The philosopher William James believes that there were two different parts of thinking; that he labeled these two parts associative thinking, and true reasoning.
According to this dual process theory, associative thinking was based in large part on past experiences from which we drew comparisons or abstractions. While true reasoning was reserved for tasks like art, designing buildings, or more difficult and careful tasks.
In modern sociology and psychology, dual process models are common and are used to understand aspects of attitude change, through a process known as heuristics. Even then, it was further delineated under Jonathan Evans who proposed that the two parts of thinking were heuristic and analytic. According to Evans, during heuristic processes, we choose (subconsciously) the information we believe is relevant to the current situation, based entirely on previous experience. When the experience is novel, we tend to fill in the unknowns with parts of our experience that come closest to the new experience. The analytic aspect may follow up on the heuristic, more carefully considering the information or the situation, and examining this new experience without reflection on any past experiences. We can understand that, in Evans’s model, heuristic is based on emotion, gut-reaction, or intuition, which biases our thinking. The analytic thinking is more careful to avoid these pitfalls when considering all aspects of the information or situation.
In 1996, Stephen Sloman reinterpreted this dual processing, believing that associate of reasoning is divided into logical classes of information based on regularity of the of the event, comparing it to experience through the use of temporal and similarity relationships to determine for the reasoning. In other words, when does this event occur in association with other events that we are more familiar? And, after further consideration, were my immediate reactions or responses accurate? Perhaps the best understanding of this dual process approach to understanding thought processes came from psychologist Daniel Kahneman, who interpreted the two styles of processing as intuition and reasoning. Intuition, termed system-1, is very similar to Sloman’s associative thinking. System-1 is automatic (subconscious) and is primarily outside of our conscious control. It is the emotional response identical to Evans’s heuristic, based on intuition and immediate response. This form of thinking is based on habits and is very difficult to change or alter. System-2, was based on reasoning and is slower and required more conscious judgment and consideration. While system-1 is unconscious, automatic, is fast, requires little effort, and is based on recognition, perception, and orientation, it is not considered a part of working memory. System-2 requires conscious reasoning, is explicit and controlled. It requires significant effort; it is slow and based on accepted rules. Neurologically, this system is a recent evolutionary part of the brain, whereas system-1 is far older.
While the automatic processing of system-1 had obvious evolutionary advantages, once humanity no longer functions as a hunter-gatherer, intuition, gut-reaction, and hyper-emotionality became far less necessary and can be a deficit in the modern society.
Many researchers believe that system-2 is such a recent neurological development, it is limited to humans, and regardless of which particular theory we might adhere to, this system requires slow and careful analysis, is domain-general, and places a high demand on working memory. Unlike the emotionality of system-1, system-2 requires that we adhere to very careful rules; the analysis is controlled, slow, and energy intensive.
Many argue that a system that has allowed our species to survive and progress for millions of years has demonstrated its necessity. However, system-1 thinking applied to a modern technological society presents us with issues ranging from stereotyping and bias to prejudice and hostility. This becomes a significant issue for people suffering from psychological trauma.
Pyszcynski and associates have to use the dual process model of terror management theory, and how the human brain manages fear. These researchers found that, at least in managing fear, the brain uses two distinct defense responses: distal and proximal. While distal response is a process of system-1 (unconscious response), proximal response can be understood as part of system-2 (conscious). Using this dual process model to understand fear, we use distal defenses when dealing with the abstract idea of death, and these are for the most part subliminal. However, proximal defenses are conscious thoughts and relate to a specific threat. These tend to be rational and arise immediately after a threat (or the remembering) of death or extreme injury. Think anxiety-producing effects of Posttraumatic stress disorder.
Posttraumatic stress disorder, or PTSD is a collection of symptoms that develop as a result of a life-threatening event or series of events that include physical or sexual abuse in childhood, warfare, severe motor vehicle accidents, or being exposed to these events occurring to another. Science, including neurology and psychology, are beginning to understand how PTSD impacts the person’s cognition. The primary symptoms identified with PTSD include exaggerated startle response, reliving the experience through remembering (including the sensory inputs at the time of the event, i.e., sounds, smells, and thoughts), heightened anxiety, and increased blood levels of stress hormones like cortisol. It has been discovered that the emotional experience of the trauma can have lifelong cognitive effects including diminished ability to pay attention, negative impacts to memory (including working memory), problem-solving, and active planning. Physiologically, the chronic activation of the hypothalamus, pituitary, and adrenal system (HPA Axis) can cause significant inflammatory reactions that include diminished immune response, metabolic issues, hypertension, and related cardiovascular symptoms.
