There is increasing media attention to conclusions from neuroscience research, many of which affect society. Unfortunately, often these conclusions are not warranted from the current level of knowledge. All types of theories about the brain, the mind, free will, ethics, and morality are circulated as facts because one of the 500,000 neuroscientists have espoused unproven and speculative viewpoints. Several books recently have pointed out that results from fMRI are, especially, being over interpreted. This post will address some of the limits of current neuroscience.
One important problem with almost all current fMRI studies was recently noted. It concerns a critical assumption in the design of most experiments that is not correct.
Each study has a group that performs a task, and another control group that it is compared to. The assumption in the experiment is that the group performing the task activates a specific part of the brain, which is an addition to the control group’s brain activity. This is called “cognitive subtraction.” It assumes that the control group’s brain state participates in some part of the task group’s brain state. An example could be the resting state during day dreaming (called the default mode network) compared with the brain state during a specific action. The new brain state is compared with the resting state and one is subtracted from the other. The new activity observed is assumed to be the brain regions of the action.
However, recent studies show that, in fact, many tasks use cognitive “addition” where parts of the brain do less when the experimental task is done. That is, it cannot be assumed that none of the resting state, some part of the resting state, or all of the resting state are used in the task. This simple assumption might invalidate many current studies and conclusions.......