Simulating Heterogeneous Farmer Behaviors
vant referents in the individual ’ s network . Last , the perceived behavioral control over behavior is given by
where c j , f is individual j ’ s belief that a control factor f is present and p j , f is the degree to which control factor f facilitates or impedes the performance of behavior . The overall perception of control is then the sum over all factors
TPB has been widely used in areas such as health behavior and consumer behavior , where studies and surveys are constructed to elicit the three components of the behavioral intent in order to predict actual behavioral action ( Carmack & Lewis-Moss , 2009 ; Pavlou & Chai , 2002 ). Godin and Kok found in their meta-analysis that TPB produced an average R 2 value of 0.41 when used to explain and predict behavioral intention ( Godin & Kok , 1996 ). They also noted significant variation in the efficiency of the theory when compared across different categories of behavior related to health choices . This variation in results underscores the limitations inherent in assuming a population is homogeneous .
Note that there is no expression of time in the above formulation of TPB . Ajzen addressed the issue of predicting behavioral action with TPB by stating that the interval between measuring the components of TPB and observing the opportunity for action needs to be sufficiently short such that all the foundational beliefs remain stable ( Ajzen , 1991 ). Ajzen went on to say that persuasive messaging has been correlated with changes in attitude , indicating that a reasonable assumption is that such messaging would have a similar relationship with SN and perceived behavioral control if the message content was directed at the normative beliefs or levers of control . So , although TPB does not elaborate on how beliefs , and therefore behavioral intention , change over time , it does allow that behavioral intention can — and most likely will — change as the individual refines their beliefs . Thus , in order to model how persuasive messaging affects the macrolevel response of a sample population , we must place TPB into a larger framework that evolves over time .
The Conceptual Model of Consumer Behavior
Janssen et al . ( 1999 ) investigated the well-known commons dilemma using an agent-based model of consumer behavior . Although behavioral actions related to persuasive messaging are a different environmental context from competition for common resources , we contend that the Janssen et al . conceptual model of consumer behavior is transferable to multiple environments of decision-making . The consumer behavior model is a multi-theoretical framework that draws on theories of human needs , motivational processes , operant conditioning , classical conditioning , decision theory , and TPB .
The consumer behavior framework builds on the idea that individuals exist in an environment where multiple systems interact and affect cognitive processing . There are four systems connected as shown in Figure 2 . The Pressure system applies forces to the needs of an individual . For example , a down-turn in the economy or the decreased availability of a resource will exert some pressure on individuals in a society . These pressures are interpreted by the individual in the State system , which contains two dimensions of cognitive processing described in greater detail below . The result of cognitive processing is some action ( or inaction ) that is carried out through the Impact sys-
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