Did Drug Use Help the Development of Human Consciousness?

So far on this page I’ve argued that human consciousness first began to radically diverge from those of other species when our ancestors started designing and using tools to transform the world, accompanied by the development of language. Both of these capacities then led to the growth and restructuring of the brain, and of conceptual thought. But what of other past influences on human consciousness? In this post I want to look at the possibility that some changes in our ancestors' mental functions were assisted by the drugs that they ingested.

The ‘stoned ape’ hypothesis, put forward by Terence McKenna in his 1992 book Food of The Gods, proposes that the proto-human species Homo erectus came across the ‘magic mushrooms’ that contain the psychedelic drug psilocybin because of the tendency of this fungus to grow in the dung of animals that they tracked for food, and that this chemical induced the Homo erectus brain to reorganize and take on new mental properties. This in turn kick-started an evolution of cognition that eventually led to the development of the sophisticated art, culture, and technology of Homo sapiens.

Like all highly speculative theories of human evolution, a major problem with the ‘stoned ape’ theory is the lack of direct supporting evidence. It is also far from clear how such a behavioural change in a proto-human species like Homo erectus would then manifest itself in the evolution of our own much later species. Nevertheless, the evidence I’ve mentioned previously here, that has been emerging about the important role of different frequency brain waves in coordinating different regions of the human brain, means that it would be unwise to be totally dismissive about the idea that a drug might have had radical effects on brain function – including such important attributes as creativity and imagination.

More recently in our prehistory, alcohol consumption may have stimulated the birth of civilisation. Until recently it was assumed that consumption of alcohol by our species on a regular basis only occurred with the agricultural revolution about 12,000 years ago, because only then would it have been possible to stay sufficiently long in a place to grow and ferment the raw materials for making an alcoholic beverage. But recent evidence suggests that production and consumption of alcohol not only predated the agricultural revolution but actually acted as a stimulus for this key event in human history.

Archaeologist Brian Hayden has recently found evidence of beer-making activities among the Natufians – sedentary hunter-gatherers who inhabited an area of the Middle East now part of Syria, Jordan, and Lebanon, and who are thought to have acted as forerunners of the agricultural revolution – as early as 13,000 years ago. Archaeological remains found in this region include stones for grinding barley and brewing vessels potentially used to make beer.

Hayden believes that cultural, and not economic, factors stimulated the domestication of grains like barley, in that once people understood the effects of alcohol on the mind, it became a central part of feasts and other social gatherings that forged bonds between people and inspired creativity. According to Hayden, 'It’s not that drinking and brewing by itself helped start cultivation, it’s this context of feasts that links beer and the emergence of complex societies.’ Such consumption of alcohol in a social setting could have been important in the development of human consciousness by allowing our ancestors to become more expansive in their thinking, as well as more collaborative and creative.

Moving on from potential past influences of drugs on our species, what can modern scientific methods tell us about how drugs may influence human consciousness in terms of effects on the brain? One neuroscientist looking at this question is Anil Seth, who examined brain scans of individuals exposed to the psychedelic substances LSD, psilocybin, and ketamine – at doses described by Seth as having ‘profound and widespread effects on conscious experiences of self and world.’ Such drugs were described by those taking them as ‘broadening’ the scope of their conscious mind’s content, with accompanying vivid changes in imagination during consciousness.

Seth and his team found that administration of these drugs led to an increase in neural activity in specific regions of the brain compared to the situation i individuals who had not taken the drugs. These are brain regions known to be important for perception, rather than involvement in language and movement.

The increase in brain activity in this study accompanied peculiar sensations that participants said ranged from floating and finding inner peace to distortions in time and a conviction that the self was disintegrating. The researchers have speculated that the increased neural activity in particular regions of the brain could explain the dreamlike hallucinations some people experience when under the influence of psychedelic substances.

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Robin Carhart-Harris, who was involved in the study, believes the sudden increase in randomness in brain activity may reflect a deeper and richer conscious state. Other studies by Carhart-Harris’s team have shown that certain types of meditation can have similar effects on the brain. He has noted that ‘people tend to associate phrases like “a higher state of consciousness” with hippie-speak and mystical nonsense. This is potentially the beginning of the demystification, showing its physiological and biological underpinnings.’

Such research could help scientists understand what neural activity corresponds to different levels of consciousness in humans. Another is that by understanding how people respond to the drugs, doctors might more accurately predict which patients could benefit from taking psychedelic drugs as therapeutic agents. This is important because recent studies have shown that ketamine may have potential in the treatment of certain types of depression, in ways that I will discuss in future posts. For Anil Seth, ‘the evidence is becoming clear that there is a clinical efficacy with these drugs. We might be able to measure the effects of LSD in an individual way to predict how someone might respond to it as treatment.’