PD Dr. Oliver Herbort

• 
  Grießbach, E., Raßbach, P., Herbort, O., & Ca~n}}al-Bruland, R. (2024). Dual-tasking modulates movement speed but not value-based choices during walking. Scientific Reports, 14(1), 6342. https://doi.org/10.1038/s41598-024-56937-y
  • [ Abstract ]
  • [ DOI ]
  Value-based decision-making often occurs in multitasking scenarios relying on both cognitive and motor processes. Yet, laboratory experiments often isolate these processes, thereby neglecting potential interactions. This isolated approach reveals a dichotomy: the cognitive process by which reward influences decision-making is capacity-limited, whereas the influence of motor cost is free of such constraints. If true, dual-tasking should predominantly impair reward processing but not affect the impact of motor costs. To test this hypothesis, we designed a decision-making task in which participants made choices to walk toward targets for rewards while navigating past an obstacle. The motor cost to reach these rewards varied in real-time. Participants either solely performed the decision-making task, or additionally performed a secondary pitch-recall task. Results revealed that while both reward and motor costs influenced decision-making, the secondary task did not affect these factors. Instead, dual-tasking slowed down participants' walking, thereby reducing the overall reward rate. Hence, contrary to the prediction that the added cognitive demand would affect the weighing of reward or motor cost differentially, these processes seem to be maintained at the expense of slowing down the motor system. This slowdown may be indicative of interference at the locomotor level, thereby underpinning motor-cognitive interactions during decision-making.
• 
  Herbort, O., Raßbach, P., & Kunde, W. (2024). Where scrollbars are clicked, and why. Cognitive Research: Principles and Implications, 9, 23. https://doi.org/10.1186/s41235-024-00551-z
  • [ Abstract ]
  • [ DOI ]
  Scrolling is a widely used mean to interact with visual displays, usually to move content to a certain target location on the display. Understanding how user scroll might identify potentially suboptimal use and allows to infer users'intentions. In the present study, we examined where users click on a scrollbar depending on the intended scrolling action. In two online experiments, click positions were systematically adapted to the intended scrolling action. Click position selection could not be explained as strict optimization of the distance traveled with the cursor, memory load, or motor-cognitive factors. By contrast, for identical scrolling actions click positions strongly depended on the context and on previous scrolls. The behavior of our participants closely resembled behavior observed for manipulation of other physical devices and suggested a simple heuristic of movement planning. The results have implications for modeling human--computer interaction and may contribute to predicting user behavior.
• 
  Vogel-Blaschka, D., Kunde, W., Herbort, O., & Scherbaum, S. (2024). Ideonamic: An integrative computational dynamic model of ideomotor learning and effect-based action control. Psychological Review, 131(1), 79–103. https://doi.org/10.1037/rev0000460
  • [ DOI ]

• 
  Gregori, A., Amici, F., Brilmayer, I., Ćwiek, A., Fritzsche, L., Fuchs, S., Henlein, A., Herbort, O., Kügler, F., Lemanski, J., Liebal, K., Lücking, A., Mehler, A., Nguyen, K. T., Pouw, W., Prieto, P., Rohrer, P. L., Sánchez-Ramón, P. G., Schulte-Rüther, M., … von Eiff, C. I. (2023). A Roadmap for Technological Innovation in Multimodal Communication Research. In V. G. Duffy (Ed.), Digital Human Modeling and Applications in Health, Safety, Ergonomics and Risk Management. HCII 2023. Lecture Notes in Computer Science (Vols. 14029, pp. 402-438). Springer. https://doi.org/https://doi.org/10.1007/978-3-031-35748-0_30
  • [ DOI ]
• 
  Krause, L.-M., & Herbort, O. (2023). Just visual context or part of the gesture? The role of arm orientation in bent pointing interpretation. Acta Psychologica, 241, 104062. https://doi.org/10.1016/j.actpsy.2023.104062
  • [ Abstract ]
  • [ DOI ]
  Pointing gestures can take on different shapes. For example, people often point with a bent wrist at a referent that is occluded by another object. We hypothesized that while the extrapolation of the index finger is the most important visual cue in such bent pointing gestures, arm orientation is affecting interpretations as well. We tested two competing hypotheses. First, the arm could be processed as a less reliable but additional direction cue also indicating the referent. Consequently, the index finger extrapolation would be biased towards the arm direction (assimilation effect). Second, the arm could be perceived as visual context of the index finger, leading to an interpretation that is repulsed from the arm direction (contrast effect). To differentiate between both, we conducted two experiments in which arm and finger orientation of a virtual pointer were independently manipulated. Participants were asked to determine the pointed-at location. As expected, participants based their interpretations on the extrapolation of the index finger. In line with the second hypothesis, the more the arm was oriented upwards, the lower the point was interpreted and vice versa. Thus, interpretation pattern indicated a contrast effect. Unexpectedly, gestures with aligned arm and index finger deviated from the general contrast effect and were interpreted linearly compared to bent gestures. In sum, the experiments show that interpretations of bent pointing gestures are not only based on the direction of the index finger but also depend on the arm orientation and its relationship to the index finger orientation.
• 
  Grießbach, E., Raßbach, P., Herbort, O., & Ca~n}}al-Bruland, R. (2023). Embodied decision biases: individually stable across different tasks?. Experimental Brain Research, 241(4), 1053-1064. https://doi.org/10.1007/s00221-023-06591-z
  • [ Abstract ]
  • [ DOI ]
  In everyday life, action and decision-making often run in parallel. Action-based models argue that action and decision-making strongly interact and, more specifically, that action can bias decision-making. This embodied decision bias is thought to originate from changes in motor costs and/or cognitive crosstalk. Recent research confirmed embodied decision biases for different tasks including walking and manual movements. Yet, whether such biases generalize within individuals across different tasks remains to be determined. To test this, we used two different decision-making tasks that have independently been shown to reliably produce embodied decision biases. In a within-participant design, participants performed two tasks in a counterbalanced fashion: (i) a walking paradigm for which it is known that motor costs systematically influence reward decisions, and (ii) a manual movement task in which motor costs and cognitive crosstalk have been shown to impact reward decisions. In both tasks, we successfully replicated the predicted embodied decision biases. However, there was no evidence that the strength of the biases correlated between tasks. Hence, our findings do not confirm that embodied decision biases transfer between tasks. Future research is needed to examine whether this lack of transfer may be due to different causes underlying the impact of motor costs on decisions and the impact of cognitive crosstalk or task-specific differences.
• 
  Herbort, O., & Krause, L.-M. (2023). The efficiency of augmented pointing with and without speech in a collaborative virtual environment. In V. G. Duffy (Ed.), Digital Human Modeling and Applications in Health, Safety, Ergonomics and Risk Management. HCII 2023. Lecture Notes in Computer Science, (Vols. 14028). https://doi.org/https://doi.org/10.1007/978-3-031-35741-1_37
  • [ Abstract ]
  • [ DOI ]
  • [ Download ]
  Pointing is a ubiquitous part of human communication. However, pointing gestures to distal referents are often misunderstood systematically, which may limit the usefulness of pointing.We examined pointing-based communication in a collaborative virtual environment (CVE) to address three questions. First, we wanted to evaluate the potential of apparently natural but technically augmented pointing in CVEs, such as presenting a warped pointer for increased legibility or the ability to assume the pointer’s perspective. Second, we wanted to test whether technical improvements in pointing accuracy also facilitate communication if pointing is accompanied by speech. Third, we wanted to check whether pointing accuracy is correlated with the efficiency of communication involving pointing and speech. An experiment revealed that pointing-based communication has considerable potential to be enhanced in CVEs, albeit the specific augmentation procedure we employed did not improve pointing-based communication. Importantly, improvements in pointing accuracy also facilitated communication when speech was allowed. Thereby, speech reduced but could not rule out misunderstandings. Finally, even a small gain in pointing accuracy allowed participants to agree on a referent faster. In summary, the experiment suggests that augmented pointing may considerably improve interactions in CVEs. Moreover, speech cannot fully compensate misunderstandings of pointing gestures and relatively small differences in pointing accuracy affect the efficiency of communication of speech is allowed.

