 1 1 1 The terms 'time' and 'space' are synony- 

 mous with the generic parameters of the physical 

 universe. Before we analyze the neuropsychological 

 mechanisms which underlie these kev terms, let us 

 look once more at the general attributes of thinking. 



CHINKING AS CORRELATION AND INTEGRATION 



Biological science is quite familiar with the term 

 'integration' and perhaps to a lesser extent with the 

 term "correlation." It shall be our immediate purpose 

 to indicate that the term 'thinking' is an envelope 

 term to cover the biological operations of correlation 

 and integration. The importance of this analvMs 

 arises from the fact that in recent years considerable 

 scientific progress has been made in our attempt to 

 understand the mechanisms of integration and corre- 

 lation in the central nervous system. We shall in the 

 following avoid where possible the private subjectivism 

 commonly implied in the layman's use of the term 

 'thinking' and restrict its use here to imply correla- 

 tion and integration. This is not to deny the role of 

 conscious experience in many forms of problem- 

 solving behavior; but since consciousness may have 

 its own neurology and physiology, it will help our 

 understanding to set it aside momentarily for separate 

 consideration. 



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