Cognition is readily seen to be connected to evolution through plots of the ratio of cranial capacity to body size of hominids which show two regions of sharply increasing ratios beginning at 2.5 and 0.5 million years ago – precisely the critical times inferred by the author from his study of tools. A similar correlation exists between current human brain growth spurts and the onsets of the Piagetian stages of reasoning development. The first goal of the author's target article is (...) stated to be “to make a case for the relevance of archeological contributions to studies of the evolution of cognition” (sect. 1, Introduction). His analysis focuses on spatial cognition. (shrink)

Pulvermüller's discussion needs more explanation of how the proposed assemblies remain assembled after formation and how they can be accessed later among all the possible assemblies, many of which involve many of the same neurons. Alternative Hebbian strengthening mechanisms may provide additional information, and, developmental studies of the assemblies might provide insights into their evolution.

Analyses of bodies of data usually omit some relevant studies. Geary omits some studies looking at functional correlates of basic biological data, studies of developmental implications for functioning, and the recent achievement of acceleration of cognitive development.

The recent dramatic development of molecular neurobiology has focused almost entirely on biological events in individual brain cells, and it seems that many of the goals of such work will soon be attained. Yet, when we attain those goals, we will still have to ask how this information will enable us to understand the properties of brain cell collectivities and their presumptive roles in higher brain functions. Even general ideas about those functions are not yet well defined. Therefore, it seems (...) worthwhile to start studying correlations of the molecular events to these higher functions to help delineate the molecular aspects that need study.It is readily appreciated that we cannot tell what other animal species see, hear, taste, smell and feel when touching something, though we can foresee the time when we will be able to detail the biochemical and biophysical consequences of all inputs to those senses. Thus, however deep our understanding of the biology of those species, we are unable to establish relations between their biological responses to inputs and their presumptive mental perceptions. Even though humans can use language to talk about those perceptions, we cannot even verify whether someone else's perceptions are the same as our own, as with the old question of whether two individuals see the same thing when viewing something blue. Questions about still higher mental functions of human brains are even less accessible to analysis and can be approached at best, by using correlations. In this article are a number of such questions and their current correlation‐level answers. (shrink)