Threshold-Based Offending
By Thomas J. Dover, Ph.D.
In the early 1980s, researcher Neil Malamuth devised a series of interesting studies. A central question of his research focused on whether there is a proclivity among men for committing rape. His findings were startling — on average, roughly 35% of the male college students he surveyed indicated that they might commit rape if they had no chance of getting caught.1 Yet, there were no indications that 35% of Malamuth’s study subjects had engaged in such activity before or after the survey. In his view, the 35% had interest but were not necessarily committed to the act.2
It is important to discuss factors that contribute to rape proclivity. However, there is another aspect to this study also worth exploring. Malamuth contextualized his question by removing a negative repercussion — getting caught. Even though he focused on rape, Malamuth’s study highlights the importance of understanding not only why perpetrators offend but also why those with a proclivity to do so sometimes do not. This has implications across the spectrum of criminal behavior and can inform law enforcement practice and policy in everything from prevention to investigation to rehabilitation.
To further explore this notion, this article will introduce the concept of threshold-based offending.3 This concept is simple: Individuals with an inclination to offend are kept from doing so by internal and external inhibitors. The totality of these inhibitors creates a threshold that when crossed can lead to active offending. Threshold-based offending focuses on why individuals with a proclivity to offend cross this threshold and what happens when they do. This is a relatively simplistic approach to understanding criminality, yet the simple tenets of threshold-based offending form a foundation to understand deceptively complex ideas about decision-making. Consequently, the concept can be applied across the spectrum of criminal activity and has a place in most any discussion about criminal behavior.
Key Concepts
Needs and Goals
Criminal behavior can be thought of as the outcome of a decision-making process. This means that the process of engaging in criminal behavior is about satisfying emerging needs by addressing goals through criminal actions.
Human behavior is tied to evolving needs. These needs are not infused with moral value but rather underlying existential requirements. Abraham Maslow identified a general set of needs organized into a hierarchy that presupposes each level of need is satisfied before moving on to the next. These needs start with base requirements for life (e.g., food, shelter, and other physiological necessities) overlaid with additional tiers, which include the need for security; love and belonging; self-esteem; and self-actualization, or fulfillment.4 Such needs are all part of the human experience and endure among offenders and nonoffenders alike.
As needs emerge, goals are generated as preferred end states to satisfy them.5 As such, a goal is something that someone wants to achieve, maintain, avoid, or end. For example, if someone is hungry (a physiological need), a goal might be to end the hunger.
Goals are achieved through different methods. Yet, limited resources, individual skill sets, and focus, among other things, all affect how someone devises a method to pursue a goal. Returning to the previous example, to address the goal of ending hunger, someone might order out for pizza, make a sandwich, go to a restaurant, or steal a loaf of bread, depending on taste, time, and available funds.6
Interest
In threshold-based offending, goals are focused on action. The methods through which actions are achieved create variations in behavior. However, an action is preceded by interest in a method to achieve it. For instance, two different people may have the same goal — exerting power and control. To achieve this, one person might seek self-improvement (action) and have an interest in exercising (method). The other might pursue sexual dominance (action) and have an interest in committing rape (method).
In each instance, the goal is to achieve power and control, and both individuals have an interest in pursuing action to satisfy the goal via a specific method. The goal is not problematic. It is the second person’s interest in satisfying this goal through the method of rape that constitutes a precursor to criminal behavior.
Conflicts
Interestingly, Maslow specified that multiple needs could drive behavior at the same time and that some may be pursued at the expense of others.7 This means that for every goal tied to a need, there may be others tied to conflicting needs, leading to conflicting interests. Consequently, the mere existence of interest in an action does not mean the individual is always free to act.
Under some circumstances, interest in one action is insufficient to overcome other interests that create internal and external barriers to that action. For this reason, goals can take two different forms — the goal to engage in action (acquisitional goal) or to refrain from action (inhibitory goal). Inhibitory goals are self-regulatory and suppress pursuit of acquisitional goals. Acquisitional goals overcome inhibitory goals and promote action. In this way, both are in a state of dynamic tension.8
Inhibitory Threshold
Inhibitory goals (whether internally generated or externally applied) are manifested as action inhibitors. Thus, an individual may fantasize about molesting a child but not pursue this fantasy due to external action inhibitors (e.g., lives with his spouse, to whom he has significant accountable time) and/or internal action inhibitors (e.g., has underlying feelings of disgust or aversion toward his own deviant fantasies).
