The driveway from the farm was lined with trees, providing a canopy and restricting the view, so only glimpses of the sky were possible through the gaps between the trees. On reaching the end of the driveway, all restrictions were removed and the vista encompassed the valley below, the surrounding hills and a large expanse of sky. On this day, the sky was a patchwork quilt of black and white clouds interspersed with bright blue sky. A shadowgraph of this natural quilt was projected onto the landscape, with shafts of sunlight spearing down through the gaps between the clouds. Despite the presence of dark clouds, the sunlight moving across the hills generated a sense of well-being and gladness.

Five minutes later, I turned into a narrow lane. The recent rain had generated a growth spurt in the bushes that lined the road, so that the foliage pressed in from the side and created a sense of claustrophobia. Only a dark grey cloud was visible through the narrow slot above. Suddenly, all feelings of well-being and gladness were dispersed and replaced by menace and foreboding. The marked change in feelings, based solely on changes in view and space and without any other significant accompanying changes, was surprising.

If you look up ‘perceive’ in a paper or online dictionary, you will see that there are many perceptions of what it can mean. However, there are two main definitions, one of which is to become aware of something through the senses. My perception in the above example was through sight and, what might be called a sixth sense, spatial awareness. Another illustration of this interpretation of ‘perceive’ occurred when I was doing a good deed and mowing the lawn for a neighbour. In the middle of the lawn was a wrought iron bird bath, which was full of water. The weather forecast for the next few days didn’t include rain, so I was loath to empty the water out. I grasped the bath and lifted it. Only it wasn’t wrought iron, as I had perceived, but plastic. As a consequence, the bath rose up faster than planned and only a quickly performed contortion constrained the soaking to my feet!

A few weeks before my sojourn into the countryside, the country had gone to the polls in the EU referendum. Waking up the following day, it was fascinating to observe the strength of the emotions on show: the ‘remain’ supporters were angry, dismayed and despondent, while the ‘leave’ supporters were jubilant and happy. Yet these emotions were engendered totally by the result; no one had a clue about the consequences or what the future may hold. This illustrates the second main definition of ‘perceive’, which is to interpret or regard someone or something in a particular way.

It is easy to understand the impact that perception has on how we feel and how we act. When you consider particular examples, such as those I have described above and those you will have experienced for yourselves, it is clear that the perception that influences us so much can be derived from very little substance and can be very fickle. Our perception can be very distant from its Latin origins of percipere: to seize entirely. An understanding of perception is important for any worker and is particularly important for NDT professionals.

The importance of decision making in NDT has been covered a number of times in this column. NDT operators gather information from visual presentations of signals and indications. Their subsequent analysis and sentencing will be influenced by their perception of what the data shows. This is not necessarily a bad thing if those perceptions are guided by relevant experience. Unfortunately, there are other influences that impact on what the operator perceives: a strong determining factor is what the operator expects to find. Perception also plays an important part in how much the work environment and the task impact on performance. When participating in sports, studies have shown that it is your perception of effort (how hard the exercise feels) that limits your endurance performance and not the actual capability of your muscles.

In a similar vein, investigations into the impact of heat and time pressure on the performance of ultrasonic operators have shown that it is not the absolute measure of the time pressure, but how the operator perceives the pressure that determines the performance. Finally, our perception of the work environment is an important consideration for safe working. Particularly important is that sixth sense, spatial awareness, supported by careful observation of the surroundings and any changes, both large and small. Hopefully, you will perceive this column as a stimulus to consider how perceptions impact on your day-to-day work activities but, if you do nothing else, make sure you check that bird bath before you lift it!

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, Midsummer House, Riverside Way, Bedford Road, Northampton NN1 5NX, UK. Tel: +44 (0)1604 438300; Fax: +44 (0)1604 438301; Email: or email Bernard McGrath direct at

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