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%
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%
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%
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%
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.
5. PAP splits (1961)
Percentage of respondents aware of event: 32.1%
The PAP had become the ruling party of Singapore after elections in 1959, but the party was not always united.
In July 1961, when then-prime minister Lee Kuan Yew sought a motion of confidence in his government, 13 PAP assemblymen abstained from the vote.
They were subsequently expelled, and the group went on to form the now-defunct Barisan Socialis that same year.
The founding chairman of the Barisan was Dr Lee Siew Choh. Dr Lee has said that differences over the proposed merger with Malaysia was the main reason for the split. In the 1963 elections, the party won 13 of 51 seats in Parliament.
After Singapore separated from Malaysia in 1965, members of parliament of Barisan boycotted parliament from December that year, claiming "undemocratic practices" by the Government.
The party refused to take part in the 1968 General Election, which resulted in a clean sweep for the PAP. When it returned to the polls in 1972, it failed to win any seats between then and 1984. It merged with the Workers' Party in 1988.
6. Merger of Nantah and University of Singapore (1980)
Percentage of respondents aware of event: 34.4%
Nantah or Nanyang University was set up in 1955 with public funds from the Chinese community. The students came from Chinese stream schools, who were denied entry into the local university, the University of Malaya, which later became the University of Singapore in 1962.
As the number of Chinese stream students dwindled in the 1970s, the enrolment and standards at Nantah fell, and a merger was proposed. At the time, Nantah students and alumni protested the move. On Aug 8, 1980, Nanyang University and the University of Singapore merged to form the National University of Singapore.
7. Formation of MAS (1970)
Percentage of respondents aware of event: 35.1%
In 1970, Parliament passed the Monetary Authority of Singapore Act leading to the formation of MAS on Jan 1, 1971. Various monetary functions associated with a central bank were centralised in the authority, which was helmed by former Minister of Finance Hon Sui Sen from 1971 to 1980.
8. Maria Hertogh riots (1950)
Percentage of respondents aware of event: 37%
The bloody racial riots in December 1950 were triggered by a highly publicised legal dispute for the custody of 13-year-old Dutch girl, Maria Hertogh.
When she was five years old, Maria had been left in the care of a Malay woman after her parents were interned by the Japanese during World War II.
After the war, her biological parents wanted to claim their daughter back, but her adopted mother said Maria had been given to her for adoption in 1942.
The court first awarded custody to her Dutch parents, but Maria was returned to her adoptive family on appeal. She was then briefly married to a 22-year-old Malay teacher.
When the High Court finally awarded custody of the girl to her biological Catholic Dutch parents and declared the marriage void, the ruling ignited days of riots. Eighteen people were killed and 173 injured.
Maria returned to the Netherlands during the riots. In 1956, she married a 21-year-old cafe owner, and they had 10 children. She died in the Netherlands in 2009 at the age of 73.
9. J.B. Jeyaretnam wins Anson by-election (1981)
Percentage of respondents aware of event: 44.1%
Opposition politician J.B. Jeyaretnam became Singapore's first opposition MP since 1966 after winning the Anson by-election in 1981. The Workers' Party secretary-general won in a three-cornered contest with 51.9 per cent of the votes. The other two parties contesting were the PAP and the United People's Front.
The by-election was triggered when incumbent MP Devan Nair stepped down to become Singapore president.
Jeyaretnam was re-elected in the 1984 General Election, but was disqualified in 1986 following a conviction for making a false declaration about his party's accounts.
In 1988, Anson was absorbed into a Group Representation Constituency.
10. Introduction of Singapore currency (1967)
Percentage of respondents aware of event: 47%
Singapore and Malaysia were in talks to issue a common currency after Singapore's split from Malaysia in 1965. After two years of negotiation, the two countries could not agree on an arrangement for a common currency. On June 12, 1967, Singapore's new currency was issued.
Back then, the Singapore dollar was freely interchangeable with both the Malaysian ringgit and the Brunei dollar. In 1973, Malaysia opted out of the arrangement, but Singapore and Brunei currencies are accepted in both countries till today.
Sources: The Straits Times, National Library Board