The Sugar Brain is not Unique

In the context of this article the Sugar-Brain refers to neural correlates regarding sugar consumption. Firstly, information is given on the classification of sugar, a brief mention of different categories of sugar, and the properties underpinning different sugars.  Secondly, a concise overview of brain reward mechanisms is appropriate.

The term sugar, in everyday discussion, generally refers to sweets or highly processed sweet tasting food. The term is excessively ambiguous, so when discussing in everyday conversation it is not always clear what one is referring to.  I usually assume the  referent is highly processed, calorie dense, sweet food, in most cases.

  

Sugar, in the context of science, is defined precisely and is dependent on various properties. Sugar (of all types ) is a carbohydrate.  The term carbohydrate was originally used to describe compounds that were hydrates of carbon; they have an empirical formula of CH2O. In my book- The Carbohydrate Files 2nd editon (2007)- I presented  two classification systems: Basic

Carbohydrate Classification System (BCCS) and the Advanced Carbohydrate Classification System (ACCS). A concise overview of the ACCS is presented here.

 

Carbohydrates are polyhydroxy aldehydes, ketones, alcohols, acids, their simple derivatives and

their polymers having linkages of the acetal (any organic compound formed by adding alcohol

molecules to aldehyde molecules) type. They may be classified according to their degree of

polymerization ((Polymerization is a chemical process that combines several monomers to form a polymer or polymeric compound.) and may be divided into three principal groups: sugars, oligosaccharides and polysaccharides. Sugars are the focus in the current article.

Monosaccharides, the basic units of a carbohydrate, are white crystalline solids that may be divided into aldoses, which have an aldehyde group on the first carbon atom, and ketoses, which typically have a ketone group on the second carbon atom. They may also be divided according to the number of carbon atoms that they contain. The suffix “-ose” is used to identify these molecules as sugars.

Triose: monosaccharide with three carbons

Tetrose: monosaccharide with four carbons

Pentose: monosaccharide with five carbons

Hexose: monosaccharide with six carbons

Heptose: monosaccharide with seven carbons

Sugars include monosaccharides, disaccharides, and polyols (sugar alcohols). The

monosaccharides are categorized as glucose, fructose, and galactose (formula C6H12O6). The disaccharides are composed of two monosaccharide units. The binding between the two

sugars results in the loss of a hydrogen atom (H) from one molecule and a hydroxyl group (OH)

from the other. The disaccharides are categorized as sucrose, lactose, trehalose, and maltose

(formula C12H22O11). Sugar alcohols, technically called polyols, are are found in numerous sports drinks, bars, and various other types of sweets. Polyols are generally known as sugar-free

sweeteners. They are carbohydrates, but they aren’t sugars. Chemically, polyols are considered polyhydric alcohols or sugar alcohols because part of their structure resembles sugar and part is similar to alcohols. However, these sugar-free sweeteners are neither sugars nor alcohols. The most widely used polyols are sorbitol, mannitol, and maltitol.

Proponents of the Sugar-Brain claim that consumption of sugar can activate the same brain reward mechanisms (dopamine pathway referred to as mesolimbic dopamine system) as the consumption of addictive drugs. This is true; so it is not a myth?  You have probably seen photos comparing the sugar-brain with the drug addiction-brain. Hold on before jumping to conclusions. The problem with the claim is the way it is presented (implications) and inferences made regarding the claim. The claim is a rhetorical device used to convince people that sugar consumption is bad, like drug consumption.

What is the mesolimbic dopamine system? Drug researchers have traditionally identified the mesolimbic dopamine system as the brain system mostly involved with drug addiction. This system may be extended to include cortical areas (in PFC)- mesolimbic cortical dopamine system (Kandel, 2012). Some sources refer to these systems as being the same; however, the mesolimbic dopamine system can be more accurately described as projecting from the ventral tegmental area to the nucleus accumbens (NA, often referred to as the major pleasure center in the brain), while the mesolimbic cortical dopamine system projects from the ventral tegmental area and extends to areas in the PFC. Their distinction is not important in the context of this article (either are involved with drug consumption and brain reward mechanisms- reward/pleasure circuitry). These circuits are rich in dopaminergic neurons. Dopamine cell bodies are located in the ventral tegmental area and substantia nigra. The focus here, is on the projection from the ventral tegmental area.

Objects, stimuli, activities or internal physical states can serve as rewards for humans and non-human animals. Rewards have positive value and facilitate feelings of pleasure and positive emotion; they act as positive reinforcers. Not only do rewards lead to the activation of dopaminergic activity, but so does expectations or anticipation of rewards. "[T]he flow of dopamine is set off by the simplest expectation of pleasure, even though the pleasure may not materialize" (Kandel, 2012, p.428).