• 
  Grießbach, E., Herbort, O., & Cañal-Bruland, R. (2022). Wechselwirkung von motorischen und kognitiven Prozessen in hierarchisch organisiertem Verhalten: Vol. Kognition und Motorik – Sportpsychologische Grundlagen und Anwendungen im Sport (S. Klatt & B. Strauß, Eds.; pp. 46-58). Hogrefe Verlag.
• 
  Grießbach, E., Raßbach, P., Herbort, O., & Cañal-Bruland, R. (2022). Embodied decisions during walking. Journal of Neurophysiology, 128(5), 1207–1223. https://doi.org/10.1152/jn.00149.2022
  • [ DOI ]

• 
  Raßbach, P., Grießbach, E., Cañal-Bruland, R., & Herbort, O. (2021). Deciding while moving: Cognitive interference biases value-based decisions. Acta Psychologica, 221, 103449. https://doi.org/10.1016/j.actpsy.2021.103449
  • [ DOI ]
• 
  Krause, L.-M., & Herbort, O. (2021). The observer’s perspective determines which cues are used when interpreting pointing gestures. Journal of Experimental Psychology: Human Perception and Performance, 47(9), 1209–1225. https://doi.org/10.1037/xhp0000937
  • [ DOI ]
• 
  Kirsch, W., Kunde, W., & Herbort, O. (2021). Impact of proprioception on the perceived size and distance of external objects in a virtual action task. Psychonomic Bulletin & Review, 28(4), 1191-1201. https://doi.org/10.3758/s13423-021-01915-y
  • [ Abstract ]
  • [ DOI ]
  Previous research has revealed changes in the perception of objects due to changes of object-oriented actions. In present study, we varied the arm and finger postures in the context of a virtual reaching and grasping task and tested whether this manipulation can simultaneously affect the perceived size and distance of external objects. Participants manually controlled visual cursors, aiming at reaching and enclosing a distant target object, and judged the size and distance of this object. We observed that a visual--proprioceptive discrepancy introduced during the reaching part of the action simultaneously affected the judgments of target distance and of target size (Experiment 1). A related variation applied to the grasping part of the action affected the judgments of size, but not of distance of the target (Experiment 2). These results indicate that perceptual effects observed in the context of actions can directly arise through sensory integration of multimodal redundant signals and indirectly through perceptual constancy mechanisms.
• 
  Herbort, O., Krause, L.-M., & Kunde, W. (2021). Perspective determines the production and interpretation of pointing gestures. Psychonomic Bulletin & Review, 28(2), 641-648. https://doi.org/10.3758/s13423-020-01823-7
  • [ Abstract ]
  • [ DOI ]
  Pointing is a ubiquitous means of communication. Nevertheless, observers systematically misinterpret the location indicated by pointers. We examined whether these misunderstandings result from the typically different viewpoints of pointers and observers. Participants either pointed themselves or interpreted points while assuming the pointer's or a typical observer perspective in a virtual reality environment. The perspective had a strong effect on the relationship between pointing gestures and referents, whereas the task had only a minor influence. This suggests that misunderstandings between pointers and observers primarily result from their typically different viewpoints.
• 
  Grießbach, E., Incagli, F., Herbort, O., & Ca~n}}al-Bruland, R. (2021). Body dynamics of gait affect value-based decisions. Scientific Reports, 11(1), 11894. https://doi.org/10.1038/s41598-021-91285-1
  • [ Abstract ]
  • [ DOI ]
  Choosing among different options typically entails weighing their anticipated costs and benefits. Previous research has predominantly focused on situations, where the costs and benefits of choices are known before an action is effectuated. Yet many decisions in daily life are made on the fly, for instance, making a snack choice while walking through the grocery store. Notably, the costs of actions change dynamically while moving. Therefore, in this study we examined whether the concurrent action dynamics of gait form part of and affect value-based decisions. In three experiments, participants had to decide which lateral (left vs. right) target (associated with different rewards) they would go to, while they were already walking. Results showed that the target choice was biased by the alternating stepping behavior, even at the expense of receiving less reward. These findings provide evidence that whole-body action dynamics affect value-based decisions.

