As noted above, the dominant analytical approach to psychological functioning begins with an exhaustive search for a definition of a concept, including the borders of where it differs from other concepts. So, to understand “attention,” one would tend to first define how it differs from “intention,” “decision-making,” “motivation,” etc. In view of a failure of this approach, as is obvious for the case of attention versus intention, two reactions are to be expected. First, one might consider the previous attempts to define attention and intention as flawed and try to improve the definitions by further reducing the conceptual overlap between the two concepts. For instance, one may further reduce the concept of attention to mere input selection and the concept of intention to output selection. Given that this would make it no longer apparent that such a reduced version of “attention” has anything to do with other “attentional” functions like integration, orientation, or vigilance, this would eventually call for dropping the concept – and the same argument holds for “intention.” On the positive side, this would prevent researchers from trying to find commonalities in processes and substrates that are unlikely to be found. On the negative side, however, there is no theoretical justification to pick just these functional aspects but not others. What looks like a definitional issue thus becomes a theoretical bias that is lacking justification.

Alternatively, one might search for hybrid approaches that allow for additional components and factors. A typical approach of this sort was the resource theory of attention, which triggered heated debates in the 1970s and 1980s (Kahneman, 1973; Navon, 1984). While the first approaches were simple and elegant by assuming one kind of resource that needs to be distributed over all mental work, the attempt to integrate an increasing number of unpredicted findings led to the invention of increasing numbers and types of separate resources. In the end, this made systematic predictions impossible (Navon, 1984), which is the main reason why this approach no longer plays an important role – except in the field of ego-depletion, where history seems to repeat itself (Friese, Loschelder, Gieseler, Frankenbach, & Inzlicht, in press). The main reason why hybrid approaches that simply lump together different factors are not overly successful rests in the fact that the respective factors are not truly integrated into a coherent framework.

A similar tendency can be seen with respect to selective attention, where Awh, Belopolsky, and Theeuwes (2012) have tried to integrate findings that are no longer consistent with the historical distinction between endogenous attention, which represents the prioritized processing of stimuli to which the agent “wants” to attend, and exogenous attention, which represents the prioritized processing of stimuli that are unrelated to the present action and goals. The history of distinguishing between endogenous and exogenous attention is very similar to the distinction between attention and intention. Each started out by trying to improve definitions about what the concept referred to, only to be faced later with the inability to systematically sort the available findings into two distinct categories. In a nutshell, endogenous attention is sometimes too automatic and exogenous attention is sometimes too dependent on the current prioritized stimulus feature or action goal to make this dichotomy fruitful and tenable (Awh et al., 2012; Folk, Remington, & Johnston, 1992; Hommel & Wiers, 2017). Awh et al. suggest solving this problem by adding a third variable – selection history – to the list of factors. In particular, the idea is that goals (the factor responsible for endogenous attention), salience (the factor responsible for exogenous attention), and selection history (a factor that does not seem to fit the previous dichotomy and is associated with previous selections and rewards generated by the selections) all contribute to selectivity by sending their output to an integrative priority map. Although this approach may account for many of the available findings, we are not convinced that it really solves the problem, but rather provides a patch that holds concepts together and, in the end, prevents or misdirects the search for suitable solutions. Instead, we suggest that a complete dismantling of the concept of attention is required.

At first there does not seem to be anything wrong with the idea that structures, or a singular structure, in the human central nervous system are devoted to collecting and integrating information that affects prioritized processing. One candidate structure is the superior colliculus, which is thought to reflect a priority map of stimuli in the visual field (Fecteau & Munoz, 2006). Importantly, and as required from the view that selectivity for behavioral relevance is the purview of the entire moving body, the superior colliculus is involved not just in eye movements, but in orienting movements of the eye, head, body, and hand (Gandhi & Katnani, 2011; Stuphorn, Hoffmann, & Miller, 1999). Emphasizing this point, Song and colleagues (Song, Rafal, & McPeek, 2011; Song & McPeek, 2015) found that the superior colliculus plays a causal role in target selection during manual reaching tasks, supporting the idea that the superior colliculus is part of a general-purpose target selection/orientation system (Nummela & Krauzlis, 2010; Song et al., 2011). On the other hand, there is no need to assume that the superior colliculus is the only map that integrates relevant information to steer attention, nor is it necessary to assume that all available information is integrated into that one map. As we argue below, the human brain can be considered to have many sources of selectivity and, in the end, it is the brain as a whole that does the integration. Given that this integration is the explanandum (the to-be-explained phenomenon), postulating the existence of one map that has no other function than achieving this integration seems to be one more attempt to “explain” a psychological phenomenon by positing the existence of a dedicated system whose only purpose is to somehow create that phenomenon.