The brain's reward mechanisms are activated when we enjoy art, experience beautiful scenery, are exposed to attractive faces, listen to pleasant music, are exposed to humor or novelty, drive a sports car and experience romantic love. The Sugar-Brain could easily be called the Love-Brain. 

 

Evaluating brain imaging is complicated, and there is often disagreement among those highly qualified regarding implications of imaging. If sugar consumption is not a rewarding act what can we expect regarding activity of brain reward circuitry? It is a drastic over-simplification to suggest that - because, consuming sugar may lead to activation (reiterating- the variability  in activation is large) of brain reward mechanisms- it should be held in the same regards as drug use. "Dopamineric neurons in the striatum respond to all kinds of pleasure." Eric Kandel- Nobel Laureate

Science sounding information is often inserted to enhance persuasive value.

References available upon request

The Apex of Human Cognition

Rational thinking and is not synonymous with rationalizing thought.  These phrases are often, mistakenly, used interchangeably. Rationalizing thought has an Aristotelian flavor, in that it involves putting forth reason for essentially any behavior or thought. Rationality is a weak concept, as it is applied in everyday dialogue. Most people are rational, if rational means an ability to provide some form of a reason for whatever. Cognitive science provides a different conceptualization of rationality; one that is consistent and is subject to assessment.  An array of the components underpinning rational thinking have been assessed. Recently a comprehensive measure of rationality was developed: Rationality Quotient.   

In discussing what makes humans unique as compared to other animals Stanovich asserts "what is really singular about humans: that they gain control of their lives in a way unique among lifeforms on Earth- by rational self determination (Stanovich, 2004, p.275)." Humans are capable of overriding automatic cognitive processes by using reflective thinking (category of Type 2 processing).

2 categories of rationality (excerpt from interview with Stanovich, West, Toplak Research Lab)

"Cognitive scientists recognize two types of rationality: instrumental and epistemic[As mentioned previously]. The simplest definition of instrumental rationality, the one that is strongly grounded in the practical world, is: Behaving in the world so that you get exactly what you most want, given the resources (physical andmental) available to you. Somewhat more technically, we could characterize instrumental rationality as the optimization of the individual’s goal fulfillment.

The other aspect of rationality studied by cognitive scientists is termed epistemic rationality. This aspect of rationality concerns how well beliefs map onto the actual structure of the world. The two types of rationality are related. In order to take actions that fulfill our goals, we need to base those actions on beliefs that are properly calibrated to the world.

Epistemic rationality is about what is true and instrumental rationality is about what to do. For our beliefs to be rational they must correspond to the way the world is—they must be true. For our actions to be rational they must be the best means toward our goals—they must be the best things to do."

 Rational thinking skills are important.  They are as important as intelligence.  Intelligence and rationality are often dissociated. Research demonstrates that intelligence is often a weak predictor of rationality.  This has been shown over a wide range of studies.  Intelligence is important, but there is more to good thinking than intelligence.  Intelligence reflects reasoning abilities across a wide variety of domains particularly novel ones.  In addition, intelligence reflects general declarative knowledge acquired through acculturated learning.  Rationality reflects appropriate goal setting, goal optimization, and holding evidence-based beliefs.

Chapter 2 from In Evidence We Trust focuses on rationality. Some key points from Chapter 2 (Hale, 2013):

"Society is replete with examples of intelligent people doing foolish things. This seems puzzling considering that intelligent people (as indicated by intelligence tests and their proxies-SAT, etc.) are generally thought of as rational, smart people. So, it may come as a surprise to find out that intelligent people are not necessarily rational people.

Many researchers suggest that a key characteristic of critical thinking is the ability to recognize one’s own fallibility when evaluating and generating evidence-recognizing the danger of weighing evidence according to one’s own beliefs. 

Kelley (1990) argues that 'the ability to step back from our train of thought . . . . is a virtue because it is the only way to check the results of our thinking, the only way to avoid jumping to conclusions, the only way to stay in touch with the facts'(p. 6).

Rationality is concerned with two key things: what is true and what to do (Manktelow, 2004).  In order for our beliefs.