• 
  Herbort, O., & Kunde, W. (2019). Emergence of anticipatory actions in a novel task. Experimental Brain Research, 237(6), 1421-1430. https://doi.org/10.1007/s00221-019-05516-z
  • [ Abstract ]
  • [ DOI ]
  Humans normally adapt earlier segments of multistep motor actions in such a way that the execution of later segments is facilitated. For example, the kinematics of grasping movements are adapted to the requirements of the intended subsequent object manipulations. Here we studied which factors foster adaptation of earlier action segments to later ones in a novel task for which no prior experience existed. Participants executed a two-step isometric force production task, in which the force produced in the first segment determined the difficulty of the second segment. Adaptation of the first segment to the second one benefited from explicit knowledge of the dependency between both segments but not from extensive prior experience with the second segment. These observations show that adaptation of motor actions to subsequent actions demands the construction of a task representation that allows to plan the first action segment with respect to its successor. How specifically the first segment is tailored to the second one does not depend on prior experience with the second segment but depends on experience from performing the interdependent two-step action sequence.
• 
  Kirsch, W., Kunde, W., & Herbort, O. (2019). Intentional binding is unrelated to action intention. Journal of Experimental Psychology: Human Perception and Performance, 45(3), 378–385. https://doi.org/10.1037/xhp0000612
  • [ DOI ]
• 
  Dignath, D., Herbort, O., Pieczykolan, A., Huestegge, L., & Kiesel, A. (2019). Flexible coupling of covert spatial attention and motor planning based on learned spatial contingencies. Psychological Research, 83(3), 476-484. https://doi.org/10.1007/s00426-018-1134-0
  • [ Abstract ]
  • [ DOI ]
  The present study tested whether the coupling of covert attentional shifts and motor planning of pointing movements can be modulated by learning. Participants performed two tasks. As a primary movement task, they executed a pointing movement to a movement target (MT) location. As a secondary visual attention task, they identified a discrimination target (DT) that was presented shortly before initiation of the pointing movement. These DTs either occurred at the same or at different locations with the MT. A common finding in such and similar settings is the enhanced visual target identification when locations of MT and DT coincide. However, it is not known which factors govern the flexibility of spatial attention--action coupling. Here, we tested the influence of previously learned spatial contingencies between MT and DT on the coupling of covert attention and motor planning. These contingencies were manipulated in three groups (always same locations, always opposite locations, non-contingent locations) in a training session. Results indicated that in a subsequent test phase, previously learned contingencies enhanced visual identification accordingly, even when targets for the movement task and the visual task were presented at opposite sides. These results corroborate previous findings of a rather flexible interaction of attention and motor planning, and demonstrate how one can learn to control attention by means of motor planning.
• 
  Herbort, O., & Kunde, W. (2019). Precise movements in awkward postures: A direct test of the precision hypothesis of the end-state comfort effect. Journal of Experimental Psychology: Human Perception and Performance, 45(5), 681–696. https://doi.org/10.1037/xhp0000639
  • [ DOI ]
• 
  Herbort, O., Kirsch, W., & Kunde, W. (2019). Grasp planning for object manipulation without simulation of the object manipulation action. Journal of Experimental Psychology: Human Perception and Performance, 45(2), 237–254. https://doi.org/10.1037/xhp0000602
  • [ DOI ]
• 
  Huestegge, L., Herbort, O., Gosch, N., Kunde, W., & Pieczykolan, A. (2019). Free-choice saccades and their underlying determinants: Explorations of high-level voluntary oculomotor control. Journal of Vision, 19(3), 14. https://doi.org/10.1167/19.3.14
  • [ DOI ]

• 
  Herbort, O., Büschelberger, J., & Janczyk, M. (2018). Preschool children adapt grasping movements to upcoming object manipulations: Evidence from a dial rotation task. Journal of Experimental Child Psychology, 167, 62–77. https://doi.org/10.1016/j.jecp.2017.09.025
  • [ DOI ]
• 
  Herbort, O., & Kunde, W. (2018). How to point and to interpret pointing gestures? Instructions can reduce pointer--observer misunderstandings. Psychological Research, 82(2), 395-406. https://doi.org/10.1007/s00426-016-0824-8
  • [ Abstract ]
  • [ DOI ]
  In everyday communication, people often point. However, a pointing act is often misinterpreted as indicating a different spatial referent position than intended by the pointer. It has been suggested that this happens because pointers put the tip of the index finger close to the line joining the eye to the referent. However, the person interpreting the pointing act extrapolates the vector defined by the arm and index finger. As this line crosses the eye-referent line, it suggests a different referent position than the one that was meant. In this paper, we test this hypothesis by manipulating the geometry underlying the production and interpretation of pointing gestures. In Experiment 1, we compared naïve pointer-observed dyads with dyads in which the discrepancy between the vectors defining the production and interpretation of pointing acts has been reduced. As predicted, this reduced pointer--observer misunderstandings compared to the naïve control group. In Experiment 2, we tested whether pointers elevate their arms steeper than necessary to orient it toward the referent, because they visually steer their index finger tips onto the referents in their visual field. Misunderstandings between pointers and observers were smaller when pointers pointed without visual feedback. In sum, the results support the hypothesis that misunderstandings between (na{ï}ve) pointers and observers result from different spatial rules describing the production and interpretation of pointing gestures. Furthermore, we suggest that instructions that reduce the discrepancy between these spatial rules can improve communicating with pointing gestures.
• 
  Wirth, R., Foerster, A., Herbort, O., Kunde, W., & Pfister, R. (2018). This Is How To Be a Rule Breaker. Advances in Cognitive Psychology, 14(1), 21-37. https://doi.org/10.5709/acp-0235-2
  • [ Abstract ]
  • [ DOI ]
  Violating rules comes with cognitive conflict for the rule-breaker. Here, we probed for means to reduce the behavioral effects of this conflict by studying the combined impact of recency and frequency of rule violations. We found that violating a rule facilitated the initiation of a subsequent rule violation, while notable costs relative to rule-based responding remained in measures of re- sponse execution. Such costs during response execution vanished, however, when frequency and recency of rule violation worked in concert. That is, it is possible to overcome the costs of rule viola- tion when (a) having violated this particular rule frequently and (b) having violated this particular rule very recently. Moreover, we demonstrated that recent rule violations reduce the costs of cogni- tive conflict in an unrelated interference task (Simon task). Based on these findings, we present a revised model of the cognitive processes underlying deliberate rule violations.

