Theory of Planned Behavior: The 3 Pillars of Behavioral Intent

Have you ever wondered what drives our decisions and actions? When examining human behavior, it often appears widely inconsistent—why do people who value health still eat junk food, or those who care about the environment fail to recycle? The Theory of Planned Behavior (TPB) offers a compelling lens through which we can explore the intricate motivations behind these behaviors, shedding light on how our thoughts and social influences shape the choices we make, even when those choices conflict with our stated desires.

Predicting behavior requires moving away from measuring broad personality traits or general attitudes, and instead focusing on specific, behavior-related intentions.

The theory of planned behavior is an extension of Icek Ajzen’s earlier theory of reasoned action. The theory posits that three constructs (base components) influence intentions. These intentions then influence behavior. Arguably this is the most cited theory for explaining human behavior (Sussman & Gifford, 2019). This theory is widely used in various fields such as health psychology, consumer behavior, and environmental psychology.

History of the Theory of Planned Behavior

Icek Ajzen developed The Theory of Planned Behavior in 1985. It is an extension of the Theory of Reasoned Action, which was proposed by Martin Fishbein and Ajzen in 1980. The theory of planned behavior incorporated the concept of perceived behavioral control to the constructs of attitudes and subjective norms included in the theory of reasoned action.

The Predecessor: The Theory of Reasoned Action (TRA)

To understand the Theory of Planned Behavior, we first need to look at its roots. In the 1960s and 1970s, Martin Fishbein and Icek Ajzen developed the Theory of Reasoned Action (TRA) (Ajzen, 1988; Fishbein & Ajzen, 1980).

The Rational Actor

At the heart of the TRA is a view of humans as rational actors. The theory assumes that human beings are usually quite rational and make systematic use of the information available to them. Rather than believing human social behavior is capricious or controlled by unconscious motives, the TRA posits that people sensibly consider the implications of their actions before they decide whether or not to engage in a given behavior. It is precisely for this reason that it was named a theory of reasoned action (Fishbein & Ajzen, 1980).

The Two Original Pillars

The TRA outlined that human behavior is determined immediately and directly by a person’s intention to perform that action. This intention, the theory argued, is formed by two primary pillars—one personal and one social (Fishbein & Ajzen, 1980):

• Attitude toward the behavior (The Personal Factor): This is a person’s positive or negative evaluation of performing the behavior in question. It is not a general attitude toward an object, but a specific judgment about whether personally executing the action is good or bad.
• Subjective norms (The Social Factor): This reflects perceived social pressure. It is the person’s perception of whether most people who are important to them think they should or should not perform the behavior (Fishbein & Ajzen, 1980).

The Flaw

The TRA was a breakthrough, but it had a notable limitation: it was developed explicitly to deal with behaviors that are entirely under a person’s volitional control. The theory worked incredibly well for actions where people faced few, if any, external problems or barriers—such as deciding who to vote for in an election. Once in the voting booth, the choice is entirely up to the voter (Ajzen, 1988).

However, the theory struggled to explain behaviors where people lacked complete control, resources, or opportunities. For example, losing weight or getting an “A” in a class are behavioral goals that depend on far more than just a strong intention. Earning an “A” requires intellectual ability, time to study, and resisting other temptations, while weight loss requires resources and the ability to adhere to a program despite obstacles.

The TRA could not adequately account for situations where a person has a strong intention to do something (like quitting smoking) but fails to attain their goal due to a lack of actual control or ability (Ajzen, 1988).

Enter the Theory of Planned Behavior: The Role of Control

To address the reality that many of our daily actions involve incomplete volitional control, Ajzen expanded the original framework into the Theory of Planned Behavior (TPB) by adding a crucial third pillar: Perceived Behavioral Control (PBC) (Ajzen, 1988). Ajzen recognized that control over our actions isn’t a simple “yes or no” question, but rather a continuum ranging from easily executed acts (like voting) to difficult goals that are heavily dependent on external circumstances or internal deficiencies (like quitting smoking or getting an “A” in a class) (Ajzen, 1988).

Simply put, Perceived Behavioral Control is the degree to which a person believes they are capable of, or have control over, performing a given behavior (Fishbein & Ajzen, 1975). It accounts for a person’s assessment of both their internal resources (such as their own skills, abilities, and willpower) and external factors (such as the availability of time, money, and the cooperation of others) (Fishbein & Ajzen, 1975; Ajzen, 1988). If you believe you have the necessary resources and anticipate few obstacles in your path, your perceived behavioral control is high.

