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Essay: On The Nature of Intelligence

Posted By Robert DePaolo On November 6, 2014 @ 8:34 pm In Psychology | Comments Disabled

By Robert DePaolo

This article discusses the neuropsychological and operational factors that go into defining the nature of intelligence with reference to academic performance, intelligence tests and social-emotional functioning.

Classical Definitions…

A number of definitions have been employed to describe the nature of intelligence. Binet felt the essential component was judgment, that other faculties were less relevant (Bergin & Cizek 2001). Wechsler defined it as a global capacity to act purposefully, to think rationally and to adapt to his environment (1958). Cyril Burt offered a rather concise definition, to wit: Innate general cognitive ability (Jensen, 1972).

More recent definitions have come from the field of neuroscience but with not much more specificity. For example in using MRI studies, Haier (2007) found a modest correlation between glucose metabolism in the brain and scores on IQ tests. McDaniel found a correlation of .40 between brain size and IQ test scores and Rushton’s research yielded similar results (2009). The problem with studies like these is that they view IQ as an independent variable and provide no insight into the nature of Intelligence.

While meaningful, these studies and descriptions are also broad and tautological, which is perhaps why one of the fail safe definitions familiar to most psychology graduate students is that intelligence is best defined as what is measured on intelligence tests.

It is probably a good idea to pivot off that sarcastic characterization in broaching this issue because so many skills, faculties, behaviors and feelings have been encompassed in the word intelligence that it is conceivable there is no such single entity; that perhaps intelligence is merely another anthropocentric manifestation of the human need to label experience.

Yet the question is important, and for several reasons. First we use intelligence as measurement for so many social, educational and vocational purposes that to dismiss it as too vague leaves out a lot of life and experience. Also, there are clinical aspects to intelligence that are important to consider; for example as a means of determining baseline levels, pre and post morbid capacities in the aftermath of organic brain damage or psychosis.

Beyond that are deeper implications, especially in light of what Darwin called sexual selection. This is a process whereby females select males based on species-specific traits deemed favorable to survival. It is no secret that human females place high value intelligence in males, whose cognitive assets would not only make them desirable mates but also make them better providers, parents, etc. In that sense intelligence would have to be socially, sexually, economically, culturally and experientially important. But then what is it?

Instruments and Rationales…

The Wechsler intelligence instruments are probably the most widely used in clinical, school and vocational settings. It is not just due to their pristine standardization formats, their performance-predictive value or their statistical correlation with other tests. The construct of these instruments is also an important reason for their popularity. With verbal comprehension, perceptual reasoning, processing speed and working memory sections, these tests would seem to tap into a variety of brain sites and functions, as well as into the mind’s capacity to integrate those functions as a measure of inter-cephalic accessibility.

In an indirect way, the Wechsler tests ask questions such as; can the visual processing occiput of the brain perceive details and utilize figure-ground perceptual skills to identify visual components based on associative relevance? Moreover, can the occiput interact with the parietal strip in the processing speed section of the Wechsler instrument so that the eyes, hands and visual memory can co-function toward a singular goal? These tests also ask whether rote memory can be separated from operational memory, where numbers and letters have to be re-organized in mind as well as be repeated from a simple, sequential recitation of digits.

While the Wechsler instruments contain four functional categories, they arguably entail neurological functions beyond the rubric of verbal comprehension, perceptual reasoning, processing speed or working memory. In fact there are neural underpinnings to each of these functions which can enable one to dig deeper into the nature of intelligence.

Complexity begets simplicity…

We can begin discussion of brain-and-intelligence by referring to information dynamics because beyond all else the brain is an information-processing system. Information has specific parameters; one of which is that it can only exist as material extracted from a prior state of uncertainty. That means intelligence must be some function of a capacity to sift through neuronal networks efficiently enough to find information pertinent to the task at hand – be it academic, social, emotional, mechanical, auditory, visual, proprioceptive, motoric or combinations of those. Thus one component of intelligence is a streamlining neural search capacity enabling the person to extract information from noise. For the sake of convenience we can call that the sifting function.

But there is more to it than that. The neurology of the noise-laden human brain, with its 86 billion neurons, places limits on searching and sifting. Each foray into neural information extraction is accompanied by an enhancement of neural activation (Lashley 1950) (Kak, 1996). Therefore one must not only be able to search and sift but do so before arousal levels reach an aversive threshold. In that context we can posit that another component of intelligence is arousal tolerance. It is perhaps akin to what Eysenck referred to as tough mindedness.

But even that won’t suffice. No one is capable of tolerating brain arousal for an extended period of time and in that sense two other factors come into play. One is rapidity – the capacity to “beat the arousal clock” so that information extraction can occur before an aversive state is reached. We can call that the rapid processing factor.