• 
  Foerster, A., Wirth, R., Herbort, O., Kunde, W., & Pfister, R. (2017). Lying Upside-Down: Alibis Reverse Cognitive Burdens of Dishonesty. JOURNAL OF EXPERIMENTAL PSYCHOLOGY-APPLIED, 23(3), 301-319.
  • [ Abstract ]
  The cognitive processes underlying dishonesty, especially the inhibition of automatic honest response tendencies, are reflected in response times and other behavioral measures. Here we suggest that explicit false alibis might have a considerable impact on these cognitive operations. We tested this hypothesis in a controlled experimental setup. Participants first performed several tasks in a preexperimental mission (akin to common mock crime procedures) and received a false alibi afterward. The false alibi stated alternative actions that the participants had to pretend to have performed instead of the actually performed actions. In a computer-based inquiry, the false alibi did not only reduce, but it even reversed the typical behavioral effects of dishonesty on response initiation (Experiment1) and response execution (Experiment 2). Follow-up investigations of response activation via distractor stimuli suggest that false alibis automatize either dishonest response retrieval, the inhibition of the honest response, or both (Experiments 3 and 4). This profound impact suggests that false alibis can override actually performed activities entirely and, thus, documents a severe limitation for cognitive approaches to lie detection.
• 
  Kirsch, W., Herbort, O., Ullrich, B., & Kunde, W. (2017). On the origin of body-related influences on visual perception. Journal of Experimental Psychology: Human Perception and Performance, 43(6), 1222–1237. https://doi.org/10.1037/xhp0000358
  • [ DOI ]
• 
  Herbort, O., Mathew, H., & Kunde, W. (2017). Habit outweighs planning in grasp selection for object manipulation. Cognitive Psychology, 92, 127–140. https://doi.org/10.1016/j.cogpsych.2016.11.008
  • [ DOI ]
• 
  Janczyk, M., Büschelberger, J., & Herbort, O. (2017). Larger between-task crosstalk in children than in adults: Behavioral results from the backward crosstalk paradigm and a diffusion model analysis. Journal of Experimental Child Psychology, 155, 95–112. https://doi.org/10.1016/j.jecp.2016.11.007
  • [ DOI ]
• 
  Kunde, W., Schmidts, C., Wirth, R., & Herbort, O. (2017). Action effects are coded as transitions from current to future stimulation: Evidence from compatibility effects in tracking. Journal of Experimental Psychology: Human Perception and Performance, 43(3), 477–486. https://doi.org/10.1037/xhp0000311
  • [ DOI ]
• 
  Mathew, H., Kunde, W., & Herbort, O. (2017). Inverting the planning gradient: adjustment of grasps to late segments of multi-step object manipulations. Experimental Brain Research, 235(5), 1397-1409. https://doi.org/10.1007/s00221-017-4892-9
  • [ Abstract ]
  • [ DOI ]
  When someone grasps an object, the grasp depends on the intended object manipulation and usually facilitates it. If several object manipulation steps are planned, the first step has been reported to primarily determine the grasp selection. We address whether the grasp can be aligned to the second step, if the second step's requirements exceed those of the first step. Participants grasped and rotated a dial first by a small extent and then by various extents in the opposite direction, without releasing the dial. On average, when the requirements of the first and the second step were similar, participants mostly aligned the grasp to the first step. When the requirements of the second step were considerably higher, participants aligned the grasp to the second step, even though the first step still had a considerable impact. Participants employed two different strategies. One subgroup initially aligned the grasp to the first step and then ceased adjusting the grasp to either step. Another group also initially aligned the grasp to the first step and then switched to aligning it primarily to the second step. The data suggest that participants are more likely to switch to the latter strategy when they experienced more awkward arm postures. In summary, grasp selections for multi-step object manipulations can be aligned to the second object manipulation step, if the requirements of this step clearly exceed those of the first step and if participants have some experience with the task.

• 
  Herbort, O., & Kunde, W. (2016). Spatial (mis-)interpretation of pointing gestures to distal referents. Journal of Experimental Psychology: Human Perception and Performance, 42(1), 78–89. https://doi.org/10.1037/xhp0000126
  • [ DOI ]

• 
  Belardinelli, A., Herbort, O., & Butz, M. V. (2015). Goal-oriented gaze strategies afforded by object interaction. Vision Research, 106, 47–57. https://doi.org/10.1016/j.visres.2014.11.003
  • [ DOI ]
• 
  Herbort, O. (2015). Too much anticipation? Large anticipatory adjustments of grasping movements to minimal object manipulations. Human Movement Science, 42, 100–116. https://doi.org/10.1016/j.humov.2015.05.002
  • [ DOI ]
• 
  Herbort, O., & Butz, M. V. (2015). Planning grasps for object manipulation: integrating internal preferences and external constraints. Cognitive Processing, 16(1), 249-253. https://doi.org/10.1007/s10339-015-0703-z
  • [ Abstract ]
  • [ DOI ]
  Grasp selection for object manipulation depend on a person's preferences (e.g., comfortable grasp) and the object's shape (i.e., how the object can be grasped). Both have to be matched when planning to grasp an object. According to the simulation hypothesis, humans simulate the action outcome for each of the grasp options to select the best grasp. However, if an object offers many different grasp options, further processing is necessary to reduce the number of possibilities. According to the preference hypothesis, a preferred grasp is first computed and then adjusted to comply with the objects' shape, if necessary. To test the hypotheses, we asked participants to grasp knobs that could be grasped with two, four, or an unconstrained range of grasps. When participants chose among two or four options, planning time increased with the number of possible grasps which is in line with the simulation hypothesis. However, when grasps were unconstrained, planning times were as short as in the two-grasp condition, suggesting another---possibly preference-based---selection process in this case. In contrast to planning time, grasp choices were comparable regardless of the knob's shape. This suggests a common criterion most likely determined grasp selection in all conditions.

