Pokazatelji dinamike funkcioniranja selektivne pažnje hrvatskih strojovođa i njihove dobne razlike
Authors: Žebec Mislav Stjepan , Crnko Ines , Palavra Vedrana , Sumpor Davor 
Published: July 2018

SUMMARY: Research that focuses on aging process of selective attention (SA) functioning dynamics is very rare, especially regarding the professional drivers’ population. Given the fact that the consequences of SA functioning in railroad engineers are extremely high for traffic safety, we considered it important to investigate the aging effects on three indicators of SA system functioning dynamics (average efficiency, stability and resilience to the adverse factors effects) with regard to different measures of SA. The study was conducted using two time limited forms of Stroop tests: the first – verbal, uncoloured (lexical) and the second – verbal, coloured paper-pencil form. Both forms were comprised of two parts/components: with incongruent stimuli (measuring SA and processing speed, i.e. PS) and neutral stimuli (measuring only PS). The participants were male railroad engineers, ages 25 to 59, unevenly distributed into 4 age categories distinguished by specific functional characteristics of professional drivers. 50 subjects completed the first test form and 52 the second. The subjects’ task was to cross out as many of the target words in the distractors context in 60 seconds as possible (whereby the distraction was more intense for the incongruent stimuli). All three indicators of SA functioning dynamics are expressed as composites of objective measures of the Stroop test components. They show an unambiguous relation to the magnitude of the associated construct, while low inter-correlations indicate their diversity. With the exception of the relative position of the first test mistake - that could not be used as a measure of resilience due to the extremely small variability - in the selected sample of Croatian railroad engineers most of the other SA dynamic indicators show good statistical features and theoretical merits. Age related changes of the three SA dynamic indicators reflect a non-linear trend that is only partly in line with the expectations, while statistically significant only for SA resilience in the coloured version of the Stroop test. Although these age-related trends were mainly non-significant, average SA efficiency and stability in the coloured version of the test showed significantly different age-related changes in comparison to the lexical version of the test. Additionally, analyses have shown that the average SA efficiency is significantly higher in Stroop test that includes traffic relevant colours, while SA stability and resilience to the adverse factors effects show similar, although not significant, trend. The findings are – with a certain caution related to the lack of control group measurement and other methodological confinements specific for applied research - interpreted by specific railroad engineers experience and are discussed in relation to the theory of cognitive aging in the general population with the implications on the railroad engineers aging process and its consequences – especially regarding traffic safety.