Note: As part of this week's launch of the HuffPost's Crime vertical, senior writer and criminal justice reporter Radley Balko outlines 10 popular myths and misconceptions about the criminal justice system. Read Part 1 and Part 2.

Myth 8: Sex offenders are more likely to reoffend than other criminals.

There's no set of crimes more plagued by misconceptions and hysteria than sex crimes. In some cities, laws restricting where convicted sex offenders can live once they're released have become so restrictive, they're forced to live under bridges or in patches of woods.

While it's understandable that lawmakers and the public in general would have little sympathy for rapists or child molesters, in truth, people have landed on sex offender lists for exposing themselves in public (remember the "streaking" craze in the 1970s?), public urination, or having sex at age 17 with someone who is 15. In Texas, children as young as 10 can be put on the sex offender list.

In some states, you can land on the sex offender list for crimes that have nothing to do with sex. In seven states, "unlawful restraint of a minor" will land you on the list. See the Illinois case of Fitzroy Barnaby, who is now forced to register as a sex offender for grabbing a girl by the arm to lecture her after she road her bike out in front of his car, nearly causing him to hit her. The federal Adam Walsh Child Protection and Safety Act, passed in 2006, requires all states to put in place similar regulations in order to continue to receive federal funding.

Because they're usually passed out of anger and passion rather than after careful contemplation, sex offender laws often make little sense. People caught with child pornography on their computers, for example, can be subject to harsher penalties than people who actually molest children, despite the fact that many people who merely consume child porn aren't a threat to actual children. (Some were molested as children themselves, and consume pornography as a form of therapy.)

As Jacob Sullum points out in a recent article for Reason magazine (my former employer), under federal law, "a defendant with no prior criminal record and no history of abusing children would qualify for a sentence of 15 to 20 years based on a small collection of child pornography and one photo swap, while a 50-year-old man who encountered a 13-year-old girl online and lured her into a sexual relationship would get no more than four years."

There's also little support for the common belief that sex offenders are especially likely to repeat their crimes after they're released from prison. Sullum points to a litany of research debunking that misconception, including a 2003 Department of Justice survey finding a 5 percent recidivism rate for sex offenders within three years of their release, versus a 22 percent rate for people convicted of nonsexual assault.

None of this is to say we should give a pass to people who actually do prey on children, or others. But our laws ought to address the actual harm, not perceived harm, and they should be passed based on real-world data, not the hysterical visions of pundits and politicians, or in response to a single incident.

Myth 9: Seeing is believing. Eyewitness testimony is a reliable way of solving crimes.

Scientists have known about the problems with eyewitness testimony going back to the 19th century, when psychologist Hermann Ebbinghaus’s research on human memory gave us the “Forgetting Curve,” a graph plotting how human recollection fades over time -- within minutes of creating a memory. Since Ebbinghaus, there have been a number of fascinating studies confirming his research.

In a 1999 Iowa State University study, participants were shown grainy video footage of a real case in which a man shot and killed a security guard while robbing a convenience store. They were then given five pictures, and told that the culprit was included in the photo set -- except that he wasn't. Yet every one of the participants still claimed they could positively identify the culprit in one of the photos.

More troubling, when the researchers positively reinforced one group's selection of the culprit, that group became more confident in their identification. Half said they were now “certain” of their identification. Those participants also said they would be more willing to testify against the suspect. They were more likely to describe the hazy security footage as “clear."

Another study released in 2009 took the 1999 experiment a step further. Psychologists Lisa Hasel of Iowa State and Saul Kassin of John Jay College staged the theft of a laptop in front of a group of students. The students were then shown a lineup of possible suspects, but the lineup did not include the actual thief. The students weren't told they had to pick someone, only if they recognized him. They were then asked to rate their confidence in their selection from one to 10. Incredibly 173 students wrongly identified a suspect from the lineup. Just 33 said they couldn't pick out a culprit.

