Jason Castro, assistant professor of psychology and neuroscience.

The first question is whether the brains of introverts and extraverts differ. Yes, says Castro, but “we don’t have experiments that really address whether those brain differences play a causal role.”

The second is what neuroscience tells us about free will. In fact, we may have free will and not even know it. “There is brain activity that registers our intent to make a decision — a spontaneous decision — well before we’ve consciously decided to make a decision,” Castro says.

Adina Roskies, an assistant professor of philosophy at Dartmouth College, discusses the limitations and potential for neuroscience in the study of free will in a talk titled Freedom Despite Mechanism at 4:15 p.m. Thursday, March 25, in Pettengill Hall’s Keck Classroom, Room G52, Alumni Walk.

Sponsored by the philosophy and psychology departments with support from the Mellon Innovation Fund, this lecture is open to the public at no cost.

Roskie, a member of Dartmouth’s philosophy department since 2004, has pursued a career in both philosophy and neuroscience. She simultaneously earned master’s degrees in both disciplines at the University of California, San Diego, and received a doctorate in neuroscience in 1995. From 1997 to 1999 she held the position of senior editor at the neuroscience journal Neuron.

In 1999 Roskies returned to the Massachusetts Institute of Technology to complete a second doctorate in philosophy. Her research topics include philosophy of mind, philosophy of science and ethics. She was a member of the McDonnell Project in Neurophilosophy, a group aiming to integrate philosophical thought with neurobiological research.

Roskies recently received a fellowship by the Australian Research Council, and has worked as a visiting professor in the philosophy department at the Australian National University.

Titled Free Will as the Expensive Control of Action and sponsored by the departments of psychology and philosophy, with support from the Mellon Innovation Fund, the talk is open to the public at no charge. For more information, please call 207-786-8204.

The Francis Eppes Professor of Social Psychology at Florida State, Baumeister has conducted extensive research on self-control and decision-making. He has explored how people regulate their emotions, resist temptation, break bad habits and perform up to their potential — and why they often fail in these efforts.

Baumeister’s talk is part of a series, arranged by the ÀÖ²¥´«Ã½ psychology and philosophy departments, examining such concepts as free will and determinism — the idea that human behavior, along with everything else, is determined by prior causes and subject to natural laws.

Some people, described as “compatibilists,” hold that free will is reconcilable with determinism, explains associate professor of psychology Michael Sargent. “Incompatibilists argue that the two ideas are irreconcilable. This debate has a long history in the discipline of philosophy, and recently has garnered attention in psychology as well.”

Last year, philosophy and psychology faculty at ÀÖ²¥´«Ã½ took part in a yearlong seminar focusing on such issues, Sargent explains. “Many of our most energetic debates were about free will, determinism and the compatibilism/incompatibilism debate.”

Supported by funding from the Mellon Innovation Fund at ÀÖ²¥´«Ã½, the speaker series began as a component of the seminar.

Baumeister’s research seeks to understand the psychological processes that constitute the phenomenon defined as free will. “How do we ‘will’ ourselves to get up in the morning and be productive, even when we’d rather keep hitting the snooze button?” Sargent offers. “In short, how do we manage to do things that we don’t want to do, but feel we should — and manage not to do things we want to do, but feel we shouldn’t?

“To the extent that each of us succeeds in not being a mere slave to our urges, how do we manage to accomplish that freedom? And at what costs?”

Baumeister argues that “free will is a relatively new kind of action control that evolved to support the particular demands and opportunities of social life, including culture,” Sargent explains.

Baumeister received his Ph.D. in social psychology from Princeton in 1978. He taught for more than two decades at Case Western Reserve University and has worked at the University of Texas, the University of Virginia, the Max-Planck-Institute and the Center for Advanced Study in the Behavioral Sciences.

Considered one of the world’s most influential psychologists, Baumeister has nearly 400 publications, and his 20 books include “Meanings of Life” (Guilford Press, 1992), “Evil: Inside Human Violence and Cruelty” (Holt, 1999) and “The Cultural Animal” (Oxford University Press, 2005).