Embodied niche construction in the hominin lineage: semiotic structure and sustained attention in human embodied cognition

Abstract

Human evolution unfolded through a rather distinctive, dynamically constructed ecological niche. The human niche is not only generally terrestrial in habitat, while being flexibly and extensively heterotrophic in food-web connections. It is also defined by semiotically structured and structuring embodied cognitive interfaces, connecting the individual organism with the wider environment. The embodied dimensions of niche-population co-evolution have long involved semiotic system construction, which I hypothesize to be an evolutionarily primitive aspect of learning and higher-level cognitive integration and attention in the great apes and humans alike. A clearly pre-linguistic form of semiotic cognitive structuration is suggested to involve recursively learned and constructed object icons. Higher-level cognitive iconic representation of visually, auditorily, or haptically perceived extrasomatic objects would be learned and evoked through indexical connections to proprioceptive and affective somatic states. Thus, private cognitive signs would be defined, not only by their learned and perceived extrasomatic referents, but also by their associations to iconically represented somatic states. This evolutionary modification of animal associative learning is suggested to be adaptive in ecological niches occupied by long-lived, large-bodied ape species, facilitating memory construction and recall in highly varied foraging and social contexts, while sustaining selective attention during goal-directed behavioral sequences. The embodied niche construction (ENC) hypothesis of human evolution posits that in the early hominin lineage, natural selection further modified the ancestral ape semiotic adaptations, favoring the recursive structuration of concise iconic narratives of embodied interaction with the environment.

Keywords: bipedalism; co-evolution; embodied cognition; hominin adaptation; iconic narrative; niche construction; semiotics.

Figure 1

Phylogenetic relationships among extant anthropoid primate lineages, including Old World monkeys, apes, and humans. Evolutionarily derived features hypothesized to distinguish embodied niche construction in the nested great ape-hominin and hominin-only clades, respectively, are highlighted in the text boxes lower right.

Figure 2

Logarithmic plot of the general population-time-scale structure of embodied cognition and niche construction in human biocultural evolution.

Figure 3

Hierarchically constructed object icons and iconic narratives—indexically linked to embodied affective states and perceived objects in the extrasomatic environment—via body-environment thresholds. Object icons are sufficiently formed through dynamic, recursive learning. Construction of indexical relationships among icons emerges through embodied interaction with the extrasomatic environment. Iconic narratives are constituted by the indexical relationships among object icons and changes in embodied affective, proprioceptive, and interoceptive states. It is hypothesized that one of the most evolutionarily primitive iconic narrative genres—likely evolved in the hominin-great ape common ancestor—is that of heroically succeeding or tragically failing to construct an enduring aspect of the world.

Figure 4

Evolutionary change in maternal and neonate body mass in the hominin lineage, compared with extant chimpanzees. Maternal body mass averages measured from fossil and modern samples shown as squares. Neonate body mass averages measured from fossil and modern samples shown as circles. Ardipithecus ramidus shown in orange. Australopithecus and Homo samples shown in green, except for Neanderthals, shown in red. The Neanderthal female and neonate fossil samples raise the possibility that this late Pleistocene (ca. 200-40 thousand year old) western Eurasian population may have evolved a higher body-mass:brain ratio, compared to contemporaneous regional human populations (VanSickle, ; DeSilva, 2011). The Neanderthal neonate body mass estimate is thus shown as a conservatively estimated range. Modern chimpanzees mothers and neonates are shown in purple. Modern and fossil maternal body mass measurements and estimates are from VanSickle (2009) and DeSilva (2011), and neonate body mass estimates are calculated after the methods in DeSilva and Lesnik (2008).

Figure 5

Evolutionary change in neonate:maternal body mass ratios in the hominin lineage, compared with extant chimpanzees. Samples are color-coded as in Figure 4. Fossil hominin samples are shown as estimate ranges. Extant human and chimpanzee sample means shown as ×s.

Figure 6

Forensic reconstruction of a male Australopithecus afarensis adult. The male and female Au. afarensis permanent dentition exhibits smaller canines than seen in Ardipithecus, suggesting evolution of honest signaling of reduced fighting ability. Photograph accessed from http://upload.wikimedia.org/wikipedia/commons/2/22/Australopithecus_afarensis.png.