Heterarchy of cognition: the depths and the highs of a framework for memory research.

To celebrate the levels-of-processing approach, I describe a multilevel evolutionary architecture for human behaviour and cognition. New experimental data on human eye movements are presented that demonstrate a possibility of splitting visual perceptual activity at least on two hierarchical but closely interrelated levels of processing. Furthermore, data from behavioural studies of human memory and neuroimaging testify that within the domain of cognition proper two higher levels can be differentiated. I call them "conceptual structures" and "metacognitive coordinations" and provide evidence that the latter may residue in the phylogenetically new structures of prefrontal and particularly right prefrontal cortices. From this point of few, the most natural framework for an analysis of the levels-of-processing effects on human memory is to consider them as interactions within the main gradients of evolution and development of the corresponding neurophysiological mechanisms. Finally, several new, still unanswered questions for the future research are formulated.