Watching reruns of the “Twilight Zone” over New Year’s weekend is a good reminder how prevalent smoking was in society years ago. People in those episodes lit up frequently and smoked in all kinds of settings that are taboo today.

The television show reflected reality, though, as people could smoke pretty much anywhere they pleased and 42.4 percent of adults were smokers half a century ago. New technology that produced cigarettes on a large scale, glamorous advertising and even the military, which gave free cigarettes to soldiers during World War I and II, led to increasing smoking rates in the 20th century through 1965.

Prior to the 1900s, lung cancer was a rare disease. As it became more common, the link to smoking came under suspicion. By the 1950s, researchers had uncovered the relationship between smoking and lung cancer.

However, tobacco companies disputed the evidence and did their best to suppress the findings. As late as 1960, only one-third of all doctors in the United States believed the case against cigarettes had been established.

Things quickly changed in the next few years, though. In the early 1960s, a larger study was done and its findings were a major contributor to the landmark 1964 surgeon general’s report on smoking and health. That led to the federal cigarette labeling and advertising act of 1965, which required the warning on packs stating that “cigarette smoking may be hazardous to your health.” Over the years, the wording was strengthened to state more specific health effects.

It just so happens that smoking started a steady, consistent decline in the United States beginning in 1965. The adult smoking rate 50 years later in 2014 was all the way down to 16.8 percent and public health officials are aiming to drive it down to 12 percent by 2020.

Warning labels weren’t the only reason for the decline. Some may say they weren’t even a reason as the Federal Trade Commission in 1981 issued a report to Congress that concluded warning labels had little effect on public knowledge and attitudes about smoking.

However, by then, the link between health and smoking was well known, at least by those people who were paying attention or were educated enough to understand what scientists were saying about the evidence. Today, people with higher rates of education smoke considerably less than other adults and their rates are declining more sharply than the rest of the population. On the other hand, 43 percent of adults with a general education diploma (GED) — about the same as all adults in 1965 — still smoke today.

Several other factors led to the overall decline.

Congress banned the advertising of cigarettes on television and radio starting on Jan. 2, 1971. In more recent years, those ads have been replaced by anti-smoking campaigns, which have been a regular part of the media landscape.

In 1975, Minnesota enacted the Minnesota Clean Indoor Air Act, making it the first state to restrict smoking in most public spaces, although that didn’t include restaurants and bars at the time. It took 19 years for the second state to follow suit, but today the majority of states have restrictions.

Perhaps the most effective means in curbing cigarette smoking — drastically higher taxes — began around 1980.

In the 1950s, a pack of cigarettes could be purchased for as little as 25 cents in some parts of the country. Today, heavy taxes have pushed the price to more than $13 in places such as New York City. Even adjusted for inflation that is greater than a fivefold increase.

Evidence shows the most correlation between price and quitting. An analysis of smoking and cigarette taxes from 1955 to 1964 before antismoking information blossomed shows the same relationship between tax increases and declining smoking rates that are prevalent today.

A specific piece of evidence shows that when Wisconsin raised its state cigarette tax to $1 per pack in 2008, a quitting hot-line received a record 20,000 calls in two months, which compared to the previous 9,000 calls annually.

It’s interesting that social engineering, which Americans generally oppose, and restricting individual rights, also detested by Americans, were so effective in turning people against tobacco.

The main reason the restrictions were accepted by the American public was because officials touted the danger of second-hand smoke, which could harm innocent bystanders. That is true for people working long hours in crowded bars with no ventilation, but research shows that deaths from passive smoking are relatively few.

However, smoking restrictions protected innocent bystanders in another way. People are more likely to smoke if their friends smoke. Research shows a small jump in percentage of smoking by an individual’s peers creates a much larger jump in probability that person will also smoke.

It appears that even smokers don’t object to the restrictions. About 90 percent of smokers say they regret having started and about 80 percent say they want to quit. Although about 40 to 50 percent try to quit each year, only about 5 percent succeed.

A 2005 study by two economists found that people with a tendency to smoke were happier in places with higher cigarette taxes. They noted that higher taxes made it easier for smokers to quit.

All this research shows attitudes about smoking have come a long way in the past half-century.

However, changes in what was common on television shows aren’t just about smoking. Viewers watching those old episodes of “The Twilight Zone” rarely see obese people. Again, it is a reflection of reality in the 1950s because there were so many fewer obese people then — about 10 percent of the population. Today, the rate is 36.5 percent.

Some social engineering — compulsory nutrition labeling and extra taxes on sugary soda pop — are taking shape to reverse the obesity epidemic. However, it remains to be seen if the populace will stomach an all-out official assault on poor choices in diet as was the case with tobacco, even if people know it would be good for their health.