Theory of visual attention (TVA) in action: Assessing premotor attention in simultaneous eye-hand movements

Abstract

Attention shifts that precede goal-directed eye and hand movements are regarded as markers of motor target selection. Recent studies found parallel allocation of visuospatial attention to saccade and reach targets during simultaneous eye-hand movements, arguing in favor of independent, effector-specific target selection mechanisms. This raises the question whether the overall attention capacity increases with the number of active effectors. In a modified Theory of Visual Attention (TVA; Bundesen, 1990) paradigm, participants reported briefly presented letters during eye, hand, or combined eye-hand movement preparation to centrally cued locations.Modeling the data according to the TVA allowed us to assess both the overall attention capacity as well as the deployment of visual attention to individual locations in the visual work space. In two experiments, we show that attention was predominantly allocated to the motor targets -without competition between effectors. The parallel benefits at eye and hand targets, however, had concomitant costs at non-motor locations, and the overall attention capacity was not increased by the simultaneous recruitment of both effector systems. Moreover, premotor shifts of attention dominated over voluntary deployment of processing resources, yielding severe impairments of voluntary attention allocation. We conclude that attention shifts to multiple effector targets without mutual competition, given that sufficient processing resources can be withdrawn from movementirrelevant locations.

Eye and hand movements disrupt attentional control

“…Eye-only and Hand-only ), combined effector movements to separate locations did neither significantly reduce discrimination performance at the eye target ( p = 0.819, d = 0.094) nor at the hand target ( p = 0.366, d = 0.225). In summary, this demonstrates that during simultaneous eye-hand movements, attention is deployed to both movement targets in parallel without any observable cost, which is in line with previous studies [ 33 – 35 ; but see 41 ].…”

“…Different aspects of our results are not compatible with other major frameworks referring to the relationship between attentional control and premotor attention. First, our present and earlier observations of multiple, simultaneous attentional peaks [ 33 – 35 , 49 , 50 ] are incompatible with priority map models assuming a strict winner-take-all attentional selection, in which performance benefits should occur only at the highest peak [ 26 – 29 ]. Second, our finding that eye and hand movements draw attention away from the voluntary attended location is incompatible with the view that motor actions merely follow the current focus of voluntary attention, as is assumed in visual search frameworks [ 2 , 26 , 51 , 52 ].…”

“…Experiment 1 comprised seven tasks (randomized block design): Attention-only , Eye-only , Hand-only , Eye-Hand , Attention-Eye , Attention-Hand , Attention-Eye-Hand . Compared to earlier studies [ 33 – 35 ] this design allows us to investigate all possible combinations of spatial attention related to eye movement preparation, hand movement preparation, and voluntary attention. Fig 1A depicts the sequence for the Attention-Eye-Hand task (see S1 Video for a trial demonstration): Participants initially fixated a central fixation target (FT) comprising a black (~0 cd/m2) and white (~98 cd/m2) “bull’s eye” (radius 0.5°) on a gray background (~60 cd/m2).…”

“…Instead, the reverse might be true, and successful movements depend on preceding attentional selection to specify the motor coordinates for an upcoming movement [ 20 , 32 ]. Based on this assumption, the attentional landscapes framework was proposed [ 20 ], which explicitly deals with multiple attentional foci, as they can occur during simultaneous eye-hand movements [ 33 – 35 ]. While cognitive control and premotor attention are closely linked in both frameworks, the implied direction of this relationship is opposite.…”

Dyslexics’ Fragile Oculomotor Control Is Further Destabilized by Increased Text Difficulty

“…Although differences in subjects could certainly produce differing results in the established literature, is there any role for how attention and engagement with the text, or how text choice itself, could affect eye movements? Some have argued that attention is a byproduct of eye movements [32][33][34][35][36]. Daniel et al argue that the vector of visual attention lies in the interaction of saccade, vergence, and accommodation [8,9,35].…”