Effects of an active visuomotor steering task on covert attention

In complex dynamic tasks such as driving it is essential to be aware of potentially important targets in peripheral vision. While eye tracking methods in various driving tasks have provided much information about drivers’ gaze strategies, these methods only inform about overt attention and provide limited grounds to assess hypotheses concerning covert attention. We adapted the Posner cue paradigm to a dynamic steering task in a driving simulator. The participants were instructed to report the presence of peripheral targets while their gaze was fixed to the road. We aimed to see whether and how the active steering task and complex visual stimulus might affect directing covert attention to the visual periphery. In a control condition, the detection task was performed without a visual scene and active steering. Detection performance in bends was better in the control task compared to corresponding performance in the steering task, indicating that active steering and the complex visual scene affected the ability to distribute covert attention. Lower targets were discriminated slower than targets at the level of the fixation circle in both conditions. We did not observe higher discriminability for on-road targets. The results may be accounted for by either bottom-up optic flow biasing of attention, or top-down saccade planning.Peer reviewe

Visual anticipation of the future path : Predictive gaze and steering

Skillful behavior requires the anticipation of future action requirements. This is particularly true during high-speed locomotor steering where solely detecting and correcting current error is insufficient to produce smooth and accurate trajectories. Anticipating future steering requirements could be supported using "model-free" prospective signals from the scene ahead or might rely instead on model-based predictive control solutions. The present study generated conditions whereby the future steering trajectory was specified using a breadcrumb trail of waypoints, placed at regular intervals on the ground to create a predictable course (a repeated series of identical "S-bends"). The steering trajectories and gaze behavior relative to each waypoint were recorded for each participant (N = 16). To investigate the extent to which drivers predicted the location of future waypoints, "gaps" were included (20% of waypoints) whereby the next waypoint in the sequence did not appear. Gap location was varied relative to the S-bend inflection point to manipulate the chances that the next waypoint indicated a change in direction of the bend. Gaze patterns did indeed change according to gap location, suggesting that participants were sensitive to the underlying structure of the course and were predicting the future waypoint locations. The results demonstrate that gaze and steering both rely upon anticipation of the future path consistent with some form of internal model.Peer reviewe

Tracking an occluded visual target with sequences of saccades

Gaze behavior during visual tracking consists of a combination of pursuit and saccadic movements. When the tracked object is intermittently occluded, the role of smooth pursuit is reduced, with a corresponding increase in the role of saccades. However, studies of visual tracking during occlusion have focused only on the first few saccades, usually with occlusion periods of less than 1 second in duration. We investigated tracking on a circular trajectory with random occlusions and found that an occluded object can be tracked reliably for up to several seconds with mainly anticipatory saccades and very little smooth pursuit. Furthermore, we investigated the accumulation of uncertainty in prediction and found that prediction errors seem to accumulate faster when an absolute reference frame is not available during tracking. We suggest that the observed saccadic tracking reflects the use of a time-based internal estimate of object position that is anchored to the environment via fixations.Peer reviewe

Physiological responses to proposals during dyadic decision-making conversations

A novel conversation-analytically informed paradigm was used to examine how joint decision-making interaction, with its various types of proposal sequences, is reflected in the physiological responses of participants. Two types of dyads–dyads with one depressed and one non-depressed participant (N = 15) and dyads with two non-depressed participants (N = 15)–engaged in a series of conversational joint decision-making tasks, during which we measured their skin conductance (SC) responses. We found that the participants’ SC response rates were higher and more synchronized during proposal sequences than elsewhere in the conversation. Furthermore, SC response rates were higher when the participant was in the role of a proposal speaker (vs. a proposal recipient), and making a proposal was associated with higher SC response rates for participants with depression (vs. participants without depression). Moreover, the SC response rates in the proposal speaker were higher when the recipient accepted (vs. not accepted) the proposal. We interpret this finding with reference to accepting responses suggesting a commitment to future action, for which the proposal speaker may feel specifically responsible for. A better understanding of the physiological underpinnings of joint decision-making interaction may help improve democratic practices in contexts where certain individuals experience challenges in this regard.Peer reviewe

