Recognizing Faces in Lithic Artifacts

(Figure Stones)

A Neuroscientific Perspective


American archaeologists have long assumed that the lithic artifacts created by early inhabitants of North America were strictly utilitarian in nature, nothing more than tools, hunting implements, and weapons, and that there was never any symbolic or icono- graphic component in these.  Likewise, it has been assumed that when iconographic material first began to be produced here (supposedly sometime in the Archaic Period) it was somehow, without more rudimentary precedent, instantly so naturalistic and of such artistic virtuosity that we in the twenty-first century A.D. would immediately see it as "art".  This is illogical and inconsistent with long-recognized artifact evidence in other areas of the world, and just wrong.  Simple zoomorphic and/or anthropomorphic imagery, usually just cursorily and apparently routinely incorporated into lithic artifacts, has long been recognized by amateur archaeologists and others just casually looking at oddly shaped stones both in North America and elsewhere.

Possibly the best known of those recognizing such iconography is the Frenchman Boucher de Perthes, who a century and a half ago played a decisive role in founding the study of lithic artifacts left behind by humans of the Palaeolithic.  It was he who, in the face of ridicule by the archaeological "establishment", demonstrated, with the aid of geologists (i.e., actual physical scientists) and many years of work, that simple but clearly manmade lithic tools were much more than four thousand years old.  While there is little discussion of this today, Boucher de Perthes also observed that much of the lithic material in context with his finds had the appearance of human modification into simple animal and sometimes human-face forms, which he termed "pierres figures", or "figure stones".  (Much amazed, I became aware of his work through internet searches in 2003, shortly after recognizing such rudimentary image-bearing artifact material here at 33GU218 in Ohio, likely Archaic to Early/Middle Woodland in age.)   As he attempted to present this aspect of his research to the public he was thwarted by the archaeological Wise Ones, already resentful of their embarrassment by his verified demonstration of great antiquity in the lithic tools.  With their "imputed authority" they simply voted that his Figure Stones had no merit, and this preconception and tactic prevail among archaeologists into the present day.  Today, when someone shows a stone with even a clear zoomorphic or anthropomorphic appearance to an archaeologist, he/she is, in almost all cases, told that the archaeologist sees nothing but a rock, and that the presenter is just "seeing images in clouds" (pareidolia), this being the standard mantra offered as counterargument.  Most people are intellectually intimidated by all this, and that is where it ends.  (In fairness, it has been my experience that in a very few cases an archaeologist will acknowledge the resemblance, even pointing out on his/her own the characteristic recurring features right down to subcomponents, but insisting that even when these appear consistently within an assemblage of such objects from a single venue they must somehow be a coincidence of unexplained geological processes.)

Whether or not it has a place within the current archaeological paradigm, the presence of readily identified simple zoomorphic and anthropomorphic imagery in recurring and consistent patterns, especially when these incorporate visible physical traces of workmanship, is an important hallmark of human agency in lithic and other artifact material, and should not be ignored -  it is part of the archaeological record.  But when one is outvoted by purported experts claiming they do not recognize patterns readily visible to most ordinary mortals, how does one demonstrate that their claims are bogus?  Recent research in the field of neuroscience (described below) now has much to offer by way of objective qualification and quantification, identifying image patterns that are pretty much instinctively and spontaneously recognized by most humans, even when these images are not very distinct.

After many rather Kafkaesque experiences presenting to archaeologists the figure stones from my now very large collection of these ("I don't see it.  It's not there.  You're just imagining it.", etc.), in 2007 I seized upon an opportunity to call their bluff by testing one of these, a particularly compelling limestone piece consistently rejected by archaeologists as "amorphous", against image-processing software developed by the Massachusetts Institute of Technology's Department of Brain and Cognitive Sciences.  (A doctorate-level petrologist and professor of geology had earlier assessed this piece as having a high probability of artificial modification.)

