Habits are learned dispositions to repeat past responses. They develop because many behavioral sequences (e.g., one’s morning coffee-making routine) are performed repeatedly in essentially the same context and in much the same order. When responses and context cues repeatedly occur together, the potential exists for associations to form between these various elements. Once these associations form, the mere perception of the context can trigger the response. Contexts include elements of the physical or social setting (places, presence of others), temporal cues (time of day), and prior events (actions in a sequence).
Typing, driving a car, and wrapping wontons all become habitual with practice. When wontons become a staple at dinner, one doesn’t need to decide specifically to wrap. Instead, wrapping is cued by time of day, hunger, and any standard prior activities. In this way, the mere perception of context cues triggers automatically the habitual response without intention. Once cued, habit performance has a ballistic quality in that it does not require additional input and is difficult to inhibit.
Habits are similar to other automatic responses that are activated directly by context cues (e.g., implementation intentions, nonconscious goals). However, habits develop with repetition, and they do not require intentions to initiate.
Historically, the construct of habits is tied to behaviorism, especially John Watson’s and B. F. Skinner’s radical behaviorism that rejected cognition as a cause of action and a mediator of stimulus-response associations. Radical behaviorism built on the classic idea that learning occurs as the formation of a direct bond between some physical event or sensory input and a muscle response, so that the external stimulation reflexively comes to cause the response. Strict behaviorist models proved limited in their ability to account for human functioning. In contrast, in modern perspectives, habits have moved decidedly into the head.
Control of Responses Changes with Repetition
There are currently three perspectives on the habit mechanisms that generate repeated behavior in everyday life. Observations of college students and adults in the community suggest that about 45% of everyday behavior is repeated almost daily and usually in the same context.
In a direct context cuing account, repeated co-activation forges direct links in memory between context and response representations. Once these links are formed, merely perceiving a context can trigger associated responses. Supporting evidence comes from research in which the mere activation of a construct, such as the elderly stereotype, leads to the activation of associated behaviors, such as physical infirmity, that manifests in actual performance.
It is not yet clear whether contexts trigger responses through such a simple mechanism in the absence of a relevant goal. Social cognition research has thus far demonstrated a limited version of direct cuing effects. Although research has yet to demonstrate that such activation can initiate responses, the possibility that action can be directly cued by contexts in the absence of goal activation is suggested by myriad findings in cognitive neuroscience revealing reduced involvement of goal-related neural structures, such as the prefrontal cortex, when behaviors have come under habitual control. Furthermore, evidence from animal learning research using a clever paradigm in which reinforcers are devalued is also commonly interpreted as indicating the direct context control of habits. When rats initially perform an instrumental behavior (e.g., pressing a bar to receive a food pellet), they appear motivated by specific goal expectations; they cease the behavior if the reward is devalued (e.g., by pairing it with a toxin). In contrast, when rats repeat the behavior sufficiently to form habits, they appear motivated directly by the performance context: They continue the behavior despite reward devaluation. Animal learning research shows that repeated responding is not oriented to attaining specific goals.
In the motivated contexts perspective, contexts themselves can acquire motivational value through their prior association with instrumental reward. If contexts predict rewards in this way, then they plausibly carry the power to energize and activate associated responses. Evidence of this predictive role comes from animal studies of the neurotransmitters that mediate reward learning. For example, Wolfram Schultz, Peter Dayan, and P. Read Montague found that when monkeys are first learning that a feature of the environment (e.g., a light) predicts a reward (e.g., a drop of juice) when a response is made (e.g., a lever press), neurotransmitter activity (i.e., dopamine release) occurs just after receipt of the reward. After repeated practice, the animal reaches for the lever as soon as the light is illuminated. Furthermore, the neurotransmitter response is no longer elicited by the juice reward but occurs instead following the initial presentation of the light. The environmental cue has thus come to predict the reward value of the imminent response.
Reward-predicting environments are thought to signal the long-run future value, the cached value, of an action without signaling a specific outcome associated with it. Put differently, this value reflects a general appetitive tag associated with the environment and not a prediction about a specific outcome (e.g., a food pellet). This diffuse motivation may explain the relatively rigid pattern of repetition in everyday life, given that cached values do not convey a specific desired outcome that could be met by multiple substitutable means. The motivated environment idea has been tested primarily with animals, and its ability to account for human habits has yet to be demonstrated. However, promising support comes from evidence of common reward-related neurotransmitter systems across species (e.g., dopamine is elicited by monetary reward in humans).
Finally, some researchers have invoked implicit goals and argued that habits develop when, in a given context, people repeatedly pursue a goal via a specific behavior. This leads to the formation of an indirect association between the context and behavior via a broader goal system or knowledge structure. However, the dynamic, flexible nature of goal pursuit—especially the idea in many goal theories that people substitute behaviors that serve a common goal—does not map well onto the rigid pattern of responding that emerged in diary studies of everyday behaviors. Thus, implicit goals do not plausibly mediate between contexts and responses in habit associations.
Assessment of Habit Strength
How should habit strength be assessed? In laboratory experiments, strong habits are formed by frequent repetition in stable contexts (e.g., completing a sentence with the same word on a computer program). In naturalistic studies, habit strength is measured from people’s reports of the behavior they frequently performed in the same contexts (e.g., always reading the newspaper after dinner). In general, the similar effects obtained for manipulated and self-reported habits confer validity to self-report measures. In additional support of this validity, self-reported habits continue to predict future performance even when other predictors are statistically controlled (e.g., behavioral intentions).
Sometimes naturalistic measures of habit strength assess only performance frequency. This should be sufficient for actions that are performed in one context (e.g., wearing seat belts). However, for actions performed in multiple contexts, habit strength also depends on the stability of the performance context, and measures should include this component.
Prediction, Change, and Regulation of Habits
The context cuing and ballistic progression of habits should be apparent in research on predicting, changing, and regulating everyday behavior. Although psychologists often predict behavior from mindful constructs such as intentions, attitudes, and decisions, the best predictor of habit performance should be the strength of context-response associations in memory. In support, research has shown that intentions predict behavior primarily when habits have not been formed. As habit strength increases, habits tend to be repeated regardless of people’s intentions. This pattern plausibly reflects the cuing and ballistic quality of habits; it is difficult to control habits that do not correspond with intentions.
Changing habits also poses unique challenges. For actions that are not easily repeated into habits, changing intentions tends to change behavior. However, given that habits are cued by contexts and proceed ballistically, changing intentions has only limited effect on habit performance. Thus, changing intentions concerning diet, seat belt use, and other often-repeated behaviors may not have much effect on performance. Yet, the dependence of habits on context cues makes them vulnerable to other types of interventions. Habit performance is especially susceptible to changes in the performance context. Effective habit change interventions likely involve structural changes that remove triggering cues or disrupt the automated mechanisms that generate repetition.
Self-regulation involves actively controlling behavior. The context-cuing, ballistic features of habit performance appear to interact with this process by influencing the ease with which responses can be executed versus withheld. The unique pattern of habit regulation emerges most strongly when people’s self-control resources are low. Then, people are able to execute habits successfully but are less able to inhibit habit performance.
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- Wood, W., Tam, L., & Guerrero Witt, M. (2005). Changing circumstances, disrupting habits. Journal of Personality and Social Psychology, 88, 918-933.