The question of whether intelligent life is more likely to arise on land or in water has long intrigued scientists. A new study by Dr. Manasvi Lingam of the Florida Institute of Technology offers a novel approach to address this question using Bayesian statistics.
“A Bayesian analysis of technological intelligence on land and oceans,” a paper by Lingam and researchers from the University of Texas and the Università di Roma, was published in the March issue of The Astrophysical Journal.
Humans are a classic example of the type of technological intelligence that can deeply sculpt the biosphere through purposeful activities and produce detectable signatures of their technology.
In the paper, the authors performed a Bayesian analysis of the probability that technologically intelligent species exist in terrestrial and oceanic habitats. It found that ocean-based habitats should be more likely to support tech species, all other things being equal, because ocean worlds are likely to be much more common.
“And yet we find ourselves emerging on land rather than oceans, so there’s a paradox, broadly speaking, out there,” Lingam said.
The paper also explored the possibilities of how the emergence of smart technology-based life may be disadvantaged in the ocean, thus dissolving this paradox.
“We say, well, maybe it takes a long time for life to emerge in the ocean due to various biophysical reasons, such as sensory capabilities on land versus water,” Lingam said.
“Another possibility is that, due to some set of factors (eg, energy sources), the oceans may not be as habitable for intelligent life as we think they should be. Currently, the conventional thinking is that liquid water is necessary for life. Well, maybe it really is imperative for life, but maybe an excess (ie just oceans) will hamper technological intelligence in some way. So that was another solution to the paradox that we came up with.”
The team was able to reach the conclusions of the document by synthesizing two different paths. First, they relied extensively on data from Earth to determine what intelligent life has been like on this planet, from primates to cephalopods (eg, octopi) to cetaceans (eg, dolphins).
By looking at the cognitive toolkit of humans, Lingam said they sought to understand how subtly human abilities differ from the cognitive ability of marine life, such as whales and dolphins. The second part of the investigation involved mathematics and physics, specifically Bayesian probability theory, which makes it possible to calculate the relevant probabilities based on some initial expectations.
While the paper’s conclusions were derived on a probabilistic basis, Lingam said there is still a lot of multidisciplinary work that can be done to refine and extend the models.
“I think one of the nice things about this model is that some of the assumptions can be tested,” Lingam said.
“They can be measured by future observational data from telescopes, or some of them can be tested by doing experiments and field studies on earth, like digging into ethology (animal behavior), digging into how cognition works on earth. animals versus aquatic animals. I think there are many different animals that could be further evaluated to refine the study. All of these questions can, and hopefully should, appeal to people from a wide range of fields.”
For Lingam, future work related to this study will include grappling with the metabolic role of oxygen in shaping the evolution of complex life and how ubiquitous the element may be on various planets. She will also try to understand what role oxygen concentration levels might play in the evolution of intelligent life.