• 
  Herbort, O., Butz, M. V., & Kunde, W. (2014). The contribution of cognitive, kinematic, and dynamic factors to anticipatory grasp selection. Experimental Brain Research, 232(6), 1677-1688. https://doi.org/10.1007/s00221-014-3849-5
  • [ Abstract ]
  • [ DOI ]
  Object-directed grasping movements are usually adjusted in anticipation of the direction and extent of a subsequent object rotation. Such anticipatory grasp selections have been mostly explained in terms of the kinematics of the arm movement. However, object rotations of different directions and extents also differ in their dynamics and in how the tasks are represented. Here, we examined how the dynamics, the kinematics, and the cognitive representation of an object manipulation affect anticipatory grasp selections. We asked participants to grasp an object and rotate it by different angles and in different directions. To examine the influence of dynamic factors, we varied the object's weight. To examine the influence of the cognitive task representation, we instructed identical object rotations as either toward-top or away-from-top rotations. While instructed object rotation and cognitive task representation did affect grasp selection over the entire course of the experiment, a rather small effect of object weight only appeared late in the experiment. We suggest that grasp selections are determined on different levels. The representation of the kinematics of the object movement determines grasp selection on a trial-by-trial basis. The effect of object weight affects grasp selection by a slower adaptation process. This result implies that even simple motor acts, such as grasping, can only be understood when cognitive factors, such as the task representation, are taken into account.
• 
  Herbort, O., Rosenbaum, D., van der Wel, R., & Weiss, D. (2014). What’s in a Grasp?. American Scientist, 102(5), 366. https://doi.org/10.1511/2014.110.366
  • [ DOI ]
• 
  Herbort, O. (2014). Intelligente Bewegungen: Wie vorausschauendes Verhalten alltägliche Bewegungen einfacher macht. The Inquisitive Mind, 2. https://de.in-mind.org/article/intelligente-bewegungen-wie-vorausschauendes-verhalten-alltaegliche-bewegungen-einfacher
• 
  Herbort, O., & Rosenbaum, D. A. (2014). What is chosen first, the hand used for reaching or the target that is reached?. Psychonomic Bulletin & Review, 21(1), 170-177. https://doi.org/10.3758/s13423-013-0488-y
  • [ Abstract ]
  • [ DOI ]
  Models of information processing generally assume that stimuli are processed before actions are selected, at least in typical laboratory experiments where stimuli are presented and responses follow. In everyday life, however, there are generally fewer constraints on the ordering of decisions pertaining to stimuli and actions. This raises the question of which sorts of decisions normally precede which others. To address this question, we asked participants to aim for either of two targets with either hand on the basis of whichever combination seemed easiest. We analyzed the choices made in this free condition with choices made when the hand was specified or when the target was specified. We found that a model assuming similar selection processes in the hand-specified condition and the free condition provided the best account for the data. The data accord with the hypothesis that hand was generally chosen first in the free-choice condition.

• 
  Ehrenfeld, S., Herbort, O., & Butz, M. V. (2013). Modular, Multimodal Arm Control Models. In G. Baldassarre & M. Mirolli (Eds.), Computational and Robotic Models of the Hierarchical Organization of Behavior (pp. 129-154). Springer Berlin Heidelberg. https://doi.org/10.1007/978-3-642-39875-9_7
  • [ Abstract ]
  • [ DOI ]
  Human and animal behavior can be amazingly flexible and adaptive. Even when only considering the dexterity of human arm movements, a rather complex control architecture appears necessary. This control architecture faces three particular challenges, which we discuss in detail. First, sensory redundancy requires the flexible consideration, combination, and integration of different sources of information about the state of the arm and the surrounding environment. Second, motor redundancy requires the flexible consideration and resolution of behavioral alternatives. Third, the continuous uncertainty about body and environment requires flexible control strategies that take these uncertainties into account. Research in cognitive modeling as well as in psychology and neuroscience suggests that the human control system effectively solves and even partially exploits these challenges to generate the observable dexterity. Besides theoretical considerations from control and cognitive modeling perspectives, we survey the capabilities and current drawbacks of the sensorimotor redundancy resolving architecture (SURE{\_}REACH) of human arm reaching. Moreover, we consider an even more modular model of human motor control, which is currently being developed. Both architectures can yield the dexterous behavioral control observable in humans, but only the latter scales to many degrees of freedom. Thus, the architectures may provide insights on how dexterous motor control is realized in humans and on how more adaptive and flexible robot control systems may be developed in the future.
• 
  Ehrenfeld, S., Herbort, O., & Butz, M. (2013). Modular neuron-based body estimation: maintaining consistency over different limbs, modalities, and frames of reference. Frontiers in Computational Neuroscience, 7. https://doi.org/10.3389/fncom.2013.00148
  • [ Abstract ]
  • [ DOI ]
  This paper addresses the question of how the brain maintains a probabilistic body state estimate over time from a modeling perspective. The neural Modular Modality Frame (nMMF) model simulates such a body state estimation process by continuously integrating redundant, multimodal body state information sources. The body state estimate itself is distributed over separate, but bidirectionally interacting modules. nMMF compares the incoming sensory and present body state information across the interacting modules and fuses the information sources accordingly. At the same time, nMMF enforces body state estimation consistency across the modules. nMMF is able to detect conflicting sensory information and to consequently decrease the influence of implausible sensor sources on the fly. In contrast to the previously published Modular Modality Frame (MMF) model, nMMF offers a biologically plausible neural implementation based on distributed, probabilistic population codes. Besides its neural plausibility, the neural encoding has the advantage of enabling (a) additional probabilistic information flow across the separate body state estimation modules and (b) the representation of arbitrary probability distributions of a body state. The results show that the neural estimates can detect and decrease the impact of false sensory information, can propagate conflicting information across modules, and can improve overall estimation accuracy due to additional module interactions. Even bodily illusions, such as the rubber hand illusion, can be simulated with nMMF. We conclude with an outlook on the potential of modeling human data and of invoking goal-directed behavioral control.
• 
  Lohmann, J., Herbort, O., & Butz, M. (2013). Modeling the temporal dynamics of visual working memory. Cognitive Systems Research, 24, 80–86. https://doi.org/10.1016/j.cogsys.2012.12.009
  • [ DOI ]
• 
  Sigaud, O., Butz, M., Pezzulo, G., & Herbort, O. (2013). The anticipatory construction of reality as a central concern for psychology and robotics. New Ideas in Psychology, 31(3), 217–220. https://doi.org/10.1016/j.newideapsych.2012.12.004
  • [ DOI ]
• 
  Herbort, O. (2013). Optimal versus heuristic planning of object manipulations: A review and a computational model of the continuous end-state comfort effect. New Ideas in Psychology, 31(3), 291-301. https://doi.org/https://doi.org/10.1016/j.newideapsych.2013.01.003
  • [ Abstract ]
  • [ DOI ]
  Human beings select actions that facilitate the execution of later actions. For example, humans tend to select grasps that ensure that forthcoming object manipulations end in a comfortable posture (“end-state comfort effect”). Basic experimental results and their explanation within the optimal control framework are reviewed. I conclude that the discrete grasp selection tasks, which are commonly used to study anticipatory planning, leave room for alternative explanations. Moreover, the results of seven experiments employing a continuous grasp selection task seem incompatible with the optimal control (of end-state comfort) account. I introduce the weighted integration of multiple biases (WIMB) model, which accounts for many aspects of the selection of human grasp orientations in continuous tasks. Additionally, it accounts for the precision effect and hysteresis effect. The model shows that the brain may rely on a simple heuristic and does not actually has to anticipate the end-state of a movement to select effective grasps for object manipulations.

