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In the field of plant-herbivore interactions, a key question is to understand which plants will be consumed. From the point of view of herbivores, this question takes the form of how animals select resources. To answer it, the theory of optimal foraging provides a mathematical framework that takes into account the constraints experienced by animals, such as the availability and diversity of resources available. Historically, plant-focused researchers have framed this question slightly differently: How to explain patterns of herbivory? Hypotheses grouped under the term associational effects aim to describe how plant community characteristics influence these patterns. Results of associational effects studies, however, are variable in magnitude, in direction and are often idiosyncratic. There is a growing awareness that associational effects could be equally well explained by optimal foraging. Several studies of associational effects, however, fail to consider factors linked with herbivores' active foraging choices such as the effects of plant size. I will try to mend the gap between fields using examples of optimal foraging framework integration in studies of associational effects, mostly with mammalian herbivores, but also with invertebrates. I review the proposed mechanisms for associational effects and evaluate whether they could be explained by optimal foraging. Finally, I propose guidance on predictions and type of studies that allow us to discriminate associational effects produced by optimal foraging from other potential mechanisms. Incorporating active foraging choices and using an optimal framework could improve our understanding of associational effects and their variations. Moreover, clearly identifying herbivores as the actor in these interactions forces us to consider their abilities and behavior. It also creates links with nutritional ecology, landscape ecology, and population dynamics and has potential implications in conservation and management practices.