How the brain works out facts from falsehood

The way the brain determines whether something is true or false is key to our understanding why something that is false may appear to be true, why we can still be conned despite being educated, smart and successful and why search and marketing are now wading in that grey zone where facts and advertising hyperbole create an uneasy mix.

First things first. A search engine, no matter how smart it is, is not yet as sophisticated as a human brain. It is however capable of a couple of key attributes that a human brain needs and cannot have to the same extent: a memory that is infallible and access to a large enough data set. 

In order to understand how we get from the organic to the silicon based world and back again let’s look at a very recent study that used fMRI imaging to examine the brain of subjects as they were presented with simple True or False questions and then, the same subjects struggling as they were presented with more complex, ambiguous questions that still needed a True or False answer.

The experimenters discovered that the primary pathway we utilize first when we decide whether something we encounter is true or false is our memory. Using the brain’s continuous semantic memory the subjects were caught by the fMRI scanners carrying out a left hemisphere extended memory search that deepened to include thematic semantic analysis (where similar subjects are analyzed for their attributes in order to understand similarities in the complexity of their working). 

When memory was insufficient to determine whether something was true or false the brain next used a more complex, energy intensive right hemisphere pathway that employed critical thinking, risk calculations, real-world knowledge assessment and likelihood weighing. 

There are two takeaways that are important here: First, real-world knowledge is active in both approaches and the deeper and more granular that is the easier is the task of deciding truth from falsehood. Second, the second pathway that requires critical thinking is more time consuming and energy intensive. 

The brain uses narrative as pathway to save energy. And narrative used in marketing is a great way to establish an authentic connection, build trust and create a sense of truthfulness.

How Search Engines Establish Truth

In principle a search engine with a far greater store of real-world objects and an infallible memory should be able to establish fact from fiction very quickly. And in closed data sets this indeed is the case. The problem, right now is that in the open web, the amount of information is so massive and still so fluid that there is not yet sufficient trustworthy information to help establish veracity in each and every case, especially when speed is an issue and freshness in the data that is encountered is a problem. 

What Marketers and Businesses Need to Know

  • Online customers value facts over marketing hype
  • Narrative that resonates frequently becomes the common touch point between a business and its customers
  • Granularity in data is key to providing search engine trustworthiness (plus it helps establish an entity more quickly)   

The easiest way to save energy, acquire authenticity and attain the kind of consistency that build up trust with your customer base is to keep it real.


Marques et al. Neural differences in the processing of true and false sentences: Insights into the nature of "truth" in language comprehension. Cortex, 2009; 45 (6): 759 DOI: 10.1016/j.cortex.2008.07.004 
Elsevier. "How We Recognize What Is True And What Is False." ScienceDaily. ScienceDaily, 19 June 2009.
Nitz, D. A. (2014). The posterior parietal cortex: interface between maps of external spaces and the generation of action sequences. Space Time Mem. Hippocampal Formation 27–54. doi: 10.1007/978-3-7091-1292-2_2


Google Semantic Search: Search Engine Optimization (SEO) Techniques That Get Your Company More Traffic, Increase Brand Impact, and Amplify Your Online Presence
SEO Help: 20 Semantic Search Steps that Will Help Your Business Grow