For example, a study by John-Dylan Haynes in 2008 showed a similar effect to the one revealed by Libet. After putting participants into an fMRI scanner, he told them to press a button with either their right or left index fingers at their leisure, but that they had to remember the letter that was showing on the screen at the precise moment they were committed to their movement.
The results were shocking. Haynes's data showed that the BP occurred one entire second prior to conscious awareness — and at other times as much as ten seconds. Following the publication of his paper, he told Nature News:
The first thought we had was 'we have to check if this is real.' We came up with more sanity checks than I've ever seen in any other study before.
The cognitive delay, he argued, was likely due to the operation of a network of high-level control areas that were preparing for an upcoming decision long before it entered into conscious awareness. Basically, the brain starts to unconsciously churn in preparation of a decision, and once a set of conditions are met, awareness kicks in, and the movement is made.
In another study, neuroscientist Itzhak Fried put aside the fMRI scanner in favor of digging directly into the brain (so to speak). To that end, he implanted electrodes into the brains of participants in order to record the status of individual neurons — a procedure that gave him an incredibly precise sense of what was going on inside the brain as decisions were being made.
His experiment showed that the neurons lit up with activity as much as 1.5 seconds before the participant made a conscious decision to press a button. And with about 700 milliseconds to go, Fried and his team could predict the timing of decisions with nearly 80% accuracy. In some scenarios, he had as much as 90% predictive accuracy.
Different experiment, similar result.
Fried surmised that volition arises after a change in internally generated fire rates of neuronal assemblies cross a threshold — and that the medial frontal cortex can signal these decisions before a person is aware of them.
"At some point, things that are predetermined are admitted into consciousness," he told Nature, suggesting that the conscious will might be added on to a decision at a later stage.