Signal-to-noise in communication

One of the main reasons I embarked on a career in NDT, and why I have enjoyed many years in the profession, is the variety of technical disciplines that need to be addressed and the variety of applications encountered. However, the range of non-technical aspects pales into insignificance when compared to the variety that human factors introduce into NDT. Within a nominally homogeneous group of operators, similarly trained and qualified and working with the same technique in the same profession, each individual applies a different set of skills, experience and thought processes.

I am reminded of this variability on a daily basis with respect to memory. My memory works in such a way that I am good at remembering faces, but I am not so good at remembering names. Both of these traits can lead to embarrassing situations: the former when I went to say hello to someone I thought I knew but remembered, just in time, that I only saw him on a regular basis working in the office behind the bank counter and had not actually had any contact with him; the latter, well you can imagine the embarrassment that can cause! In a similar vein, there are events in the past of which I have no recollection, whilst I have clear, distinct and persistent memories of certain moments of no particular importance.

One such moment happened many years ago as I was travelling south on the M6. The motorway was as clear as the M6 can be and I was able to glance at the undulating countryside next to the motorway. I looked at the trees and could clearly see the individual leaves with their crenated edges. My recollection of my thoughts at the time is as clear as my memory of the place and situation. “Human eyes are amazing. I can see detail on a leaf. I can see the multitude of leaves on the tree. That alone is a lot of information to be able to receive and process. However, I am travelling at 70 mph with an angular field of view and the scene I am looking at is changing rapidly. I am taking in and processing an incredible amount of information.” It was a moment of wonder that has stayed with me.

Last week, whilst browsing in the airport bookshop, I glanced through a book I had referenced in this column in April 2015. Back then, I was championing the proof that humans cannot multitask. The title of the book is: The Organised Mind: Thinking Straight in the Age of Information Overload, by author and neuroscientist Daniel J Levitin. The moment I described in the previous paragraph took place after the black and white period, but pre-internet and wireless connectivity. These days, in addition to the information from the natural world, we have a lot more material goods and are bombarded with information from the virtual world. As the title suggests, the book describes how we can now be easily overloaded with information. We only have a limited amount of energy for processing information and it is important that we conserve it for the more important tasks. All the decisions we make use up neural resources and small decisions appear to use up as much energy as larger, significant ones. 

When I go out running early on a Sunday morning, the bird song in the woods, though produced by many different birds, is clear, harmonious and enjoyable. Recently, whilst I was in the garden, a flock of birds in the trees squawked loudly and chaotically, which overloaded my aural system and was particularly annoying. I realised then that Twitter is well named. Occasionally, a series of tweets exhibits a certain quality of communication, but the vast majority just create a background noise that makes it hard to identify the tweets that are of interest.

As NDT professionals, we know all about signal-to-noise and the problems that poor signal-to-noise can cause when it comes to interpreting the data and extracting the key information. When trying to communicate, the noise not only distorts or hides the message, but it also uses up our limited mental resources. This makes it incumbent on all of us to consider what and how we want to communicate, be that in an email, in a procedure or in a software interface.

These days, when driving on the motorway, in addition to the natural environment described above and the increased volumes of traffic, we now have the overhead gantries contributing to information overload. ‘Junction 21, 2 miles, 2 minutes’. What use is that? In two minutes you would know you are at Junction 21. Two minutes is not enough time to allow you to do anything in response to the information given! We could all benefit from following Gandhi’s advice: ‘Speak only if it improves upon the silence.’

Please note that the views expressed in this column are the author’s own personal ramblings for the purpose of encouraging discussion within the NDT Newspaper. They do not represent the views of Amec Foster Wheeler or the HSE who funded the PANI projects.

Letters can be mailed to The Editor, NDT News, Newton Building, St George’s Avenue, Northampton NN2 6JB. Fax: 01604 89 3861; Email: or email Bernard McGrath direct at

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