# **1 Introduction**

Increases in productivity are key to growth and poverty reduction, yet productivity in many domains is lacking far behind technological possibilities. This is particularly true for agricultural productivity in many parts of the developing world, especially in SubSaharan Africa (Jama and Pizarro, 2008; World Bank, 2008). One puzzling observation is that farmers do not make use of measures that have relatively low costs but are believed to offer high returns. In particular, modern farm inputs, such as fertilizer and improved seeds, have been demonstrated in a variety of contexts to have significant expected returns, yet are frequently not adopted and, conditional on adoption, inputs are used in suboptimal amounts. To help farmers overcome the underlying constraints, a major policy instrument used is the provision of agricultural extension and advisory services.<sup>1</sup> A growing body of empirical evidence suggests that these services can have significant positive effects, including on farmers’ management practices and adoption of better technologies (Cole and Fernando, 2013; Buehren et al., 2019), crop yields (Casaburi et al., 2014), profits (Bandiera et al., 2018), and poverty reduction (Dercon et al., 2009). Yet, demand for extension services is often low. In our dataset, which consists of nationally representative samples of farmers in three African countries, only 19% of farmers actively solicit agricultural advice (including from other farmers). The fairly low interest in agricultural advice despite the apparent potential for high returns is particularly puzzling in light of the low (most frequently zero) monetary user cost associated with receiving such advice.<sup>2</sup> In this paper, we use a rational inattention model to argue that costly attention may be part of the explanation for this. Our model centers around the idea that farmers (like anybody else) face a limited capacity to attend to information, which causes attention to be a scarce resource.<sup>3</sup> Given that participation in extension programs is only worthwhile if farmers devote sufficient attention to listening to and implementing the provided advice, the decision to request extension services will depend on the amount of attention that farmers are willing to devote to their agricultural production process. Based on 1According to different sources, there are between half a million and one million agricultural extension workers worldwide, of which 90% are located in developing countries (Feder, 2005; Anderson and Feder, 2007).

> 2In our sample, 92% of respondents report having paid nothing for the advice that they received. Also note that the share of districts in which at least one farmer reports having received agricultural advice is 95% (84% of district-years), which suggests that extension services are widely available in the countries we study. This view is also in line with the findings of other studies. For example, surveying recent studies on extension services in Malawi, Ragasa (2018) report that three-quarters of Malawian farm households received agricultural advice in the last two years, and half of households received advice in the last 12 months.

> 3This feature is in line with a large body of psychological and experimental evidence on the limits of human cognition (DellaVigna, 2009; Caplin and Dean, 2013; World Bank, 2015), as well as a growing literature on the link between poverty and lack of mental resources (Banerjee and Mullainathan, 2008; Mani et al., 2013; Haushofer and Fehr, 2014).

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