No-support Condition Research Articles

Interactions of sprint interval exercise and psychological need-support on subsequent food intake among physically inactive men and women.

The aim of this study was to investigate the effect of sprint interval training (SIT) and psychological need-support in exercise on postexercise appetite and energy intake. Forty physically inactive men and women (body mass index, 24.6 ± 4.8 kg·m-2; peak oxygen consumption, 26.6 ± 4.9 mL·kg-1·min-1) were randomised to either a need-support or no-support condition, with each participant completing 2 experimental trials involving 30 min of moderate-intensity continuous training (MICT; 60% peak oxygen consumption) and SIT (alternating 15 s at 170% peak oxygen consumption and 60 s at 32% peak oxygen consumption) matched for total work. Perceptions of appetite and appetite-related blood variables were assessed, together with ad libitum energy intake for 3 h following exercise using a laboratory test meal and available snacks. Greater enjoyment, perceived exertion, heart rate, and blood lactate were observed in SIT compared with MICT (all p ≤ 0.006). Ratings of perceived appetite were similar across conditions and trials (p > 0.05); however, active ghrelin was lower following SIT compared with MICT (p < 0.001), and there was a significant condition-by-type interaction for energy intake (p = 0.033), with participants in the support group consuming less energy from foods following SIT (1895 ± 1040 kJ) than MICT (2475 ± 1192 kJ). Findings from this work highlight the need to reconsider traditional exercise guidelines where dietary intake is a concern. Novelty Enjoyment was greater during SIT compared with MICT. Enjoyment and choice were higher among participants provided with psychological need-support. In a need-supportive environment, SIT reduced subsequent energy intake compared with MICT.

Trust and Acceptance of Adaptive and Conventional Collision Avoidance Systems

A simulator driving experiment was conducted to test the implementation of an adaptive driver support system for avoiding collisions caused by hazardous lane changes. Conventional (nonadaptive) collision avoidance systems with fixed function allocation might be effective from a safety perspective, but they are not always desirable from human factors perspective due to problems related to performance, trust, and acceptance. We therefore propose an adaptive collision avoidance system to provide support depending on the situation in consideration of the driver’s ability to handle the situation and the time to collision. Four driving modes were compared: no support, a haptic shared steering control system with an adaptive haptic authority based on time to collision, a cooperative steering control system that decoupled the driver’s steering input and controlled the vehicle’s direction temporarily, and an adaptive steering control system in which both haptic and cooperative control systems were integrated to provide different automated interventions at the steering wheel depending on the situation. The simulation participants were subjected to various potentially hazardous lane change maneuvers that provided significant differences in their abilities to perceive the risk and handle the situation. Compared to the no-support condition, all systems were more effective in accident prevention. The adaptive system was more effective than the haptic system and less effective than the cooperative system in terms of safety. However, driver performance, trust, and acceptability were significantly improved with the adaptive system compared to the nonadaptive systems.

Solving the second-order free rider problem in a public goods game: An experiment using a leader support system.

Punishment of non-cooperators—free riders—can lead to high cooperation in public goods games (PGG). However, second-order free riders, who do not pay punishment costs, reduce the effectiveness of punishment. Here we introduce a “leader support system,” in which one group leader can freely punish group followers using capital pooled through the support of group followers. In our experiment, participants engage in three stages repeatedly: a PGG stage in which followers decide to cooperate for their group; a support stage in which followers decide whether to support the leader; and a punishment stage in which the leader can punish any follower. We compare a support-present condition with a no-support condition, in which there is an external source for the leader’s punishment. The results show that punishment occurs more frequently in the support-present condition than the no-support condition. Within the former, both higher cooperation and higher support for a leader are achieved under linkage-type leaders—who punish both non-cooperators and non-supporters. In addition, linkage-type leaders themselves earn higher profits than other leader types because they withdraw more support. This means that leaders who effectively punish followers could increase their own benefits and the second-order free rider problem would be solved.

Avoiding the problem state bottleneck by strategic use of the environment

We investigated whether environmental support can be used to circumvent the problem state bottleneck in human multitasking. Previously, it was shown that people can only maintain a single chunk of information in their problem state resource, the central part of working memory. Consequently, when the problem state resource was required by multiple tasks concurrently, performance decreased. This phenomenon was termed the problem state bottleneck. To investigate whether the environment can be used to circumvent this bottleneck, we conducted an experiment with two main conditions. In the No-Support condition we replicated an earlier experiment that indicated the existence of the problem state bottleneck. In the Support condition we presented external cues, reducing the load on the problem state resource. To support the results of the experiment we present a computational cognitive model. The experiment and model indicated that the problem state bottleneck can be avoided by using external cues. However, subjects only used external cues when this led to faster behavior. These results were interpreted in the light of the Soft Constraints Hypothesis, which states that humans always follow the fastest strategy possible, as opposed to the most accurate strategy.

