Trunk-Assisted Prehension: Specification of Body Segments With Imposed Temporal Constraints

The authors used a trunk-assisted prehension task to examine intersegment coordination. Participants (N = 7) reached to grasp an object placed beyond full arm extension, thus requiring trunk flexion to achieve the target object, under 4 varying temporal constraints. Kinematic analyses were performed in which the motions of the arm, the trunk, and the endpoint were characterized. The spatial trajectories and the segments' peak velocity data revealed that under high temporal constraints the arm was more responsible for endpoint motion than the trunk, whereas in the unconstrained condition the trunk was more involved. In addition, the arm exhibited a decline in spatial variability toward the end of the movement in all conditions, whereas the trunk did not. The present study is the first to show that when temporal demand is increased for a trunk-assisted prehensile task, the arm plays a larger role than the trunk in the transport of the hand to the object The data also suggest that the arm participates in the fine accuracy control of the reach, whereas the trunk does not.     

The Learning of Programmed- and Feedback-Based Processes Controlling the Production of a Positioning Response in Two Dimensions

Two experiments were conducted to investigate the learning of the programmed- and feedback-based processes controlling the production of a slow, self-paced positioning response in two dimensions (direction and extent) in the horizontal plane. Both experiments had two phases: an acquisition phase of 60 trials with KR, followed by a KR withdrawal phase of 20 trials. In Experiment 1, one group (N=15) had visual feedback about the ongoing movement and the other group (N=15) did not. In Experiment 2, one group (N=15) practiced initiating the response in the criterion direction and moving the criterion extent, whereas, the other group (N=15) practiced initiating the response in the criterion direction and moving randomly varied extents. The results of Experiment 1 indicated that the learning of a programmed-based process is a gradually acquired freedom from visual feedback. Experiment 2 revealed that a programmed-based process can be learned independent of a feedback-based process.     

Motor Schema Formation and Retention in Young Children

The variability-of-practice hypothesis, a major prediction of Schmidt’s (1975) motor schema theory, was tested in an attempt to investigate motor-schema formation. In addition, schema retention was observed after a 2-week retention interval. The task involved preschool children in tossing a bean bag for appropriate distance. Four treatment groups received 100 practice trials equally divided over five days. Variation was provided by varying the weights of the bean bags. The testing situations involved tossing a criterion weighted bean bag as well as a novel weighted bean bag which none of the groups had experienced previously. In addition, all groups were tested on a new but similar task. The results supported the variability-of-practice hypothesis in terms of schema formation and transfer to novel tasks in the same movement class. After a two-week retention interval, loss in performance was significantly less for the group with variability of practice than all other groups.     

Robot studies on saccade-triggered visual prediction

Three robot studies on visual prediction are presented. In all of them, a visual forward model is used, which predicts the visual consequences of saccade-like camera movements. This forward model works by remapping visual information between the pre- and postsaccadic retinal images; at an abstract modeling level, this process is closely related to neurons whose visual receptive fields shift in anticipation of saccades. In the robot studies, predictive remapping is used (1) in the context of saccade adaptation, to reidentify target objects after saccades are carried out; (2) for a model of grasping, in which both fixated and non-fixated target objects are processed by the same foveal mechanism; and (3) in a computational architecture for mental imagery, which generates “gripper appearances” internally without real sensory inflow. The robotic experiments and their underlying computational models are discussed with regard to predictive remapping in the brain, transsaccadic memory, and attention. The results confirm that visual prediction is a mechanism that has to be considered in the design of artificial cognitive agents and the modeling of information processing in the human visual system.     

The Influence of Predeployment Training on Coordination in Multinational Headquarters: The Moderating Role of Organizational Obstacles to Information Sharing

Coordination is critical to the success of multinational military operations and may be fostered by predeployment training. We argue that whether such training is related to a high degree of perceived coordination at the individual level is likely to depend on whether individuals experience a low degree of organizational obstacles to information sharing. We examined this using data from the North Atlantic Treaty Organization (NATO) Kosovo Force headquarters (survey: n = 131). We controlled for whether it was the participants’ first deployment, the participants’ background (military or civilian), the amount of time spent in the headquarters by participants, whether differences pertaining to culture and opinions were valued by the organization, the quality of supervisor/subordinate relationships, and the degree of national cultural obstacles to information sharing. The results showed no significant direct effects on coordination from 3 different training configurations: national training, multinational training, and a combination of national and multinational training. However, we found a negative direct effect from organizational obstacles to information sharing on coordination, and support for organizational obstacles to information sharing as negatively moderating the multinational predeployment training and coordination relationship. Qualitative interviews (n = 14) indicated that informal information sharing, and the problems exchanging information from tactical to operational levels could hinder coordination. Interventions to foster coordination could benefit from a focus on multinational training and lowering organizational obstacles to information sharing. Our findings contribute to more precisely pinpointing the types of training that are useful in multinational operations, as well as the factors upon which training transfer is contingent.     

