Semantic Maps

Sensory Data and Mental Worldview

At the end of the sensory discussion, I mentioned that sense data are integrated into a situation.

Although “situation” is a generic term, Figure 11.1 illustrates how I use the term. In the left of Figure 11.1, raw sense data arrives at dedicated neural brain modules where the sensory information is sharpened. An iterative process of comparing the current experience with stored sensory categories occurs, further defining the experience. Objects and the relationships between objects are derived. They form the base of the situation. As indicated at the bottom of the figure, certain events—combinations of specific objects and relationships—can have a particular salience for the individual’s worldview with the potential to satisfy needs, desires, or safety. These events, perturbations, drive decision-making.

In the following discussion of semantic maps, we will be exploring the steps that go into the formation of the situation and its effect on the internal worldview. Together they influence the choices one sees as available.

Our neurons group sensory input into categories. Other names for the categories are patterns, formed by abstraction. Some specific details are lost as the pattern progresses step-by-step, away from raw data, up the ladder of abstraction towards placement in our worldview. A red Corvette may become a fancy red car and then a status symbol in our brain, as we apply our values onto situational experiences, in preparatory steps upon which we base decisions in choosing our behaviors.

Memory of past situations plays an important role in evaluating the current happenstance and integrating it into our working view of the world.

The discussion of memory on this page is summarized and geared to this explanation. Memory is not a video of events taking place. It is an active construction/reconstruction of a situation. We remember the categories by which we organize experience. That is the source from which memories are recalled. It is also widely recognized that memory has two basic components—episodic memory (occurrences that happened to us) and academic memory (facts and theories that we are taught).

3S Imperatives

The 3S stands for satiety, sex, and safety. They are singled out for two reasons.in a memory discussion.  First, our memories are colored by the impact of situations on these drives. Second, we choose our actions based on how the current situation is likely to result in the 3S drives being met.

• Satiety (or satisfaction) in terms of food, water, and bodily temperature. Those things, essential for the continued existence of a person as well as any organism, are captured in the term homeostasis, a biological thermostat which prompts actions to relieve any deviation from the optimal level.
  • The drive to satisfaction of one’s need for food, water, etc., is stable over one’s lifetime with a several hours long cycle in which it ranges from completely satisfied, thus having no role in current decisions and behaviors, to needing satisfaction and playing a dominant role in our actions.
  • For most members of modern, advanced societies the provision of the essentials for homeostasis are met, shortening the periodicity.
• Sex gives rise to descendants. Darwin used procreation as the fundamental trait to develop his evolutionary theory.
  • Before puberty, the need for sex does not drive our behavior. From early teenage years through late middle age, sex is a potential factor in nearly every decision. In our old age, although the drive still exists, its potency (hah!) is reduced.
• Safety corresponds to the fight or flight impulse, a reaction traced to the limbic reaction marked by releasing the neurotransmitters in stressful situations.
  • Our security from harm is not something that we can blithely take for granted; yet, in modern society, danger from animal predators is greatly reduced. The threat from other humans still exists, although the need for flight-or-fight action is rare and transient. And yet the need for safety persists in affecting our thinking across our entire life span.

The 3S drives are satisfied—completely, partly, or not at all—by individual situations. These drives do not sum like 1 + 1 + 1 = 3. Suppose a given situation satisfies half of one’s homeostasis needs, none of one’s sexual wants, and all of one’s safety concerns. In this scenario, the result of 1/2 + 0 + 1 is not 1 1/2, but at most 1 (that is, the neuron threshold is exceeded, on the right of Figure 11.2). The emotional valence is the net weighting of a situation based on its satisfaction of the 3S Imperatives—Satiety, Sex, Safety.

