To stay or to leave? Decision rules for partner species relocation in two symbiotic pairs of desert beetles

Four nocturnal Kalahari desert tenebrionid beetles live in closely associated species pairs. The larger member of each pair, Parastizopus and Gonopus, are the primary burrowers while their smaller associates, Eremostibes and Herpiscius, inhabit the burrows with them and feed on detritus the larger beetles carry in. During summer drought, the two large species have different emergence times, surface activity patterns (vagilities) and different probabilities that burrows will be reoccupied before sunrise or remain empty for longer periods. Because their partners leave the burrows, the smaller species must make a decision either to stay in the expectation of a burrow being reinhabited, or leave and locate a new partner. The vagility and burrow fidelity of the associating species were studied using marked individuals in free-living populations. Field inclusion/exclusion experiments to test what influences the decision process showed that neither continual partner presence nor food induced the smaller beetles to remain. Different percentages, depending on species, left overnight. For both associates, these proportions corresponded exactly to the probability that the burrow would not be inhabited by their partner species the next day. Neither species predicted the probability of burrow reoccupation after a short vacancy and adopted a “waiting” strategy. Received: 13 January 1998 / Accepted after revision: 20 May 1998     

Integrating models of self-regulation and optimal experiences: A qualitative study into flow and clutch states in recreational distance running

ObjectiveIn this study, we aimed to understand the self-regulatory processes facilitating optimal experiences in running by integrating models of self-regulation with flow and clutch states.MethodUsing an event-focused approach, we interviewed 16 runners less than one day on average after recreational running activities (M = 22.17 hours later, range = 3–46) they described as positive, rewarding experiences. Our analysis drew on principles for thematic and connecting analyses.ResultsWe structured our analysis of the self-regulatory processes facilitating flow and clutch states into three overarching themes: forethought; monitoring; and control. Flow was facilitated by intrinsic experiential motives and non-specific goals, whereas clutch states involved an intrinsic motive to accomplish specific goals. The perceived ease and pleasure during flow motivated runners to continue this experience, which appeared to be aided by active and involuntary distraction. Conversely, clutch states were described as more effortful and less pleasant during the run, with active self-regulation strategies used to exert control over cognition and manage feelings of difficulty. Attending to specific outward or internal sensory stimuli appeared to initiate changes that contributed to the disruption of flow, although many runners described transitioning into a clutch state after flow disruption. No runner reported transitioning from a clutch state into flow.ConclusionsOur study offers novel insights into optimal experiences in running by integrating models of self-regulation with flow and clutch states. We discuss how these insights can inform research and applied practice seeking to develop interventions for promoting optimal experiences during running.     

Integrating technology in psychological skills training for performance optimization in elite athletes: A systematic review

ObjectivesThe aim of the current study was to systematically review the literature on the integration of technology in psychological skills training (PST) to optimize elite athletes’ performance.DesignSystematic review.MethodPublished English, Italian, and Russian language articles were identified using electronic databases. Eighteen articles (out of 3753 records) fulfilled the inclusion criteria, and their quality was assessed using the Mixed Method Appraisal Tool (MMAT). Six papers were judged to be excellent and four to be high quality. There were significant methodological inconsistencies across eight studies. An overall score of quality assessment ranged from 20% to 100%.ResultsThe included studies implemented various technologies, in combination with PST, to identify, monitor and/or have an intervention aimed at optimizing elite athletes' performance. The results suggested that the integration covered different meanings, i.e., functional integration, integration between technologies and measures, integration between technology, theoretical framework, and psychological skills training. There was no distinct consistency between the studies with regards to the theory or model used.ConclusionsTechnology and mental training should not be viewed as interchangeable facets of performance enhancement, but rather as complementary ones – where technology integrated in psychological skills training can lead to identify and monitor optimal performance and to implement more effective interventions.     

Safe and optimal navigation for autonomous multi-rotor aerial vehicle in a dynamic known environment by a decomposition-coordination method

In this paper, we present a new solution for the Autonomous navigation problem, using a Decomposition-Coordination Method (DCM) 1. The main purpose of this work is to compute an optimal and safe path for the multi-rotor Unmanned Aerial Vehicle (UAV) in a dynamic environment, moving from an initial location to the desired state. We assume that the flight environment is totally known to a supervisory unit, and the positions and trajectories of dynamic obstacles could be known in real-time, thus to perform in such environment a high reactivity is required as well as good connectivity with the supervisory unit that provides the safe path, each time one obstacle or more are detected on the road, so that the UAV could autonomously diverts from the unsafe path to the new safe one, and avoid the potential collisions. First and foremost, we choose a generalized nonlinear model for the multi-rotors in view of the rotational and translational dynamics of the UAV. We then associate that model with the objective functions. After that, we proceed to the resolution of the multi-objective optimization problem using our approach of decomposition-coordination. The principle of this method consists in decomposing the system into several smaller subsystems to simplify the treatment. Then we achieve the coordination afterward using Lagrange multipliers. To prove the convergence and stability of our method we make use of a Lyapunov function chosen particularly for this system. In the last section we present the simulation results, to confirm the reliability of our method.     

A Conundrum Concerning Creation

In this paper, I expose a conundrum regarding divine creation as Leibniz conceives of such creation. What energizes the conundrum is that the concept of omnibenevolence—“consequential omnibenevolence”—that the Leibnizian argument for the view that the actual world is the best of all possible worlds presupposes, appears to sanction the conclusion that God has no practical reasons to create the actual world.

