Pragmatic competence i.e., the ability to understand intended meaning is a long standing challenge in communication. This work proposes a computational framework for pragmatic inference that is based on reasoning by taking into account the realistic assumption that any communication could be deceptive and that intentions can be re ected in language use. Pragmatic inference is examined under the light of culture since as literature manifests, cultural di erences is a crucial parameter in the communication process and often a cause of misinterpretations (e.g., false alarms about the deceptiveness of a message). In contrast to the current situation, the proposed approach takes a holistic stance, aiming to infer knowledge both from surface patterns in raw text and more formal structures beyond the text level.
Every day, people through their interpersonal interactions run into deceptiveprone situations struggling to decipher deceptive signals in messages. In highstake situations and in situations, where justice and equal treatment must be ensured, the ability to detect deception is of utmost importance. An example that falls into the above cases is the examination of asylum applications from trained personnel, a task neither easy nor rare.1
Let's consider Nizar, a 29 years old Syrian forced to leave his country and seeks asylum in an European country. Some of the questions that are raised during his interactions with the Asylum O ce personnel: { In case the communication is not totally honest, which strategies of deception are employed maybe from both parties (e.g., blu , information hiding, outright lie, exaggeration etc.)? { What both parties hypothesize about the portion of information the other party possess or ignore? What are their hypotheses about the beliefs of each side (e.g., Nizar believes that the examiner of his application believes that he didn't lie about his marital status or his political beliefs)? 1 By the end of 2015, asylum-seekers were 3.2 million (UNHCR). { How the train of thought will change/revise when a deceptive e ort come to light? How the beliefs of both parties revised? { Does the di erent culture a ect deceptive signals and may this condition cause misconceptions? In the above context, the participants whoever role they hold must be extremely skilled at mind-reading in order to interpret implicit or seemingly uncorrelated information and to reason about unexpressed beliefs and intentions. The problem is further exacerbated by the di erent cultural and cognitive background of the involved actors (Nizar and the Asylum o ce personnel).
The proposed work is motivated by such situations and aims to research deception, by concentrating on a more holistic angle compared to existing literature. We aim at providing a computational framework that will gain advantage from deception detection techniques over a text message in order to enhance and inform complex reasoning tasks (e.g., given that a message of A is deceptive, A hides something else, what points an agent chooses to undermine or stress). We believe that by combining deception detection techniques with reasoning approaches over the communicated content we can achieve a deeper understanding of a message and to infer information that is implied or is hidden. Next, we brie y discuss the three basic axes we decided to rely on namely deception, text and culture.
Deception is omnipresent in every facet of human life [
The input to our deception detection algorithms will be simple textual data.
This approach has recently gained momentum in the eld of deception
detection. A combination of factors seem to lead in this turn namely the advances
in elds of Natural Language Processing (NLP) and Computational Linguistics,
the enormous production of textual data, the seminal work of Vrij [
We place great emphasis on examining deception taking into account the
cultural characteristic of the potential liar. As studies show, people of other ethnic
group when try to detect deception perform even worse than judging people of
their own ethnic group [
The starting point of this work is that deception indicators are critical to be extracted not only from surface patterns in textual data (e.g., news articles, dialogues, reports etc) but also by taking advantage of the overall context that can reveal the intention behind a deception e ort and implied information. This requires the formal (abstract) representation of the communication content and subsequently the application of the appropriate forms of reasoning. 2
The passage from unrestricted free form text to a formalization that will enable
complex reasoning process is a genuine arduous project. A lot of endeavours
for the representation of semantics and pragmatics to logical forms have been
presented in the literature. A comprehensive overview of this e orts such as LFG
(Lexical functional Grammar), HPSG (Head-driven phrase structure grammar)
and DRT (Discourse Representation Theory) is provided in [
As far as the deception representation and reasoning is concerned a recent
and very close to our goals work is that of Licato [
In the context of culture modelling an important contribution is o ered in
[
