Although dual-process theories have become popular over the last few decades, ideas about mental division have existed for centuries. Significant philosophers and psychologists, such as Plato and Sigmund Freud, believed that the mind was partitioned, and the early work in this area has contributed much to modern dual-process theories. These theories, which have recently become popular in a variety of psychologies, share the notion that humans possess two distinct modes of information processing. One, which is commonly called System 1, the impulsive system, or the automatic system, is often characterized as fast, effortless, automatic, nonconscious, and it places little demand on working memory. It is a form of universal cognition that humans share with animals. System 2, sometimes referred to as the reflective system or controlled system, is commonly described as slow, effortful, controlled, conscious, and it is demanding on working memory. It permits abstract reasoning and hypothetical thought, and it is uniquely human. Early evidence for these two information processing systems was obtained from research in which participants were asked to respond to vignettes from three perspectives: how they believed most people would behave in the situation described, how they themselves would behave, and how a logical person would behave. Participants tended to indicate that people, including themselves, would often not act in accordance with logic.
Many dual-process theorists contend that processing in System 1 relates to the automatic access of knowledge or affective reactions that have become associated with a cue. The repeated pairing of a stereotype (slow) to a social group (elderly), for example, can lead to automatic access to the stereotype after perception of the group. Behavior and judgments can then align (or, in some cases, conflict) with the primed stimulus. Although this associative system operates fast, it is built via a slow conditioning process. Processing in System 2 is often discussed as analytical and rule based, and one which can draw from both slow-learning and fast-learning memory systems. The actual operation of System 2 is significantly slower than that of System 1.
Factors That Influence People’s Reliance on Systems 1 or 2
System 1 and System 2 compete for control of our inferences and actions. System 1 is generally more influential under conditions of low motivation, whereas System 2 can override the impulses of System 1 when motivation is available. The rule-based system that System 2 operates under is subjectively effortful and requires attentional resources. Thus, if people are not motivated to engage in this form of processing, responses will be governed by the effortless operation of System 1.
Cognitive capacity, as well as motivation, is important in determining the contributions of System 1 and System 2. Capacity refers to available processing time as well as attentional resources. Thus, responses that are made quickly or when the perceiver is busy or distracted will be governed by the associative processing of System Alternatively, if an individual is given adequate time and is not distracted, System 2 may override the operations of System 1.
Type of Judgment
Motivation and cognitive capacity are perhaps the two most widely recognized factors that impact the utility of Systems 1 and 2. Nevertheless, other factors, including type of judgment, have also been proposed to influence people’s reliance on the two systems. Those judgments that are more intuitive and affective, for example, “How would you feel if an opponent injured you behind play?” seem to be more influenced by System 1 than more rational judgments that are governed primarily by System 2 like “Why did the player injure you behind play?”
Generality of Stimuli or Judgment
The average of a collection of attitudes toward individual members of a team might be quite disparate from an overall attitude of the team. One reason for this is that the associative processing of System 1 seems to prefer specific, concrete stimuli, whereas general and abstract stimuli are better processed by symbolic rules (System 2). Thus, the systems are likely to contribute differently to questions or responses that vary in generality.
The associative system (System 1) is more often relied upon when positive mood is experienced, whereas negative mood promotes rule-based processing (System 2). Evolutionary reasons have been proposed to cause this effect, such as that consciousness is employed to direct individuals away from the aversive stimuli causing the negative mood. A positive mood implicitly indicates that all is well, and the effortless System 1 is more likely to be allowed control in these circumstances.
An Example of the Effects of Systems 1 and 2 in Exercise
The motivation of an individual to attend an exercise class might be primarily a function of System 1, System 2, or a combination of both. A person for whom exercise is habitual will rely on System 1; motivation (and behavior) for the class will be activated automatically, and they will begin the session without much conscious effort. Alternatively, a new exerciser might contemplate attendance at an exercise class, and will therefore engage System 2. As a final alternative, both systems might be operational. A person’s conscious thoughts about the benefits of an exercise class (System 2), for example, might be biased according to the operation of System 1.
- Chaiken, S., & Trope, Y. (Eds.). (1999). Dual-process theories in social psychology. New York: Guilford Press.
- Evans, J. St. B. T. (2003). In two minds: Dual-process accounts of reasoning. Trends in Cognitive Sciences, 7, 454–459.
- Evans, J. St. B. T., & Frankish, K. (2009). In two minds: Dual processes and beyond. Oxford, UK: Oxford University Press.