=Paper=
{{Paper
|id=Vol-3418/DC04
|storemode=property
|title=Addressing Trust and Mutability Issues in XAI utilising Case Based Reasoning
|pdfUrl=https://ceur-ws.org/Vol-3418/ICCBR_2022_DC_paper19.pdf
|volume=Vol-3418
|authors=Pedram Salimi
|dblpUrl=https://dblp.org/rec/conf/iccbr/Salimi22
}}
==Addressing Trust and Mutability Issues in XAI utilising Case Based Reasoning==
Addressing Trust and Mutability Issues in XAI utilising
Case Based Reasoning
Pedram Salimi1,∗
1
Robert Gordon University, Garthdee House, Garthdee Rd, Garthdee, AB10 7AQ, Aberdeen, United Kingdom
Abstract
Explainable AI (XAI) research is required to ensure that explanations are human readable and under-
standable. The present XAI approaches are useful for observing and comprehending some of the most
important underlying properties of any Black-box AI model. However, when it comes to pushing them
into production, certain critical concerns may arise: (1) How can end-users rely on the output of an
XAI platform and trust the system? (2) How can end-users customise the platform’s output depending
on their own preferences In this project, we will explore how to address these concerns by utilising
Cased-based Reasoning. Accordingly, we propose to exploit the neighbourhood to improve end-user
trust by offering similar cases and confidence scores and using different retrieval strategies to address
end-user preferences. Additionally, this project will also look at how to leverage Conversational AI and
Natural Language Generation approaches to improve the interactive and engaging user experience with
example-based XAI systems.
Keywords
Explainable AI, Cased-based Reasoning, Conversational AI, Natural Language Generation
1. Introduction
Due to recent breakthroughs in Artificial intelligence (AI) such as deep learning approaches,
AI models are getting more accurate and powerful while also becoming more complicated [1].
However, because of their complexity, comprehending how these models work and making
judgments has proven difficult. Earlier AI systems were build on approaches that are fundamen-
tally explainable (i.e. white-box) where Rule-based methods, Decision Trees, Hidden Markov
Models, and Logistic Regressions are some examples. Thanks to recent breakthroughs, novel AI
techniques such as deep learning are more accurate and powerful than traditional approaches;
however, they are also more complicated [1, 2]. Due to complexity of the models (i.e. black-box),
comprehending how they work and make decision is difficult. Consequently they reduce model
explainability.
Accordingly, there is an armory of Explainable AI (XAI) methods developed in recent literature
to explain black-box AI models and the decisions they make. Example-based explanations
assist people in developing mental models of the machine learning method and the data on
which the machine learning method was trained[3]. Literature shows that humans tend to
provide contrastive explanations when explaining their decisions to one another. Accordingly,
explaining an AI decision using counterfactual examples can be most understandable to humans
ICCBR DC’22: Doctoral Consortium at ICCBR-2022, September, 2022, Nancy, France
Envelope-Open p.salimi@rgu.ac.uk (P. Salimi)
© 2022 Copyright for this paper by its authors. Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
CEUR
Workshop
Proceedings
http://ceur-ws.org
ISSN 1613-0073
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Pedram Salimi ICCBR’22 Workshop Proceedings
because they both have the same conceptual model as human explanations [4]. Therefore, In
this project, we are focusing on example-based XAI and we propose to use CBR approaches to
address two existing challenges in this domain.
Example-based XAI systems, similar to other methods have been good at explaining the
current user problem. Also, they are able to guide the users to solve their problems. However,
there are several limits to these XAI methods. In this project we are focusing on two of these
limitations. One of them is that current approaches are static, which means they provide
explanations based on the user query but cannot react to user modifying the query based on
their own personal preferences [5]. There is also a lack of trust between the user and the XAI
system that is yet to be addressed. User studies by [4] and [6] are few those who highlight this
issue of trust in XAI system with respect to applications in speech recognition, forest coverage
prediction and recidivism.
Case-Based Reasoning (CBR) is a methodology that emulate how humans reason from prece-
dent and examples and it has a central role in XAI systems [7]. CBR has been the underpinning
of many example-based XAI methods providing explanations ranging from factual to counter-
factuals [8]. Accordingly, we ask the following research questions:
• RQ1: How can we approach the issue of trust in an interactive example-based XAI
system using the CBR system?
• RQ2: How can a case-based approach assist us in dealing with mutability of features
when generating counterfactual explanations?
2. Background
In this section, we will first study example-based XAI approaches before briefly discussing the
CBR methodology.
2.1. Example-based Explanations
Example-based approaches are classified into three categories: factual, semi-factual, and coun-
terfactual.
Factual Explanations provide information about why a certain outcome was received based
on query features [9]. Using nearest neighbours is an example-based approach for finding factual
explanations. For example, in loan application a factual explanation using nearest neighbors
could be “Your loan got rejected because there is another person whose situation is quite similar
to you and had their loan declined”. Explanations-by-example is a factual explainer algorithm
where nearest-neighbours are found using Critical Classification Regions in images[10].
