A highly critical introduction to Scientology on Operation Clambake says this about the techniques of Scientology:

The results of applying their crackpot psychotherapy (called “auditing”) is to weaken the mind. The mind goes from a rational state to an irrational one as the delusional contents of the subconscious mind are brought to the surface and are assumed to be valid. It also makes a person more susceptible to suggestion since it submerges the critical thinking faculties of the mind into a partial subconscious state. It results in a permanent light hypnotic trance and so from thenceforth that person can be more easily controlled. The person will, to a much greater extent, believe and do whatever they are told. And of course this is used to the full in persuading them to hand over further money and dedicating themselves further to the cult.

The results of applying their oversimplified and inapplicable rules in life is to lose the ability to think rationally and logically. A person loses the ability to think for themselves and so they lose the ability to challenge incorrect ideas. This makes them easier to control. It also isolates and alienates the person from society so that they withdraw from normal society and into their “Scientology” society. This further increases their susceptibility to the influence of their group. They end up being afraid of society, believing all society to be controlled by a group of drug companies, psychiatrists and financiers all of whom report to more remote masters. In other words they are in a state of mass paranoia. They therefore avoid reading newspapers and the like since they fear it will disturb their safe Scientology world. It is a downward spiral into madness.

I wonder about the psychology of brainwashing. What is actually happening to such a person’s mind during the process?

Short of a neurological defect, I suspect that it is impossible for a person to entirely “lose the ability to think rationally and logically.” After all, even the most brainwashed Scientologist must use reason and logic in order to get through the day. Even obeying orders requires us to think. So the tactics of Scientology can’t possibly eliminate all thinking, although perhaps it can eliminate critical thinking about Scientology itself.

As for strongly discouraging critical thinking about Scientology, both internal and external pressures can certainly be effective. If a person believes that the outside world is totally corrupt, that Hubbard will fix these abuses as soon as he learns of them, that thoughts critical of Scientology are a sign of mental illness, and so on, then critical thinking about Scientology becomes extremely difficult. Those are the internal pressures. If voicing any criticism will result in punishment or expulsion or loss of privilege or social ostracism, then critical thinking about Scientology becomes all the more difficult. Those are the external pressures. The combination of these two can be deadly.

These internal and external pressures exist for people in regular life all the time. A wife might not want to think about the meaning of her husband’s infidelity, so she pushes it out of her mind. A parent might refuse to acknowledge child’s drug problem, for fear that her friends will think her a bad mother. A Catholic may fear leaving the church for fear of going to hell. These are all pressures not to think, or at least not to think too much about something.

What makes brainwashing different is, I think, simply the amount of pressure exerted and the effectiveness of that pressure. The goal of the group, in such cases, is the precisely elimination of critical thought about the group. As a result, the pressures exerted are more likely to be strong and effective. When such pressures take hold in a person’s mind, the likelihood that the person will engage in critical thinking may sink to just about zero. Perhaps an accurate description would be that such a person has effectively lost the capacity to think rationally about a given subject.

Of course, that doesn’t mean that the capacity to think has been lost. After, if it was completely gone, it would be hard to explain how people like Monica Pignotti leave Scientology if all capacity for rational thought about Scientology had been compromised.

I admit that bursting through these internal and external pressures not to think may require more mental effort and endurance than most people have at their disposal. But an unwillingness to resist the pressures of Scientology is not the same as an incapacity to do so. Of course, for most, the distinction is likely to be sadly irrelevant.