• 
  Herbort, O. (2012). Where to Grasp a Tool?: Task-Dependent Adjustments of Tool Transformations by Tool Users. Zeitschrift für Psychologie, 220(1), 37–43. https://doi.org/10.1027/2151-2604/a000089
  • [ DOI ]
• 
  Herbort, O., & Butz, M. V. (2012). The continuous end-state comfort effect: weighted integration of multiple biases. Psychological Research, 76(3), 345-363. https://doi.org/10.1007/s00426-011-0334-7
  • [ Abstract ]
  • [ DOI ]
  The grasp orientation when grasping an object is frequently aligned in anticipation of the intended rotation of the object (end-state comfort effect). We analyzed grasp orientation selection in a continuous task to determine the mechanisms underlying the end-state comfort effect. Participants had to grasp a box by a circular handle---which allowed for arbitrary grasp orientations---and then had to rotate the box by various angles. Experiments 1 and 2 revealed both that the rotation's direction considerably determined grasp orientations and that end-postures varied considerably. Experiments 3 and 4 further showed that visual stimuli and initial arm postures biased grasp orientations if the intended rotation could be easily achieved. The data show that end-state comfort but also other factors determine grasp orientation selection. A simple mechanism that integrates multiple weighted biases can account for the data.
• 
  Herbort, O., Koning, A., van Uem, J., & G. J. Meulenbroek, R. (2012). The end-state comfort effect facilitates joint action. Acta Psychologica, 139(3), 404–416. https://doi.org/10.1016/j.actpsy.2012.01.001
  • [ DOI ]
• 
  Kirsch, W., Herbort, O., Butz, M. V., & Kunde, W. (2012). Influence of Motor Planning on Distance Perception within the Peripersonal Space. PLOS ONE, 7(4), 1-9. https://doi.org/10.1371/journal.pone.0034880
  • [ Abstract ]
  • [ DOI ]
  We examined whether movement costs as defined by movement magnitude have an impact on distance perception in near space. In Experiment 1, participants were given a numerical cue regarding the amplitude of a hand movement to be carried out. Before the movement execution, the length of a visual distance had to be judged. These visual distances were judged to be larger, the larger the amplitude of the concurrently prepared hand movement was. In Experiment 2, in which numerical cues were merely memorized without concurrent movement planning, this general increase of distance with cue size was not observed. The results of these experiments indicate that visual perception of near space is specifically affected by the costs of planned hand movements.
• 
  Herbort, O., & Butz, M. V. (2012). Too Good to be True? Ideomotor Theory from a Computational Perspective. Frontiers in Psychology, 3. https://doi.org/10.3389/fpsyg.2012.00494
  • [ Abstract ]
  • [ DOI ]
  In recent years, Ideomotor Theory has regained widespread attention and sparked the development of a number of theories on goal-directed behavior and learning. However, there are two issues with previous studies’ use of Ideomotor Theory. Although Ideomotor Theory is seen as very general, it is often studied in settings that are considerably more simplistic than most natural situations. Moreover, Ideomotor Theory’s claim that effect anticipations directly trigger actions and that action-effect learning is based on the formation of direct action-effect associations is hard to address empirically. We address these points from a computational perspective. A simple computational model of Ideomotor Theory was tested in tasks with different degrees of complexity. The model evaluation showed that Ideomotor Theory is a computationally feasible approach for understanding efficient action-effect learning for goal-directed behavior if the following preconditions are met: (1) The range of potential actions and effects has to be restricted. (2) Effects have to follow actions within a short time window. (3) Actions have to be simple and may not require sequencing. The first two preconditions also limit human performance and thus support Ideomotor Theory. The last precondition can be circumvented by extending the model with more complex, indirect action generation processes. In conclusion, we suggest that Ideomotor Theory offers a comprehensive framework to understand action-effect learning. However, we also suggest that additional processes may mediate the conversion of effect anticipations into actions in many situations.

• 
  Herbort, O., & Butz, M. V. (2011). Habitual and goal-directed factors in (everyday) object handling. Experimental Brain Research, 213(4), 371-382. https://doi.org/10.1007/s00221-011-2787-8
  • [ Abstract ]
  • [ DOI ]
  A habitual and a goal-directed system contribute to action selection in the human CNS. We examined to which extent both systems interact when selecting grasps for handling everyday objects. In Experiment 1, an upright or inverted cup had to be rotated or moved. To-be-rotated upright cups were more frequently grasped with a thumb-up grasp, which is habitually used to hold an upright cup, than inverted cups, which are not associated with a specific grasp. Additionally, grasp selection depended on the overarching goal of the movement sequence (rotation vs. transport) according to the end-state comfort principle. This shows that the habitual system and the goal-directed system both contribute to grasp selection. Experiment 2 revealed that this object-orientation-dependent grasp selection was present for movements of the dominant- and non-dominant hand. In Experiment 3, different everyday objects had to be moved or rotated. Only if different orientations of an object were associated with different habitual grasps, the grasp selection depended on the object orientation. Additionally, grasp selection was affected by the horizontal direction of the forthcoming movement. In sum, the experiments provide evidence that the interaction between the habitual and the goal-directed system determines grasp selection for the interaction with every-day objects.

