Seeing through our ancestors' eyes: Prioritized attention to animals and people
One lesson that I have drawn from natural selection is that not all objects in the world are equally deserving of attention. Instead, some types of objects and events may have been of such critical importance in ancestral environments that attending to them became an inherent priority in the visual system. In particular, I proposed that animate objects should be one of the greatest priorities, given the overriding importance of social relationships in human beings’ ancestral environments and of encounters with other animals that represented both enormous benefits as prey and dangers as predators.
I tested this prediction using a ’flicker’ change-detection paradigm in which observers viewed alternating versions of a natural scene, and had to ‘spot the difference’ between them (New, Cosmides, & Tooby, 2007, Proceedings of the National Academy of Science). With this method, observers are not overtly directed towards any particular objects or locations, which allows their search to be guided by implicit attentional biases. My results revealed that observers were substantially faster and more accurate at detecting changes made to animate objects (people or animals) than changes made to all the other categories of inanimate objects (including plants and vehicles). A series of control experiments showed that this phenomenon could not be explained by appeal to lower-level visual characteristics, to how interesting the target objects judged to be, or to other types of experience or expertise. These results suggest that attention, even today, is inherently biased towards certain kinds of objects by virtue of their membership in ancestrally important categories, regardless of their current utility.
New, J., Cosmides, L., & Tooby, J. (2007). Category-specific attention for animals reflects ancestral priorities not expertise. Proceedings of the National Academy of Sciences, 104, 16598-16603. (PDF).
New, J. J., Schultz, R. T., Wolf, J., Niehaus, J. L., Klin, A., German, T. C., & Scholl, B. J. (2010). The scope of social attention deficits in autism: Prioritized orienting to people and animals in static natural scenes. Neuropsychologia, 48, 51-59. (PDF).
Wang, S., Tsuchiya, N., New, J., Hurlemann, R., & Adolphs, R. (in press with advance access). Preferential attention to animals and people is independent of the amygdala. Social Cognitive and Affective Neuroscience. (PDF).
Spiders at the cocktail party: Reflexive awareness of an evolutionary threat
Whereas my studies of visual attention considered animate objects categorically, my studies of visual awareness have focused on one particular ancestral hazards, spiders. Commonly advanced as a model instance of a biologically prepared fear, spiders have posed such specific and immediate threats that the visual system may retain ancestral mechanisms dedicated to their rapid detection. I tested this prediction using the inattentional blindness paradigm in which a single unexpected stimulus is briefly displayed peripherally to, and coincidentally with, a central, task-related stimulus. Although observers are frequently entirely unaware of – that is, inattentionally blind to – stimuli shown under these conditions, participants proved uniquely capable of detecting, locating, and identifying iconic spiders (New & German, in press, Evolution and Human Behavior). This ability was highly specific to stimuli which conformed to a spider “template”: participants were frequently inattentionally blind to scrambled versions of the spider stimuli, and to a modern threat (hypodermic needle), and even a different animal (housefly). This demonstrates that some evolutionary-relevant threats are highly-specified and can evoke what is perhaps best termed ‘reflexive awareness’: an immediate and elaborated perception sufficient to guide an adaptive behavioral response.
New, J. J. & German, T. C. (in press with advance access). Spiders at the cocktail party: An ancestral threat that surmounts inattentional blindness. Evolution and Human Behavior. (PDF).