Playing 20 Questions with the Mind: Collaborative Problem Solving by Humans Using a Brain-to-Brain Interface

Abstract

We present, to our knowledge, the first demonstration that a non-invasive brain-to-brain interface (BBI) can be used to allow one human to guess what is on the mind of another human through an interactive question-and-answering paradigm similar to the “20 Questions” game. As in previous non-invasive BBI studies in humans, our interface uses electroencephalography (EEG) to detect specific patterns of brain activity from one participant (the “respondent”), and transcranial magnetic stimulation (TMS) to deliver functionally-relevant information to the brain of a second participant (the “inquirer”). Our results extend previous BBI research by (1) using stimulation of the visual cortex to convey visual stimuli that are privately experienced and consciously perceived by the inquirer; (2) exploiting real-time rather than off-line communication of information from one brain to another; and (3) employing an interactive task, in which the inquirer and respondent must exchange information bi-directionally to collaboratively solve the task. The results demonstrate that using the BBI, ten participants (five inquirer-respondent pairs) can successfully identify a “mystery item” using a true/false question-answering protocol similar to the “20 Questions” game, with high levels of accuracy that are significantly greater than a control condition in which participants were connected through a sham BBI.

Rehabilitative Surgery

“…Zhao et al transfected animals with ChABC expressing lentiviral vectors and found better recovery [367]. In 2012, Starkey et al showed that ChABC promoted compensatory sprouting of remaining corticospinal axons and improved forelimb function after unilateral pyramidotomy [308]. In 2015, Mondello et al found that 4 weeks of ChABC treatment promoted earlier recovery in cats after SCI [232].…”

Navigating a 2D Virtual World Using Direct Brain Stimulation

“…In our experiments, a total of 72 bits were transferred on average per subject in approximately 60 min; to our knowledge, this is both the largest CBI information transfer using TMS [superior to Rao et al (2014) and Stocco et al (2015)] as well as the largest CBI bit-rate to date. The type of information delivered to the brain was, however, quite restricted.…”

“…If the subject did not perceive a phosphene by the 75% mark, a new location was examined. Based on the results of Stocco et al (2015), the first stimulation site examined was 2 cm dorsal, 1 cm left of the inion. Subsequent sites were then examined at increasing distance from this starting point.…”

“…Transcranial magnetic stimulation has been and continues to be used as an important investigative tool for cortical "knockout" studies (Pascual-Leone et al, 1999;Devlin and Watkins, 2007), neurophysiology (Terhune et al, 2015), and medical treatment (Menkes et al, 1999;George et al, 2000). The realm of applications of TMS has recently expanded as it has emerged as a tool for non-invasive neural encoding of information via a computerbrain interface (CBI), specifically within the context of human brain-to-brain communication (Grau et al, 2014;Rao et al, 2014;Stocco et al, 2015). Rao et al (2014) utilized TMS over the primary motor cortex to elicit a hand movement in correspondence with changes in the motor rhythms (mu band power) of another subject.…”

“…The presence or absence of phosphenes, temporary visual percepts of lines or spots that can occur upon neuromodulation of the visual cortex represented a binary message that was used to build simple words. Stocco et al (2015) also utilized phosphene perception in a different brain-to-brain interface that allowed 2-way communication. In this case, Yes/No answers in a 20-questions game were decoded from one subject's steady-state visually evoked potentials (SSVEPs) and sent in real-time to another subject, where this information was encoded in the presence or absence of phosphenes.…”