Animals with overlapping visual fields have with each eye slightly different views of an objective due to the horizontal separation of the two eyes (Bruce, V., Green, P.R., Georgeson M.A. 2003 p.171). If you look at your thumb by holding it out at arm's length and start to twinkle, you get the impression that your thumb jumps from right to left and back.

Theoretical Background

“Analogical reasoning is a fundamental cognitive skill, involved in classification, learning, problem-solving and creative thinking” (Goswami 1992). It “is a powerful cognitive mechanism that people use to make inferences and learn new abstractions” (Gentner & Holyoak 1997).    

Spreckelsen (1992) developed a teaching strategy in primary science education of reasoning by analogies. He advice that students should do several experiments concerning to one principle. Students will start to draw analogies between the experiments. More and more students will reason about relational similarity and start to generalize. They discover scientific laws by inductive reasoning. In several qualitative studies Spreckelsen proved, that primary school students are able to reason by analogies in physics and that it is very helpful to let them do several experiments belonging to one physical principle. But it was never proved in biology.

Wagenschein (1971) a German author in education of physics, wrote about a girl, who experienced parallax with the thumb by chance and wondered, whether her thumb really moved. We wanted to find out whether primary school students are able to describe the reason for the ‘jumping thumb’ after having done several experiments to this phenomenon of visual perception.

Research questions

Do primary school students of first and fourth grade get the impression that their thumb moves or jumps when they experience the parallax with their thumb?

Are primary-school-students able to explain this phenomenon?

Does the ability of primary school students to explain this phenomenon increase, if they do several experiments?

Bruce, V., Green, P.R. & Georgeson M.A. (2003). Visual perception. Hove: Psychology Press. Gentner, D. & Holyoak, K. J. (1997). Reasoning and learning by analogy. American Psychologist, Vol 52(1), 32-34. Goswami, U. (1992). Analogical reasoning in children: Essays in developmental psychology. Hillsdale, NJ, England: Lawrence Erlbaum Associates, Inc. Spreckelsen, K. (1992). Weltverstehen im Sachunterricht und Selbständigkeitsentwicklung. Grundschule Vol (17) 9, 30 - 32. Wagenschein, M., Bannholzer, A. & Thiel, S.(1971). Kinder auf dem Wege zur Physik. Stuttgart: Klett.