Dual-Process Theory

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

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.


  1. Chaiken, S., & Trope, Y. (Eds.). (1999). Dual-process theories in social psychology. New York: Guilford Press.
  2. Evans, J. St. B. T. (2003). In two minds: Dual-process accounts of reasoning. Trends in Cognitive Sciences, 7, 454–459.
  3. Evans, J. St. B. T., & Frankish, K. (2009). In two minds: Dual processes and beyond. Oxford, UK: Oxford University Press.

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