Semi-factual Explanations present the maximum distance an instance may go without
changing the black-box outcome. A semi-factual explanation for a reject loan application would
be, “Even if the installment amount is increased, loan would be still rejected”. PIECE is a
case-based method for generating semi-factual explanations which uses a convolutional model
to detect important features and to generate semi-factual explanations [11].
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Pedram Salimi ICCBR’22 Workshop Proceedings
Counterfactual Explanations define a causal, synthetic or past event with the smallest
change in feature values that causes the prediction to shift to a desired outcome. A counterfactual
explanation for a rejected loan application would be, “If the loan amount is reduced, loan would
have been accepted”. Some of the state-of-the-art counterfactual methods are as follows:
• NICE approach is divided into two steps. First, the nearest unlike neighbour (NUN) is
retrieved, which leads to the finding of non-overlapping features against the query. Then
the algorithm iteratively attempts to determine the optimal counterfactual using a reward
function that consider properties like [12].
• DisCERN is a case-based counterfactual explanation method. Here, counterfactuals are
created by substituting feature values of the query from the NUN until an outcome change
is detected. Features to substitute are selected based on feature attributions. [13].
2.2. Case-based Reasoning
Most XAI methods, including ones discussed above, fail to establish trust with the end-user as
discussed in the introduction. Their one-shot nature (instead of being interactive) also fail to
incorporate user preferences. To address these challenges, in this project, we explore techniques
from Case-based Reasoning (CBR). A CBR methodology consists of four stages: retrieve, reuse,
revise, and retain [14]. The first stage involves providing an input that describes the present
user query and retrieving similar cases in the case base by employing similarity metrics. The
second stage utilises retrieved cases and use adaption knowledge to present the user with a
solution to their query. The user may accept or reject the solution for a variety of reasons,
for example, user could be unable to accept the entire proposed solution, based on their own
preferences. In the case of rejection, the following step is to revise. In most cases, the revise
stage includes incorporating feedback acquired from testing the suggested solution. During the
final step, the new case may be retained in the case base for future use.
3. Approach / Methodology
In this section we are going to explore the research questions identified using CBR techniques.
3.1. RQ1: How to address trust in an example-based XAI system using CBR?
This RQ explore how to establish trust between an XAI system and a user once they are presented
with an explanation. Specifically we want to identify what additional information or explanation
will help the user to better believe the recommendations provided by an XAI system in terms of
reliability of the XAI system. Following CBR approaches may assist us in addressing the trust
issues:
• Nearest Neighbors may be to retrieve the nearest neighbours of the provided solution
which previously were successful examples
• Coverage and population density of instances which are similar to the provided counter-
factual in a case base[15].
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Pedram Salimi ICCBR’22 Workshop Proceedings
For evaluating the impact of proposed methods on trust, a user study is proposed. This work is
informed by XAI evaluation methods like the Hoffman Trust scale when seeking feedback from
users [16].
3.2. RQ2: How to address feature mutability preferences using CBR?
The interactive system should allow the user to modify the criteria on which an explanation is
generated by considering mutability of features. In another words, mutability in an XAI system
is about to giving the control to the user in terms of the degree of complexity and difficulty of
what they can change. To address this we explore following techniques from CBR:
• Collaborative Filtering It is a mechanism for proposing alternative solutions to a user
based on similarities (similarity assessment [17]) in the user’s prior behaviour and that of
other users.
• Adaptation When the best partial-matching case from the case repository does not
perfectly match the new case, the previous solution must be altered to fit the new case
solution more accurately. There are several adaptation methods such as null adaptation,
structural adaptation, or a combination of methods[18].
Figure 1 depicts an example interaction between a user and AI that demonstrates how such a
system might deal with trust and mutability issues.
Figure 1: Employing Nearest Neighbors and Collaborative Filtering in order to deal with trust and
mutability issues correspondingly.
4. Progress Summary
Recent work has explored several ways for data-to-text generation in terms of numerical
reasoning, with the objective of mapping counterfactuals to a natural language representation
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Pedram Salimi ICCBR’22 Workshop Proceedings
which would facilitate a more engaging interaction with the end user. We have designed
two distinct template-based text generation algorithms, one with features grouped based on
attribution change and the other without. This is illustrated in Figure 2 with two presentations
of the counterfactual with and without the feature grouping template for a loan application.
Figure 2: Different template based text generation based on feature grouping. This classification is part
of the user research to determine which one is more plausible.
Our immediate next task is to design a user study to assess such generation templates
and to understand to what extent it could impact end-user engagement and trustworthiness.
A questionnaire will be prepared to gather feedback on several counterfactual explanation
scenarios. In our user study we are going to consider three framing concept in order to prevent
potential biases in our user study[19]. For example, we are going to employ NASA Task Load
Index questionnaire.But we are going to modify them with respect to positive framing concept in
a manner that instead of asking how much the user got frustrated during the task, we are going
to ask how much the task was easy to do. Results of the user study will inform us to identify
best template generation strategies in terms of the quality of generated textual explanation and
also provide insights for addressing the project’s research questions.
Having input from a DC mentor to help improve the user study design will be very valuable;
as would directions for integrating case-based strategies for improving user trust.
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