David Mair, a Swansea University cyber-terrorism researcher, has helped scrutinise the jihadist messages published online by terrorist groups.
He said there were also key differences in ideology - most notably between so-called Islamic State and al-Qaeda.
He presented his research to a Nato counter-terrorism summit in Turkey.
Mr Mair was part of a Swansea team collaborating with the University of Massachusetts' Centre for Terrorism and Security Studies to analyse jihadist messages contained in online terrorist magazines.
He argues the differences in ideologies among terrorist groups means, rather than one anti-terrorism counter-narrative, the West needs to tailor individual messages to debunk each competing philosophy.
"As their name suggests, Islamic State's propaganda focuses closely on building a caliphate [a state governed in accordance with Islamic law, or Sharia, by God's deputy on Earth, or caliph]," he said.
"They're reaching out to disaffected young men, and claim to be offering them the chance to come to Syria and be part of a brotherhood, to belong in a way that they argue Muslims can't in the West.
"Al-Qaeda's message is much more focused on the religious imperative of jihad against the 'Crusaders', providing instructions to create your own bomb, and exalting individual 'lone wolf'-type attacks at home in Europe and America.
"They're two very different themes, which need countering separately.
"Whilst we need to demonstrate why life with IS doesn't offer the way out they're claiming, we also need to tackle head-on the false-religion arguments put forward by al-Qaeda."
However, Mr Mair believes that, in order to start winning the battle for hearts and minds, the West needs to overcome credibility issues it has in the eyes of many radicalised youngsters.
"A common theme in all the terrorist magazines was the process of 'othering', whereby they create a them-and-us narrative of Western oppression of Muslims which can only be defeated through violent jihad," he said.
"In the light of that, any opposing view put forward by white middle-class people like me is just playing into their hands.
"What we need to do is to empower the voices of people from within the Muslim community; in particular women and younger people who can have an enormous influence on thinking.
"We need to provide the platforms and the data to allow these people to make their point, but the government can't be seen to be the ones who're pulling the strings or we'll be undermining the message all over again."
Mr Mair said tackling the "push-factors" of poverty, social exclusion and a lack of positive role models for young Muslim men was also vital in countering radicalisation.
He also believes recent media coverage of the Paris atrocities have been a positive step in undermining terrorist propaganda.
"Much like the Blitz, terrorist attacks are much more about the people that survive than the people who are killed," he added.
"They want to scare people out of their normal way of life and, after 9/11, they nearly succeeded in bankrupting the airline industry.
"However, as well as reporting on the casualties, after the Paris attacks media coverage has very much focused on how it has brought people together.
"Stories of the taxi drivers who turned off their meters to drive people home for free and the families who welcomed strangers into their house are the single best way of destroying the terrorists' perceived power."
Gaining control of the online propaganda battle could be the most vital component in defeating Islamist militants, an expert has said.