Maurizio Porfiri

A new study from NYU Tandon School of Engineering suggests that when it comes to visualizations of mass shooting data, political ideology plays a more significant role in shaping emotional responses than racial identity. The research challenges assumptions about how people interpret data related to gun violence.

The study involved 450 participants who were shown visualizations  — in this case, bar charts — of mass shooting victim data highlighting different racial groups. Contrary to the researchers' expectations, participants did not show stronger emotional responses when viewing data about victims of their own race.

"We anticipated seeing evidence of racial homophily, the tendency for people to identify more strongly with members of their own group," said Poorna Talkad Sukumar, a postdoctoral associate in NYU Tandon’s Technology Management and Innovation Department and the lead author on the research which will be presented at VIS2024 next month. "But our findings suggest that the gravity of mass shootings as a topic may override such in-group preferences."

Instead, the study found that political views were the strongest predictor of how participants reacted emotionally to the visualizations. Those with more liberal political leanings tended to have more negative emotional responses across all conditions. 

Oded Nov, the NYU Tandon Morton L. Topfer Professor of Technology Management and a member of NYU Tandon’s Center for Urban Science and Progress (CUSP), is another author of the paper. He said the findings highlight the complex interplay between personal beliefs and data interpretation. "This research underscores how pre-existing ideological frameworks can shape our emotional reactions to information, even when presented in a seemingly neutral, visual format.”

Maurizio Porfiri, Director of CUSP and an Institute Professor in the Department of Mechanical and Aerospace Engineering and in the Department of Biomedical Engineering, is also an author of the paper. He suggested that “studies like this are critical to helping us identify best practices to present data on firearm violence and sensitize the general public about firearm-related harms.”

The study also revealed that even relatively simple bar charts elicited strong negative emotions from participants, regardless of their race or the racial group highlighted in the data. This finding could have implications for how sensitive topics are visually presented in media and public policy discussions.

The researchers note that their study had limitations, including a relatively small sample size, which limits the detection of subtle effects. They call for further research exploring different types of societal issues and visualization designs to better understand how viewer characteristics interact with data presentation.

As debates around gun violence and racial disparities continue to occupy national attention, this study offers valuable insights into how Americans process related information. It suggests that bridging ideological divides may be more crucial than addressing racial differences when it comes to fostering a shared understanding of mass shooting data.

This study contributes to Porfiri, Nov, and colleagues’ ongoing data-based research related to U.S. gun prevalence and violence, which they are pursuing under a 2020 $2 million National Science Foundation grant to study the “firearm ecosystem” in the United States.  Prior published research under the grant explores:

• the role that population size of cities plays on the incidences of gun homicides, gun ownership and licensed gun sellers; 
• motivations of fame-seeking mass shooters; 
• factors that prompt gun purchases;
• state-by-state gun ownership trends; and
• forecasting monthly gun homicide rates. 

arXiv:2408.03269v1 [cs.HC] 6 Aug 2024

In the world of social creatures, from humans to ants, the spread of behaviors through a group — known as social contagion — is a well-documented phenomenon. This process, driven by social imitation and pressure, causes individuals to adopt behaviors observed in their peers, often resulting in synchronized mass actions; Think of stampedes, or standing ovations. 

Social contagion is a double-edged sword in highly integrated societies. While it facilitates cohesion and collective efficiency, unchecked contagion can lead to detrimental mass behaviors, such as mass panic. Thus, nature has evolved regulatory mechanisms to keep such behaviors in check. 

One such mechanism is reverse social contagion. In reverse social contagions, increased interactions between individuals engaged in a behavior lead to a higher likelihood of them stopping that behavior, rather than engaging in it.

In a new paper published in PNAS Nexus, researchers led by Maurizio Porfiri — NYU Tandon Institute Professor of Professor of Biomedical Engineering, Mechanical and Aerospace Engineering, and Civil and Urban Engineering, as well as the director of its Center for Urban Science and Progress (CUSP) — describe this unique phenomenon in colonies of harvester ants (Pogonomyrmex californicus) in order to understand the energetic consequences of highly integrated social behavior. 

“Ants colonies reduce their energy spending per individual as the colony grows, similar to the size-dependent scaling of metabolic costs in birds and mammals discovered by Kleiber almost a century ago,” said Porfiri. “To date, a convincing explanation of how this collective response emerges is lacking.” 

Utilizing tracked video recordings of several colonies, they discovered that individual ants did not increase their activity levels in proportion to the colony size. This was a curious finding, because larger colonies means more interactions between their members, and more opportunities for reinforcing behaviors. 

To decode this behavior, the team — who also includes Pietro De Lellis from the University of Naples, Eighdi Aung and (Tandon alum) Nicole Abaid from Virginia Tech, Jane S. Waters from Providence College, and Santiago Meneses and Simon Garnier from the New Jersey Institute of Technology — applied scaling theories typically used to study human settlements. They derived relationships linking colony size to interaction networks and activity levels, hypothesizing that reverse social contagion was at play. Their hypothesis was supported by respirometry data, which revealed a potential connection between ant activity and metabolism.

