Broadly I study social intelligence, although much of my work is devoted to understanding the nature of personal identity or the self: its contents, limits, and perceptual beginnings. Part of being a self also involves reflecting on what is ours, including our mental contents, and doing so recursively with respect to the mental contents of others. So, I also naturally study the strategic nature of social intelligence. More broadly, my work tends to focus on the sorts of concepts that typically get invoked when people are trying to determine how to lead their lives, including not just the self, but also morality, happiness, and meaning in life. 

I approach these problems using the tools of behavioral psychology (incl. psychophysics) and AI, while drawing on insights from philosophy, game theory, and evolutionary biology.

The True Self & Personal Identity

Representations of and beliefs about the concept of “a self” vary across cultures, perspectives (first vs. third), and individuals. Yet my collaborators and I have found evidence suggesting that people exhibit a robust, invariant tendency to believe that deep inside every individual there is a “good true self” calling them to behave in a morally virtuous manner. We propose that this belief arises from a general cognitive tendency known as psychological essentialism.


Common Knowledge, Coordination, and Strategic Mentalizing in Moral Life

My collaborators and I have investigated how representations of knowledge -- including shared knowledge (e.g., you know X, I know that you know X), and common knowledge (you know X, I know that you know X, you know that I know that you know X, ad infinitum) -- affect diverse social phenomena such as the bystander effect and perceptions of charitability. We propose that -- rather than being represented as an explicit, multiply nested proposition -- common knowledge may be a distinctive cognitive state, corresponding to the sense that something is public or "out there". 


Limits on Self Allocation and Personal Identity

A cornerstone of cognitive science is that mental systems are limited: There is a maximum amount of information they can process or store, beyond which performance breaks down. We find that people can only personally identify with one imagined self at a time, a limit that occurs across decision-making, associative learning, and long-term memory. At the same time, we also discover ways in which thinking about the self is flexible, despite this limit.

  • De Freitas, J., Rips, L., & Alvarez, G. A. Personal identity, self-reference, and intransitivity. Under review. 

  • De Freitas, J., Rips, L., & Alvarez, G. A. The capacity of self-relevant long-term memories. Under review.

  • De Freitas, J., Rips, L., & Alvarez, G. A. The limit of active self representation. Under review. 

  • Paul, L. A., Ullman, T.D., De Freitas, J., & Tenenbaum, J.B., Reverse engineering a self. Under review. 

Ethics of Autonomous Vehicles

Because autonomous vehicles will operate in populated environments, for the first time in history we need to create complex autonomous systems that have 'ethically acceptable' behavior. How can we achieve this feat? 

  • De Freitas, J., Anthony, Censi, A., & Alvarez, G. A. Doubting driverless dilemmas. Perspectives on Psychological Science**Review**

  • De Freitas, J., Censi, A., Anthony, S. E., Frazzoli, E., Di Lillo, L. From driverless dilemmas to more practical ethics tests for autonomous vehicles. Under review. 

  • De Freitas, J., Censi, A., Di Lillo, L. What is the correct ethics goal for autonomous vehicles? Under review. 

The Origins of Animate Attention

Humans naturally pay attention to other animate agents in their environment, a prosocial behavior that has been documented as early as a few weeks. What internal mechanisms give rise to this behavior? A standard hypothesis is that the human brain has a built-in module that specifically detects animacy from visual input. Yet we find evidence that animate attention naturally arises from a more general process of curiosity driven learning. This work utilizes a threeD environment that we created for model and human testing (using VR), as well as real-world robot setups. 

  • Kim, K. H., Sano, M., Haber, N., De Freitas, J., & Yamins, D. L. K. Learning world models with progress-driven exploration. Under review. 

  • De Freitas, J., Kim, K. H., Haber, N., Conwell, C., Alvarez, G. A., Yamins, D. L. K. Intrinsic curiosity may give rise to animate attention. Under review. 

  • Gan, C., Schwartz, J., Alter, S., Schrimpf, M., Traer, J., De Freitas, J., Bhandwaldar, A., Sano, M., Kim, K. H., Wang, E., Mrowca, D., Lingelbach, M., Curtis, A., Feigelis, K., Haber, N., Gutfreund, D., Cox, D., DiCarlo, J., McDermott, J., Tenenbaum, J., Yamins, D. L. K. ThreeDWorld: A Platform for interactive multi-modal physical simulation. Under review. 

Moral Judgment

Some of these papers investigate how we come to form moral judgments, including how the mind maps from vision to the propositional ingredients of moral judgment, and the effect of  'teleological' (rather than mental) factors on moral judgment. The other papers reveal the pervasive impact of morality on non-moral intuitions in intuitive physics and psychology, e.g., whether someone caused an outcome, or is happy. Finally, I've also written about how to to ensure that autonomous systems such as driverless cars exhibit ethically acceptable behavior.  

Other Papers