444,158 research outputs found
The Pragmatic Turn in Explainable Artificial Intelligence (XAI)
In this paper I argue that the search for explainable models and interpretable decisions in AI must be reformulated in terms of the broader project of offering a pragmatic and naturalistic account of understanding in AI. Intuitively, the purpose of providing an explanation of a model or a decision is to make it understandable to its stakeholders. But without a previous grasp of what it means to say that an agent understands a model or a decision, the explanatory strategies will lack a well-defined goal. Aside from providing a clearer objective for XAI, focusing on understanding also allows us to relax the factivity condition on explanation, which is impossible to fulfill in many machine learning models, and to focus instead on the pragmatic conditions that determine the best fit between a model and the methods and devices deployed to understand it. After an examination of the different types of understanding discussed in the philosophical and psychological literature, I conclude that interpretative or approximation models not only provide the best way to achieve the objectual understanding of a machine learning model, but are also a necessary condition to achieve post hoc interpretability. This conclusion is partly based on the shortcomings of the purely functionalist approach to post hoc interpretability that seems to be predominant in most recent literature
On Human Predictions with Explanations and Predictions of Machine Learning Models: A Case Study on Deception Detection
Humans are the final decision makers in critical tasks that involve ethical
and legal concerns, ranging from recidivism prediction, to medical diagnosis,
to fighting against fake news. Although machine learning models can sometimes
achieve impressive performance in these tasks, these tasks are not amenable to
full automation. To realize the potential of machine learning for improving
human decisions, it is important to understand how assistance from machine
learning models affects human performance and human agency.
In this paper, we use deception detection as a testbed and investigate how we
can harness explanations and predictions of machine learning models to improve
human performance while retaining human agency. We propose a spectrum between
full human agency and full automation, and develop varying levels of machine
assistance along the spectrum that gradually increase the influence of machine
predictions. We find that without showing predicted labels, explanations alone
slightly improve human performance in the end task. In comparison, human
performance is greatly improved by showing predicted labels (>20% relative
improvement) and can be further improved by explicitly suggesting strong
machine performance. Interestingly, when predicted labels are shown,
explanations of machine predictions induce a similar level of accuracy as an
explicit statement of strong machine performance. Our results demonstrate a
tradeoff between human performance and human agency and show that explanations
of machine predictions can moderate this tradeoff.Comment: 17 pages, 19 figures, in Proceedings of ACM FAT* 2019, dataset & demo
available at https://deception.machineintheloop.co
Against Game Theory
People make choices. Often, the outcome depends on choices other people make. What mental steps do people go through when making such choices? Game theory, the most influential model of choice in economics and the social sciences, offers an answer, one based on games of strategy such as chess and checkers: the chooser considers the choices that others will make and makes a choice that will lead to a better outcome for the chooser, given all those choices by other people. It is universally established in the social sciences that classical game theory (even when heavily modified) is bad at predicting behavior. But instead of abandoning classical game theory, those in the social sciences have mounted a rescue operation under the name of “behavioral game theory.” Its main tool is to propose systematic deviations from the predictions of game theory, deviations that arise from character type, for example. Other deviations purportedly come from cognitive overload or limitations. The fundamental idea of behavioral game theory is that, if we know the deviations, then we can correct our predictions accordingly, and so get it right. There are two problems with this rescue operation, each of them is fatal. (1) For a chooser, contemplating the range of possible deviations, as there are many dozens, actually makes it exponentially harder to figure out a path to an outcome. This makes the theoretical models useless for modeling human thought or human behavior in general. (2) Modeling deviations are helpful only if the deviations are consistent, so that scientists (and indeed decision makers) can make predictions about future choices on the basis of past choices. But the deviations are not consistent. In general, deviations from classical models are not consistent for any individual from one task to the next or between individuals for the same task. In addition, people’s beliefs are in general not consistent with their choices. Accordingly, all hope is hollow that we can construct a general behavioral game theory. What can replace it? We survey some of the emerging candidates
