Mental Construction Model

Figure 23.1 Mental Construction Model

Figure 23.1 Mental Construction Model

Mental Construction Model (Figure 23.1) uses the 3S Imperatives (survival) to generate needs, desires, and fears (emotions) which are satisfied through either the fast, inductive process and the slower, deductive process which share the highest level of cognition.

The Mental Construction model of cognition modifies the triune model and applies a dual process cap (Figure 23.2) The triune brain model segments decision-making in three layers: survival, emotion, and rational. The dual process model formalizes the idea that reasoning occurs in two ways: 1) fast, automatic, and unconscious and 2) slow, with more flexibility, yet requiring effort.

Figure 23.2 The triune mind and the dual process model

Figure 23.2 The triune mind and the dual process model


With induction (similarity) and deduction (logic) occurring in parallel, you might wonder about the potential for chaos and conflict in decision-making. Although that does happen occasionally, the brain’s operation is as smooth as it is because our decision-making has two purposes.

  • Immediate demands are satisfied by inductive answers.
  • Future goals are considered by deductive options.

I would never assert that decision-making is perfect. Under stress, good logical options under consideration can be tossed aside as satisfy an immediate demand. In other cases, significant internal conflict can be experienced when a long-term goal means immediate satisfaction must be given up.

Demands on the Brain

We have a primary and a secondary concern. Make it through the moment and, only after that’s assured, improve our situation.

Induction is non-verbal reasoning based on similarities. It is fast, requiring minimal effort; unfortunately along with those benefits, this also introduces the possibility of error, associating ideas which can overlook  important distinctions.

Deduction is word-based reasoning based on logic. It requires effort and is constrained by the limited size of working memory. Deduction’s great benefit is that can make complication calculations with its conclusions guaranteed, if its premises are true.

Mental Construction proposes a hierarchical model of decision-making(Figure 23.3). The 3S imperatives (satiety, sex, and safety) are to be appeased through their psychological manifestations as needs, desires, and fears through choices prepared simultaneously by our two cortical hemispheres. The non-verbal frontal lobe focuses on the immediate physical situation, while the dominant hemisphere (the hemisphere generating and decoding speech) considers possibilities suggested by logical consideration of the word-labelled characteristics.

Figure 23.3 Mental construction decision-making

Figure 23.3 Mental construction decision-making

Cortical Hemisphere Interaction

Words and patterns are preferentially processed in separate hemispheres, but they are not isolated. They shuttle across to the other side, words enforcing categories onto information and patterns relating associations.

The hemisphere with primary verbal tasks is called the dominant hemisphere. This chart of handedness (Figure 23.4) indicates that about 94% of people use the left hemisphere for speech. Consider the fraction of people who are right handed that use the left hemisphere for primary speech plus the fraction who are left handed or ambidextrous that use the left hemisphere for speech. 90% * 98% + 10% * 60% = 94.2%.


Figure 23.4 Handedness and dominant hemisphere for words. 90% of all people are right handed and 98% of them use the left hemisphere for primary verbal handling

Figure 23.4 Handedness and dominant hemisphere for words


Despite the separation of processing function within the cortical hemispheres, the hemispheres communicate across the corpus callosum. Although the nondominant side processes data by its own metric—association—at this point the focus is how the words of the dominant hemisphere interact and are enhanced by communication with the nondominant.

Synchronization of Cognitive Processes

Figure 23.5 Key Hemisphere Differences

Figure 23.5 Key Hemisphere Differences

In the top of Figure 23.5, key differences between the cortical hemispheres are noted. The dominant hemisphere uses words to label, categorize, and logically manipulate its internal view of reality. Using words allows deductions and planning to meet one’s goals, present and future. These verbal techniques, performed by specialized neural networks, take time and effort.

The non-dominant hemisphere processes new data as patterns. Although abstraction always takes place at Almost Gates, the pattern loss is more minor than when a word is substituted for the diversity of a phenomenon.

Although often casually discussed as distinct, the hemispheres are not divorced from each other, except in rare cases when they are surgically severed. Abstractions (words and patterns) are shared along the corpus callosum, allowing the best of categorization and association to be weighed before action must be taken.

Words Come into Play

Sensory processing initially quite similar paths in the cortical hemispheres. It’s not until words are assigned to phenomena that differential categorization takes place. About 94% of the time, this categorization takes place in the left hemisphere. Once the phenomenon has a word handle, the word becomes a unit of mentalese. Power is gained because logical consequences can be deduced from verbal propositions; however, details are shed when a word replaces a phenomenon.

The literal meanings of the words form the scope of the dominant hemisphere’s reality, which is composed of facts as well as explanations and predictions.

Corpus Callosum

Figure 23.6 The corpus callosum fanning out and joining every part of the two hemispheres. (The front of the brain is at the top of the picture.)

Figure 23.6 The corpus callosum fanning out and joining every part of the two hemispheres. (The front of the brain is at the top of the picture.)

The brain is viewed from above in Figure 23.6. On the right side, an inch or so of the top cortical layer has been removed. The front of the brain is at the top of the image.

Exposed is the band of the corpus callosum, 200 million axons  connecting the two sides of the brain’s cortex. The primary function of the corpus callosum is to integrate motor, sensory, and cognitive performances between the cerebral cortex on one side of the brain to the same region on the other side.

With 200 million axons linking together 15–20 billion cortical neurons, there is a communication between every 75–100 neural activity steps. That is, as sensory input is processed for delivery to the prefrontal lobe and then a decision communicated back to initiate behavioral activity.

