By Margarita Nahapetyan
A recent neuroimaging international study has discovered that the ability to distinguish between true and false in our daily lives includes two distinct processes.
Writing about their new findings, which is titled June Cortex, a team of Portuguese and Italian scientists from the Universities of Lisbon and Vita-Salute, Milan, have pointed out that when we are making a decision about a true statement, we are using our memory, but when it comes to determining whether the statement is false, our brain relies mostly on reasoning and problem-solving processes.
In their study, the experts examined the impact of true and false sentences on brain activity by means of a feature verification task and functional Magnetic Resonance Imaging (fMRI). Individuals who took part in an experiment, were asked to read simple sentences that were composed of a concept-feature pair (e.g. 'the plane lands'). The participants then were asked to determine whether the sentence was true or false.
After a thorough analysis of the results, the experts revealed that true and false statements were equated in terms of ambiguity, and exactly the same concepts and features were used across the two types of sentences. Researchers have also observed that false statements activated the right fronto-polar cortex in a different way, in areas that have been previously associated with reasoning tasks.
The activations that were related to true statements happened in the left inferior parietal cortex and the caudate nucleus bilaterally. The former activation may be hypothesized to reflect continued thematic semantic analysis and a much broader memory search. The caudate activation may also be reflecting this search and similar processes as well as the fact that recognizing a sentence as true is in itself a positive reward for the subject, as this area of the brain is also involved in processing of the information that is related to reward.
Taking into consideration the results from the present experiment and the findings from past research, it is possible to reconcile the historically conflicting positions about language comprehension dating to Protagoras and Socrates. No matter how paradoxically it may sound, it appears that when the differences between truth and false statements are being detected, people start behaving like relativists, and use similar processes to arrive at a decision. However, in case when differences seem to be more subtle, (as in the current study), individuals adhere to a categorical distinction and use qualitatively different processes in order to decide what is true and what is false.