The Conjoined Effect of Naturalistic Perceived Available Support and Enacted Support on Cardiovascular Reactivity During a Laboratory Stressor

Studies have suggested that enacted social support has salutogenetic effects on cardiovascular activation during stress. This study aims to examine the conjoined effect of naturalistic perceived available support and enacted support on cardiovascular reactivity to a laboratory stressor. Seventy-one participants assigned themselves to one of two conditions: enacted social support before the onset of a stressor or no support. Perceived available support was assessed via a questionnaire, and heart rate (HR), heart rate variability (HRV), mean arterial blood pressure (MAP), and baroreceptor reflex sensitivity (BRS) were analyzed in response to a speech task. Whereas perceived available support was unrelated to cardiovascular activity in the no-support condition, it was accompanied by attenuated HR and increased HRV in the enacted-support condition. Moreover, perceived available support was associated with greater HR, HRV, and BRS reactivity to the speech task and better MAP recovery. Together, these findings support the assumption that different aspects of social support are related to different physiological processes.

The ground reaction curve of underwater tunnels considering seepage forces

When a tunnel is excavated below groundwater table, the groundwater flows into the excavated wall of tunnel and seepage forces are acting on the tunnel wall. Such seepage forces significantly affect the ground reaction curve which is defined as the relationship between internal pressure and radial displacement of tunnel wall. In this paper, seepage forces arising from the ground water flow into a tunnel were estimated quantitatively. Magnitude of seepage forces was estimated based on hydraulic gradient distribution around tunnel. Using these results, the theoretical solutions of ground reaction curve with consideration of seepage forces under steady-state flow were derived. A no-support condition was taken into account. The theoretical solution derived in this study was validated by numerical analysis. The changes in the ground reaction curve according to various ground and groundwater conditions were investigated. Based on the results, the application limit of theoretical solution was suggested.

Comparison of two heights for forward-placed trunk support with standing work

Two forward-placed supports with different heights are investigated using human motion capture and EMG. Ten male participants stood in 10° increments of trunk flexion between 0 and 40° for three conditions; leaning on a desk adjusted to the height of the pelvis, leaning on a prototype support at the height of the sternum and with no external support. Low back and hip extensor muscle activity was reduced by an average 60% with leaning against the prototype compared to the no-support condition whereas leaning on a desk produced no significant change in muscle activity. Supported conditions resulted in greater forward displacement of the trunk by at least two-fold compared to no-support representing a longer reach distance. No adverse changes in kinematics indicate that either support blocked segmental flexion of the pelvis, lumbar spine or thoracic spine. These findings suggest that leaning against a higher-placed trunk support could be beneficial for tasks requiring forward flexion.

Effects of video-relayed social support on hemodynamic reactivity and salivary cortisol during laboratory-based behavioral challenge.

The authors tested the effects of a laboratory analogue of social support on reactivity to laboratory-based behavioral challenge. Video-relayed supportive commentary was provided by a same-sex confederate while participants (40 healthy men and women assigned to support and no-support groups) performed a demanding computer task, and their heart rate, systolic and diastolic blood pressure, and salivary cortisol were measured. The authors found that heart rate and cortisol level (but not blood pressure) were attenuated in the support condition for both genders. Objective performance on the task was similar in both groups, but the social support group reported higher levels of perceived support and rated the task as easier than did participants in the no-support condition. Video presentation offers new opportunities for systematically examining social support and its effects.

An Evaluation Study of the Effectiveness of Multi-attribute Decision Support as a Function of Problem Complexity

This study focuses on the evaluation of multi-attribute (MAU) decision support for problems differing in complexity. In this study we compared decision making with a computerized decision support system (DECAID) with the unaided process. Overall, results indicate that MAU support led to a more thorough decision process, had more impact on preference formation, and led to a larger decrease of perceived difficulty of the decision problem as compared to the no-support condition. The MAU decision aid turned out to be less lime efficient than the unaided mode, especially with increasing numbers of alternatives. Results suggest that the MAU decision aid is effective for problems of low and moderate complexity only. For highly complex problems, results are less favorable.