Consensus scoring, correct responses and reliability of the MSCEIT V2

The scoring protocol adopted by the MSCEIT V2 has been criticised since its development. The present study raises questions regarding the value of consensus scoring by analysing responses within the categorical subscales of Changes and Blends using the Optimal Scaling technique within the Categorical Principal Components Analysis (CATPCA) via Statistical Package for the Social Sciences (SPSS), (n = 206). On a number of occasions, there was no clear agreement as to the “correct” response to items within these categorical subscales. Such an issue seems integral to the application of the MSCEIT V2 and one which deserves more attention. On a more positive note, improvements were made to the reliabilities of the subscales of Changes and Blends, using Optimal Scaling, but less so for Changes. Nevertheless, this raises the possibility of improving the reliabilities of other subscales in the MSCEIT V2 and in turn improving the power of subsequent statistical tests.     

Fishing for the right words: decision rules for human foraging behavior in internal search tasks

Animals depleting one patch of resources must decide when to leave and switch to a fresh patch. Foraging theory has predicted various decision mechanisms; which is best depends on environmental variation in patch quality. Previously we tested whether these mechanisms underlie human decision making when foraging for external resources; here we test whether humans behave similarly in a cognitive task seeking internally generated solutions. Subjects searched for meaningful words made from random letter sequences, and as their success rate declined, they could opt to switch to a fresh sequence. As in the external foraging context, time since the previous success and the interval preceding it had a major influence on when subjects switched. Subjects also used the commonness of sequence letters as a proximal cue to patch quality that influenced when to switch. Contrary to optimality predictions, switching decisions were independent of whether sequences differed little or widely in quality.     

Audiovisual integration increases the intentional step synchronization of side-by-side walkers

When people walk side-by-side, they often synchronize their steps. To achieve this, individuals might cross-modally match audiovisual signals from the movements of the partner and kinesthetic, cutaneous, visual and auditory signals from their own movements. Because signals from different sensory systems are processed with noise and asynchronously, the challenge of the CNS is to derive the best estimate based on this conflicting information. This is currently thought to be done by a mechanism operating as a Maximum Likelihood Estimator (MLE). The present work investigated whether audiovisual signals from the partner are integrated according to MLE in order to synchronize steps during walking. Three experiments were conducted in which the sensory cues from a walking partner were virtually simulated. In Experiment 1 seven participants were instructed to synchronize with human-sized Point Light Walkers and/or footstep sounds. Results revealed highest synchronization performance with auditory and audiovisual cues. This was quantified by the time to achieve synchronization and by synchronization variability. However, this auditory dominance effect might have been due to artifacts of the setup. Therefore, in Experiment 2 human-sized virtual mannequins were implemented. Also, audiovisual stimuli were rendered in real-time and thus were synchronous and co-localized. All four participants synchronized best with audiovisual cues. For three of the four participants results point toward their optimal integration consistent with the MLE model. Experiment 3 yielded performance decrements for all three participants when the cues were incongruent. Overall, these findings suggest that individuals might optimally integrate audiovisual cues to synchronize steps during side-by-side walking.     

The effects of open vs. specific goals on flow and clutch states in a cognitive task

ObjectivesRecent qualitative evidence suggests that two optimal psychological states (flow and clutch) underlie excellent performance in sport. That research further suggests that the type of goal pursued influences which state is experienced. This study aimed to examine the effects of goal types (i.e., open, specific, and do-your-best goals) on flow and clutch states during performance in a cognitive task, which was developed and has been used in sport. Secondary aims were to investigate the effects of goal types on objective and subjective performance, confidence, and perceived challenge.DesignThis study employed a repeated measure design (mixed model).MethodParticipants (N = 95; M_age = 24.89, SD = 9.27) were randomised to one of three goal conditions and asked to perform a Letter and Number Identification Task, which was repeated for six attempts.ResultsParticipants prescribed open or do-your-best goals experienced significantly higher levels of flow than those prescribed specific goals, who conversely experienced significantly higher levels of clutch states. Participants assigned specific goals performed significantly better than those prescribed open or do-your-best goals. Those assigned open or do-your-best-goals reported greater perceived performance, higher confidence, and feeling more optimally challenged.ConclusionsThese findings provide experimental support for the role of goal types in determining flow and clutch states, and further understanding of the psychological effects of these goal types. Implications are discussed, and recommendations are made for future research into the role of goals in experiencing flow and clutch states in sport and exercise.     

Robust versus optimal strategies for two-alternative forced choice tasks

It has been proposed that animals and humans might choose a speed-accuracy tradeoff that maximizes reward rate. For this utility function the simple drift-diffusion model of two-alternative forced-choice tasks predicts a parameter-free optimal performance curve that relates normalized decision times to error rates under varying task conditions. However, behavioral data indicate that only ≈30% of subjects achieve optimality, and here we investigate the possibility that, in allowing for uncertainties, subjects might exercise robust strategies instead of optimal ones. We consider two strategies in which robustness is achieved by relinquishing performance: maximin and robust-satisficing. The former supposes maximization of guaranteed performance under a presumed level of uncertainty; the latter assumes that subjects require a critical performance level and maximize the level of uncertainty under which it can be guaranteed. These strategies respectively yield performance curves parameterized by a presumed uncertainty level and required performance. Maximin performance curves for uncertainties in response-to-stimulus interval match data for the lower-scoring 70% of subjects well, and are more likely to explain it than robust-satisficing or alternative optimal performance curves that emphasize accuracy. For uncertainties in signal-to-noise ratio, neither maximin nor robust-satisficing performance curves adequately describe the data. We discuss implications for decisions under uncertainties, and suggest further behavioral assays.