There is no single theory that conclusively explains the motivation for rape; the motives of rapists can be multi-factorial and are subject to debate. Several factors have been proposed: anger, a desire for power, sadism, sexual gratification, and evolutionary pressures.
Victims of rape can be severely traumatized by the assault and may have difficulty functioning as well as they had been used to prior to the assault, with disruption of concentration, sleeping patterns and eating habits, for example. They may feel jumpy or be on edge. After being raped, it is common for the victim to experience acute stress disorder, including symptoms similar to those of posttraumatic stress disorder, such as intense, sometimes unpredictable emotions, and they may find it hard to deal with their memories of the event. In the months immediately following the assault, these problems may be severe and upsetting and may prevent the victim from revealing their ordeal to friends or family, or seeking police or medical assistance. Additional symptoms of Acute Stress Disorder include:
- depersonalization or dissociation (feeling numb and detached, like being in a daze or a dream, or feeling that the world is strange and unreal)
- difficulty remembering important parts of the assault
- reliving the assault through repeated thoughts, memories, or nightmares
- avoidance of things, places, thoughts, and/or feelings that remind the victim of the assault
- anxiety or increased alertness (difficulty sleeping, concentrating, etc.)
- avoidance of social life or place of rape
For one-third to one-half of the victims, these symptoms continue beyond the first few months and meet the conditions for the diagnosis of posttraumatic stress disorder. In general, rape and sexual assault are among the most common causes of PTSD in women.
"Victim blaming" is holding the victim of a crime to be in whole or in part responsible for the crime. In the context of rape, this concept refers to the Just World Theory and popular attitudes that certain victim behaviours (such as flirting, or wearing sexually-provocative clothing) may encourage rape. In extreme cases, victims are said to have "asked for it", simply by not behaving demurely. In most Western countries, the defense of provocation is not accepted as a mitigation for rape. A global survey of attitudes toward sexual violence by the Global Forum for Health Research shows that victim-blaming concepts are at least partially accepted in many countries. In some countries, victim-blaming is more common, and women who have been raped are sometimes deemed to have behaved improperly. Often, these are countries where there is a significant social divide between the freedoms and status afforded to men and women. Amy M. Buddie and Arthur G. Miller, in a review of studies of rape myths, state:
Rape victims are blamed more when they resist the attack later in the rape encounter rather than earlier (Kopper, 1996), which seems to suggest the stereotype that these women are engaging in token resistance (Malamuth & Brown, 1994; Muehlenhard & Rogers, 1998) or leading the man on because they have gone along with the sexual experience thus far. Finally, rape victims are blamed more when they are raped by an acquaintance or a date rather than by a stranger (e.g., Bell, Kuriloff, & Lottes, 1994; Bridges, 1991; Bridges & McGr ail, 1989; Check & Malamuth, 1983; Kanekar, Shaherwalla, Franco, Kunju, & Pinto, 1991; L'Armand & Pepitone, 1982; Tetreault & Barnett, 1987), which seems to evoke the stereotype that victims really want to have sex because they know their attacker and perhaps even went out on a date with him. The underlying message of this research seems to be that when certain stereotypical elements of rape are in place, rape victims are prone to being blamed.
However, they also state that "individuals may endorse rape myths and at the same time recognize the negative effects of rape."
A number of gender role stereotypes can play a role in rationalization of rape. In the case of male-on-female rape, these include the idea that power is reserved to men whereas women are meant for sex and objectified, that women want forced sex and to be pushed around, and that male sexual impulses and behaviors are uncontrollable and must be satisfied. In the case of female-on-male rape, the victim may either be perceived as weak or, in cultures where men acquire status by sexual conquest, as fortunate.