When people believe that they have the required resources and opportunities (e.g., skills, time, money, cooperation by others) and that the obstacles they are likely to encounter are few and manageable, they should have confidence in their ability to perform the behavior and thus exhibit a high degree of perceived behavioral control (or self-efficacy).

~Martin Fishbein & Icek Ajzen (1975, p. 169).

The Self-Efficacy Connection

To fully appreciate the power of PBC, it helps to reach outside the strict confines of the TPB and look at the wider field of psychological research. PBC is conceptually almost identical to “self-efficacy,” a highly popular and foundational concept developed by psychologist Albert Bandura (1977).

In his social cognitive theory, Bandura defines self-efficacy as a person’s belief in their capability to organize and execute the specific courses of action required to reach a goal (Fishbein & Ajzen, 1975). It represents the confidence a person has in their ability to succeed through ingenuity and perseverant effort, even when confronted by difficult obstacles.

Within the broader landscape of motivation psychology, the introduction of this control mechanism was revolutionary. It moved behavioral prediction past older, more generalized concepts like Julian Rotter’s “locus of control”—which measured a broad personality trait regarding whether people felt life events were driven by internal effort or external chance,. Instead, PBC and self-efficacy are highly task-specific (Ajzen, 1988).

Extensive research across psychology demonstrates that this sense of confidence and control does more than just shape our intentions. When individuals have high self-efficacy, they actually invest more effort, set higher and more challenging goals for themselves, and show far greater resilience and persistence in the face of setbacks (Bandura, 2013; Ajzen, 1988). By adding this third pillar, Ajzen bridged a critical gap: he acknowledged that human action isn’t just driven by what we want to do (attitude) or what we think we should do (norms), but is fundamentally tethered to what we genuinely believe we can do (Fishbein & Ajzen, 1975).

The Role of Intention in Behavior

According to the Theory of Planned Behavior, intention plays a crucial role. Intention captures motivational factors behind behaviors. They correspond with how much effort a person plans to exert to successfully perform a behavior. In motivation theory, the intention-behavior loops are key to understanding goal achievement and failure.

Ajzen explains:

“Intentions reflect primarily an individual’s willingness to try enacting a given behavior. These intentions often are not founded on realistic obstacles. Perceived behavior control, on the other hand, is likely to take into account some of the realistic constraints that may exist” (Ajzen, 1988, p. 134).

The stronger the intention to engage in a behavior, the more likely the person will perform the behavior. The three variables that form the strength of intention in the theory of planned behavior are:

• Personal attitudes towards the behavior,
• Subjective norms,
• Perceived behavioral control .

Essentially, intention acts as a mediator between these factors and the actual behavior, reflecting the individual’s motivation and readiness to act.

The 3 Components of TPB: Attitude, Norms, and Control

At the core of the TPB are three factors that influence an individual’s intention to perform a behavior: attitude, subjective norm, and perceived behavioral control.

Attitude

This factor refers to an individual’s overall evaluation of the behavior in question. It encompasses beliefs about the outcomes of the behavior and the value placed on those outcomes. For example, a person’s attitude towards regular exercise will greatly influence their intention to engage in physical activity.

Not all attitudes are explicit. Many operate under the surface quietly and powerfully manipulating intentions and the subsequent behavior. Martin Fishbein and Icek Ajzen posit that an explicit attitude, however, can override these hidden biases.

Fishbein and Ajzen wrote:

“The implicit attitude (or stereotype) is assumed to be automatically activated, whereas activation of the explicit attitude is said to require cognitive effort. In this view, the implicit as well as the explicit attitude may be considered to reflect ‘true’ attitudes. The implicit prejudicial attitude is activated automatically, but, as in the models previously described, given sufficient motivation and cognitive resources the explicit egalitarian attitude can be retrieved and override the effect of the implicit prejudicial attitude” (Fishbein & Ajzen, 1975).

See Attitude: A Character Trait for more on this topic

Subjective Norm

The subjective norm plays a pivotal role in shaping an individual’s behavioral intentions. This element encompasses the perceived social pressure or influence exerted by relevant others, impacting the decision to either engage in or abstain from a particular behavior. Individuals often look to those around them—friends, family, colleagues, and societal expectations—to gauge how they should act.