The role of decision confidence in advice-taking and trust formation
In a world where ideas flow freely between people across multiple platforms,
we often find ourselves relying on others' information without an objective
standard to judge whether those opinions are accurate. The present study tests
an agreement-in-confidence hypothesis of advice perception, which holds that
internal metacognitive evaluations of decision confidence play an important
functional role in the perception and use of social information, such as peers'
advice. We propose that confidence can be used, computationally, to estimate
advisors' trustworthiness and advice reliability. Specifically, these processes
are hypothesized to be particularly important in situations where objective
feedback is absent or difficult to acquire. Here, we use a judge-advisor system
paradigm to precisely manipulate the profiles of virtual advisors whose
opinions are provided to participants performing a perceptual decision making
task. We find that when advisors' and participants' judgments are independent,
people are able to discriminate subtle advice features, like confidence
calibration, whether or not objective feedback is available. However, when
observers' judgments (and judgment errors) are correlated - as is the case in
many social contexts - predictable distortions can be observed between feedback
and feedback-free scenarios. A simple model of advice reliability estimation,
endowed with metacognitive insight, is able to explain key patterns of results
observed in the human data. We use agent-based modeling to explore implications
of these individual-level decision strategies for network-level patterns of
trust and belief formation
Local and Global Explanations of Agent Behavior: Integrating Strategy Summaries with Saliency Maps
With advances in reinforcement learning (RL), agents are now being developed
in high-stakes application domains such as healthcare and transportation.
Explaining the behavior of these agents is challenging, as the environments in
which they act have large state spaces, and their decision-making can be
affected by delayed rewards, making it difficult to analyze their behavior. To
address this problem, several approaches have been developed. Some approaches
attempt to convey the behavior of the agent, describing the
actions it takes in different states. Other approaches devised
explanations which provide information regarding the agent's decision-making in
a particular state. In this paper, we combine global and local explanation
methods, and evaluate their joint and separate contributions, providing (to the
best of our knowledge) the first user study of combined local and global
explanations for RL agents. Specifically, we augment strategy summaries that
extract important trajectories of states from simulations of the agent with
saliency maps which show what information the agent attends to. Our results
show that the choice of what states to include in the summary (global
information) strongly affects people's understanding of agents: participants
shown summaries that included important states significantly outperformed
participants who were presented with agent behavior in a randomly set of chosen
world-states. We find mixed results with respect to augmenting demonstrations
with saliency maps (local information), as the addition of saliency maps did
not significantly improve performance in most cases. However, we do find some
evidence that saliency maps can help users better understand what information
the agent relies on in its decision making, suggesting avenues for future work
that can further improve explanations of RL agents
Grad-CAM++: Improved Visual Explanations for Deep Convolutional Networks
Over the last decade, Convolutional Neural Network (CNN) models have been
highly successful in solving complex vision problems. However, these deep
models are perceived as "black box" methods considering the lack of
understanding of their internal functioning. There has been a significant
recent interest in developing explainable deep learning models, and this paper
is an effort in this direction. Building on a recently proposed method called
Grad-CAM, we propose a generalized method called Grad-CAM++ that can provide
better visual explanations of CNN model predictions, in terms of better object
localization as well as explaining occurrences of multiple object instances in
a single image, when compared to state-of-the-art. We provide a mathematical
derivation for the proposed method, which uses a weighted combination of the
positive partial derivatives of the last convolutional layer feature maps with
respect to a specific class score as weights to generate a visual explanation
for the corresponding class label. Our extensive experiments and evaluations,
both subjective and objective, on standard datasets showed that Grad-CAM++
provides promising human-interpretable visual explanations for a given CNN
architecture across multiple tasks including classification, image caption
generation and 3D action recognition; as well as in new settings such as
knowledge distillation.Comment: 17 Pages, 15 Figures, 11 Tables. Accepted in the proceedings of IEEE
Winter Conf. on Applications of Computer Vision (WACV2018). Extended version
is under review at IEEE Transactions on Pattern Analysis and Machine
Intelligenc
- …