Barbara

That does not mean that all people need to understand the details of most scientific discoveries and issues, but they do need to understand the nature of science, its power and limits, and they need to be able to discriminate science from pseudo-science

This is because they measure the structure of the brain rather than the brain activity that changes from moment to moment. In order to read out the current mental state of a person a measurement of their current brain activity is required

Brain activity can be measured using a number of techniques: electromagnetic brain activity signals can be measured using electroencephalography (EEG) and magnetoencephalography (MEG).

These techniques map brain activity with high temporal resolution (in the millisecond range), but their spatial resolution is very low (several centimeters). Already in the 1960s researchers used EEG for brain-based spelling devices. Subjects learned

The key problem is that the brain represents information in fine-grained columnar maps with a resolution of approximately 0.5mm (Tanaka 1997). These activation patterns are far too small to be resolved with EEG

because brain activity is estimated via its effects on the oxygen content of blood.

Similar to a fingerprint, a brain activity pattern as a unique and unmistakable brain signal indicates a specific thought

A typical brain reading procedure starts by measuring the brain activity patterns that occur when a person has a specific thought

Then a computer is trained to recognize the specific patterns of brain activity that are associated with the different thoughts

It is possible to read out implicit and even unconscious mental states, such as unconscious percepts and decisions (for an overview see Haynes and Rees 2006; Norman et al. 2006)