For the first time in its 168-year history, the University of Melbourne has awarded simultaneous PhDs to identical twins.

Nadeesha and Thejani Gunaratne commenced PhDs with the University in 2016 following studies in Food Science and Technology at the University of Sri Jayewardenepura in their home country of Sri Lanka.

Both received their doctorates on Saturday 17 December in Melbourne, one day before International Twins Day.

During their PhD, both twins researched new ways to measure and analyse consumers’ emotional and sensory responses to chocolate in complementary research, with Thejani focusing on the impact of chocolate flavour and Nadeesha on the impact of packaging.

Their PhD research topics were:

Nadeesha Gunaratne – Implementation of non-invasive biometrics to identify effects of chocolate packaging towards consumer emotional and sensory responses

Thejani Gunaratne – Development and implementation of novel sensory evaluation procedures of consumer acceptability towards chocolate based on emotions and biometric responses.

Their graduation ceremony was originally planned for March 2020 but delayed due to the pandemic.
Thejani is now a Senior Experimental Scientist – Sensory and Consumer Science at CSIRO in Melbourne and Nadeesha is a Research Scientist – Sensory and Consumer Products at Amway in Los Angeles.

“Being born twins, we have a unique bond that’s hard to explain to other people,” Thejani said.

“The fact that we have completed all important milestones together, primary school, high school and now university, has made our lives even more enjoyable. We were eagerly waiting to attend the PhD graduation together as it means a lot to us.”

Although the twins now live on opposite sides of the world, Nadeesha says they’re closer than ever.

“We still talk multiple times a day whether it’s by text, over the phone or on Zoom,” she said. “The fact that we’re finally together and were able to graduate together in person is a dream come true for both of us and our family.”

Under the supervision of Professor Frank Dunshea, Associate Professor Sigfredo Fuentes and Dr Damir Torrico, during their individual PhDs the twins used technology developed in the University of Melbourne’s Sensory Lab to apply biometrics – including skin temperature, facial micro-expressions and heart rate – to develop machine learning models and an evidence-based understanding of how consumers respond to both chocolate and its packaging, consciously and unconsciously.

They achieved seven academic journal publications in their PhDs, all with both twins as co-authors.
Their research highlights that our enjoyment of chocolate products and other foods – and our decisions to purchase them – are driven by far more factors than taste alone.

“When we buy food based on its packaging and labels, we expect it to both taste good and match what that packaging tells us,” Nadeesha said.

“In the past, sensory research relied heavily on what participants said or did, which provides useful information on how consumers consciously respond to products, but limited on scientific data such as unconscious and emotional responses, which have a major impact on their experience and whether they’ll buy the same product again.”

Professor Dunshea said the biometric techniques applied by Nadeesha and Thejani in their research at the University has added to our ability to conduct data-based sensory science research in recent years.

“For the food industries, particularly small and medium sized enterprises in Australia with an export focus, this allows greater certainty that new foods will appeal to consumers and are more likely to result in repeat purchases. 

For consumers, it means more enjoyable foods that live up to the promise of what the packaging communicates,” Professor Dunshea said.

- with input from agencies