From Mimic to Mirror: the Rise of Human Digital Twins

By Anne-Frances Hutchinson

It goes like this, the fourth, the fifth

The minor falls, the major lifts

                                     Leonard Cohen, Hallelujah

As we greet the early dawn of the Fifth Industrial Revolution, all eyes are on advanced automation. Where Industry 4.0 ushered in the connected IoT and smart equipment, 5IR is about refining, strengthening, and transforming the partnership between humans and machines. Technology, the ultimate accelerant, is charging ahead at light speed whether society is ready or not.

The World Economic Forum explains the root causes of 5IR’s rapid arrival this way: “Major technology domains, including AI, quantum computing, bio-engineering, augmented reality and virtual reality, robotics, advanced materials and next-generation energy are witnessing a nexus in development, resulting in leaps in technological evolution today.”

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The hallmark of the emergent era is the focus on humans as the soul of our technological future through the advancement of smart machines with cognitive intelligence. The evolution of the human-machine relationship is expected to reach far beyond our current paradigm of coexistence, cooperation, and collaboration to compassion and coevolution.

Industry 4.0 supplied machine operators with the skills and tools needed to become more efficient and productive. In contrast, 5IR is about adapting technological systems to humans, and that calls for awareness of what it means to be human.

In 2024, researchers wrote the following in Robotics and Computer-Integrated Manufacturing: “It is not enough for machines to react to humans’ movements and actions. They need to be aware of humans’ physiological, psychological and even cognitive state. Ultimately, they have to become ‘empathic machines’ and learn continuously to grow together with human co-workers.”

On the shop floor, HDTs can take merely creating a safe environment for human workers and kick it up a very big notch to integrate our feelings of belonging, esteem and, self-actualization. In this way we can grow out of being regarded as operators or cogs in machines to becoming human value-adds recognized for our creativity, decision-making, and reliance. Enhancing human ability is the purpose, not replacement.

Advancements that are now commonplace – cyber–physical systems, the IoT and IIoT, and digital twins – will be the root system of 5IR, but human digital twin technology (HDT) may become its greatest source of growth into a future that will be once again transporting us from fantasy to yet another new reality.

We’re not being cloned – yet

The wearables and smart appliances we use every day are essential to the development of HDTs. From our FitBits, Apple Watches, and Oura rings to GPS and climate control systems, every aspect of human existence that can be reliably tracked will inform the technology. HDTs are dynamic representations of each of us, capable of simulating bodily functions, cognitive behaviors, and psychological and physiological states.

A human digital twin isn’t a clone; rather, it’s an AI-powered virtual mirror of a person’s physiological state compiled from real-time data generated by sensors and medical devices. HDTs use cutting-edge algorithms and machine learning to recognize and interpret our facial expressions, the tones of our voices, and other physiological signals to “understand” our emotions. Genomics – the study of our DNA including how our genes interact – is an important part of the equation, as is behavioral analysis.

There are three AI systems used to bring so-called “cognitive clones” closer to reality. The development of Generative AI was a significant driver for the advancement of HDTs, and in combination with large language models has been used to reproduce human behaviors and decision-making patterns. Narrow AI systems are trained on personalized data to predict outcomes such as disease progression and fitness levels, and the Big AI hybrid system combines physics-based models with data-driven AI.

The marriage of AI and additive manufacturing has birthed the technological field of bioprinting. Bioprinting uses 3D printing techniques to layer biolinks – living cells, biomaterials, and growth factors – to make active tissue models. Bioprinting enables digital medical data to recreate bone, artificial skin, cartilage, vascular grafts, and other tissue used in regenerative medicine and drug development. It is also used in personalized medicine to make new tissue from a patient’s cells to stop immune rejection that can happen after transplants.

While very promising, HDTs aren’t ready to be used clinically. HDTs aim to collect real-time health data and constantly compare it with vast amounts of other information, such as population studies, clinical pathology results, and specific data on disease progression, diagnostics, and available medications.

“In principle, the digital patient twin might process recordable data received from a wide variety of sources without having to store the data in a single place – and ideally for the patient’s lifetime,” according to the Siemens Healthineers.

Stanford University’s Digital Twin Health Affiliate Program aims to remove the technical issues around data integration, model validation, and integrated deployment that have prevented HDTs from being safe and reliable for clinical use. “We will use innovations in biomedical research, artificial intelligence, and computing technologies to realize a DT to help decide treatment strategies,” the researchers explained.

Their first proof of concept will be the development of an adaptive dynamic HDT as a predictive tool in cancer therapy, foretelling how effective treatment will be for an afflicted patient and to make fast changes if it isn’t working. “This DT will help physicians make initial treatment determinations, monitor treatment response and effectiveness, and decide when to discontinue or change approach,” they noted.

HDTs are inspiring hope beyond cancer research, particularly for Alzheimer’s and Parkinson’s sufferers, as well as for people with rare diseases.

5IR is here, and as revolutions will do, it heralds tremendous economic potential and societal hopes, dreams, consequences and dangers. As for HDTs, there’s a great deal of work to do around privacy issues, human agency, and regulatory concerns. But that shouldn’t stop us from appreciating their incredible promise – and looking toward a brighter future for humanity. As Cohen wrote: “There’s a blaze of light in every word. It doesn’t matter which you heard.”