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.
Basically, if you ask participants in clever experimental set-ups to judge whether some event (e.g., icon moving on a computer screen) was the outcome of their agency or someone else’s (i.e., “I did that” judgments), participants tend to misjudge an outcome to be a result of their own agency if it is a positive one and misjudge an outcome to be the result of another’s agency if it is a negative one.
That is, there is a self-serving bias to explicit sense of agency judgments (For interesting results in this regard see Wegner and Wheatley’s 1999 paper here and other earlier work in psychology on attribution theory).
Cognitive neuroscientists have found a methodology to study our sense that we are in control of our actions and actional outcomes without surveying participants’ explicit “I did that” judgments. Instead, experimenters asked participants to judge the time of various events, including their movements (e.g., a button press) and the sensory outcomes of those movements (e.g., a beep following the button press).
Related: How Cognitive Distortions Harm Us
What researchers have found is that if you voluntarily press a button and hear a tone as a consequence, you are going to judge that the time of the movement and the time of the tone are much closer together in perceived space than if you are caused to move (via neural stimulation) and hear a tone as a consequence.
In other words, the perceived time of the action and the tone “bind together” in perceptual space when you act voluntarily as opposed to when you are caused to move or simply judge the time of events without acting (here). What’s intriguing about this research on agency, then, is that our perceptual judgments about the world seem to distinguish when we act from when something is done to us. Research work on intentional binding has tackled more ecologically valid issues of sense of agency when acting under emotional distress, due to coercion, and in the face of options.*
* Neuroscientists working on more representative kinds of decisions and/or sense of agency in more ecologically valid contexts include researchers in the UCL Action and Body Lab at University College London and The Brain Institute at Chapman University, among others.