Hibbing et al. propose a fascinating account of how individual variation in the negativity bias explains variations in political ideology. This account raises a critical question: What explains individual variation in the negativity bias? The authors present an evolutionary hypothesis to explain this individual variation, but this need not mean that the variation is innate and present from birth (Gottlieb Reference Gottlieb2007; McClintock Reference McClintock1979). To fully understand the foundations of individual variation in the negativity bias, it is equally important to consider the emergence of the bias in human ontogeny. The authors review two important studies that tie early psychological attributes to later political attitudes (Block & Block Reference Block and Block2006; Fraley et al. Reference Fraley, Griffin, Belsky and Roisman2012); we propose that research exploring how biological and environmental factors contribute to the early development of, and variability in, the negativity bias could be profitably integrated with this approach.

Research in developmental psychology reveals that the negativity bias guides human cognition as early as infancy and continues throughout childhood. For example, infants look longer at fearful than at happy faces and modify their own behavior more strongly in response to others' negative than others' positive expressions (see Vaish et al. Reference Vaish, Grossmann and Woodward2008 for a review), and preschool-aged children selectively remember the faces of threatening individuals (Kinzler & Shutts Reference Kinzler and Shutts2008). Yet, very little is known about the nature of early individual differences in the negativity bias. Understanding how and whether early individual differences in attention to negative stimuli guide later attitudes – and the process by which early individual differences unfold and are shaped by both genes and environment – is critical for gaining traction on the nature of psychological and political attitudes across the lifespan.

One area of investigation that promises to be extremely fruitful in this regard is that of genetic variation. Indeed, one recent study shows that genetic variation accounts for differences in infants' negativity bias in processing fearful faces (Grossmann et al. Reference Grossmann, Johnson, Vaish, Hughes, Quinque, Stoneking and Friederici2011). Equally, one can ask about the role of early experience in establishing the negativity bias. The authors note that parents' political beliefs have only meager effects on their children's eventual political orientations. Yet parenting may have very important effects on the emergence of the negativity bias in early development. As illustration, infants who have had more frequent exposure to happy expressions (because they have happy, positive mothers) show a greater negativity bias than infants whose mothers are not as happy and positive (de Haan et al. Reference de Haan, Belsky, Reid, Volein and Johnson2004). Thus, the influence of parenting on the factors that contribute to political attitudes may be more robust than is currently known. Further research is needed to understand how such biological and environmental factors, as well as their interaction, impact individuals' attention to negative events throughout development.

The target article provides evidence that individual differences in the negativity bias are stable over time, yet when do such stable differences emerge? Although diverse studies suggest that the negativity bias emerges as early as infancy, no research to date has explored whether infants' reactions are predictive of later attitudes. The authors briefly make reference to Jerome Kagan's work on early temperament, but this relation needs to be empirically explored. Moreover, it is unknown whether individual differences in early attention to negative social stimuli relate to individual differences in other aspects of temperament (though see Grossmann et al. Reference Grossmann, Johnson, Vaish, Hughes, Quinque, Stoneking and Friederici2011). It is plausible that early attention to negative information could be meaningfully related to infants' novelty seeking behaviors. If so, this might suggest an early coherence across psychological profiles that relate to later political attitudes. If not, this would suggest a potential complexity in the developmental trajectory of early social behaviors and attitudes, and raise new questions regarding how such individual variation serves as a precursor to later attitudes.

In their discussion, the authors put forth the possibility that different subcategories of negative emotion may differentially impact attitudes toward diverse issue sets. Is attention to some kinds of negative information early in development most predictive of later political attitudes? For example, there is evidence that threatening information (as opposed to information that is negative but non-threatening, such as sadness) may be most attention grabbing early in development (Kinzler & Shutts Reference Kinzler and Shutts2008; Lobue Reference LoBue2009). It is conceivable that individual differences in early attention to threat, but not all subcategories of negative information, may predict the emergence of diverse political profiles. It also remains to be seen whether the category threat may be even further meaningfully subdivided – for instance, is early attention to social threats different from attention to non-social threats? A more nuanced understanding of the parameters of early negativity bias that predict later political profiles may help uncover new insight regarding the nature of political attitudes among adults, and could help resolve apparent incongruities in the kinds of negative information (e.g., threats from people versus threats from the environment) that elicit different reactions among conservatives and liberals.

To conclude, the authors argue that their approach can be useful in identifying which political attitudes are “peripheral” and which are “core.” We agree. Furthermore, if core attitudes are identified, might the hallmarks of those attitudes be present early in development? And if so, which candidate aspects of children's early lives, choices, and social experiences might reflect those attitudes? We submit that inquiries at the intersection of developmental and political psychology will generate new productive research programs that inform our understanding of the factors contributing to political attitudes across the lifespan and will reveal many fascinating insights into the human mind in social and political context.