Going Down the Abstraction Stream with Augmented Reality and Tangible Robots: the Case of Vector Instruction

Despite being used in many engineering and scientific areas such as physics and mathematics and often taught in high school, graphical vector addition turns out to be a topic prone to misconceptions in understanding even at university-level physics classes. To improve the learning experience and the resulting understanding of vectors, we propose to investigate how concreteness fading implemented with the use of augmented reality and tangible robots could help learners to build a strong representation of vector addition. We design a gamified learning environment consisting of three concreteness fading stages and conduct an experiment with 30 participants. Our results shows a positive learning gain. We analyze extensively the behavior of the participants to understand the usage of the technological tools -- augmented reality and tangible robots -- during the learning scenario. Finally, we discuss how the combination of these tools shows real advantages in implementing the concreteness fading paradigm. Our work provides empirical insights into how users utilize concrete visualizations conveyed by a haptic-enabled robot and augmented reality in a learning scenario.

Resolving Spurious Correlations in Causal Models of Environments via Interventions

Causal models could increase interpretability, robustness to distributional shift and sample efficiency of RL agents. In this vein, we address the question of learning a causal model of an RL environment. This problem is known to be difficult due to spurious correlations. We overcome this difficulty by rewarding an RL agent for designing and executing interventions to discover the true model. We compare rewarding the agent for disproving uncertain edges in the causal graph, rewarding the agent for activating a certain node, or rewarding the agent for increasing the causal graph loss. We show that our methods result in a better causal graph than one generated by following the random policy, or a policy trained on the environment's reward. We find that rewarding for the causal graph loss works the best.

Fatal Brain Damage

The loss of a few neurons in a brain often does not result in a visible loss of function. We propose to advance the understanding of neural networks through their remarkable ability to sustain individual neuron failures, i.e. their fault tolerance. Before the last AI winter, fault tolerance in NNs was a popular topic as NNs were expected to be implemented in neuromorphic hardware, which for a while did not happen. Moreover, since the number of possible crash subsets grows exponentially with the network size, additional assumptions are required to practically study this phenomenon for modern architectures. We prove a series of bounds on error propagation using justified assumptions, applicable to deep networks, show their location on the complexity versus tightness trade-off scale and test them empirically. We demonstrate how fault tolerance is connected to generalization and show that the data jacobian of a network determines its fault tolerance properties. We investigate this quantity and show how it is interlinked with other mathematical properties of the network such as Lipschitzness, singular values, weight matrices norms, and the loss gradients. Known results give a connection between the data jacobian and robustness to adversarial examples, providing another piece of the puzzle. Combining that with our results, we call for a unifying research endeavor encompassing fault tolerance, generalization capacity, and robustness to adversarial inputs together as we demonstrate a strong connection between these areas. Moreover, we argue that fault tolerance is an important overlooked AI safety problem since neuromorphic hardware is becoming popular again.