In an abstract level the the proposed approach constitutes of two processes (Figure 1). The rst one is responsible to decide about the overall deceptiveness of a textual message and the extraction of ne-grained information such as type of deception based mainly on NLP approaches. This task feeds the pragmatics inference task that realizes the modelling of complex situations where reasoning beyond the text level is needed to understand hidden intentions and beliefs as those re ected in the introductory example. As Figure 1 depicts, culture is a modular parameter for both tasks, thus our approach can be applied also in contexts where culture is not so critical. Deception detection from a computational linguistics viewpoint focuses on linguistics di erences between deception and truth-telling. A lot of theories back up this approach (psychoanalytic approach of Freud, Lexical Hypothesis) and in this respect a long list of lexical features almost for any level level of lexical analysis (e.g., morphology, syntax, discourse, psycholinguistics) has been examined. Since this research goal is out of the focus of this paper we brie y mention the directions that we will base our e orts upon:
A reasonable argument that has already started to be explored [
A large body of the deception literature has been devoted to the typology of
deception and to the identi cation of subtle di erences between types of deception
[
As far as the input data availability is concerned the vivid interest for deception detection has lead to the creation of a considerable number of publicly available textual datasets from diverse domains (e.g., news, reviews, court data). We plan to base our work is such datasets and perhaps to expand this pool of data with datasets for the Greek language. 3.2
The rst step in this task is the structured representation of the communicated
content. We anticipate to formalize natural language just to the extent that it
allows us to transfer certain information to a formal context taking advantage of
the recent advances in this direction [
In our case, a critical requirement is nonmonotonicity due to dynamic changes in belief, intentions and knowledge. For instance, the presence of a deceptive message maybe lead to the revision of the existing knowledge or the creation of alternative paths that due to explosion in the quantity of knowledge must be handled. The parameter of time is another important requirement since the sequence of facts cannot be ignored.
As we have already argued, in an inter-cultural setting, the cultural gap may
play a decisive role in communication since often it could be the cause of
misconceptions and misunderstandings. In this respect, we must be able to incorporate
knowledge about culture. This culture-driven knowledge can take two forms: a.
the form of context-dependent knowledge about values, norms, relations,
opinions, stance towards life (e.g., perceptions about family bonds) and b. linguistic
2 The relationship between language and culture is supported by several theories
among them the Sapir-Wholf hypothesis that language in uences cognition.
expression of cultural di erences (e.g., some cultures are engaged to small talk
while others are more tolerant to persuasion). The theoretical support is
provided by the research for cross-cultural deception detection [
The nature of the examined problem guide us to forms of reasoning that make inferences beyond the scope of the premises as well as the ability to backtrack. For that reason, we plan to de ne a new form of reasoning that can be placed under the umbrella of Ampliative and Defeasible Reasoning. In addition, we must also take into account the di erences in reasoning that emerge from culture (e.g., since a culture expressed in a particular way what conclusion could be inferred). Lastly, returning to the initial discussion about mind-reading a challenge is to incorporate aspects of Counterfactual Reasoning as a way to examine the viewpoint of the \Other" and avoid problems like con rmation bias. Table 1 provides a sketch of the key requirements that must be ful lled in respect of representation and reasoning.
Events in a course of a dialogue, time sequence in a narrative
All Europeans citizens are individualists X Nizar believes that the examiner of his application believes that the well-being of his family is a priority for him X Investigator ignores that...
X Investigator hides from Nizar that he holds information about his past, Nizar lied about his involvement in the civil war of this country, O cer blu s about...
Defeasible If Nizar lied for his economical status, he previously also lied... Ampliative Nizar does not disclose information about his war experiences. I can conclude that maybe su ers for post-traumatic stress disorder Counterfactual Examine the case when a lie was not a lie but the result of conrmation bias Cultural Nizar as collectivist, values high the institution of family, so the white lie in relation to some family members was indeed an e ort to protect them
In this paper, we present our proposal for a deceptive-aware computational framework for pragmatics inference. We aim at a closer collaboration between Knowledge Representation and Reasoning with NLP in order to o er a deeper understanding of the communicated content. We prioritize the in uence of culture since, as literature emphatically manifests, it is a crucial parameter and a constant source of misconceptions. Our prospective goal is two-fold, from one side to o er more realistic deceptive aware multi-agent environments that require complex forms of reasoning and from the other side to contribute to Computational Pragmatics by based on formal logic for the pragmatic interpretation.
Our immediate steps is to complete our requirements analysis for the deceptiveaware modal logic while in parallel we work on towards the deception detection from text task.
This work is funded by the Institute of Computer Science (ICS) of the Foundation for Research and Technology - Hellas (FORTH) and is conducted under the supervision of Prof. Dimitrios Plexousakis and in cooperation with Dr. Giorgos Flouris, Dr. Theodoros Patkos and Prof. Ion Androutsopoulos.