With that we come to the next requisite component. With so many neurons and inter-axial, dendritic connections one can only process so rapidly. It isn’t just speed of processing that does the trick but a capacity to streamline the search, that is, to narrow it down so that extraction is made more convenient. That is done in several ways. One of which is by having what Piaget called effective schemata. These are expectations of what an answer or response should look like, i.e. an a priori mechanism for judging relevance so pathways can proceed from global to narrow (task-specific) activation.

Streamlining can occur in several ways. One is through neural synchrony; which is a rhythmic coordination between excitatory and inhibitory neuronal activity in the brain that can override randomness by a well-coordinated, regulatory tempo. That in turn requires that brain waves be relatively free of spike activity, with smooth check and balance interaction among brain sites to create the optimal learning wave activity – which is in most instances is high frequency, low amplitude activity typified by beta waves.

Most learners are not aware of being able to summon beta wave activity at will, and with certain cognitive assets do not have to be, particularly if they can streamline the search through use of a cataloguing mechanism. This component is analogous to the card catalogue system in a library which preclude our having to search for books at random. it is called categorical language.

Mass Encoding in the Brain…

Once upon a time language was presumed to reside in frontal-parietal sections of the human brain, in areas known as the Broca and Wernicke lobes. More recent research has shown that human language deriving circuits are actually spread widely throughout the brain (Binder, Frost et. al 1997). Such linguistic dispersion is a tip-off to its most essential function.

While language certainly enhances social communication, cultural advancement and any number of other aspects of life, its main purpose might be to guide and streamline the inter-cerebral search for information so as to prevent hyper arousal, categorize memory and place a secondary code on experience so that memory can itself be spread around the brain (Luria 1973) (Windolz 1990).

If language is a beacon of light cutting through the fog of neuronal complexity, then one obvious criteria in defining intelligence would be a linguistic categorical capacity. Note that this is different from language per se, i.e. its idioms, inferences, tonality etc. It is a labeling mechanism. For example, saying my cat is cute and cuddly is an example of language but it is not necessarily categorical. Lots of things are cute and cuddly. On the other hand saying, my cat is a mammal and member of the genus Felidae with a flexible backbone enabling it to leap from heights without hurting itself is highly categorical.

In that context, one could ask why categorical language is so important in the retrieval/arousal modulating process. One reason is that every label provides two bits of information that corresponds to the excitatory/inhibitory process. A label tells us what something is, and by extrapolation what it is not. In other words labeling a cat in a specific way, excludes it from being some other creature. In that sense every categorical language bit enhances the efficiency of the brain’s rhythm via orchestration of excitation and inhibition. The fact that language phenomena are dispersed throughout the brain speeds up the information retrieval process.

Internal Speech…

When one discusses language the usual reference is to overt language, that is, the spoken word in all its manifestations. Yet as Luria pointed out language development is more complex than that (1973). Speech is like reading, it begins with overt expression then in the course of development gets whittled down into fractionated, silent language via the inhibitory incorporation of language pathways in the prefrontal lobes. Through that developmental process we become capable of talking to ourselves in sub-audible ways.

The notion of self-talk regulation is as old as history itself. It was discussed by the Roman emperor and philosopher Marcus Aurelius and in modern times has been incorporated into the various rational and cognitive-behavior therapy formats.

Internal speech is a bugaboo in the field of education, with regard to assessing not only intelligence but also academic performance and emotional behavior patterns. Modern educators refer to a similar process as metacognition, and insist it is a necessary skill in thinking, writing, reading and performing in general. Clinicians in the field of psychology view it as essential in the development of self-control and conscience. Yet it is basically immeasurable. There are no tests that issue standard scores on internal speech capacities, therefore no way to gauge anyone’s capacity to guide themselves through intellectual tasks or emotional turmoil. There are a few tests and tools to assess metacognition, for example the Multiple Intelligences Test and Index of Learning Styles Questionnaire, but these instruments address overt behavior and language – as all tests must, and, except by inference cannot get inside the brain to evaluate moment to moment internal commentary. That critical component of intelligence is unfortunately hidden within the recesses of mind. Yet it is part of what makes up intelligence and is therefore included in this analysis.
Thus far, the criteria for defining collectively the nature of intelligence have been described as…

Noise-breaking (efficient uncertainty reduction) in the brain, i.e. the sifting function

Arousal tolerance during retrieval

Speed of information processing in ameliorating duration and level of arousal

Neuronal rhythmic efficiency as a means by which to speed up response time via excitation/inhibition co-activity within brain pathways.

