Harnessing emotion for NDT

I certainly jumped the gun last month when I wrote about “seeing clearly now that the lockdown has eased”. Just as the new issue of NDT News dropped through our letterboxes, new restrictions were imposed, pulling the rug from under my optimism. The result is a profusion of mixed emotions: frustration and sadness at what is considered a step backwards and the squashing of hopes for the immediate future; worry and fear about the sudden increase in COVID-19 cases and the potential impact; and relief that action is being taken.

There has been a lot of emotion on show during this pandemic. This is despite the efforts to ‘follow the science’. Science is perceived to be devoid of emotion, as it is derived by logic and reason based on objective measurements. This is patently not the case, as has been shown on numerous occasions. Science is studied by humans and all humans have emotions, which are difficult to totally suppress or ignore. This opens up an area of philosophy about which I do not pretend to have even a basic knowledge. However, through a book I am currently reading, I have been exposed to ideas that connect this and other issues raised in previous articles.

The book is a biography of Alexander von Humboldt. If you have not heard of him, you are likely to have heard of the Humboldt current, which runs up the coast of Chile, or another of the many geographical features and biological species that are named after him. An inspired scientist and explorer, von Humboldt’s curiosity led him to investigations in many different disciplines and he meticulously and systematically took scientific measurements with the most advanced instruments available. The book describes the debates at the time between the pros and cons of knowledge based on reason and logic, derived by the mind, and knowledge based on observed, experimental evidence obtained through the senses. Reason was considered objective. Empirical evidence, because it is obtained through the senses, was considered to have a degree of subjectivity. But even reason has a subjective component, because the thought processes belong to human beings with all the influences that affect their behaviour.

While von Humboldt was a strong proponent of empirical evidence, he firmly believed in the need to get out and experience the natural phenomena he was investigating. He did not take such measurements in isolation, but viewed them in the context of the system as a whole. When I was reading about his interactions with Goethe, who combined science with art, I started to consider whether there was any relevance to NDT.

I have written a few times about the historic reliance of NDT on empirical data, about the recent development of accessible theoretical models and, in January 2017, on observation and measurement. The key issue concerns what is considered objective, and therefore something that can be relied upon, and what is considered subjective, with the possibility of a degree of unreliability. Obviously, manual inspection techniques are expected to have the largest input of subjectivity and hence have been the focus of human factors and reliability studies over the years. Automated inspection techniques have been seen as a route to reducing the influence of the operator on inspections, but again studies have shown that different subjective influences come in to play with potentially similar consequences. The golden bullet of artificial intelligence and machine learning does not escape; there have been any number of instances of algorithms and datasets showing subjective bias.

However, subjective input into an inspection need not be detrimental if the operator is applying an appropriate level of experience. By appropriate, I mean experience based not just on years of testing but on observing the responses of many defects, something that is not easy to come by. This brings me to my question. Consider such an experienced operator who is applying either a manual or an automated inspection. The signal shows an anomaly, but falls short of a pattern that a machine would recognise. The operator has an intuition – an emotional response or gut feeling – that there is a defect present. Would that be acceptable? Have you ever had that experience? Or am I letting my emotions run away with me?

Please note that the views expressed in this column are the author’s own personal ramblings for the purpose of encouraging discussion within NDT News. They do not represent the views of Jacobs or BINDT.

Letters can be mailed to The Editor, NDT News, Midsummer House, Riverside Way, Bedford Road, Northampton NN1 5NX, UK. Fax: +44 (0)1604 438301; Email: ndtnews@bindt.org or email Bernard McGrath direct at bernard.mcgrath1@jacobs.com

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