Development of Cognitive Skills in Children with Motor Coordination Impairments at 12-Month Follow-up

The current study presents a 1-year follow-up investigation of the development of executive functions (i.e., inhibition, updating, and shifting) in children with motor coordination impairments. Cognitive and motor coordination skills of children (N = 94) aged between 5 and 7 years with and without motor coordination impairments were compared. A second focus of the study was on pre-academic skills. The results indicate marked stability of motor coordination impairments and persistent executive functioning deficits in motor-impaired children. Inhibition and shifting performance was consistently lower, compared to the children without motor coordination impairments. Moreover, children with motor coordination impairments showed lower pre-academic skills, facing a substantial disadvantage at the beginning of formal schooling. The combined cognitive and motor problems may be the result of an underlying inhibition deficit or a general automation deficit. Implications for intervention are discussed.     

A social-psychological perspective on tacit coordination: How it works,when it works, (and when it does not)

We present a programmatic line of experimental studies which focus on the how and when of tacit coordination (i.e., the phenomenon that people can successfully coordinate their decisions without communication). We investigated this phenomenon using different types of economic games (i.e., social dilemmas as well as coordination games). Our studies broadly cover three themes: (a) fairness as a coordination rule, (b) uncertainty and common understanding, (c) social information as a cue. By focusing on these themes we have obtained several new insights on the prerequisites and boundary conditions of tacit coordination. We conclude that tacit coordination is often facilitated by mutual adherence to social norms (e.g., fairness rules, rules of deference, etcetera), but that in order to employ such norms people need sufficient environmental and/or social information.     

The effects of emotional stimuli on target detection: indirect and direct resource costs

The present study was designed to explore the performance costs of negative emotional stimuli in a vigilance task. Forty participants (20 women) performed a vigilance task in two conditions: one with task-irrelevant negative-arousing pictures and one with task-irrelevant neutral pictures. In addition to performance, we measured subjective state (energetic arousal, tense arousal, task-related and task-unrelated thoughts) and frontal cerebral activity with near infrared spectroscopy. Overall performance in the negative picture condition was lower than in the neutral picture condition and the negative picture condition had elevated levels of energetic arousal, tense arousal and task-related thoughts. Moreover, there was a significant relationship between the impact of the negative pictures on tense arousal and task-related thoughts and the impact of the negative pictures on performance (in comparison to the neutral picture stimuli task). These results provide support for indirect cost models of negative emotional stimuli on target detection performance.     

Object-based auditory facilitation of visual search for pictures and words with frequent and rare targets

Auditory and visual processes demonstrably enhance each other based on spatial and temporal coincidence. Our recent results on visual search have shown that auditory signals also enhance visual salience of specific objects based on multimodal experience. For example, we tend to see an object (e.g., a cat) and simultaneously hear its characteristic sound (e.g., “meow”), to name an object when we see it, and to vocalize a word when we read it, but we do not tend to see a word (e.g., cat) and simultaneously hear the characteristic sound (e.g., “meow”) of the named object. If auditory–visual enhancements occur based on this pattern of experiential associations, playing a characteristic sound (e.g., “meow”) should facilitate visual search for the corresponding object (e.g., an image of a cat), hearing a name should facilitate visual search for both the corresponding object and corresponding word, but playing a characteristic sound should not facilitate visual search for the name of the corresponding object. Our present and prior results together confirmed these experiential association predictions. We also recently showed that the underlying object-based auditory–visual interactions occur rapidly (within 220 ms) and guide initial saccades towards target objects. If object-based auditory–visual enhancements are automatic and persistent, an interesting application would be to use characteristic sounds to facilitate visual search when targets are rare, such as during baggage screening. Our participants searched for a gun among other objects when a gun was presented on only 10% of the trials. The search time was speeded when a gun sound was played on every trial (primarily on gun-absent trials); importantly, playing gun sounds facilitated both gun-present and gun-absent responses, suggesting that object-based auditory–visual enhancements persistently increase the detectability of guns rather than simply biasing gun-present responses. Thus, object-based auditory–visual interactions that derive from experiential associations rapidly and persistently increase visual salience of corresponding objects.     

Sequential dependencies in driving

The effect of recent experience on current behavior has been studied extensively in simple laboratory tasks. We explore the nature of sequential effects in the more naturalistic setting of automobile driving. Driving is a safety-critical task in which delayed response times may have severe consequences. Using a realistic driving simulator, we find significant sequential effects in pedal-press response times that depend on the history of recent stimuli and responses. Response times are slowed up to 100 ms in particular cases, a delay that has dangerous practical consequences. Further, we observe a significant number of history-related pedal misapplications, which have recently been noted as a cause for concern in the automotive safety community. By anticipating these consequences of sequential context, driver assistance systems could mitigate the effects of performance degradations and thus critically improve driver safety.