Evolution of social attentional cues: Evidence from the archerfish.

Social cues such as gaze, head, and body orientation are essential for the survival of any social animal. The gaze cuing paradigm is a well-studied experimental manipulation, employed to detect automatic attentional shifts in humans. To the best of our knowledge, no previous study has tested non-primates in a paradigm that is similar to the one typically used on humans. Herein, three archerfish observed a conspecific picture oriented toward the right or the left, followed unpredictably by a visual target presented in the socially cued or un-cued location. Similar to the pattern observed in humans, fish demonstrated faster reaction times for targets presented at the socially cued location. Results suggest that social cues may have an early evolutionary origin and can elicit automatic attentional orienting even in species without a visual cortex.

Monocular channels have a functional role in endogenous orienting.

The literature has long emphasized the role of higher cortical structures in endogenous orienting. Based on evolutionary explanation and previous data, we explored the possibility that lower monocular channels may also have a functional role in endogenous orienting of attention. Sensitive behavioral manipulation was used to probe the contribution of monocularly segregated regions in a simple cue - target detection task. A central spatially informative cue, and its ensuing target, were presented to the same or different eyes at varying cue-target intervals. Results indicated that the onset of endogenous orienting was apparent earlier when the cue and target were presented to the same eye. The data provides converging evidence for the notion that endogenous facilitation is modulated by monocular portions of the visual stream. This, in turn, suggests that higher cortical mechanisms are not exclusively responsible for endogenous orienting, and that a dynamic interaction between higher and lower neural levels, might be involved.

Endogenous orienting in the archer fish.

The literature has long emphasized the neocortex's role in volitional processes. In this work, we examined endogenous orienting in an evolutionarily older species, the archer fish, which lacks neocortex-like cells. We used Posner's classic endogenous cuing task, in which a centrally presented, spatially informative cue is followed by a target. The fish responded to the target by shooting a stream of water at it. Interestingly, the fish demonstrated a human-like "volitional" facilitation effect: their reaction times to targets that appeared on the side indicated by the precue were faster than their reaction times to targets on the opposite side. The fish also exhibited inhibition of return, an aftermath of orienting that commonly emerges only in reflexive orienting tasks in human participants. We believe that this pattern demonstrates the acquisition of an arbitrary connection between spatial orienting and a nonspatial feature of a centrally presented stimulus in nonprimate species. In the literature on human attention, orienting in response to such contingencies has been strongly associated with volitional control. We discuss the implications of these results for the evolution of orienting, and for the study of volitional processes in all species, including humans.