Goto

Collaborating Authors

 Maldonado, Jaime


Robot Pouring: Identifying Causes of Spillage and Selecting Alternative Action Parameters Using Probabilistic Actual Causation

arXiv.org Artificial Intelligence

In everyday life, we perform tasks (e.g., cooking or cleaning) that involve a large variety of objects and goals. When confronted with an unexpected or unwanted outcome, we take corrective actions and try again until achieving the desired result. The reasoning performed to identify a cause of the observed outcome and to select an appropriate corrective action is a crucial aspect of human reasoning for successful task execution. Central to this reasoning is the assumption that a factor is responsible for producing the observed outcome. In this paper, we investigate the use of probabilistic actual causation to determine whether a factor is the cause of an observed undesired outcome. Furthermore, we show how the actual causation probabilities can be used to find alternative actions to change the outcome. We apply the probabilistic actual causation analysis to a robot pouring task. When spillage occurs, the analysis indicates whether a task parameter is the cause and how it should be changed to avoid spillage. The analysis requires a causal graph of the task and the corresponding conditional probability distributions. To fulfill these requirements, we perform a complete causal modeling procedure (i.e., task analysis, definition of variables, determination of the causal graph structure, and estimation of conditional probability distributions) using data from a realistic simulation of the robot pouring task, covering a large combinatorial space of task parameters. Based on the results, we discuss the implications of the variables' representation and how the alternative actions suggested by the actual causation analysis would compare to the alternative solutions proposed by a human observer. The practical use of the analysis of probabilistic actual causation to select alternative action parameters is demonstrated.


Cause-effect perception in an object place task

arXiv.org Artificial Intelligence

Algorithmic causal discovery is based on formal reasoning and provably converges toward the optimal solution. However, since some of the underlying assumptions are often not met in practice no applications for autonomous everyday life competence are yet available. Humans on the other hand possess full everyday competence and develop cognitive models in a data efficient manner with the ability to transfer knowledge between and to new situations. Here we investigate the causal discovery capabilities of humans in an object place task in virtual reality (VR) with haptic feedback and compare the results to the state of the art causal discovery algorithms FGES, PC and FCI. In addition we use the algorithms to analyze causal relations between sensory information and the kinematic parameters of human behavior. Our findings show that the majority of participants were able to determine which variables are causally related. This is in line with causal discovery algorithms like PC, which recover causal dependencies in the first step. However, unlike such algorithms which can identify causes and effects in our test configuration, humans are unsure in determining a causal direction. Regarding the relation between the sensory information provided to the participants and their placing actions (i.e. their kinematic parameters) the data yields a surprising dissociation of the subjects knowledge and the sensorimotor level. Knowledge of the cause-effect pairs, though undirected, should suffice to improve subject's movements. Yet a detailed causal analysis provides little evidence for any such influence. This, together with the reports of the participants, implies that instead of exploiting their consciously perceived information they leave it to the sensorimotor level to control the movement.