Alan Kingstone

The eyes have it! Reflexive orienting is triggered by nonpredictive gaze

Normal subjects were presented with a simple line drawing of a face looking left, right, or straight ahead. A target letter F or T then appeared to the left or the right of the face. All subjects participated in target detection, localization, and identification response conditions. Although subjects were told that the line drawing’s gaze direction (the cue) did not predict where the target would occur, response time in all three conditions was reliably faster when gaze was toward versus away from the target. This study provides evidence for covert, reflexive orienting to peripheral locations in response to uninformative gaze shifts presented at fixation. The implications for theories of social attention and visual orienting are discussed, and the brain mechanisms that may underlie this phenomenon are considered.

Are eyes special? It depends on how you look at it

Recent behavioral data have shown that central nonpredictive gaze direction triggers reflexive shifts of attention toward the gazed-at location (e.g., Friesen & Kingstone, 1998). Friesen and Kingstone suggested that this reflexive orienting effect is unique to biologically relevant stimuli. Three experiments were conducted to test this proposal by comparing the attentional orienting produced by nonpredictive gaze cues (biologically relevant) with the attentional orienting produced by nonpredictive arrow cues (biologically irrelevant). Both types of cues produced reflexive orienting in adults (Experiment 1) and preschoolers (Experiment 2), suggesting that gaze cues are not special. However, Experiment 3 showed that nonpredictive arrows produced reflexive orienting in both hemispheres of a split-brain patient. This contrasts with Kingstone, Friesen, and Gazzanigas (2000) finding that nonpredictive gaze cues produce reflexive orienting only in the face-processing hemisphere of split-brain patients. Therefore, although nonpredictive eyes and arrows may produce similar behavioral effects, they are not subserved by the same brain systems. Together, these data provide important insight into the nature of the representations of directional stimuli involved in reflexive attentional orienting.

Attentional effects of counterpredictive gaze and arrow cues.

The authors used counterpredictive cues to examine reflexive and volitional orienting to eyes and arrows. Experiment 1 investigated the effects of eyes with a novel design that allowed for a comparison of gazed-at (cued) target locations and likely (predicted) target locations against baseline locations that were not cued and not predicted. Attention shifted reflexively to the cued location and volitionally to the predicted location, and these 2 forms of orienting overlapped in time. Experiment 2 discovered that another well-learned directional stimulus, an arrow, produced a different effect: Attention was shifted only volitionally to the predicted location. The authors suggest that because there is a neural architecture specialized for processing eyes, gaze-triggered attention is more strongly reflexive than orienting to arrows.

Orienting of Visual Attention

Spatial selectivity, which is essential in the perception of any visual scene or display, can be accomplished in two quite distinct ways. First, overt adjustments of gaze direction can be made to control which regions of the visual scene are processed by the sensitive fovea and its associated neural machinery. Second, covert adjustments can be made to determine which specific objects or regions are selected (in the absence of gaze changes) for preferential treatment. Overt orienting can be directly observed in the form of eye movements; convert orienting involves an internal adjustment and must be inferred from performance patterns. James (1890) probably had a distinction of this sort in mind when he contrasted adjustment of the sensory organs with an internal “anticipatory preparation.”

Visual offsets facilitate saccadic latency: does predisengagement of visuospatial attention mediate this gap effect?

Saccadic reaction time (RT) is reduced when a fixation stimulus is extinguished 200 ms before a target appears. An attentional predisengagement theory (APT) may explain this gap effect: When covert attention is engaged (e.g., on fixation), the saccadic system is inhibited and RT is delayed; when the attended stimulus is extinguished, attention is disengaged, the inhibition is removed, and RT is facilitated. In 3 experiments covert attention was endogenously or exogenously cued to an object on the vertical meridian. Onset of a saccadic target on the horizontal meridian could be preceded by the offset of an attended or unattended object. Contrary to APT, RTs were identical after attended and unattended offsets. Results suggest that the gap effect has 2 components, and covert visual attention plays no role. One component is motor system preparation; the other is a fixation offset effect specific to the oculomotor system. Language: en