TASKS THAT FAIL TO SHOW ASSOCIATIONS WITH COGNITIVE ABILITY

Noncausal base-rate usage (Stanovich & West, 1998c, 1999, 2008)

Conjunction fallacy between subjects (Stanovich & West, 2008)

Framing between subjects (Stanovich & West, 2008)

Anchoring effect (Stanovich & West, 2008)

Evaluability less is more effect (Stanovich & West, 2008)

Proportion dominance effect (Stanovich & West, 2008)

Sunk cost effect (Stanovich & West, 2008; Parker & Fischhoff, 2005)

Risk/benefit t confounding (Stanovich & West, 2008)

Omission bias (Stanovich & West, 2008)

Perspective bias (Stanovich & West, 2008)

Certainty effect (Stanovich & West, 2008)

WTP/WTA difference (Stanovich & West, 2008)

My-side bias between and within S (Stanovich & West, 2007, 2008)

Newcomb’s problem (Stanovich & West, 1999; Toplak & Stanovich, 2002)"

[intelligence tests measure cognitive ability]

Often, people mistakenly make the assumption that Stanovich is implying the intelligence is not important. He asserts that Intelligence is an important cognitive ability associated with an array of outcomes. Rationality is also important and it measures different cognitive skills than what is measured on intelligence tests and their proxies. Rationality assesses cognitive ability and cognitive style. It is ideal to rate high in intelligence and rationality.

Learn more about In Evidence We Trust

Scientific Cognition: Implications for Learning Science

Scientific cognition (thinking) involves complex cognitive mechanisms.  Scientific Cognition involves much  more than: gen. scientific knowledge, procedural skills to conduct research, attaching "science says" to your statements, a science degree, perpetuating views of popularizers of science, identifying yourself as evidence based, asking for evidence, being skeptical, etc.  Scientific thinking involves an array of components and can be used in everyday out of the lab thinking as well as when evaluating research and examining science texts.

Deanna Kuhn asserts that the essence of scientific thinking is coordinating belief with evidence (2001).  At the very least scientific cognition involves philosophy of science, scientific methodology, quantitative reasoning, probabilistic reasoning and elements of logic. Scientific cognition requires specific cognitive abilities and cognitive style (thinking disposition).

In a recent study we investigated whether or not scientific cognition and scientific literacy (general scientific knowledge) scores were associated, and whether or not there were gender differences for total scores for each scale (Hale, Sloss, & Lawson, Paper Forthcoming).  The scientific literacy and scientific cognition assessment consisted of mostly questions  derived from measuring devices used in the past. The assessments were administered as part of an online survey. The participants were 202 university students. The study was approved by the university's Institutional Review Board. The results indicate a positive association between scientific literacy and scientific cognition, and no gender differences for total scores from the scales. Additional analyses indicate there was gender differences for some of the items. There was gender differences for one item from the scientific literacy assessment and for two items from the scientific cognition assessment. One of the important findings that was found in the study was that students confused science with pseudo- science. The overwhelming majority of students (79%) in the study report that astrology is scientific, or is at least partly scientific. Only twenty one percent of participants in the study answered the following question correctly: "Which of the following statements are true? A) Astrology is not at all scientific B) Astrology is partly scientific C) Astrology is a legitimate field of scientific study."  The correct answer is A. The astrology question is an item from the scientific literacy assessment.  Another important finding was, consistent with finding in past studies, students didn't do well on a covariation task.  Knowledge in research methodology should assist students in providing the correct answer for this item. The question most often answered incorrectly, from the scientific cognition assessment,  was a question involving identifying a relationship between treatment and effects, and making use of comparison groups. These skills are taught in research methods courses. The question was presented as "A new medical treatment was designed to treat a serious health problem. Using the information provided below decide whether the treatment was effective: 200 people were given the treatment and improved 75 people were given the treatment and did not improve 50 people were not given the treatment and improved 15 people were not given the treatment and did not improve A) Treatment was effective B) Treatment was not effective." The probability that the treatment is effective is (200/275) .727. The probability that the treatment is not effective is (50/65) .769.  The answer is B.  Approximately 53% of the students answered the question incorrectly.

 

The cognitive processes underpinning scientific cognition are important and can be extended to various conditions. To reiterate, scientific cognition is about much more that remembering scientific theories, laws and principles.  Scientific cognition is essentially analytical thinking that can be used, and should be used in a wide range of conditions. At the very least in an effort to develop better scientific cognition students should be educated in the areas of the philosophy of science, research methodology, quantitative reasoning (probabilistic reasoning) and logic. These components are involved with scientific thinking. Science educators and the media do a disservice when they promote science and its wide range of relevant concepts as "just" being able to remember scientifically derived information, or promoting science as if it is all about a just having a sense of "wonder."  Being able to recollect scientific facts, being skeptical and having a sense of wonder is important regarding science, but those qualities alone do not ensure high levels of scientific thinking. Myself and colleagues would like to see future research indicating a strong positive association between scientific cognition and scientific literacy.

References available upon request