Humans use Optokinetic Eye Movements to Track Waypoints for Steering

It is well-established how visual stimuli and self-motion in laboratory conditions reliably elicit retinal image stabilizing compensatory eye movements (CEM). Their organization and roles in natural-task gaze strategies is much less understood: are CEM applied in active sampling of visual information in human locomotion in the wild? If so, how? And what are the implications for guidance? Here, we directly compare gaze behavior in the real world (driving a car) and a fixed base simulation steering task. A strong and quantifiable correspondence between self-rotation and CEM counter-rotation is found across a range of speeds. This gaze behavior is “optokinetic”, i.e. optic flow is a sufficient stimulus to spontaneously elicit it in naïve subjects and vestibular stimulation or stereopsis are not critical. Theoretically, the observed nystagmus behavior is consistent with tracking waypoints on the future path, and predicted by waypoint models of locomotor control - but inconsistent with travel point models, such as the popular tangent point model.It is well-established how visual stimuli and self-motion in laboratory conditions reliably elicit retinal-image-stabilizing compensatory eye movements (CEM). Their organization and roles in natural-task gaze strategies is much less understood: are CEM applied in active sampling of visual information in human locomotion in the wild? If so, how? And what are the implications for guidance? Here, we directly compare gaze behavior in the real world (driving a car) and a fixed base simulation steering task. A strong and quantifiable correspondence between self-rotation and CEM counter-rotation is found across a range of speeds. This gaze behavior is “optokinetic”, i.e. optic flow is a sufficient stimulus to spontaneously elicit it in naïve subjects and vestibular stimulation or stereopsis are not critical. Theoretically, the observed nystagmus behavior is consistent with tracking waypoints on the future path, and predicted by waypoint models of locomotor control - but inconsistent with travel point models, such as the popular tangent point model.Peer reviewe

Humans Use Predictive Gaze Strategies to Target Waypoints for Steering

A major unresolved question in understanding visually guided locomotion in humans is whether actions are driven solely by the immediately available optical information (model-free online control mechanisms), or whether internal models have a role in anticipating the future path. We designed two experiments to investigate this issue, measuring spontaneous gaze behaviour while steering, and predictive gaze behaviour when future path information was withheld. In Experiment 1 participants (N = 15) steered along a winding path with rich optic flow: gaze patterns were consistent with tracking waypoints on the future path 1–3 s ahead. In Experiment 2, participants (N = 12) followed a path presented only in the form of visual waypoints located on an otherwise featureless ground plane. New waypoints appeared periodically every 0.75 s and predictably 2 s ahead, except in 25% of the cases the waypoint at the expected location was not displayed. In these cases, there were always other visible waypoints for the participant to fixate, yet participants continued to make saccades to the empty, but predictable, waypoint locations (in line with internal models of the future path guiding gaze fixations). This would not be expected based upon existing model-free online steering control models, and strongly points to a need for models of steering control to include mechanisms for predictive gaze control that support anticipatory path following behaviours.A major unresolved question in understanding visually guided locomotion in humans is whether actions are driven solely by the immediately available optical information (model-free online control mechanisms), or whether internal models have a role in anticipating the future path. We designed two experiments to investigate this issue, measuring spontaneous gaze behaviour while steering, and predictive gaze behaviour when future path information was withheld. In Experiment 1 participants (N = 15) steered along a winding path with rich optic flow: gaze patterns were consistent with tracking waypoints on the future path 1–3 s ahead. In Experiment 2, participants (N = 12) followed a path presented only in the form of visual waypoints located on an otherwise featureless ground plane. New waypoints appeared periodically every 0.75 s and predictably 2 s ahead, except in 25% of the cases the waypoint at the expected location was not displayed. In these cases, there were always other visible waypoints for the participant to fixate, yet participants continued to make saccades to the empty, but predictable, waypoint locations (in line with internal models of the future path guiding gaze fixations). This would not be expected based upon existing model-free online steering control models, and strongly points to a need for models of steering control to include mechanisms for predictive gaze control that support anticipatory path following behaviours.Peer reviewe

Making Food Decisions Together : Physiological and Affective Underpinnings of Relinquishing Preferences and Reaching Decisions

We used a novel interdisciplinary experimental paradigm where two types of dyads-15 dyads with one depressed and one non-depressed participant and 15 dyads with two non-depressed participants-engaged in a series of food-decision-making tasks. We examined how different communicative events during the decision-making process were reflected in the affective responses of the interacting participants, as indicated in their skin conductance (SC) response rates. The participants' SC response rates were found to be higher during the emergence of the final decision, compared to the other segments during the process. Furthermore, relinquishing one's initially expressed preferences was associated with SC response rates higher than the baseline. However, during the relinquishment segments, there was a negative interaction between depression diagnosis and SC response rates, which suggests that, compared to their non-depressed comparisons, it is affectively less arousing for the participants with depression to give up their previously expressed preferences.Peer reviewe

The psychophysiological experience of solving moral dilemmas together : An interdisciplinary comparison between participants with and without depression

