For top-secret reasons too lengthy to be discussed here, I was researching lie detector tests today. That led me to an interesting Wikipedia article on something I’ve never heard of: brain fingerprinting. Basically, the idea is that when you are confronted with a word or image that you’re familiar with, your brain reacts differently than it would if the object was unfamiliar. And there are techniques and tools that can measure these brain changes. So, for instance, if you suspected a man was sleeping with your wife, you could kidnap him, drag him to your secret compound, hook him up to the brain fingerprinting device and show him an image of your wife. If his brain insinuated that he was familiar with her visage, you could confidently torture him to death. There may be other uses as well.

Here’s a bit of info…

Brain fingerprinting was invented by Lawrence Farwell. The theory is that the brain processes known and relevant information differently from the way it processes unknown or irrelevant information (Farwell & Donchin 1991). The brain’s processing of known information, such as the details of a crime stored in the brain, is revealed by a specific pattern in the EEG (electroencephalograph) (Farwell & Smith 2001, Farwell 1994). Farwell’s brain fingerprinting originally used the well-known P300 brain response to detect the brain’s recognition of the known information (Farwell & Donchin 1986, 1991; Farwell 1995a). Later Farwell discovered the P300-MERMER (“Memory and Encoding Related Multifaceted Electroencephalographic Response”), which includes the P300 and additional features and is reported to provide a higher level of accuracy and statistical confidence than the P300 alone (Farwell & Smith 2001, Farwell 1994, Farwell 1995b, Farwell et al. 2012). In peer-reviewed publications Farwell and colleagues report less than 1% error rate in laboratory research (Farwell & Donchin 1991, Farwell & Richardson 2006) and real-life field applications (Farwell & Smith 2001, Farwell et al. 2012). In independent research William Iacono and others who followed identical or similar scientific protocols to Farwell’s have reported a similar low level of error rate and high statistical confidence (e.g., Allen & Iacono 1997).

To ensure accuracy and statistical confidence, brain fingerprinting tests are conducted according to specific scientific standards, which are specified in Farwell 2012 and Farwell et al. 2012).

Brain fingerprinting has been applied in a number of high-profile criminal cases, including helping to catch serial killer JB Grinder (Dalbey 1999) and to exonerate innocent convict Terry Harrington after he had been falsely convicted of murder (Harrington v. State 2001). Brain fingerprinting has been ruled admissible in court (Harrington v. State 2001, Farwell & Makeig 2005, Farwell 2012).

Of course, the technique has been criticized. If you’re interested, you can read details at the article.