A systematic review of perception of affordances for the person-plus-object system

Human behavior often involves the use of an object held by or attached to the body, which modifies the individual's action capabilities. Moreover, most everyday behaviors consist of sets of behaviors that are nested over multiple spatial and temporal scales, which require perceiving and acting on nested affordances for the person-plus-object system. This systematic review investigates how individuals attune to information about affordances involving the person-plus-object system and how they (re)calibrate their actions to relevant information. We analyzed 71 articles-34 on attunement and 37 on (re)calibration with healthy participants-that experimentally investigated the processes involved in the perception of affordances for the person-plus-object system (including attunement, calibration, and recalibration). With respect to attunement, objects attached to the body create a multiplicity of affordances for the person-plus-object system, and individuals learned (1) to detect information about affordances of (and for) the person-plus-object system in a task and (2) to choose whether, when, and how to exploit those affordances to perform that task. Concerning (re)calibration, individuals were able (1) to quickly scale their actions in relation to the (changed) action capabilities of the person-plus-object system and (2) to perceive multiple functionally equivalent ways to exploit the affordances of that system, and these abilities improved with practice. Perceiving affordances for the person-plus-object system involves learning to detect the information about such affordances (attunement) and the scaling of behaviors to such information (calibration). These processes imply a general ability to incorporate an object attached to the body into an integrated person-plus-object system.

Principles of the Guidance of Exploration for Orientation and Specification of Action

To control movement of any type, the neural system requires perceptual information to distinguish what actions are possible in any given environment. The behavior aimed at collecting this information, termed "exploration", is vital for successful movement control. Currently, the main function of exploration is understood in the context of specifying the requirements of the task at hand. To accommodate for agency and action-selection, we propose that this understanding needs to be supplemented with a function of exploration that logically precedes the specification of action requirements with the purpose of discovery of possibilities for action-action orientation. This study aimed to provide evidence for the delineation of exploration for action orientation and exploration for action specification using the principles from "General Tau Theory." Sixteen male participants volunteered and performed a laboratory-based exploration task. The visual scenes of different task-specific situations were projected on five monitors surrounding the participant. At a predetermined time, the participant received a simulated ball and was asked to respond by indicating where they would next play the ball. Head movements were recorded using inertial sensors as a measure of exploratory activity. It was shown that movement guidance characteristics varied between different head turns as participants moved from exploration for orientation to exploration for action specification. The first head turn in the trial, used for action-orientation, showed later peaks in the velocity profile and harder closure of the movement gap (gap between the start and end of the head-movement) in comparison to the later head turns. However, no differences were found between the first and the final head turn, which we hypothesized are used mainly for action orientation and specification respectively. These results are in support of differences in the function and control of head movement for discovery of opportunities for action (orientation) vs. head movement for specification of task requirements. Both are important for natural movement, yet in experimental settings,orientation is often neglected. Including both orientation and action specification in an experimental design should maximize generalizability of an experiment to natural behavior. Future studies are required to study the neural bases of movement guidance in order to better understand exploration in anticipation of movement.

Analysis of Affordance, Time, and Adaptation in the Assessment of Industrial Control System Cybersecurity Risk

Industrial control systems increasingly use standard communication protocols and are increasingly connected to public networks-creating substantial cybersecurity risks, especially when used in critical infrastructures such as electricity and water distribution systems. Methods of assessing risk in such systems have recognized for some time the way in which the strategies of potential adversaries and risk managers interact in defining the risk to which such systems are exposed. But it is also important to consider the adaptations of the systems' operators and other legitimate users to risk controls, adaptations that often appear to undermine these controls, or shift the risk from one part of a system to another. Unlike the case with adversarial risk analysis, the adaptations of system users are typically orthogonal to the objective of minimizing or maximizing risk in the system. We argue that this need to analyze potential adaptations to risk controls is true for risk problems more generally, and we develop a framework for incorporating such adaptations into an assessment process. The method is based on the principle of affordances, and we show how this can be incorporated in an iterative procedure based on raising the minimum period of risk materialization above some threshold. We apply the method in a case study of a small European utility provider and discuss the observations arising from this.