Categorical language as a pan-cephalic mechanism serving to narrow down information search and retrieval.

Internalization of categorical language to enhance cognition, motivation and streamline task focus.

Faculties and Integration…

The above factors provide a rough outline of how intellectual ability is defined and executed. They do not address the specific systems of the brain and how they interact. It is of important to factor in those elements but customary descriptions of how these faculties parlay into a concept of intelligence are in some instances vague and problematic.

Obviously for intelligence to be manifest requires adequate capacity for sensation. For the sake of convenience specific sensory functions will be put aside, in favor of a discussion of how sensory, motor and other faculties operate integratively.

Whether in terms of specific test procedures like the Wechsler, or in every day examples of intelligence, most if not all cognitive behavior involves a meshing of sensory systems. Reading a newspaper involves the visual centers of the occiput, language processing circuits within the brain, and perhaps, depending on the nature of the article, even the emotion-registering centers within the limbic brain. Thus a facile interaction among these brain sites would seem to be prerequisite to any use of functional intelligence.

The question arises as to how integration is facilitated, and more specifically, how brain function would affect the expression of intelligence. In some sense the answer is quite simple and can be formulated in two ways. First, since these various sensory locales provide separate functions, and in many instances feature different neuronal structures, integrating them would appear to be a difficult task. Disparate pathways would have to be traversed in order to conceptualize experience. Certainly language provides a bridge across sensory systems. For example the phrase… the local football team, the ol’ red and blue is red hot after running over opponents in their first five games… is a sentence with tactile, visual and motor components brought together by language codes. But beyond language synthesis, other factors must come into play. Neural connectivity must be efficient and flexible enough to not only build bridges but do so quickly enough to prevent aversive states of arousal from overriding the need to know.

One way for that to occur is to have parts of the brain that are not in themselves concerned with specific functions, therefore neuronally malleable. These non-specific circuits would be able to scan the brain, adapt to inputs and in effect serve as regulatory, monitoring mechanisms in the integration of experience.

Anatomically there are such structures. One lies in the prefrontal lobe of the cortex. The other lies in the cerebellum, which is situated in the back of the brain. The fact that these two circuits have the greatest number of connective neural branches with other parts of the brain suggests they are oversight circuits.

Indeed the prefrontal cortex and cerebellum have been described as regulatory computers in the brain because of this structural and functional oversight capacity (Miller, Cummings 2007 ),(Herculano- Houzel, 2010), Timman (2007). Each operates in a different manner, however and that has implications for how they affect the expression of intelligence. The prefrontal lobe is an extension of the fronto-parietal lobes which have language functions. As one travels across the brain from the parietal to the prefrontal lobe there is a shift from overt language functions to more covert, self- directed language functions. In effect the prefrontal lobe enables the person to talk to himself – which provides self-regulation, subcomponents of which include moral regulation, social empathy and the aforementioned metacognition.

Meanwhile, the cerebellum provides a broad balancing function, so that other systems can operate automatically. It not only allows the person to take movement for granted – for example being able to, in the famous phrase…walk and chew gum at the same time. It also does the same for cognitive functions. For instance it enables one to concentrate through background noise, maintain fine motor stability so that a student can both anchor his left arm down on a desk and write a composition for English literature class with his right. Due to the provision of pan-stability the cerebellum facilitates sensory integration as well. Thus while the frontal lobes provide categorical and self-directive motives and information search streamlining, the cerebellum eliminates extraneous inputs and puts peripheral functions on hold by rendering them automatic and therefore less intrusive with respect to the conscious execution of specific tasks.

Ordinarily these two functions are referred to as executive functioning and automaticity. Since integration is so central to intellectual functioning and since they facilitate that process, those two components would seem to warrant inclusion into a conceptual definition of intelligence.

The Testing Zeitgeist…

At present many of these functions are measured by separate tests; for example the BRIEF instrument is used to gauge executive functional capacities. Various occupational therapy tests are used to measure motor balance. The WISC-IV integrative instrument assesses integration of various skills indigenous to the Wechsler procotol. One has to wonder if at some point a test of intelligence (as defined here, however speculatively) might be developed to encompass all the skills discussed above. Such an instrument would enable clinicians and educators to have, at long last, an instrument by which to co-evaluate intelligence and brain function. Doing so might involve amalgamation of current test formats, for example the BRIEF, Wechsler, Multiple Intelligences Test and other instruments. Or perhaps new test items could be developed to measure these skills through a test format brief enough to sustain but not overtax the client or student’s investment, lengthy enough to have face and construct validity and definitive enough to determining with precision both the nature of intelligence and the intellectual capacities of any given subject.


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