Research

Publications

  • Vaughn DA & Eagleman (Under Review) “Briefly Glimpsed People are More Attractive”
    • Abstract: Assessments of attractiveness underlie selection and pursuit of potential mates.  Previous research has shown that people are sometimes perceived to be more attractive with a brief glimpse, yet there is no explanation for why this effect might exist.  Here, participants rated the attractiveness of males and females photographs, viewed in two conditions: once for 225 ms, and once without time constraints. In the former case, attractiveness judgments were on average higher: briefly glimpsed people were judged to be more attractive.  This ‘glimpse effect’ was sex-dependent, being most pronounced when males rated photos of females.  We discuss several possible explanations for these results, including the speculation that the brain determines attractiveness based on Bayesian risk, in which attractiveness ratings are upwardly biased by the high cost of missing a potential mate.
  • Vaughn DA & Eagleman (Submitted) “Temporal extrapolation is insensitive to optic flow direction”
    • Abstract: In the Hering illusion, two parallel lines appear bowed when viewed against a background of radial lines.  A recent framework suggests that the radial lines imply forward motion induce the visual system to extrapolate forward to the upcoming visual scene.  This hypothesis implies that the same geometric illusion should result with a background of implied ego-motion, which we verified by replacing the radial lines of the background with optic flow.  Surprisingly, we found that the magnitude and direction of the Hering illusion were identical whether the motion was expanding or contracting, implicating a neural mechanism that is sensitive to three inducers: radial lines, expanding motion, and contracting motion.  Moreover, low level cues that evinced a separation of the bars from the background reduced the size of the illusion, demonstrating temporal extrapolation occurs subsequent to an active scissioning process.  These data suggest that a single mechanism — orientation selectivity cells in primary visual cortex — underlie a class of both static and dynamic illusions, and implicate orientation-selective neurons of the primary visual cortex in the temporal extrapolation of visual scenes.

Ongoing Research

Freewill

The concept that each human is free to choose their own actions is fundamentally embedded in our culture and jurisprudence.  Philosophers have pondered the nature of free will for millennia but in the last 40 years, neuroscience research has been able to contribute to the conversation.  Starting with Benjamin Libet’s initial investigations in the 1970s and resurging recently with several fMRI studies, scientists have found increasing evidence of neural activity preceding conscious awareness of a decision.  Put another way, before you areaware of a simple motor act you’re about to make, there is activity in your brain that predicts, above chance, what you’re going to do.  Spooky, right?

In the Eagleman Lab, I investigate this phenomenon, using fMRI.  Specifically, I am researching whether this preconcious activity is actually predicting behavior above chance, or if instead, non-randomness in human behavior accounts for previous findings.  Data collected so far strongly suggests the later.

 

Modulating the Human Empathic Response

The empathic response is fundamental to normal human social interaction; a lack of empathy separates normal humans from psychopaths.  Empathy also affects a range of important behaviors, from jury decision-making to bystander behavior in emergency situations.  It has been previously shown that empathic neural responses can be modulated by the perceived fairness of another.

Given that another’s actions can change the response of your empathic network, the burning question seems to be: can just labeling another person as belonging to a different group change your reaction.  Previous psychology research would suggest that, indeed, it can, so I am testing this question with religious labels.  Our results strongly suggest that, on average, the mere presence of an out-group religious label slightly, but significantly reduces the response of one’s empathic network when seeing that person in pain.  We have beginning the next phase of this experiment to test whether or not we see the same in-group/out-group difference when randomly dividing participants into groups and labeling each person with a group name instead of a religious one.

 

Sensory Substitution: Feeling Echolocation

In a side project, I am experimenting with feeding echolocation information (gathered with sonar) to people through a vibrating motor on the skin.  In it’s most basic level  My hope is that the brain can wrap itself around the spatial/haptic information