• 
  Herbort, O., Butz, M. V., & Pedersen, G. (2010). The SURE_REACH Model for Motor Learning and Control of a Redundant Arm: From Modeling Human Behavior to Applications in Robotics. In O. Sigaud & J. Peters (Eds.), From Motor Learning to Interaction Learning in Robots (pp. 85-106). Springer Berlin Heidelberg. https://doi.org/10.1007/978-3-642-05181-4_5
  • [ Abstract ]
  • [ DOI ]
  The recently introduced neural network SURE_REACH (sensorimotor unsupervised redundancy resolving control architecture) models motor cortical learning and control of human reaching movements. The model learns redundant, internal body models that are highly suitable to flexibly invoke effective motor commands. The encoded redundancy is used to adapt behavior flexible to situational constraints without the need for further learning. These adaptations to specific tasks or situations are realized by a neurally generated movement plan that adheres to various end-state or trajectory-related constraints. The movement plan can be implemented by proprioceptive or visual closed-loop control. This chapter briefly reviews the literature on computational models of motor learning and control and gives a description of SURE_REACH and its neural network implementation. Furthermore, we relate the model to human motor learning and performance and discuss its neural foundations. Finally, we apply the model to the control of a dynamic robot platform. In sum, SURE_REACH grounds highly flexible task-dependent behavior on a neural network framework for unsupervised learning. It accounts for the neural processes that underlie fundamental aspects of human behavior and is well applicable to the control of robots.
• 
  Herbort, O., & Butz, M. V. (2010). Planning and control of hand orientation in grasping movements. Experimental Brain Research, 202(4), 867-878. https://doi.org/10.1007/s00221-010-2191-9
  • [ Abstract ]
  • [ DOI ]
  Humans grasp objects in a way that facilitates the intended use of the object. We examined how humans grasp a circular control knob in order to turn it in different directions and by different extents. To examine the processes involved in anticipatory planning of grasps, we manipulated advance information about the location of the control knob and the target of the knob-turn. The forearm orientation at the time of grasping depended strongly on the knob-turn, with the direction of the knob-turn having a stronger effect than the extent of the knob-turn. However, the variability of the forearm orientations after the knob-turn remained considerable. Anticipatory forearm orientations began early during the grasping movement. Advance information had no influence on the trajectory of the grasp but affected reaction times and the duration of the grasp. From the results, we conclude that (1) grasps are selected in anticipation of the upcoming knob rotation, (2) the desired hand location and forearm orientation at the time of grasping are specified before the onset of the grasp, and (3) an online programming strategy is used to schedule the preparation of the knob-turn during the execution of the grasp.
• 
  Butz, M. V., Thomaschke, R., Linhardt, M. J., & Herbort, O. (2010). Remapping motion across modalities: tactile rotations influence visual motion judgments. Experimental Brain Research, 207(1), 1-11. https://doi.org/10.1007/s00221-010-2420-2
  • [ Abstract ]
  • [ DOI ]
  Multisensory interactions between haptics and vision remain poorly understood. Previous studies have shown that shapes, such as letters of the alphabet, when drawn on the skin, are differently perceived dependent upon which body part is stimulated and on how the stimulated body part, such as the hand, is positioned. Another line of research within this area has investigated multisensory interactions. Tactile perceptions, for example, have the potential to disambiguate visually perceived information. While the former studies focused on explicit reports about tactile perception, the latter studies relied on fully aligned multisensory stimulus dimensions. In this study, we investigated to what extent rotating tactile stimulations on the hand affect directional visual motion judgments implicitly and without any spatial stimulus alignment. We show that directional tactile cues and ambiguous visual motion cues are integrated, thus biasing the judgment of visually perceived motion. We further show that the direction of the tactile influence depends on the position and orientation of the stimulated part of the hand relative to a head-centered frame of reference. Finally, we also show that the time course of the cue integration is very versatile. Overall, the results imply immediate directional cue integration within a head-centered frame of reference.

• 
  Herbort, O., & Butz, M. V. (2009). Anticipatory Planning of Sequential Hand and Finger Movements. Journal of Motor Behavior, 41(6), 561-569. https://doi.org/10.3200/35-09-003-RA
  • [ DOI ]
• 
  Lohmann, J., Herbort, O., Wagener, A., & Kiesel, A. (2009). Anticipation of Time Spans: New Data from the Foreperiod Paradigm and the Adaptation of a Computational Model. In G. Pezzulo, M. V. Butz, O. Sigaud, & G. Baldassarre (Eds.), Anticipatory Behavior in Adaptive Learning Systems (pp. 170-187). Springer Berlin Heidelberg.
  • [ Abstract ]
  To act successfully, it is necessary to adjust the timing of one's behavior to events in the environment. One way to examine human timing is the foreperiod paradigm. It requires experimental participants to react to events that occur at more or less unpredictable time points after a warning stimulus (foreperiod). In the current article, we first review the empirical and theoretical literature on the foreperiod paradigm briefly. Second, we examine how behavior depends on either a uniform or peaked (at 500ms) probability distribution of many (15) possible foreperiods. We report adaptation to different probability distribution with a pronounced adaptation for the peaked (more predictable) distribution. Third, we show that Los and colleagues' [1] computational model accounts for our results. A discussion of specific findings and general implications concludes the paper.