Perceiving nested affordances for another person's actions

Affordances are available behaviors that emerge out of relations between properties of animals and properties of their environment. Affordances are nested within one another. One way to conceptualize this nesting is through a mean-ends hierarchy. Previous research has shown that perceivers are sensitive to hierarchical means-ends relationships when perceiving affordances for their own actions. Affordances are also nested in a social context. We investigated perception of hierarchical mean-ends nesting of affordances for another person's actions. We asked participants to judge the maximum reaching height of another person (the "actor"). Judgments of the actor's maximum reaching height reflected manipulated constraints on the reaching task, suggesting that participants were sensitive (prospectively) to hierarchical relations between lower order affordances and higher order affordances. In addition, the results revealed that judgments scaled to the reaching ability of the actor and not that of the perceiver. We argue that perceivers were sensitive to hierarchical means-ends nesting of affordances for another person across two-levels of this hierarchy, and that perceivers' judgments were based upon perceptual information about the actor's action capabilities, rather than being based upon simulation of perceivers' own abilities.

Nesting in perception of affordances for stepping and leaping

Perception of affordances for a given behavior typically reflects the task-specific action capabilities of the perceiver. However, many experiments have shown a discrepancy between the perceptual and behavioral boundaries for a given behavior. One possibility for such a discrepancy is that the context of many experimental tasks transformed what is typically a dynamic perception-action task into an analytical or reflective judgment. We investigated this hypothesis with respect to perception of maximum stepping and leaping distance. For both behaviors, perception of these affordances more closely reflected action capabilities when the perceptual task was nested within a superordinate task than when it was not (regardless of whether the behavior itself was performed). Additionally, verbal reports of perception of maximum leaping distance more closely reflected action capabilities when there was an explicit time limit on such reports. The results are discussed in the context of the ecological principle of nesting and in attentional focus during motor control tasks.

Physical fidelity versus cognitive fidelity training in procedural skills acquisition

OBJECTIVE

The current study examined whether training simulators for the acquisition of procedural skills should emphasize physical fidelity or cognitive fidelity of the task.

BACKGROUND

Simulation-based training for acquiring and practicing procedural skills is becoming widely established. Generally speaking, these simulators offer technological sophistication but disregard theory-based design, leaving unanswered the question of what task features should be represented in the simulators.The authors compared real-world training and two alternative virtual trainers, one emphasizing physical fidelity and the other cognitive fidelity of the task.

METHOD

Participants were randomly assigned to one of four training groups in a LEGO assembly task: virtual-physical fidelity, cognitive fidelity, real world, and control. A posttraining test to assess the development of procedural skills was conducted.

RESULTS

Both the virtual-physical fidelity and cognitive fidelity training methods produced better performance time than no training at all, as did the real-world training. The cognitive fidelity training was inferior in terms of test time compared to the real-world training, whereas the virtual-physical fidelity training was not. In contrast, only the real-world and the cognitive fidelity groups, and not the virtual-physical fidelity group, required significantly less time than the control group for error correction.

CONCLUSION

The two training methods have complementary advantages.

APPLICATION

Combining physical fidelity and cognitive training methods can enhance procedural skills acquisition when real-world training is not practicable.

Nested prospectivity in perception: perceived maximum reaching height reflects anticipated changes in reaching ability

Perception of possibilities for behavior is a necessarily prospective (i.e., forward-looking) act. Such prospectivity is highlighted by the fact that, in general, behaviors are nested within behaviors over a number of spatial and temporal scales. Participants reported their maximum vertical reaching height when they expected to walk across the room and (1) reach for an object while standing on the floor, (2) step up on a step stool and then reach for the object, and (3) pick up a plastic rod and use it to reach for the object. The results show that perception of maximum reaching height was action scaled both when participants expected to perform a nested behavior that would change their action capabilities and when they expected to perform a nested behavior that would not do so. Moreover, the results suggest that nested behaviors that change reaching ability in functionally equivalent ways may bring about functionally equivalent changes in perception of maximum reaching height.