Elliot Aronson wrote in the context of influence and behavior that “we need to know is the enormous power a social situation can exert on individual behavior. It is a truism that humans are social animals—that we are all deeply influenced by other people and the ways they treat us, as well as by the general social climate of any situation” (Aronson, 2001).

For instance, a person might feel compelled to adopt healthier habits if their peers prioritize fitness and well-being. Conversely, if someone is surrounded by individuals who dismiss healthy living as unnecessary or unimportant, they may be less inclined to make positive changes in their own life. Thus, the subjective norm serves as a crucial motivator that can either encourage or deter certain behaviors based on perceived approval or disapproval.

Subjective Norm and Theory of Mind

Moreover, the subjective norm is intricately linked to an individual’s beliefs regarding what significant others think about specific behaviors within their social sphere. We create a theory of what others are thinking. This theory then motivates our intentions whether or not the theory is correct. In psychology we refer to this as Theory of Mind.

David Premack and Guy Woodruff introduced the term ‘theory of mind’ in 1978 their seminal paper, “Does the chimpanzee have a theory of mind?” (Premack & Woodruff, 1978). They defined ToM as the ability to attribute mental states—such as beliefs, intents, desires, emotions, and knowledge—to oneself and others, and to understand that others have beliefs, desires, and intentions that are different from one’s own.

This cognitive interpretation of internal states of others creates a significant sway over our intentions to act. Whether true or not, if we believe the underlying thoughts of others are kind or judgmental, our theory plays a significant role in forming our intentions to act.

When individuals perceive strong support for a behavior from their social network—such as participating in community service—they are more likely to develop favorable intentions toward engaging in that behavior themselves. On the other hand, if there is widespread negative sentiment surrounding an action—like smoking or excessive drinking—individuals may feel pressured not just by personal convictions but also by societal expectations that discourage such conduct.

Perceived Behavioral Control

The factor mentioned pertains to the individual’s perception of the ease or difficulty of performing a particular behavior. It encompasses various components such as self-efficacy, available resources, as well as environmental constraints. A person’s belief in their capability to successfully carry out the behavior plays a crucial role in this context. This belief, often referred to as self-efficacy, can significantly influence an individual’s willingness and determination to engage in a specific behavior.

Furthermore, the presence of adequate resources and the absence of environmental constraints can further enhance a person’s inclination towards undertaking the behavior. Therefore, considering and addressing these factors is essential in promoting and supporting positive behavioral changes.

Ajzen explains: “People who believe that they have neither the resources nor the opportunity to perform a certain behavior are unlikely to form strong behavioral intentions to engage in it even if they hold favorable attitudes toward the behavior and believe that important others would approve of their performing the behavior” (Ajzen, 1988, p. 134).

Perceived Behavior Control and Empowerment Theory

The concept of perceived behavior control mixes well with empowerment theory’s three elements necessary for a sense of empowerment. Basically, psychological empowerment is an integration of self-motivation, past skill development, and supportive environments. Accordingly, all three of these components elevate an individual’s perception of behavior control. Also, in this same vein, C. Richard Snyder’s hope theory also shares these elements. He defines hops as having three elements: goals, agency, and pathways (Snyder, 2003). With pathways equivalent to perceived behavioral control.

See Locus of Control, Empowerment Theory and Self-Efficacy for more information on this topic

Integrating the Three Base Components into a Functional Behavior

Importantly, these factors collectively shape an individual’s behavioral intention, which subsequently leads to the actual performance of the behavior. Basically, according to this theory “modifying attitudes, social norms, and perceptions about the control people have over their behavior can lead them to set…goals for themselves” (Oettingen, 2014). Accordingly, by changing any one of these factors (attitude, subjective norm, or perception of behavioral control) a person’s goals will change, and subsequently the end behavior will also change.

Ajzen notes that “the theory of planned behavior does not deal directly with the amount of control a person actually has in a given situation; instead, it considers the possible effects of perceived behavioral control on achievement of behavioral goals” (Ajzen, 1988, p. 133).

