Short answers, pulled from the story.
Beatings or blunt trauma are the most common form of physical torture, reported by about two-thirds of survivors. These range from unsystematic blows to targeted techniques such as falanga, which involves repeated strikes to the soles of the feet.
Most victims of torture are poor and marginalized people suspected of crimes. Groups especially vulnerable include unemployed young men, the urban poor, LGBTQ people, refugees and migrants, ethnic and racial minorities, indigenous people, and people with disabilities.
The United Nations drew up the 1948 Universal Declaration of Human Rights, which prohibited torture. The United Nations Convention against Torture followed in 1984. The prohibition is now a peremptory norm in international law, meaning it is forbidden for all states under all circumstances.
Most scholars of torture are skeptical about its effectiveness at obtaining accurate information. Research has found that coercive interrogation presents a higher risk of false confession than cognitive interviewing, and many torture victims will say whatever the torturer wants to hear in order to end the pain.
An average of 40 percent of torture survivors develop long-term post-traumatic stress disorder, a higher rate than for any other traumatic experience. Common problems also include traumatic stress, anxiety, depression, and sleep disturbance; chronic pain and pain-related disability are frequently reported as well.
Psychiatrist Pau Pérez-Sales finds that torturers act from motives including ideological commitment, personal gain, group belonging, fear, and avoiding guilt from previous acts. Fear is the most common driver, and most perpetrators do not volunteer; many are desensitized through training and feel peer pressure from competitive group dynamics.