The NDP has been without a leader since Jack Layton died in August. (CBC)

A professor of political science says the lack of fireworks at NDP leadership debates thus far is in keeping with the party's culture and ideology.

The eight New Democratic Party leadership hopefuls will be in Halifax on Sunday for the second of several official debates in the run-up to the vote on March 24 when party members will choose their new leader.

The candidates have been mostly collegial, sticking to tried-and-true social democratic bromides at other unofficial debates and one official event in Ottawa last month.

But the lack of contention is not unusual, said Nelson Wiseman, a professor of political science at the University of Toronto.

"Some people want it to be a shootout like they had between (Bob) Rae and (Michael) Ignatieff, and between (Stephen) Harper and (Belinda) Stronach ... but that isn't the culture of the NDP," said Wiseman from his home Friday.

"There's a fundamental cultural difference, and operational difference, between the NDP and the other parties. In the other parties, policy is very much determined by the leaders."

"The NDP is fundamentally different that way," Wiseman added. "It styles itself as a mass party."

Consequently, the race has been more focused on personality and the candidate's leadership qualities rather than specific policies, said Hugh Thorburn, a retired political science professor from Queen's University in Ontario.

But that's an obvious hurdle when replacing the late Jack Layton, who conducted a "masterful campaign" during his dying days, leading the NDP to Official Opposition status for the first time in the party's history, said Thorburn.

"The problem is how to continue this dynamism, and you have to first get someone who can enter into that," said Thorburn from his home in Kingston, Ont., on Friday. "I think this leadership race is really a tryout for that role, and we'll see who wins."

Who are the candidates?

Another issue is a lack of profile among the candidates, with the exception of Montreal MP Thomas Mulcair and former party president Brian Topp, the experts say.

A survey conducted by Ottawa-based Abacus Data suggested that 40 per cent of Canadians do not know any of the candidates.

Among NDP supporters, 35 per cent said they were unaware of any of the candidates and 54 per cent said they were aware of fewer than two candidates.

The poll was conducted from Jan. 16 to 19 and surveyed 1,000 randomly selected Canadians. It carried a margin of error of 3.1 per cent, 19 times out of 20.

The other six leadership hopefuls are Paul Dewar, Peggy Nash, Niki Ashton, Nathan Cullen, Martin Singh and Romeo Saganash.

On Sunday, they'll be tasked with addressing a number of party concerns. Topping that list will be how to protect the ground gained in Quebec during the last election, said Thorburn.

Under Layton's leadership, Quebec delivered more than half the party's 103 seats.

Sunday's debate will be followed every two weeks by others in Quebec City, Winnipeg, Montreal, Vancouver and at the March convention in Toronto.