Dyads with a depressed and a non-depressed participant (N = 15) and two nondepressed participants (N = 15) discussed a moral dilemma, during which the participants’ gaze direction and skin conductance (SC) were measured. Partner gazing occurred most frequently when a speaker took a strong stance toward saving a person in the dilemma, depressed participants however looking at their co-participants less often than non-depressed participants. The participants’ SC response rates were higher during responsive utterances expressing disagreement (vs. agreement) with co-participant ideas or suggesting that a person be sacrificed (vs. saved). We argue that a better understanding of the affective corollaries of human social interaction necessitates a balanced consideration of both contents of talk and behavioral patterns.Peer reviewe

Humans Use Predictive Gaze Strategies to Target Waypoints for Steering

major unresolved question in understanding visually guided locomotion in humans is whether actions are driven solely by the immediately available optical information (model-free online control mechanisms), or whether internal models have a role in anticipating the future path. We designed two experiments to investigate this issue, measuring spontaneous gaze behaviour while steering, and predictive gaze behaviour when future path information was withheld. In Experiment 1 participants (N = 15) steered along a winding path with rich optic flow: gaze patterns were consistent with tracking waypoints on the future path 1–3 s ahead. In Experiment 2, participants (N = 12) followed a path presented only in the form of visual waypoints located on an otherwise featureless ground plane. New waypoints appeared periodically every 0.75 s and predictably 2 s ahead, except in 25% of the cases the waypoint at the expected location was not displayed. In these cases, there were always other visible waypoints for the participant to fixate, yet participants continued to make saccades to the empty, but predictable, waypoint locations (in line with internal models of the future path guiding gaze fixations). This would not be expected based upon existing model-free online steering control models, and strongly points to a need for models of steering control to include mechanisms for predictive gaze control that support anticipatory path following behaviours. Peer reviewed Document type: Articl

Kovertti tarkkaavaisuus visuaalisessa ohjaustehtävässä

Kovertilla tarkkaavaisuudella viitataan ihmisen kykyyn suunnata tarkkaavaisuutta ääreisnäön alueella oleviin kohteisiin ilman katseen siirtämistä. Dynaamisissa ympäristöissä kuten liikenteessä on oleellista pystyä havainnoimaan ääreisnäön alueella esiintyviä kohteita ja suunnitelemaan omaa toimintaa tämän perusteella. Silmänliiketutkimuksella on tuotettu huomattava määrä tietoa mm. autolla ajajien katsekäyttäytymistä. Tämä tutkimus on kuitenkin yksi ensimmäisistä yrityksistä tutkia kovertin tarkkaavaavaisuuden suuntautumista aktiivista ohjausta vaativan ajotehtävän aikana. Tutkimuksessa pyrittiin selvittämään kuinka aktiivinen ohjaustehtävä ja visuaalinen tienäkymä mahdollisesti vaikuttavat kovertin tarkkaavaisuuden suuntautumiseen. Aiemman silmänliiketutkimuksen perusteella tiedetään, että ajajat tekevät systemaattisesti fiksaatioita tulevalle ajolinjalle. Tarkkaavaisuuden premotorisen teorian mukaan kovertin tarkkaavaisuuden suuntaaminen kohteeseen on ollennaisesti sama prosessi kuin sakkadin suunniteleminen kohteeseen. Tämän perusteella ennustetiin, että myös koverttia tarkkaavaisuutta mahdollisesti suunnataan enemmän tulevalle ajolinjalle kuin sen ulkopuolelle. Tutkimus suoritettiin ajosimulaattorilla. Koehenkilöt (n = 26) oli ohjeistettu pitämään katseensa tiellä sijaitsevan fiksaatiympyrän sisällä, samalla kun he ohjasivat virtuaalista ajoneuvoa mutkaisella tiellä ja pyrkivät tunnistamaan perifeerisen näön alueella esitettäviä kohdeärsykkeitä. Ärsykelokaatiot oli valittu siten, että osa ärsykkeistä sijaitsi koehenkilön tulevalla ajolinjalla ja osa sen ulkopuolella. Koehenkilöt pelasivat ohjaustehtävän lisäksi myös verrokkitehtävää, jossa ohjaus oli automatisoitu ja tienäkymä oli peitetty harmaan taustan alle. Tutkimuksesta havaittiin, että ohjauksen lisäämä kuormitus tai visuaalisen ohjausympäristön vaikutus näytti heikentävän kykyä jakaa tarkkaavaisuutta ruudulla esitettyihin ärsykkeisiin. Sen sijaan ei kuitenkaan havaittu, että tarkkaavaisuutta jakaututisi enemmän tulevalle ajolinjalle