The stance espoused in the target article confounds cultural symbolic achievements with individual cognitive competences. With no explicit role for learning, the core rationale for claiming a major functional discontinuity between humans and other species rests on a hybrid formal model LISA (Learning and Inference with Schemas and Analogies) now overtaken by new models of cognitive growth and new empirical studies within an embodied systems stance.

We argue that Halford et al.'s characterisation of relational complexity offers an unadaptive principle in terms of cognitive economy, that its relation with the empirical evidence is highly selective, and that the task behaviours used in support of a multivector processing space are better described by linear serial processes which do not require n-dimensional mappings for their emergence.

Ballard et al. neatly demonstrate the tradeoff between memory and externalised serial deictic functions which help the agent achieve economy. However, the target article represents an implementation which does not seem to reveal the hidden level of cognitive control enabling tasks, contexts, and the agent's own needs to specify and recruit information from the visual layout.