This study examined reasoning skills in children, specifically transitive reasoning and the visual impedance effect, with a new visual/pictorial task. The visual impedance effect is the effect produced by the possible interference in the reasoning process of irrelevant details elicited from the premises of a reasoning task. The new task had no reading requirements, which made it suitable for testing reasoning in primary school children, especially children with reading difficulties (RD), such as dyslexia. The study aimed also to validate the possible use of the task for studying reasoning and detecting the visual impedance effect without the interference of reading skills and to investigate the association between transitive reasoning and reading abilities. A pilot study (N = 10) was used to test the suitability of the new task for primary school children. Afterwards, the task was tested on a larger sample of children of third to sixth Grade, with and without RD (N = 84). Results showed that the new task is able to detect the main reasoning effects as well as the visual impedance effect. The findings are discussed, with the new task considered appropriate for studying reasoning skills in child populations both with and without RD. © 2019 John Wiley & Sons, Ltd.