Does a suspect's psychological state after arrest correlate to guilt or innocence? e.g. do only the guilty sleep in jail?

Question

A common cop procedural trope suggests only the guilty sleep in jail. It shows up in Law and Order: SVU (S6E04), award winning movies, and even articles about poker tells. The guilty, or so the argument goes, are so relieved to be caught they accept their fate and get some rest. The innocent are so stressed by their wrongful arrest they suffer insomnia.

The tropes about a suspect's behavior extend far beyond whether or not he or she sleeps, and into the anecdotal literature around police interrogation. Psychopaths cannot empathize, thus the guilty exhibit egotism and narcissism. The "Reid [interrogation] technique" suggests innocent suspects will act angry when confronted with a false allegation (search for "Step One -- The Positive Confrontation" section, third paragraph), but warns not to read too deeply into it.

For better or worse, measuring "hours slept while in the hole" makes for messy data collection. I suspect "do only the guilty sleep in jail?" is unanswerable. The psychological state of suspects after arrest might be much easier to measure. Is there any evidence to suggest the psychological state of a suspect after arrest, but before arraignment, correlates to his or her guilt or innocence? Is there any truth to the tropes?

Answer 1

The question "Do only the guilty sleep in jail?" is easier to answer than "Does innocence/guilt affect psychological state?" which is presumably true, but harder to define. I couldn't find anything about sleep the first night in jail.

Insomnia is a serious issue in prisons. [Ref]

It correlated with many factors (not merely a sense of feeling wronged), [Ref] including:

• writing letters, diaries or a book in prison,
• “arts-related” activities such as painting and listening to music.
• Worries about medical problems
• being separated or divorced (odds ratio: 8.8)
• having experienced stressful events during the past week
• having poor mental health (GHQ scale)

Factors that reduced the (correlated) risk included:

• practicing sports
• watching television
• discussing and meeting other detainees.

In fact, a Finnish forensic psychologist found [Ref] a result that suggests the opposite to the original claim:

A clearly greater quantity of sleep disorders [...] occurred in the persons who had committed offence against life than in the others.

It seems those who have a greater burden of guilt may find it more difficult, not less difficult to sleep.

(I have only read the abstract to this paper, and it did not contain enough info to confirm the result.)

Answer 2

As far as I can tell from looking at databases of journals, there's no study that looks for this correlation in the literature. And in the context of the movie quote (which predates your other sources) the purpose isn't to give the idea credibility, but rather to highlight the blind spot of the character speaking.

Let's look at the movie quote:

First day on the job, you know what I learned? How to spot a murderer. Let's say you arrest three guys for the same killing. You put them all in jail overnight. The next morning, whoever's sleeping is your man. You see, if you're guilty, you know you're caught, you get some rest, you let your guard down.

Does that even make sense? If you're innocent, you might think that this is a all a misunderstanding, it'll blow over, so you sleep. You know you didn't do it, you don't worry about it. If you're guilty, you might think that you can get away with it if you can figure out how, spend all night going over your story, your alibis, figuring out what do do. This doesn't even pass the smell test for the audience.

A literary function of that quote might be to highlight the arrogance of a character that we later find out was focused on his own obsessions to the point of missing what was right under his nose (if you listen closely, the character of Verbal literally confesses to killing Keaton to Kujon's face, and Kujon doesn't catch it.) It also is used to allow foreshadowing, the character who did steal the truck is the only one trying to sleep in the cell.

I'm also not sure that "only the guilty sleep in jail" is a Hollywood trope. It isn't listed as one of the tropes in "The Usual Suspects". A quick internet search doesn't show any evidence of this idea in popular culture prior to "The Usual Suspects".

So I'd have to say that no, there is no clinical evidence to support this idea, and the origin of the idea in popular culture is likely from the movie itself.