Attention, Researchers! It Is Time to Take a Look at the Real World:

Theories of attention, too often generated from artificial laboratory experiments, may have limited validity when attention in the natural world is considered. For instance, for more than two decades, conceptualizations of “reflexive” and “volitional” shifts of spatial attention have been grounded in methodologies that do not recognize or utilize the basic fact that people routinely use the eyes of other people as rich and complex attentional cues. This fact was confirmed by our novel discovery that eyes will trigger a reflexive shift of attention even when they are presented centrally and are known to be spatially nonpredictive. This exploration of real-world attention also led to our finding that, contrary to popular wisdom, arrows, like eyes, are capable of producing reflexive shifts of attention—a discovery that brings into question much of the existing attention research. We argue that research needs to be grounded in the real world and not in experimental paradigms. It is time for cognitive psychology to reaffirm the difficult task of studying attention in a manner that has relevance to real-life situations.

Reflexive Joint Attention Depends on Lateralized Cortical Connections

Joint attention, the tendency to spontaneously direct attention to where someone else is looking, has been thought to occur because eye direction provides a reliable cue to the presence of important events in the environment. We have discovered, however, that adults will shift their attention to where a schematic face is looking—even when gaze direction does not predict any events in the environment. Research with 2 split-brain patients revealed that this reflexive joint attention is lateralized to a single hemisphere. Moreover, although this phenomenon could be inhibited by inversion of a face, eyes alone produced reflexive shifts of attention. Consistent with recent functional neuroimaging studies, these results suggest that lateralized cortical connections between (a) temporal lobe subsystems specialized for processing upright faces and gaze and (b) the parietal area specialized for orienting spatial attention underlie human reflexive shifts of attention in response to gaze direction.

The ventriloquist in motion: illusory capture of dynamic information across sensory modalities.

Integrating dynamic information across the senses is crucial to survival. However, most laboratory studies have only examined sensory integration for static events. Here we demonstrate that strong crossmodal integration can also occur for an emergent attribute of dynamic arrays, specifically the direction of apparent motion. The results of the present study show that the perceived direction of auditory apparent motion is strongly modulated by apparent motion in vision, and that both spatial and temporal factors play a significant role in this crossmodal effect. We also demonstrate that a split-brain patient who does not perceive visual apparent motion across the midline is immune to this audiovisual dynamic capture effect, highlighting the importance of motion being experienced in order for this new multisensory illusion to occur.

Look away! Eyes and arrows engage oculomotor responses automatically

The present study investigates how people’s voluntary saccades are influenced by where another person is looking, even when this is counterpredictive of the intended saccade direction. The color of a fixation point instructed participants to make saccades either to the left or right. These saccade directions were either congruent or incongruent with the eye gaze of a centrally presented schematic face. Participants were asked to ignore the eyes, which were congruent only 20% of the time. At short gaze—fixation-cue stimulus onset asynchronies (SOAs; 0 and 100 msec), participants made more directional errors on incongruent than on congruent trials. At a longer SOA (900 msec), the pattern tended to reverse. We demonstrate that a perceived eye gaze results in an automatic saccade following the gaze and that the gaze cue cannot be ignored, even when attending to it is detrimental to the task. Similar results were found for centrally presented arrow cues, suggesting that this interference is not unique to gazes.

Unmasking the inhibition of return phenomenon.

Conventional wisdom holds that a nonpredictive peripheral cue produces a biphasic response time (RT) pattern: early facilitation at the cued location, followed by an RT delay at that location. The latter effect is called inhibition of return (IOR). In two experiments, we report that IOR occurs at a cued location far earlier than was previously thought, and that it is distinct from attentional orienting. In Experiment 1, IOR was observed early (i.e., within 50 msec) at the cued location, when the cue predicted that a detection target would occur at another location. In Experiment 2, this early IOR effect was demonstrated to occur for target detection, but not for target identification. We conclude that previous failures to observe early IOR at a cued location may have been due to attention being directed to the cued location and thus “masking” IOR.