Application of Theory of Planned Behavior

Researchers and practitioners have utilized the TPB to design effective interventions aimed at promoting positive behavior change. By identifying and understanding the determinants of specific behaviors, psychologists and other professionals can develop targeted strategies. Better strategies effectively influence behavioral intentions and ultimately bring about desired changes in individuals and communities.

Professionals have applied the Theory of Planned Behavior (TPB) across a wide range of fields to understand and predict human behavior.

Examples of Application of TPB

• Health Sciences: Medical professionals and behavior scientists use TPB to predict behaviors like smoking cessation, exercise habits, and adherence to medical treatments.
• Environmental Science: It helps in understanding behaviors related to recycling, conservation, and the use of sustainable resources.
• Business and Management: TPB can explain consumer behavior, workplace conduct, and decision-making processes.
• Educational Research: Behavior scientists and educators apply this theory to study student motivation, teacher expectations, and educational outcomes.
• Public Health: Public officials and agencies have used this theory to design interventions that encourage healthy behaviors and reduce the spread of disease.
• Political Science: TPB helps in analyzing voting behavior, political participation, and public opinion formation.
• Sustainability: Public agencies and governments use TPB to promote sustainable behaviors in various contexts, including energy use and transportation.

These applications demonstrate the versatility of TPB in predicting and influencing behavior by considering attitudes, subjective norms, and perceived behavioral control.

Associated Concepts

• Achievement Goal Theory: This theory provides a psychological framework to explore how individuals’ beliefs about their abilities and the motivations behind their actions shape their behavior.
• Freud’s Drive Theory: This theory proposes that two basic and primary drives motivate human behavior: the life instinct (Eros) and the death instinct (Thanatos).
• General Adaptation Syndrome: This concept refers to the role of stress in motivating action. It posits that a stress response is composed of several stages of arousal and in completion the organism returns to a homeostatic state.
• Goal Setting Theory: This theory presents a goal setting framework, suggesting that setting specific, challenging goals can lead to higher performance and motivation.
• Organismic Integration Theory: This theory provides a framework for motivation. It focuses on the different forms of motivation that drive human behavior.
• Terror Management Theory: This theory explain how individuals cope with the anxiety and fear associated with their own mortality.

A Few Words By Psychology Fanatic

In conclusion, the Theory of Planned Behavior offers a valuable framework for understanding the complexities of human behavior. By examining the interplay of attitudes, social influences, and perceived control, psychologists can gain valuable insights. Accordingly, They can use this knowledge to the development of impactful interventions and initiatives across various domains.

The TPB continues to be a valuable tool in the field of psychology. This theory provides a nuanced understanding of the factors that drive human behavior. Consequently, it provides clues to practical applications that promote positive change.

Last Update: March 11, 2026

References:

Ajzen, Icek (1988). ‎Attitudes, Personality, and Behavior. Open University Press. ISBN: 9780335217038; APA Record: 1989-97547-000
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Ajzen, Icek; Fishbein, Martin (1980). Understanding Attitudes and Predicting Social Behavior. Prentice-Hall. ISBN: 9780139364358

Aronson, Elliot (2001). Nobody Left to Hate: Teaching Compassion after Columbine. Holt Paperbacks; 1st edition. ISBN: 9780805070996
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Bandura, Albert (1977). Self-efficacy: Toward a unifying theory of behavioral change. Psychological Review, 84(2), 191-215. DOI: 10.1037/0033-295X.84.2.191
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Bandura, Albert (2013). The Role of Self-Efficacy in Goal-Based Motivation. In: Edwin A. Locke and Gary P. Latham (eds.), New Developments in Goal Setting and Task Performance. Routledge. ISBN: 9780815390879; APA Record: 2013-00428-000

Oettingen, Gabriele (2014). Rethinking Positive Thinking: Inside the New Science of Motivation. Current; Reprint edition. ISBN-10: 1617230235
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Premack, D., & Woodruff, G. (1978). Does the chimpanzee have a theory of mind?. Behavioral and Brain Sciences, 1(04), 515-526. DOI: 10.1017/S0140525X00076512
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Snyder, C. R. (2003) Psychology of Hope: You Can Get Here from There. Free Press. ISBN-10: 0743254449; APA Record: 1994-98690-000
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Sussman, Reuven; Gifford, Robert (2019). Causality in the Theory of Planned Behavior. Personality and Social Psychology Bulletin, 45(6), 920-933. DOI: 10.1177/0146167218801363
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