Cueing Effects Emerge When Humans (Homo sapiens) View Images of Mammals (Mammalia) and Birds (Aves)

Humans use eye- and head-gaze cues to facilitate social interactions among members of their own species. Research examining nonhuman animal-to-human cueing effects has received little attention, but may provide valuable insight into the mechanisms that have enabled species to coexist and thrive in shared environments. The objective of the current studies was to determine how gaze cues influence the attention and target detection of humans when they view images of mammals (human, orangutan, and dog; Experiment 1) and aves (owl, macaw parrot, and duck; Experiment 2). Participants were presented with an image of a forward-facing head that was suddenly replaced with an image of the head facing to the left or right, creating an apparent head rotation and change of orientation. A target appeared randomly on the left or right side of the head-gaze cue after 1 of 4 stimulus-onset asynchronies (SOAs; 100, 300, 600, or 1,000 ms). Participants were asked to indicate the location of the target by pressing a spatially corresponding key. The analysis of response times (RTs) revealed facilitatory cueing effects (RTs to cued targets were shorter than to uncued targets) across all SOAs in Experiment 1 (images of mammals). Such facilitatory cueing effects were only present at short SOAs (i.e., 100 and 300 ms) in Experiment 2 (images of aves). These findings provide initial evidence that the processing of gaze cues observed during human-to-human interactions is similar to that observed during mammal-to-human interactions, but is different in aves-to-human interactions. Alternative interpretations of the data are discussed.