Two days later, the researchers brought the students back. Some were told that one of the suspects had confessed. Half the students who originally (and correctly) refused to finger a suspect from the lineup then changed their minds, now asserting that the person who confessed was indeed the person they saw. Of those who identified the suspect who later confessed, their confidence level in their identification increased from a six to an 8.5.

It's important to note that the students weren't asked to rate their confidence in the suspect’s guilt, only in their ability to identify him from memory. Memory fades over time, but positive feedback from authority figures can actually make an eyewitness more confident in a false recollection.

The criminal justice system has been disturbingly slow to embrace the established science on human memory. More than three of every four wrongful convictions overturned by DNA testing were in part the result of faulty eyewitness testimony.

Simple reforms would go a long way, such as making witness and photo lineups double-blind, where neither the officer conducting the lineup nor the witness knows which person is the suspect. Lineups should also include people that the police know are innocent. If a witness selects someone police know is innocent, police and prosecutors will then know that particular witness's memory isn't reliable.

Yet police departments have been slow to embrace change. Stephen Saloom, policy director for the Innocence Project, told Nature last year that despite the research showing clear problems with eyewitness identification, and the simple reforms that could compensate for them, "The majority of jurisdictions are simply sticking with what they have always done."

Myth #10: Wrongful convictions are tragic, but they're inevitable in an imperfect system. We at least take care of the wrongly convicted once we realize there has been a mistake.

With some notable and laudable exceptions, prosecutors often find it difficult to let go of a conviction -- even once it's clear that they got the wrong man. Currently in Texas, where there's strong evidence that the state has already executed an innocent man, public officials from the local prosecutor all the way up to the governor are fighting to prevent death row inmate Hank Skinner from testing DNA from his case that could prove his innocence (or clearly establish his guilt).

In Mississippi, District Attorney Forrest Allgood fought for years to prevent death row inmate Kennedy Brewer from running the DNA from his case through a state database to see if it matched a known convict. When Brewer finally won the right to run the test, it not only exonerated Brewer, but showed that Allgood had also convicted another innocent man in another case, Levon Brooks. The DNA pointed to a man named Albert Johnson, who later confessed to both crimes.

Illinois Assistant State's Attorney Michael Mermel has had DNA tests clear a number of suspects in cases his office was handling in Lake County, yet he has been stubborn in clearing their names. In one particularly egregious case, Mermel suspected a man named Jerry Hobbs of raping and killing his 8-year-old daughter and her friend. When DNA testing showed that the semen found in the mouth, rectum and vagina of Hobbs' daughter didn't belong to Hobbs, Mermel dismissed the results, explaining that the girls must have inadvertently picked up the semen while playing in a woods where teenagers were known to have sex.

Even after there's a consensus that the state has convicted the wrong person, it can be a struggle for the exonerated to get compensation. In 23 states, there's still no automatic compensation for the wrongly convicted. They have to go to court. And in states that do have compensation laws, the exonerated are deemed ineligible if they contributed to their own conviction by, for example, giving a false confession (see "Myth 7: No one confesses to a crime he didn't commit").

In other states, the wrongly convicted are only eligible for compensation if they're cleared by DNA testing, even though DNA evidence is only dispositive of guilt in a small percentage of cases. So in Missouri, for example, when Josh Kezer was exonerated by a judge after serving 15 years for a murder he didn't commit, he wasn't eligible for the state's compensation law.

Perversely, if Kezer had committed the crime, then been paroled after 15 years, he would have been eligible for job training and other state assistance programs designed to integrate ex-cons back into society. But because Kezer was declared innocent, he wasn't eligible for those programs, either. (Kezer was eventually awarded a settlement by the county that convicted him, but the county wasn't obligated to settle under state law).

In many states, compensation is awarded for each year of wrongful incarceration, but it's paid out not in a lump sum, but in annual installments, usually spread out over 20 years. So a man imprisoned for decades for a crime he didn't commit, but who isn't exonerated until he's 70, isn't likely to live long enough to see much of his compensation.

The exonerated are also often subject to codes of conduct in order to continue to receive compensation. It's as if they're on parole, even though they've been cleared of the crime for which they were convicted.