Apart from this more general meta-theoretical problem, adding one more factor to a model that just assumes that integration takes place without explaining how that can be done is unlikely to guide further research. In the case of Awh et al. (2012), one reason is that selection history overlaps considerably with goal-induced endogenous selectivity and salience-induced exogenous selectivity. For instance, the fact that planning and carrying out particular kinds of actions systematically facilitates the processing of particular object features (e.g., of size and orientation for grasping, location for reaching: Bekkering & Neggers, 2002; Craighero et al., 1999; Fagioli et al., 2007) is unlikely to be genetically determined, but rather the consequence of learning and experience of selecting different features for grasping over the lifespan (Hommel, 2010). Indeed, prioritizing shape and orientation when grasping objects makes more sense than prioritizing color because those features are more likely to determine a successful or an unsuccessful grasp. Hence, establishing a bias for shape and orientation over color when grasping would be a functional adaptation. However, this influence implies that selection history affects how goals impact (endogenous) attention. Along the same lines, the relative salience of the visual dimension changes substantially during the first years of life (e.g., Suchman & Trabasso, 1966), which at least opens the possibility that selection history impacts salience.

While these arguments are fully consistent with Awh et al.’s suggestion to consider selection history as a third factor involved in attentional control, they also imply that the resulting three factors are not independent but strongly overlapping and intertwined – both empirically and conceptually. As we have tried to explain, these conceptual-overlap problems are unlikely to be resolved by more definitions. Rather, what is needed is a theory that not only assumes that integration takes place but that explains how that integration works.

Another reason why just adding selection history as an additional factor raises more questions than answers is that the concept itself is unclear, particularly in its overlap with other related factors beyond exogenous and endogenous control. One such factor that is intertwined with selection history is reward history. It is uncontroversial that previously rewarded stimuli receive preferential processing (Anderson, Laurent, & Yantis, 2011; Anderson & Yantis, 2012), suggesting that reward history is important in determining salience. Conventionally, stimuli must have been selected in order for the organism to have received a reward, thus conflating the two concepts. Awh et al. (2012) appear to acknowledge this tension, considering both previous reward and previous stimulus selections to be exemplars of “selection history” while facing the fact that selection history and reward history cannot be identical (given that previous selections might not have received reward). However, the fit of reward history into this joint category is much less obvious than this theoretical integration suggests since reward history is itself likely composed of many differentiable factors.

For instance, the preference for rewarding stimuli is stronger when the larger expected gain of the stimulus is due to an increased probability of receiving a reward than when there is a lower cost of failure (Neyedli & Welsh, 2015b). This finding suggests that what participants take to be rewarding is itself multifaceted – not just the magnitude of the reward, but also how likely it is that they will receive the reward. Furthermore, across a series of reach-decision experiments, a multitude of biasing factors have been observed including: reward value and probability (Chapman, Gallivan, & Enns, 2015a), the best option in a decision set (Wispinski, Truong, Handy, & Chapman, 2017), current level of accumulated wealth (Neyedli & Welsh, 2015a), the number of targets and not the perception of them (Milne et al., 2013), and how the number of choice-options is represented (Chapman et al., 2014). The problem here is similar to the one Awh et al. (2012) tried to solve: the definition of the concept under investigation is too restricted. In their case, endogenous and exogenous control were insufficient to account for the variety of pheomenena being ascribed to the concept of attention, so they added selection history. Selection history is itself decomposable into (at least) selection and reward history, and reward history is itself decomposable even further. Thus, the nature and the influence of reward is itself dependent on numerous contextual factors and the expression of the confluence of these factors is not easily captured in a unitary construct.

The picture gets even more complicated when one considers studies comparing the impact of rewards of equal magnitude but in opposite directions (e.g., positive/gain vs. negative/loss). For example, loss aversion, made famous by the work of Kahneman and Tversky (1979), shows that people treat potential losses as being more aversive than equivalent gains are rewarding. Interestingly, when decisions between positively and negatively rewarding stimuli are made rapidly (Chapman et al., 2015b), asymmetries in choice behavior are also observed, but go opposite to loss aversion. That is, in these situations, participants appear to be disproportionately drawn toward options giving gains, while the aversive impact of loss-related choices is attenuated. These findings highlight an additional complication – that different biases are likely to operate on different timelines. For instance, in the study of the asymmetry in decisions to go for a good option versus avoid a bad one, participants were biased toward positively valanced targets 100 ms earlier than they were biased to move away from negative ones (Chapman et al., 2015b). This finding echoes related work showing that more time is required to select optimally between visuomotor choices when they differ based on negative value information compared to when they differ based on the probability of reward (Neyedli & Welsh, 2015b).

Taken together, these and other findings strongly suggest that selection history is tightly interconnected with reward history and that neither of these concepts are particularly well understood. Hence, adding selection history to the two other not well understood concepts of exogenous and endogenous attention is unlikely to help much in understanding the mechanisms underlying human selective attention. To be clear, we are not advocating an alternative theory at this point, but rather we suggest an alternative theoretical perspective: Let us replace the analytical approach, which seeks to explain complex phenomena by first carefully defining them and then subdividing them into simpler elements, with a synthetic approach that considers how simple mechanisms and functional processes, each of which is itself behaviorally relevant, can together give rise to complex phenomena.