Interest in pursuing an action can be suppressed by multiple action inhibitors representing why the individual does not want to act (figure 1). For instance, while an individual may have an emerging interest in committing rape, he may also have significant action inhibitors against it.9 These inhibitors may include moral objections (inhibitory goal #1), the desire to maintain a positive self-image (inhibitory goal #2), and fear of getting caught (inhibitory goal #3).
Such action inhibitors reinforce each other, and the accumulation of all three constitute an inhibitory threshold.10 Although an individual’s interest may eventually surpass some of the inhibitors (e.g., moral objection and self-image), if his interest remains below the overall inhibitory threshold, he does not pursue action because his inhibitory threshold against rape dominates (figure 1).
Figure 1: Layers of inhibitory goals manifested as action inhibitors create an inhibitory threshold. If interest over time remains below the threshold, inhibitory goals dominate and action remains suppressed.
“This is a relatively simplistic approach to understanding criminality, yet the simple tenets of threshold-based offending form a foundation to understand deceptively complex ideas about decision-making.”
The weakening or reinforcement of action inhibitors can have a significant effect on the overall inhibitory threshold and its ability to effectively suppress action. For instance, as Malamuth noted in his studies on rape proclivity, persistent rape myths tend to desensitize men to the realities of rape.11 This may result in a lowering of action inhibitors and thereby increase potential for a threshold breach and pursuit of action. On the other hand, for some men, exposure to victim statements about the physical, psychological, and emotional damages resulting from rape may strengthen the action inhibitors, thereby fortifying the inhibitory threshold and discouraging the act.12
Threshold Breach
Needs, goals, and interest are dynamic and change over time. If interest eventually does breach the inhibitory threshold (e.g., desire to commit rape surpasses the accumulated action inhibitors against it), then the acquisitional goal becomes dominant (figure 2).
Figure 2: If interest breaches the inhibitory threshold, then the acquisitional goal dominates and the individual may pursue action.
Simply put, a breach of the inhibitory threshold will occur when either interest surpasses inhibitors, or the inhibitors drop below interest. This is the core dynamic of threshold-based offending.
Such a threshold breach can emerge from various circumstances. It is important to keep in mind that from a threshold-based offending perspective, the underlying reason(s) why the individual has an interest is not as important as why (and when) that interest breaches the inhibitory threshold and leads to the pursuit of action.
Innumerable examples exist of how these threshold breaches might manifest in an actual case. However, there are four general circumstances in which a change in interest or inhibitory threshold may lead to a threshold breach.
- Interest increases without a sufficient increase in the inhibitory threshold.
- Interest increases with a decrease in the inhibitory threshold.
- Interest does not change, but the inhibitory threshold is reduced.
- Interest decreases, but the inhibitory threshold decreases at a greater rate.
In the first circumstance, an emerging interest in action accumulates without a sufficient increase in the inhibitory threshold to suppress it (figure 3). For instance, an individual’s interest in rape increases, fueled by violent fantasy. At the same time, the action inhibitors the individual has against rape do not change, or they increase at a lower rate than his interest. Eventually, what at one time kept him from acting is not enough to suppress action given his persistently increasing interest.
Figure 3: Emerging interest increases without a sufficient increase in the inhibitory threshold.
In the second circumstance, an increasing interest is accompanied by a reduction in the inhibitory threshold (figure 4). For example, someone who has increasing political frustration is kept from acting violently on it due to underlying moral inhibitions against violence. However, if he joins a group that promotes the idea that under some circumstances political violence is necessary, then over time his action inhibitors (moral objections) may be reduced or mitigated. Given his rising frustrations and decreasing moral inhibitions against political violence, he may eventually act.
Figure 4: Increasing interest is accompanied by a reduction in the inhibitory threshold.
In the third circumstance, interest remains relatively unchanging, but the inhibitory threshold is suddenly reduced or even eliminated (figure 5). For instance, an individual with an interest in rape may not act because he lives with his wife, to whom he is accountable. Under these conditions, she unknowingly acts as an action inhibitor, and his desire to maintain the relationship and/or avoid detection provides a sufficient set of inhibitory goals. Yet, if she leaves for a significant period (e.g., goes out of town to visit an ailing parent), her effect as an action inhibitor is reduced or eliminated. Effectively, unbeknownst to the wife, her absence creates a threshold breach that allows him to act. Given pursuit of action is predicated on a missing action inhibitor and a relatively consistent interest, the reintroduction of that inhibitor may effectively resuppress the action. Thus, for example, the offender’s interest is constant, but he only attempts to offend when his wife is out of town.
