Representing visual recursion does not require verbal or motor resources

• Recursion can be defined at different levels – process, structure and representation – and these levels can be dissociated.
• An empirically useful definition of recursion is the ability to represent hierarchical self-similarity.
• Defined as such, recursion allows the generation of hierarchies of infinite depth using finite elements and rules.
• Recursive representations are used in several domains such as in language and vision.
• Here, we empirically demonstrate that visual recursion can be represented independently of language.

The ability to form and use recursive representations while processing hierarchical structures has been hypothesized to rely on language abilities. If so, linguistic resources should inevitably be activated while representing recursion in non-linguistic domains. In this study we use a dual-task paradigm to assess whether verbal resources are required to perform a visual recursion task. We tested participants across 4 conditions: (1) Visual recursion only, (2) Visual recursion with motor interference (sequential finger tapping), (3) Visual recursion with verbal interference – low load, and (4) Visual recursion with verbal interference – high load. Our results show that the ability to acquire and use visual recursive representations is not affected by the presence of verbal and motor interference tasks. Our finding that visual recursion can be represented without access to verbal resources suggests that recursion is available independently of language processing abilities.