Imagine you are an ant, and you see one of your fellow workers foraging for food. If you are governed by social contagion, you might also begin foraging so you don't look lazy. But the energy you expend foraging might not be worth it if one ant can efficiently gather the food. In this case, reverse social contagion tells you to kick your feet up and relax while you let your compatriot do the work, because you’ll need your energy later for another task. In this way, restraining social contagion makes the colony more efficient.

The study draws a fascinating parallel between insect colonies and human cities. In both systems, social interactions influence energy expenditure, but in opposite directions. Insect colonies exhibit hypometric scaling—activity levels do not increase proportionally with colony size. In contrast, human cities show hypermetric scaling, where energy expenditure grows faster than the population size.

“Human behavior is often driven by personal gain” says Simon Garnier, Associate Professor of Biological Sciences at NJIT and senior author on the paper. “Ants, on the other hand, tend to prioritize the needs of the colony over their own. This has huge implications for understanding the differences between the organization of human and social insect societies.” 

Unlike humans, ants manage their energy as a colony rather than individually, somehow displaying a cooperative response. This study shows that ants use reverse social contagion to regulate their overall activity and energy use. Essentially, when many ants are busy with a task, some will stop to prevent the entire colony from overworking. This behavior aligns with scaling laws and metabolic patterns seen in other biological systems.

In simpler terms, think of an ant colony as one big organism where every ant's actions are coordinated for the colony's benefit, not just their own. Future research will look into how exactly these ants communicate and manage their energy so efficiently.

This research not only sheds light on the regulatory mechanisms in ant colonies but also offers insights into the broader principles of social regulation across species. As we continue to explore these parallels, we may uncover more about the fundamental dynamics that govern both natural and human-made systems.

“This is the first step we are taking to understand and model energy regulation in ant colonies,” said Porfiri. “Is energy regulation accompanied by improved performance for the collective? Can we design algorithms for robot teams inspired by ants that can maximize performance and minimize energy costs? Can we learn some lessons for our city transportation networks? These are just some of the questions we would like to address next. ”

This work was funded in part by a $3 million grant from the National Science Foundation, which over five years will aim to create a new paradigm for a better understanding of how loosely connected units can nonetheless collectively maintain function and homeostasis.

Porfiri, M., De Lellis, P., Aung, E., Meneses, S., Abaid, N., Waters, J. S., & Garnier, S. (2024). Reverse social contagion as a mechanism for regulating mass behaviors in highly integrated social systems. PNAS Nexus, 3(7). https://doi.org/10.1093/pnasnexus/pgae246

For survivors of strokes, which afflict nearly 800,000 Americans each year, regaining fine motor skills like writing and using utensils is critical for recovering independence and quality of life. But getting intensive, frequent rehabilitation therapy can be challenging and expensive.

Now, researchers at NYU Tandon School of Engineering are developing a new technology that could allow stroke patients to undergo rehabilitation exercises at home by tracking their wrist movements through a simple setup: a smartphone strapped to the forearm and a low-cost gaming controller called the Novint Falcon.

The Novint Falcon, a desktop robot typically used for video games, can guide users through specific arm motions and track the trajectory of its controller. But it cannot directly measure the angle of the user's wrist, which is essential data for therapists providing remote rehabilitation.

In a paper presented at SPIE Smart Structures + Nondestructive Evaluation 2024,  the researchers proposed using the Falcon in tandem with a smartphone's built-in motion sensors to precisely monitor wrist angles during rehab exercises.

"Patients would strap their phone to their forearm and manipulate this robot," said Maurizio Porfiri, NYU Tandon Institute Professor and director of its Center for Urban Science + Progress (CUSP), who is the paper’s senior author. "Data from the phone's inertial sensors can then be combined with the robot's measurements through machine learning to infer the patient's wrist angle."

The researchers collected data from a healthy subject performing tasks with the Falcon while wearing motion sensors on the forearm and hand to capture the true wrist angle. They then trained an algorithm to predict the wrist angles based on the sensor data and Falcon controller movements.

The resulting algorithm could predict wrist angles with over 90% accuracy, a promising initial step toward enabling remote therapy with real-time feedback in the absence of an in-person therapist.

"This technology could allow patients to undergo rehabilitation exercises at home while providing detailed data to therapists remotely assessing their progress," Roni Barak Ventura, the paper’s lead author who was an NYU Tandon postdoctoral fellow at the time of the study. "It's a low-cost, user-friendly approach to increasing access to crucial post-stroke care."

The researchers plan to further refine the algorithm using data from more subjects. Ultimately, they hope the system could help stroke survivors stick to intensive rehab regimens from the comfort of their homes.

"The ability to do rehabilitation exercises at home with automatic tracking could dramatically improve quality of life for stroke patients," said Barak Ventura. "This portable, affordable technology has great potential for making a difficult recovery process much more accessible."

