Walking reveals trunk orientation bias for visual attention

Abstract

688Psychologists have long recognized that people have finite capacities to attend to different sources of information (Broadbent, 1958;Deutsch & Deutsch, 1963;James, 1948). Because we live in a dynamic environment and cannot fully attend to all information at once, we must flexibly deploy our limited attentional resources in different degrees to various information streams (Kahneman, 1973). Although researchers have identified a number of factors that influence the deployment of attention, until recently the influence of trunk orientation has been largely ignored or taken for granted.To the extent that the configuration of our body parts constrain, our actions at any moment, they influence where we direct spatial attention. Our perceptual systems serve to plan adaptive actions (Previc, 1998;Prinz, 1997), and attention is the process by which we filter and select the most task-relevant perceptual information (Kahneman & Treisman, 1984). Consequently, attention should be deployed to those regions of space most relevant for performing the action.In particular, trunk orientation should be an important anchor for spatial attention (Jeannerod & Biguer, 1987;Karnath, Schenkel, & Fischer, 1991;Ventre, Flandrin, & Jeannerod, 1984). When using sensory information to guide actions, we must determine the relative configuration of the sensory and effector organs. For example, a visually detected object's retinotopic position indicates its location relative to the eye, but we need to know the object's position relative to the hand in order to plan an appropriate reach. This sensorimotor transformation requires that we account for the orientation of each connected structure between the eye and hand-orientation of the eye relative to the head, orientation of the lower arm relative to the upper arm, and so on (Biguer, Jeannerod, & Prablanc, 1985;Karnath, 1997). Structurally, the trunk is the hub to which our head, arms, and legs are flexibly attached. As a result, trunk orientation influences sensorimotor planning for many typical actions and should therefore affect the distribution of spatial attention.The trunk is often aligned with behaviorally important regions of space. First, although we may turn our head and eyes to look in other directions, we usually move in the direction in which the trunk points. The direction of attention toward the path of motion helps us to avoid collisions when locomoting through the environment. A trunk orientation bias for attention would literally help University of Denver, Denver, ColoradoOur trunks influence where we perform actions in space. Thus, trunk direction may define a region of space that is accorded special treatment by the attention system. We investigated conditions under which a trunk orientation bias for attention might be relevant for healthy adults. Three experiments compared visual detection performance for participants standing and walking on a treadmill. Together, the experiments disambiguate the relative contributions of motor activity, motor load, and cognitive load on ...

Dissociating contributions of head and torso to spatial reference frames: The misalignment paradigm

“…Hasselbach-Heitzeg and Reuter-Lorenz (2002) also found that rightward rotation reduced response times for targets on the right. Using a similar paradigm (adapted to enable treadmill walking) Grubb, Reed, Bate, Garza, and Roberts (2008) show that torso orientation facilitates target detection only when subjects are under increased motor load.…”

Grab it! Biased attention in functional hand and tool space

“…As a result, body part location should influence where spatial attention is allocated across visual space. Several studies in neurologically intact populations have documented that attention and lateralized visual target detection are biased by trunk orientation both when one is standing and when one is walking (Grubb & Reed, 2002;Grubb, Reed, Bate, Garza, & Roberts, 2008;HasselbachHeitzeg & Reuter-Lorenz, 2002).…”

Body position differentially influences responses to exogenous and endogenous cues

“…A tilt of the head has also been shown to induce rotations of a produced figure during hand drawing (Guerraz, Boulin, & Vercher, 2003). Similarly, the orientation of the trunk relative to an impending target location and the direction that a person is walking can also affect our responses to visual information (Grubb, Reed, Bate, Garza, & Roberts, 2008). In addition, orienting the trunk toward the left visual field in people influenced by hemispatial neglect has been shown to compensate for performance deficits in saccadic reaction times (Karnath, Schenkel, & Fischer, 1991).…”

“…While one is statically positioned in the HDNF orientation, the orientation of gravity relative to the head differs drastically from that of a typical head-upright position. Because a change in body orientation relative to potential target locations (Grubb et al, 2008;Karnath et al, 1991), changes in hand position relative to potential targets (Reed, Grubb, & Steele, 2006), and dynamic body maneuvers have all been shown to modify visual attention (e.g., Paige, Telford, Seidman, & Barnes, 1998;Seidman et al, 1998), it is entirely possible that the static HDNF position could influence visual attention. The combination of visual and vestibular inputs affects the current state of the system because the atypical positioning of the vestibular apparatus causes an increased demand on the multisensory processing that occurs within the central nervous system (Grubb et al, 2008).…”

“…Because a change in body orientation relative to potential target locations (Grubb et al, 2008;Karnath et al, 1991), changes in hand position relative to potential targets (Reed, Grubb, & Steele, 2006), and dynamic body maneuvers have all been shown to modify visual attention (e.g., Paige, Telford, Seidman, & Barnes, 1998;Seidman et al, 1998), it is entirely possible that the static HDNF position could influence visual attention. The combination of visual and vestibular inputs affects the current state of the system because the atypical positioning of the vestibular apparatus causes an increased demand on the multisensory processing that occurs within the central nervous system (Grubb et al, 2008). In this study, because of the static and continuous stimulation of the vestibular apparatus indicating an unusual orientation of gravity while in the HDNF position that would necessitate further multisensory integration (Angelaki, Gu, & DeAngelis, 2009;Stein & Stanford, 2008), participants were expected to experience less of an orienting response to the exogenous cue.…”