The nonphysical impacts of PTSD include detrimental impact on cognitive functioning, and a major concern for therapy is in understanding how emotion and cognition are associated. It is thought that information processing that is involved with threat detection and survival is always switched on, and the system (Fight or flight), and the attentional focus for imagined threats hold sway over other cognitive operations. Research suggests that sensory information (including emotional responses) tend to be better remembered and recalled than non-threatening or neutral information; traumatic memories bias us toward seeing neutral stimuli as threatening (system-1). In PTSD, patients tend to recall the emotions far easier than other information supporting the belief that emotion enhances long-term memory.
PTSD researchers are discovering that the accuracy of the memory is not in question, but rather the person’s response to the memory. This response biases us toward new experiences that may be neutral or even positive. Some studies suggest that false memories (or at least inaccurate) have little to do with the emotional response. This emotionality disrupts the ability of the brain to perform cognitive tasks, especially in states of elevated arousal.
Distorted memories (even when based on actual events) cause elevated stress in people suffering from PTSD. In fact, in a study from 1995, researchers found that subjects suffering from posttraumatic stress had difficulty in remembering specific details, however, relied instead on the emotions they experienced during the event or events. Exactly why this occurs is debatable, it may be that the person has difficulty in accurate memory retrieval due to the association with unpleasant emotional memories, or it may be the mind avoiding recalling too many unpleasant or terrifying details. Because of the inability to recall accurate details, the unconscious mind may see neutral or even positive events as threatening. The modulation hypothesis suggests that emotional events are far easier to remember, due to the engagement of the brain’s emotional gateway (Amygdala). FMRI for individuals with PTSD showed greater activity in the amygdala and hippocampus when successfully remembering past events compared to remembering emotional memories, that bias us toward avoiding situations that are seen as threatening.
System-1 is also at work with our belief systems, which are simply the quick judgment on the arguments based only on plausibility rather than the realistic conclusions. While some developmental psychologists view this as a competition between the two systems, others like Jonathan Evans, do not, instead seeing system-1 as biased towards held beliefs. Still, other researchers, including Vinod Goel, used fMRI studies to look for dual processing of reasoning in the human brain.
It may come as a surprise to many that distinct parts of the brain are responsible for these two very different kinds of reasoning. Content-based reasoning activated the left temporal hemisphere while problem reasoning was focused on the parietal system. Further studies using fMRI discovered that different mental processes seem to be competing for control of responses to problems of bias. While the prefrontal cortex was critical in both detecting and reasoning conflict (System-2), the ventromedial pre-frontal cortex, long known to be associated with intuitive (heuristic) responses (system-1), seemed to be in opposition with the prefrontal cortex.
As we might imagine, psychologists, neurologists, and sociologists have become very good at measuring how we utilize our dual system thinking. Some tests have been devised to measure (with or without fMRI) the response to questions of bias. How we respond to belief-biased reasoning tests allows us to see how well our dual systems are functioning, particularly, system-2. In strengthening system-2, we must realize the power of system-1, and I understand that these responses are for the most part outside of our control. Only upon careful reflection can we engage system-2, which will allow us to approach the issue (puzzle, problem, assessment) more carefully. And while system-1 has existed for millions of years, helping us survive in a dangerous world, it was not until the higher cognitive abilities of Homo sapiens emerged that lead to system-2, sometime around 50,000 years ago which many believe are depicted in emergence of cave art.
It is argued that the ability to understand art, imagery, to design tools for future use, and to improve on existing tools required system-2 thinking. One might imagine that the thought process to design and build a firearm required system-2, while the likelihood of its use too often associated with system-1.
For further reading on dual process theory:
Motivation and Justification: A Dual‐Process Model of Culture in Action by Stephen Vaisey.
The empirical case for two systems of reasoning by S. A. Sloman.
Thinking, fast and slow by Daniel Kahneman.
Association between trauma from assault in childhood and metabolic syndrome by W. Sumner Davis