This study adds to NYU Tandon’s body of work that aims to improve stroke recovery. In 2022, Researchers from NYU Tandon began collaborating with the FDA to design a regulatory science tool based on biomarkers to objectively assess the efficacy of rehabilitation devices for post-stroke motor recovery and guide their optimal usage. A study from earlier this year unveiled advances in technology that uses implanted brain electrodes to recreate the speaking voice of someone who has lost speech ability, which can be an outcome from stroke.

In addition to Porfiri and Barak Ventura, the study’s authors are Angelo Catalano, who earned an MS from NYU Tandon in 2024, and Rayan Succar, an NYU Tandon PhD candidate. The study was funded by grants from the National Science Foundation. 

Roni Barak Ventura, Angelo Catalano, Rayan Succar, and Maurizio Porfiri "Automating the assessment of wrist motion in telerehabilitation with haptic devices", Proc. SPIE 12948, Soft Mechatronics and Wearable Systems, 129480F (9 May 2024); https://doi.org/10.1117/12.3010545

The Venus flower basket sponge, with its delicate glass-like lattice outer skeleton, has long intrigued researchers seeking to explain how this fragile-seeming creature’s body can withstand the harsh conditions of the deep sea where it lives.

Now, new research reveals yet another engineering feat of this ancient animal’s structure: its ability to filter feed using only the faint ambient currents of the ocean depths, no pumping required. 

This discovery of natural ‘“zero energy” flow control by an international research team co-led by University of Rome Tor Vergata and NYU Tandon School of Engineering could help engineers design more efficient chemical reactors, air purification systems, heat exchangers, hydraulic systems, and aerodynamic surfaces.

In a study published in Physical Review Letters, the team found through extremely high-resolution computer simulations how the skeletal structure of the Venus flower basket sponge (Euplectella aspergillum) diverts very slow deep sea currents to flow upwards into its central body cavity, so it can feed on plankton and other marine detritus it filters out of the water.

The sponge pulls this off via its spiral, ridged outer surface that functions like a spiral staircase. This allows it to passively draw water upwards through its porous, lattice-like frame, all without the energy demands of pumping.  

"Our research settles a debate that has emerged in recent years: the Venus flower basket sponge may be able to draw in nutrients passively, without any active pumping mechanism," said Maurizio Porfiri, NYU Tandon Institute Professor and director of its Center for Urban Science + Progress (CUSP), who co-led the study and co-supervised the research. "It's an incredible adaptation allowing this filter feeder to thrive in currents normally unsuitable for suspension feeding."

At higher flow speeds, the lattice structure helps reduce drag on the organism. But it is in the near-stillness of the deep ocean floors that this natural ventilation system is most remarkable, and demonstrates just how well the sponge accommodates its harsh environment. The study found that the sponge’s ability to passively draw in food works only at the very slow current speeds – just centimeters per second – of its habitat.

"From an engineering perspective, the skeletal system of the sponge shows remarkable adaptations to its environment, not only from the structural point of view, but also for what concerns its fluid dynamic performance," said Giacomo Falcucci of Tor Vergata University of Rome and Harvard University, the paper’s first author. Along with Porfiri, Falcucci co-led the study, co-supervised the research and designed the computer simulations. "The sponge has arrived at an elegant solution for maximizing nutrient supply while operating entirely through passive mechanisms."

Researchers used the powerful Leonardo supercomputer at CINECA, a supercomputing center in Italy, to create a highly realistic 3D replica of the sponge, containing around 100 billion individual points that recreate the sponge's complex helical ridge structure. This “digital twin” allows experimentation that is impossible on live sponges, which cannot survive outside their deep-sea environment.

The team performed highly detailed simulations of water flow around and inside the computer model of the skeleton of the Venus flower basket sponge.  With Leonardo's massive computing power, allowing quadrillions of calculations per second, they could simulate a wide range of water flow speeds and conditions. 

The researchers say the biomimetic engineering insights they uncovered could help guide the design of more efficient reactors by optimizing flow patterns inside while minimizing drag outside. Similar ridged, porous surfaces could enhance air filtration and ventilation systems in skyscrapers and other structures. The asymmetric, helical ridges may even inspire low-drag hulls or fuselages that stay streamlined while promoting interior air flows.

The study builds upon the team’s prior Euplectella aspergillum research published in Nature in 2021, in which it revealed it had created a first-ever simulation of the deep-sea sponge and how it responds to and influences the flow of nearby water. 

In addition to Porfiri and Falcucci, the current study’s authors are Giorgio Amati of CINECA; Gino Bella of Niccolò Cusano University; Andrea Luigi Facci of University of Tuscia; Vesselin K. Krastev of University of Rome Tor Vergata; Giovanni Polverino of University of Tuscia, Monash University, and University of Western Australia; and Sauro Succi of the Italian Institute of Technology.

A grant from the National Science Foundation supported the research. Other funding came from CINECA, Next Generation EU, European Research Council, Monash University and University of Tuscia.