In these studies, participants watch a continuous stream of letters on a computer while spontaneously pressing a button. Every now and then, though, the letters change color. When this happens participants are told to press the button just then if they were already aware of their preparing to press the button soon. These kinds of online measures of awareness may yet prove to be more reliable ways of getting at whether people have conscious intentions to act in the lab.
What’s the latest work on the neuroscience of free will?
Two of the hottest topics seem to be, first, what exactly the RP, that negative build-up of brain activity pre-movement, really signifies and, second, how we can make our voluntary actions in the lab more ecologically valid.
As to the first, the past decade has seen researchers investigating if we have evidence that the RP really does stand for a decision to move or, alternatively, if the RP just is the brain’s being biased to move in some way (say, left, instead of right) without the commitment to do so.
Others test the possibility that the RP isn’t really movement specific activity at all (e.g., general cognitive preparation to perform a task voluntarily). Others, such as Schurger and colleagues, have argued via empirical studies that the RP is the neural signature that we pick up when are actions are generated by neural noise crossing some threshold (here). That possibility would be alarming as then our actions, which we take to be undertaken by me for reasons, may really just be the passive result of fluctuating brain activity.
As to the second hot issue, researchers are now attempting to design tasks in the lab that are closer to the kind of decisions and activities that we engage in daily. Libet argued that a simple movement like a wrist flexor button press could stand-in for the more complex actions, as the RP has been shown to occur prior to more complex movements in the lab. Hence we could give a unified explanation of the timing of events involving practical decisions and bodily movements.
But many, myself included, have voiced concern that when to press a button or whether to press a left or right button, just isn’t the right kind of action to stake a claim that we as agents don’t initiate our actions via our conscious intentions to act.
Hence, some of the ongoing work involves making the choice of which button to press or when to press it meaningful via rewards or penalties for skipping ahead or value-laden options, such as charity donations.*
And, of course, there are plenty of neuroimaging tools at the disposal of cognitive neuroscientists. Some of the most interesting replications and extensions of the Libet findings have been done using singe-cell recording and fMRI among other technologies (see here and here, respectively).
In fact, the neuroscience of free will has been and currently is the focus of some major research grants, such as the Big Questions in Free Will project (2010-2014, Principal Investigator Dr. Alfred Mele) and the Consciousness and Free Will project (2019-, a collaboration across 17 PIs), each of which involves philosophers and numerous neuroscientific labs worldwide. From these grants, I think we should expect further clarity on what’s going on under the hood, so to speak, when we decide what to do and act voluntarily.
Are there any other results in neuroscience that tell us something intriguing about our agential control?
Yes, one of the aspects of our lives that seems the most undeniable is that we really do experience ourselves as in control of our movements and their effects in the world. There is a large body of work in cognitive neuroscience which focuses on this sense of agency via research on what’s been termed intentional binding.