• 
  Butz, M. V., & Herbort, O. (2008). Context-dependent predictions and cognitive arm control with XCSF. Proceedings of the 10th Annual Conference on Genetic and Evolutionary Computation, 1357–1364. https://doi.org/10.1145/1389095.1389360
  • [ Abstract ]
  • [ DOI ]
  While John Holland has always envisioned learning classifier systems (LCSs) as cognitive systems, most work on LCSs has focused on classification, datamining, and function approximation. In this paper, we show that the XCSF classifier system can be very suitably modified to control a robot system with redundant degrees of freedom, such as a robot arm. Inspired by recent research insights that suggest that sensorimotor codes are nearly ubiquitous in the brain and an essential ingredient for cognition in general, the XCSF system is modified to learn classifiers that encode piecewise linear sensorimotor structures, which are conditioned on prediction-relevant contextual input. In the investigated robot arm problem, we show that XCSF partitions the (contextual) posture space of the arm in such a way that accurate hand movements can be predicted given particular motor commands. Furthermore, we show that the inversion of the sensorimotor predictive structures enables accurate goal-directed closed-loop control of arm reaching movements. Besides the robot arm application, we also investigate performance of the modified XCSF system on a set of artificial functions. All results point out that XCSF is a useful tool to evolve problem space partitions that are maximally effective for the encoding of sensorimotor dependencies. A final discussion elaborates on the relation of the taken approach to actual brain structures and cognitive psychology theories of learning and behavior.
• 
  Butz, M. V., Herbort, O., & Pezzulo, G. (2008). Anticipatory, Goal-Directed Behavior. In G. Pezzulo, M. V. Butz, C. Castelfranchi, & R. Falcone (Eds.), The Challenge of Anticipation: A Unifying Framework for the Analysis and Design of Artificial Cognitive Systems (pp. 85-113). Springer Berlin Heidelberg. https://doi.org/10.1007/978-3-540-87702-8_5
  • [ Abstract ]
  • [ DOI ]
  David Hume may be one of the first who thought about the causes that actually enable us to act goal-directedly in our pursuit of happiness. Besides having usually an end, or goal, in mind, Hume realized that the end must elicit those means that were learned to correlate with the end. Such correlation knowledge, according to Hume (1748), was based on three types of connecting ``ideas'': resemblance, contiguity in time and place, and cause and effect. Knowledge of correlations and cause-effect relations alone, though, do not directly lead to effective behavior. Thus, not only the question how we learn correlations in the environment needs to be addressed, but also how we can exploit the obtained knowledge, if learned properly. While Hume did mainly address the former question, the latter question was acknowledged by Hume only in so far that the acquired knowledge may be used to pursue our goals.
• 
  Butz, M. V., Reif, K. L., & Herbort, O. (2008). Bridging the Gap: Learning Sensorimotor-Linked Population Codes for Planning and Motor Control. Proceedings of the International Conference on Cognitive Systems 2008. https://api.semanticscholar.org/CorpusID:3964257
• 
  Herbort, O., Butz, M. V., & Hoffmann, J. (2008). Multimodal Goal Representations and Feedback in Hierarchical Motor Control. Proceedings of the International Conference on Cognitive Systems 2008.

• 
  Butz, M. V., Herbort, O., & Hoffmann, J. (2007). Exploiting redundancy for flexible behavior: Unsupervised learning in a modular sensorimotor control architecture. Psychological Review, 114(4), 1015–1046. https://doi.org/10.1037/0033-295x.114.4.1015
  • [ DOI ]
• 
  Herbort, O., & Butz, M. V. (2007). Encoding Complete Body Models Enables Task Dependent Optimal Behavior. 2007 International Joint Conference on Neural Networks, 1639-1644. https://doi.org/10.1109/IJCNN.2007.4371203
  • [ Abstract ]
  • [ DOI ]
  Many neural network models of (human) motor learning focus on the acquisition of direct goal-to-action mappings, which results in rather inflexible motor control programs. We propose a neural network architecture (SURE_REACH) that acquires complete body models through unsupervised learning. It encodes redundancy on the kinematic and on the motor command level in order to exert highly flexible, task-dependent optimal control. This paper shows that our approach accounts for two forms of effective human behavior based on exploiting kinematic redundancy. First, depending on the starting posture, hand targets are pursued in different ways optimizing movement efficiency. Second, the arm posture at the end of a movement can be aligned anticipatorily to facilitate a subsequent movement. A discussion of computational implications and relations to behavioral and neurophysiological findings concludes the paper.
• 
  Herbort, O., Ognibene, D., Butz, M. V., & Baldassarre, G. (2007). Learning to select targets within targets in reaching tasks. 2007 IEEE 6th International Conference on Development and Learning, 7-12. https://doi.org/10.1109/DEVLRN.2007.4354040
  • [ Abstract ]
  • [ DOI ]
  We present a developmental neural network model of motor learning and control, called RL_SURE_REACH. In a childhood phase, a motor controller for goal directed reaching movements with a redundant arm develops unsupervised. In subsequent task-specific learning phases, the neural network acquires goal-modulation skills. These skills enable RL_SURE-REACH to master a task that was used in a psychological experiment by Trommershauser, Maloney, and Landy (2003). This task required participants to select aimpoints within targets that maximize the likelihood of hitting a rewarded target and minimizes the likelihood of accidentally hitting an adjacent penalty area. The neural network acquires the necessary skills by means of a reinforcement learning based modulation of the mapping from visual representations to the target representation of the motor controller. This mechanism enables the model to closely replicate the data from the original experiment. In conclusion, the effectiveness of learned actions can be significantly enhanced by fine-tuning action selection based on the combination of information about the statistical properties of the motor system with different environmental payoff scenarios.
• 
  Hoffmann, J., Berner, M., Butz, M. V., Herbort, O., Kiesel, A., Kunde, W., & Lenhard, A. (2007). Explorations of anticipatory behavioral control (ABC): a report from the cognitive psychology unit of the University of Würzburg. Cognitive Processing, 8(2), 133-142. https://doi.org/10.1007/s10339-007-0166-y
  • [ Abstract ]
  • [ DOI ]
  The report comprises recent theoretical considerations, experimental research, and simulations which all aim at a clarification of anticipatory mechanisms of behavioral control.
• 
  Hoffmann, J., Butz, M. V., Herbort, O., Kiesel, A., & Lenhard, A. (2007). Spekulationen zur Strukturideo-motorischer Beziehungen. Zeitschrift für Sportpsychologie, 14(3), 95–103. https://doi.org/10.1026/1612-5010.14.3.95
  • [ DOI ]
• 
  Butz, M. V., Lenhard, A., & Herbort, O. (2007). Emergent Effector-Independent Internal Spaces: Adaptation and Intermanual Learning Transfer in Humans and Neural Networks. 2007 International Joint Conference on Neural Networks, 1970-1975.

• 
  Herbort, O., Butz, M. V., & Hoffmann, J. (2005). Towards an Adaptive Hierarchical Anticipatory Behavior Control System. In C. Castelfranchi, C. Balkenius, M. V. Butz, & A. Ortony (Eds.), From reactive to anticipatory cognitive embodied systems: Papers from the AAAI fall symposium (pp. 83-90). AAAI Press.
• 
  Herbort, O., Butz, M. V., & Hoffmann, J. (2005). Towards the Advantages of Hierarchical Anticipatory Behavioral Control. In K. Opwis & I.-K. Penner (Eds.), Proceedings of the KogWis05. The German Cognitive Science Conference (pp. 77-82). Schwabe.
• 
  Oertel, K., Schultz, R., Blech, M., Herbort, O., Voskamp, J., & Urban, B. (2005). EmoTetris for recognition of affective states. International Conference on Human-Computer Interaction (HCI International) 2005. https://publica.fraunhofer.de/handle/publica/349077