Category Archives: Body representation

Luke Miller Dissertation Defense 9/16 11am – Tool Use and Body Representations

Dissertation Defense

The Body in Flux: Tool Use Modulates Multisensory Body Representations


Wednesday, Sept 16, 2015, 11 am

Cognitive Science Building, Room 003

Tool use is a hallmark of the human species and an essential aspect of daily life. Tools serve to functionally extend the body, allowing the user to overcome physical limitations and interact with the environment in previously impossible ways. Tool-body interactions lead to significant modulation in the user’s representations of body size, a phenomenon known as tool embodiment. In the present dissertation, I used psychophysics and event-related brain potentials to investigate several aspects of tool embodiment that are otherwise poorly understood.

First, we investigated the sensory boundary conditions of tool embodiment, specifically the role of visual feedback during tool use. In several studies, we demonstrate that visual feedback of tool use is a critical driver of tool embodiment. In one such study, we find that participants can embody a visual illusion of tool use, suggesting that visual feedback may be sufficient for tool-induced plasticity.

Second, we investigated the level of representation modulated by tool use. Is embodiment confined to sensorimotor body representations, as several researchers have claimed, or can it extend to levels of self-representation (often called the body image)? Utilizing well-established psychophysical tasks, we found that using a tool modulated the body image in a similar manner as sensorimotor representations. This finding suggesting that similar embodiment mechanisms are involved at multiple levels of body representation.

Third, we used event-related brain potentials to investigate the electrophysiological correlates of tool embodiment. Several studies with tool-trained macaques have implicated multisensory stages of somatosensory processing in embodiment. Whether the same is true for humans is unknown. Consistent with what is found in macaques, we found that using a tool modulates an ERP component (the P100) thought to index the multisensory representation of the body.

The work presented in this dissertation advances our understanding of tool embodiment, both at the behavioral and neural level, and opens up novel avenues of research.

Please join us and find out more about some of Luke’s exciting research in the lab over the past few years!

Why You Should Do Research as an Undergrad

Hello! This is Cindy, and I am a research assistant at the Saygin Lab of Cognitive Neuroscience and Neuropsychology. I’ve been doing this for a few quarters now, and it’s been a great experience. You should join me!

Being a research assistant for the Saygin Lab really solidified why I became a cognitive science major. I switched into it not really knowing what my major was about, but through the weekly lab meetings and conversing with others, I came to realize how lucky I was to have stumbled upon UCSD’s diamond in the rough.

I knew about the work that our lab does beforehand was because I am a chronic frequenter of geek websites, such as Although perhaps not the most established forum, it often brings up sci-fi related research, such as was being done in the lab. Robots are a common topic, and the phenomenon of the Uncanny Valley inevitably came up. Imagine how surprised I was when I was reading up on the research opportunities at the CogSci department at UCSD, and found that that research had been accomplished by one of the professors! I sent in an application and was ecstatic when I was accepted.

I didn’t know what I was getting myself into, since my pre-med friends were always going on about how they created buffer solutions in chem research or cut up rats in bio research. Turns out that the experiments I was running for my grad student researcher was most like psychology research. Luke (the grad student) had us running a two session, two hour each experiment, which was not the most interesting thing I’ve ever done. When I talked to him about what I was collecting data for though, that was what was the exciting part. The overarching theme was something about embodied cognition and how we projected ourselves in space. For example, how do amputees see and feel about their prosthetics? It’s not technically a part of them, yet it should ideally function just as well or even better than what the respective limb did. He went on to do some research concerning a large plastic hand, similar to Edward Scissorhands. I did some external research and thought that this particular invention, a prosthetic arm that biomimics an octopus arm would yield interesting results pitting conventional arms vs. functionality.

How would these affect the self-perception of a human?


Lab members attend mini symposiums and conferences about where advances in cognitive science could lead to (in regards to technology). One that I was able to attend concerned the future of brain-computer interfaces or BCIs. Most of the technical engineering talk was lost on me, but the main thing I came away with was that pretty soon, we will be able to manipulate objects with our “minds.” This lead me to do some other outside research, and I found this prototype fashion accessory being demonstrated in conventions around the world: Necomimi Cat Ears. Its claim to fame is that it can change shapes when the wearer is focused or relaxed. This seems like an extraordinarily trivial application of this technology, but the concept is the same as more serious uses of BCIs. It is using EEG waves produced by the brain to control objects that aren’t necessarily part of a body.

An application of BCI technology: Wiggle your cat ears with your brain waves!

The coolest thing about researching in this lab while being a CogSci major was probably seeing how this current research was being taught in our classes. The fMRI book we discuss in meetings have direct repercussions on what I’m learning in my neuroscience class, and knowing that there’s still much debate going on whether cognition is distributed or specialized puts a whole different spin on my distributed cognition class. It’s also opened up a lot of doors. This summer, I advised a couple high school students getting their first taste of research and during the school year (we will have another blog post about that soon), I will be in the process of completing the Cognitive Science Honors Program.

I hope this has convinced you to do research as an undergrad! Use your four years wisely.

Saygin Lab Taco and "Spinal Tap" Viewing Party

Some members of Saygin Lab - Back row: Edward Nguyen (undergraduate), Maria Florendo (undergraduate), Ayse Saygin (professor), Angela Chan (undergraduate, now graduated), Burcu Urgen (graduate student). Front row: Jingwei Li (undergraduate, now graduated), Luke Miller (graduate student), Cindy Ha (undergraduate)

Here is the attachments of this Post