Visual perception and workload of office workers in various acoustic conditions

Noise in the office work environment can negatively affect workers cognitive performance, number of errors made and comfort. The aim of the study was to determine the effects of various types of acoustic conditions in the mental work environment on visual perception (eye-tracking parameters) and workload. Method: In the experiment a group of 39 people aged 20 to 34 was asked to perform two eye-tracking tests (Perceptiveness and Speed Tests (PTs) and to read the text of a fictional biography, and then to answer questions about the reading). Mental workload was evaluated in each condition using NASA TLX questionnaire. The tests were performed in various acoustic conditions: variant W1 - no presentation of acoustic stimuli, variant W2 - sounds of office equipment, variant W3 - sounds of office equipment with quiet conversation in native language, variant W4 - sounds of office equipment with loud conversation in native language, variant W5 - filtered pink noise. In variants from W2 to W5 the equivalent sound level A was 55 dB. Results: The assessment of work efficiency in the reading test indicates the existence of statistically significant differences. The most errors were made during mental work with the audible sounds of office equipment with a loud conversation (Variant W4) and during mental work performed with audible filtered pink noise (W5). While reading the text, different acoustic conditions do not differentiate statistically significantly visual perception described by eye-tracking parameters. In turn, in the PTs test, statistically significant differences between the variants were found in the Digit test (average blink duration) and the Fraction test (average blink duration, average fixation duration and saccades frequency parameters). In conclusion, visual perception depends on the type of noise. Acoustic factors aggect workers cognitive functions, mostly in more difficult tasks.