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Lie Detection

This repository contains the code for a critique paper published to ICPR 2022.

Summary

I started working on an open-ended project of lie detection at the start of my Master's project. Reading the literature, I saw some state-of-the-art papers which achieved suspiciously high results (as high as 99% accuracy on a balanced dataset).

I checked the datasets which were used in these papers and noticed that females in the dataset lie significantly more than males. This means that if an ML algorithm is trained on the dataset, it could learn to identify sex and achieve statistically significant results on the task of deception i.e. the models exploit the dataset bias to appear as if they learned how to predict lying. Of course, sex is just one type of dataset bias and there might be others that I haven't specifically considered.

This package contains the code and experiments I ran to test if this is indeed the case. The experiments show that it is possible statistically significant (and, in some cases, surprisingly high) results using nothing but the dataset bias.

Reading the paper will provide you more details and context on this repository if interested. It should probably be in the ICPR 2022 website somewhere but, if you don't find it, please feel free to email me and I can send the paper to you.

Experiments

We train a machine learning classifier to predict sex labels. On a test data point, the classifier predicts sex and uses this as a proxy for predicting deception – predicting lie if the predicted sex is female and vice-versa. This ad-hoc, discriminatory classifier simulates a classifier which uses nothing but dataset bias. The purpose of the classifier is to show that it can achieve statistically significant results without using any information of deception whatsoever.

For the Real-life Trial dataset [1], using IDT features similarly to [2], we achieve comparable results with this ad-hoc method. The notebook for this experiment is IDT.ipynb. Using manually annotated micro-expressions, we achieve 65% using sex labels whereas training on lie/truth labels we achieve 78% which shows that even manually annotated micro-expressions are correlated with sex and are biased. The experiment for this is in micro-expressions.ipynb.

For the Bag-of-Lies dataset, using gaze features, we achieve 54.4% using the ad-hoc which is statistically significant. Using features such as audio and video should give considerably higher accuracies. The experiment for this is in Bag-of_Lies.ipynb. To run this experiment, you need to sign a license agreement to obtain the data and then put the data under the BagOfLies directory.

Reproducing

You need numpy-1.18.1, scikit-learn-0.22.1, matplotlib-3.1.3 and pandas-1.0.1 libraries to run the code (I only used standard functions so different versions will likely work). Go to a directory where you want to clone the repository and run:

git clone https://github.com/AraMambreyan/LieDetector-IDT.git

Open the notebook for the experiment you want to run. Change the run_experiment_with_sex_labels variable to the experiment you'd like to run. Then click run all and our results will be reproduced.

References

[1] R. Mihalcea, V. P´erez-Rosas, M. Abouelenien and M. Burzo. Deception detection using real-life trial data. In Proceedings of the 2015 ACM on International Conference on Multimodal Interaction, page 59–66, 2015.

[2] Z. Wu, B. Singh, L. S. Davis, and V. S. Subrahmanian. Deception Detection in Videos. In AAAI, 2018.

[3] V. Gupta, M. Agarwal, M. Arora, T. Chakraborty, R. Singh, and M. Vatsa, “Bag-of-lies: A multimodal dataset for deception detection,” in IEEE Conference on Computer Vision and Pattern Recognition Workshops (CVPR), 2019, pp. 83–90

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