By way of background, laboratory studies using functional MRI show that certain images elicit responses that are innate and independent of experience, training, or cultural influences.  A very powerful one is a simple pattern corresponding in contrast ratios and spatial juxtaposition to the two eyes and a mouth on the human face.  We are biologically "hard-wired" to quite spontaneously respond to this with "Face!", without conscious thought, whether we want to or not.  (As a practical illustration of this, just consider the simple smiley-face-derived "emoticons" and "emojis" so widely employed in text-based communication to fill in for deficient verbal skills.)  A human infant exhibits this response from the time it is first able to focus its eyes.  All this takes place within the fusiform gyrus, a part of the brain in the temporal lobes.  Functional MRI shows a strong response to this pattern, much more intense than that to inanimate objects.  (Simple animal images also evoke a strong response, although in intensity fifty percent below that to the basic human face template.)  The MIT laboratory has developed software that determines whether or not a given image is immediately recognizable as a human face.  This algorithm is based on a study of subjects with normal pattern recognition skills looking at face images presented at varying degrees of resolution and degradation, thus providing the statistically important "interrater reliability" factor.  The program has proven to be highly reliable.

In a fit of hubris I submitted to the MIT laboratory the photo shown below of the aforementioned hard limestone piece declared by archaeologists (including Ohio's Bradley Lepper) to be amorphous, asking if they might have time to run it through their software:

Human Face Figure in Limestone - Day's Knob Archaeological Site

A few days later I phoned Dr. Pawan Sinha, the director of the lab, to inquire whether or not the photo had arrived in suitable format.  He said it had, and that there was hardly a need to run it since it would clearly register as recognizable as a face by anyone with normal neural functionality.  Expressing an interest in the application of this technology in archaeology, he very generously agreed to run the image anyway, despite the heavy demands on the laboratory.  Not only that, he sent me the results in the form of a PowerPoint presentation containing the following images confirming the stone's con- formity to the geometry and luminance inequalities of their face template:

A Lithic Artifact's Correspondence to the Face Template

Now one has to ask why a highly trained professional archaeologist would perceive (or at least claim to perceive) the image as amorphous, given that a normally functioning ("neurotypical") brain responds to it as a face.  (This aberration occurs most commonly among persons suffering from a cognitive disability within the autism spectrum, including Asperger's syndrome at the mildest level.)  Four possibilities immediately present themselves, at varying levels of probability:

1.  Most archaeologists are autistic.  From my many interactions with archaeologists, I think this is not the case.  Most seem to be of at least average intelligence and well attuned to social cues, indicating against this syndrome.

2.  Initiation into the archaeological cognoscenti entails surgical removal of a portion of the temporal lobes.  Given its complexity and the risk involved in such an operation, and the odds against its being kept from public knowledge, this seems highly improbable.

3.  Prolonged exposure to classical archaeological training causes part of the fusiform gyrus to be replaced by scar tissue and/or pus.  While some conversations have led me to think this is plausible, this explanation seems much less likely than possibility #4.

4.  Being far from cognitively impaired, trained archaeologists probably do in fact spontaneously recognize the face image, but have a vested interest in old paradigms and prefer not to deal with the "establishment's" displeasure that would ensue from their acknowledging this.  Also, they may have learned from experience that saying they see the image often leads to awkwardly trying to explain away physical evidence of artificiality that is clearly present and verifiable.  It is easier to just deny seeing the image in the first place, knowing that their colleagues will support them in this, and that the presenter will probably be intimidated and go away.  But sometimes this does not work.  A fun instance of rejection and subsequent embarrassment involved this anthropomorphic/polyiconic Figure Stone from the 33GU218 site:

Human Head Figure - Artifact from Day's Knob Archaeological Site

A description of this quartz sandstone - initially dismissed by a state archaeologist as a product of purely natural geological processes - and its assessment by a professional geologist/petrologist is presented at Human Figure in Quartz Sandstone.  A shorter version of this dealing only with the stone's petrological/artifactual aspects was pub- lished in the Winter 2007 edition of Ohio Archaeologist magazine, a very mainstream journal.

Please, no "conspiracy theory" is implied here!  Along with preconceptual thinking, to which every one of us is subject, it seems that simple peer pressure is the main roadblock in the way of objectively assessing so much of the archaeological evidence.

"Know what you see - don't just see what you know."


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