Patterns between the two hemispheres are exchanged all the way from shortly after initial sensory receipt up through the multiple stages of integrating the various sensory modes together to merge with memory and worldview. Along the way, the dominant hemisphere assigns words to the information.

Once words are attached, the left side’s communication across the corpus callosum is the word, a defined collection of features.

Across the Corpus Callosum

Nondominant Hemisphere

The right side retains a fuller representation of the phenomenon. Particular details remain longer with the original, particular data.

  • When the right hemisphere receives the word (a convention set of features) across the corpus callosum, the receipt triggers a neural process.
  • This process runs the word through the existing phenomenon context.
    • Case 1. Both the word and the pattern surmount the existing phenomenon context’s Almost Gate, the pattern is returned to the dominant hemisphere.
    • Case 2. The word surmounts the Almost Gate and the pattern does not. The pattern is replaced by the word and continues in the nondominant hemisphere as a pattern (i.e. losing associations with other words).
    • Case 3. The pattern surmounts the Almost Gate and the word does not, the pattern continues.
    • Case 4. Neither word nor pattern surmounts the Almost Gate for the existing context, the original pattern continues.

Dominant Hemisphere

  • The dominant hemisphere receives the nondominant’s active pattern. A neural process is triggered, comparing the result of the pattern with that of the word.
  • Analogous cases 1–4 exist, with the role of word and pattern reversed.


On a macroscopic level, metaphors are a good example of this operation (Figure 23.6)

Figure 23.6 Metaphors in Cognitive Process

Figure 23.6 Metaphors in Cognitive Process

. Let’s consider a simple synchronization first.

  • The left assigns the word “bright” to a summer day.
  • The right hemisphere doesn’t dispute that, but it may amplify the memory of bright because another summer day had something particularly good associated with it.
  • The left, receiving that information across the corpus callosum, changes its description to “promising.” That’s a figurative change from the nondominant hemisphere that adds meaning.

Synchronization is attempted from our most immediate sensation to our most advanced conceptions. Also, see left-right brain discussion which discusses the common overstatements about the hemispheres.

Immediate Response

An excellent example of our need to handle  immediate worldview is playing sports. When we really get physically involved in a sport, our internal monologue, the voice of our left hemisphere, can be totally silenced.

When an immediate response is required, induction yielding results by ignoring distinctions and substituting close similarities gives faster answers, which usually are fine.

Planning for Later Success

Deduction allows consideration of alternative future worldviews. It can search for those which satisfy more of our needs and desires goals and squelches our fears, all predicated on our 3S imperatives. Verbal processing, checking for logical links between disparate concepts, requires us to focus our attention, but there remains the constraint of limited working memory. Logical analysis is fatiguing and requires inattention to much immediate sensations.

Induction and Deduction Together

Why ever consciously choose induction, which might lead to a false conclusion, when deduction always leads to a valid conclusion? Simply because we rarely have enough perfect information to compose an iron-clad deductive argument.

Stanovich (p 63) discusses cognitive misers, arising from the observation that most people will take the easiest means to obtain answers at all times, even when more deliberate analysis can lead to a better response. The tendency to be cognitive misers is the tendency to rely on induction and similarity for ordinary thought. In ;Thinking Fast and Slow, Daniel Kahneman (p 32) mentions

Hess … had noticed that the pupils are sensitive indicators of mental effort – they dilate substantially when people multiple two-digit numbers and they dilate more if the problems are hard than if they are easy.

Deduction requires firm facts on which to reason. These facts are coded in words and fixed relationships.

The important question of the neuro-biological process which causes the switch-over from immediate response to delayed gratification is not addressed by them. Both Stanovich and Kahneman assume it occurs and proceed from that recognition.

It’s likely that some combination of the neural threshold leading to the action choice prompts neuromodulators, like norepinephrine and dopamine (Spitzer p 272), sharpens the contrast between the selected action path and alternative action paths.

A deliberate mechanism for uniting the powers of induction and deduction and to overcome their respective weaknesses is displayed in the scientific method.

Scientific Method

Figure 23.2 Scientific method steps

Figure 23.2 Scientific method

Science grows by an intelligent combination of induction and deduction.

Induction is utilized in the development of the hypothesis. At the start, there is insufficient data to prove or disprove the hypothesis. The scientist goes beyond the deductive implications of current theory to postulate a hypothesis that can answer questions that are open or make predictions of results that current theory can’t predict.

The scientist performs an experiment.

Then result in hand, the scientist logically compares the result to the prediction, deducing a conclusion.

The hypothesis is either strengthened by a consistency between forecast and result or it is rejected if the results are contrary to the forecast.

In this manner, induction and deduction grow the scope of scientific explanation and shrink the errors.


Using a similar, hypothetical approach to daily life, we can grow our understanding of our world. Of course this requires us to give up ideas that are disproven by events. Unfortunately most of us make each hypothesis a part of our personality. When a result contradicts a part of our worldview, instead of revising the hypothesis, we reject the fact by adding conditions to its occurrence which explains the anomaly.

Despite the difficulty of treating our internal worldview as a theory or an hypothesis, the scientific method applied our worldview is the best way to logical derive the consequences of our induction creations and remain tied to the external reality our lives are experienced in.

For a quick recap of the website, the Mental Construction Summary is available.

Thank you for visiting Mental Construction. Comments, critiques, and feedback are welcome.



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