Modern interrogation is a study in human nature. Most of us are more likely to talk to people who appear to be like us. Once we start talking, it's hard for us to stop. Once we start telling the truth, it's harder to start lying. When a police officer tells us our fingerprints were found on the inside doorknob of a home that was robbed two days ago, we get nervous, even if we wore gloves the whole time we were inside.
With a few exceptions, the police are allowed to lie to a suspect to get him to confess. The belief is that an innocent person would never confess to a crime she didn't commit, even if she were confronted with false physical evidence of her involvement. Unfortunately, that's not always the case (more on false confessions in the next section), but it's a big part of the reason why the police are allowed to employ deceptive tactics in interrogation.
The psychological manipulation begins before the interrogator even opens his mouth. The physical layout of an interrogation room is designed to maximize a suspect's discomfort and sense of powerlessness from the moment he steps inside. The classic interrogation manual "Criminal Interrogation and Confessions" recommends a small, soundproof room with only three chairs (two for detectives, one for the suspect) and a desk, with nothing on the walls. This creates a sense of exposure, unfamiliarity and isolation, heightening the suspect's "get me out of here" sensation throughout the interrogation.
The manual also suggests that the suspect should be seated in an uncomfortable chair, out of reach of any controls like light switches or thermostats, furthering his discomfort and setting up a feeling of dependence. A one-way mirror is an ideal addition to the room, because it increases the suspect's anxiety and allows other detectives to watch the process and help the interrogator figure out which techniques are working and which aren't.
Before the nine steps of the Reid interrogation begin, there's an initial interview to determine guilt or innocence. During this time, the interrogator attempts to develop a rapport with the suspect, using casual conversation to create a non-threatening atmosphere. People tend to like and trust people who are like them, so the detective may claim to share some of the suspect's interests or beliefs. If the suspect starts talking to the interrogator about harmless things, it becomes harder to stop talking (or start lying) later when the discussion turns to the crime.
During this initial conversation, the detective observes the suspect's reactions -- both verbal and non-verbal -- to establish a baseline reaction before the real stress begins. The detective will use this baseline later as a comparison point.
One method of creating a baseline involves asking questions that cause the suspect to access different parts of his brain. The detective asks non-threatening questions that require memory (simple recall) and questions that require thinking (creativity). When the suspect is remembering something, his eyes will often move to the right. This is just an outward manifestation of his brain activating the memory center. When he's thinking about something, his eyes might move upward or to the left, reflecting activation of the cognitive center. The detective makes a mental note of the suspect's eye activity.
In the United States, as many as 80 percent of suspects waive their rights to silence and counsel, allowing police to conduct a full-scale interrogation.
The next step is to turn the questioning to the task at hand. The detective will ask basic questions about the crime and compare the suspect's reactions to the baseline to determine if the suspect is being truthful or deceptive. If the interrogator asks the suspect where he was the night of the crime and he answers truthfully, he'll be remembering, so his eyes may move to the right; if he's making up an alibi, he's thinking, so his eyes might move to the left. If the interrogator determines that the suspect's reactions indicate deception, and all other evidence points to guilt, the interrogation of a guilty suspect begins.