Due to  experience, the 3S Imperatives develop a mapping of needs, desires, and fears which attach to situations, indicating the relative success or failure of the combination of the imperatives being satisfied (Figure 11.3). Even at this high level it’s apparent that a desire may indicate a satisfaction of satiety (perhaps eating an excellent meal) or the physical pleasure of a romantic evening. Our vocabulary is blurred with respect to the underlying drive being satisfied. In addition, in many cases where but a single behavior can be selected, none of needs, desires, or fears are totally satisfied. Our emotions—love, hate, fear, sadness, joy, disgust, anticipation, and so on—are the manifestations of needs, desires, and fears. Emotions are a conscious mental reaction (such as anger or fear) subjectively experienced as strong feeling usually directed toward a specific object and typically accompanied by physiological and behavioral changes in the body. They are defined as being of limited duration. When they are long-lasting predispositions, they are part of personality.

Combining these ideas into one diagram (Figure 11.4) makes for a daunting image; however it is simplified radically from the actual cortical activity that it models. Let’s take this simplification. The first stages are the same as the earlier external to internal discussion.

• On the far left is the vast external world.
• Next, nerves to sensory receptors into specific cortical regions information about external reality is extracted.
  • Optical data to vision takes about 15 steps, for edges,color, movement, object extraction, identification, and location.
  • Auditory data to hearing also has multiple steps, to detect meaningful sounds, origination,
  • Connections between sights, sounds, touch, smell, and taste are made.
• From the internal worldview, we place objects, sounds, and sensory information relative to our physical location. Also we make comparisons between our memories and our current environment. Our memories include knowledge about past situations,satisfying a need or meeting a goal – or not.
  • Information, both sensory and internal, is abstracted. This is an iterative process which depends on our past experiences as well as our current needs and goals.
• The final decision maximizes the overall satisfaction of the three motives, often resulting in partial satisfaction and dissatisfaction for each motive.That summation that surmounts the Almost Gate can be labeled the emotional valence.
  • It is a rare case where one of Needs, Desires, or Fears (Satiety, Sex, or Safety) completely dominates.

The emotional valence of a situation is the neural summation of the individual drives’ satisfaction levels in the various components of the situation. For example, there may be 10 components in a situation, each of which has a satisfaction level for each of the 3S drives. All of these intermediate results are axon impulses delivered across synaptic gaps into a neuron, which will fire its axon only if its neural threshold is breached.

Free Association

Semantic maps are concepts associated by experience. Since David Hume, the idea of association between ideas has been investigated and assumed to be a significant part of our mental functions. There is copious evidence that associations of ideas exist in our brains.

Free association is an available, concrete example. We all know psychiatrists prompt their patients to says the first word that pops into their head, giving them insight to their mind. That’s a useful method for revealing the organization of a person’s thoughts.

Many levels of abstraction exist in our brains. If a psychoanalyst prompts with “Black,” the patient will likely respond with “White.” They are at the same level of abstraction. The patient doesn’t respond with “a little toy my grandmother gave me when I was five. It happened to be white.” No, that thought may occur but only after “white.” Associations guide our mind along paths that greatly flavor our thinking, our experience, and decision-making, as will be discussed in the section on sources of thoughts.

London Cab Drivers

There’s an interest finding that semantic maps grow and are reflected by physical changes in the brain. The evidence comes from a study of London Black Cab drivers. London is a warren’s nest of many thousands of streets, monuments, and landmarks, connected in many often convoluted ways. It takes a prospective London Black Cab driver 3 or 4 years to learn all of those connections. In before-and-after examinations, with the latest technologies like fMRI, neurobiologists have discovered that the hippocampus of those who became cabbies grew in size.

Professor Maguire, a Wellcome Trust Senior Research Fellow explains

The human brain remains plastic even in adult life allowing it to adapt when we learn new tasks.

By following the trainee taxi drivers over time as they acquired – or failed to acquire – the Knowledge, a uniquely challenging spatial memory task, we have seen directly and within individuals how the structure of the hippocampus can change with external stimulation.

Next, we will move to the brain in aggregate, starting with organisms that have neither volition nor culture to obscure their raw brain operations.