SINGAPORE - An Institute of Policy Studies (IPS) survey from August to October 2014 has found that certain events in Singapore's history are remembered by less than one-fifth of Singaporeans.
More than 98 per cent of the 1,500 who took part in the survey recalled recent events such as the opening of the two casinos in 2010 and the Sars outbreak in 2003.
Historical milestones that are included in textbooks, like the landing of Sir Stamford Raffles in 1819 and the Japanese Occupation from 1942 to 1945, also left an impression in people's minds.
What about the events that seem to have faded with time? Here's a little memory jolt for the 10 least-remembered out of the 50 events selected by IPS researchers:
1. Operation Coldstore (1963)
Percentage of respondents aware of event: 16.6 per cent
Operation Coldstore refers to the arrest of at least 100 persons in 1963 by the Special Branch, the agency that preceded the Internal Security Department. Those detained included leftist opposition party leaders and unionists such as Lim Chin Siong, S. Woodhull, Fong Swee Suan and Dominic Puthucheary.
The arrests were a heavy blow to the communist network in Singapore, as well as to the opposition Barisan Socialis.
The pro-communist leaders were opposed to Singapore's merger with Malaysia, which would take place in September 1963. The authorities had reason to believe that the detainees were involved in subversive activities and could resort to violence to disrupt the merger.
2. "Marxist Conspiracy" plot uncovered (1987)
Percentage of respondents aware of event: 18.5 per cent
In May 1987, 16 people were nabbed under the Internal Security Act; six more people were arrested in June. They were accused of planning to overthrow the Government, under the cover of the Catholic Church.
The detainees included church workers, professionals, businessmen and theatre practitioners. The 22 confessed on television interviews and statements that they were part of a Marxist conspiracy. All but one were released by December 1987.
After their release, nine of the detainees issued a statement alleging mistreatment during their detention, and said they were pressured to confess. Eight were re-arrested. They were released after signing declarations reaffirming their earlier confessions.
Key figure Vincent Cheng was said to be acting under the instructions of mastermind Tan Wah Piow, who had fled Singapore in 1976. Tan's aim was to "establish a Marxist regime" in Singapore, reports then said.
3. Laju hostage incident (1974)
Percentage of respondents aware of event: 22.1 per cent
Two Japanese from the Japanese Red Army and two Arabs from the Popular Front for the Liberation of Palestine jointly bombed Shell Oil's refinery on Pulau Bukom. When the attack failed, they hijacked the ferry Laju, holding the five-man crew hostage. The hostages were held for a week as the Government frantically negotiated their release. Two escaped during that time.
The hijackers asked for a plane to fly them to Kuwait but no airline was willing to risk its planes. Finally, their associates in Kuwait took the entire Japanese embassy there hostage to force Japan to provide them with an airliner.
Thirteen Singapore Government officials including former President S R Nathan, who was then the director of Security and Intelligence Division at the Ministry of Defence, and former Police Commissioner Tee Tua Bah, flew with the hijackers to Kuwait on a special Japan Air Lines flight as guarantors of safe passage.
4. Debate on Graduate Mother Scheme (1984)
Percentage of respondents aware of event: 24.9 per cent
The controversial Graduate Mother Scheme of 1984 gave financial incentives and school enrolment privileges to graduate mothers to encourage them to have more than two children. It also offered financial benefits to non-graduate mothers who volunteered to be sterilised.
Then Prime Minister Lee Kuan Yew wished to encourage graduate mothers to have more babies, but the Government did not anticipate the vociferous protests, many of which came from the very group the policy was targeted at - graduate women. The scheme was scrapped a year later.
The outcry over the policy was one of the factors that led to a significant slide in the People's Action Party's (PAP) vote share in the 1984 General Election.