Figure 5: Interest remains consistent, but the inhibitory threshold is significantly reduced.
In the fourth circumstance (figure 6), while both the interest and inhibitory threshold are decreasing, action inhibitors are decreasing at a faster rate. For example, an individual may have a decreasing interest in theft (e.g., he has found another legitimate or illegitimate way to make money). However, at the same time, his action inhibitors against theft are also reduced because he does not anticipate punishment for committing certain types of theft (e.g., shoplifting). Although his interest is not as great as it once was, the inhibitors against theft are so low that his waning interest breaches the threshold nonetheless and dominates his action.
This last scenario presents two interesting considerations. First, changes in interest are secondary to the overall threshold breach that occurs. This is an important point because what results is an individual with acquisitional goals that may not be actively or vigorously pursued due to waning interest. Even so, this person may act opportunistically if he encounters a circumstance in which he can engage in the action because there are no inhibitors holding him back. Second, the reintroduction of “certainty of punishment” may have a dramatic effect of bumping the inhibitory threshold above the interest and keeping the individual’s interest in theft from becoming action.
Figure 6: Both the interest and inhibitory threshold are decreasing. However, the inhibitory threshold is decreasing at a faster rate than interest.
Each of the circumstances for a threshold breach depends on an increase in interest and/or a decrease in action inhibitors. Increasing interest may emerge from internal processes (e.g., grievance or fantasy) or external sources (e.g., stressors). Simultaneously, action inhibitors can be reduced through internal changes (e.g., attitude, shifting perspective, or cognitive distortion) and external factors (e.g., lack of accountability to others).
Primed State
When the inhibitory threshold is breached and the acquisitional goal dominates, the individual has entered a primed state (figure 7). Action inhibitors no longer provide barriers — the individual is free to pursue action. This does not mean that he has successfully acted upon his interest, but it does mean he is seeking (or at least open to) the opportunity to do so because nothing is holding him back.
Figure 7: The inhibitory threshold has been breached by interest, and the individual is primed to pursue action.
However, to act, his interest must remain above the inhibitory threshold for enough time to engage in action. If internal or external action inhibitors intercede and his interest drops below the threshold prior to acting, then he will not act. The circumstances and triggers for increased action inhibitors or decreased interest depend on the individual offender.
For instance, if an offender’s interest in action is stress based, a reduction in the stress experienced by the individual may sufficiently reduce interest to below the inhibitory threshold. In other circumstances, factors associated with the victim may have an impact. As an example, a victim vomiting may trigger a loss of interest for a rape offender because it does not feed into his fantasy.13 In other circumstances, encountering a picture of the victim’s young child may humanize the victim and intensify action inhibitors for an offender.14
If the individual remains in a sustained primed state, he is focused on pursuing action. To act, he needs to address a second set of inhibitors — factors he must overcome to create an opportunity for action. Unlike action inhibitors, which keep the pursuit of an action in check through self-regulation, opportunity inhibitors are environmentally based tactical barriers to the offender’s intended action while in a primed state. In other words, once the potential offender is primed, he must adapt to overcome opportunity inhibitors to select, access, and act upon the victim, and egress from the scene.15
The difference between action inhibitors and opportunity inhibitors is where they occur within the decision-making process. Action inhibitors present barriers to turning interest into the pursuit of action (e.g., an individual with rape fantasies may not act on them for fear of getting caught).
On the other hand, opportunity inhibitors are practical barriers that impede the opportunity to successfully offend (e.g., a rape offender — to successfully rape — may need to gain entrance to a victim’s apartment undetected).
Threshold-based offending can play an important part in understanding victim selection. An individual’s interest in action may revolve around a specific person or victim prior to entering a primed state. However, in a primed state the offender begins to solidify practical selection of a victim and engage opportunity inhibitors to interacting with (and acting upon) that victim.
For example, an offender may fantasize about raping a specific celebrity or a woman from a certain socioeconomic group. However, the offender may not have access to this type of victim. For this reason, in the primed state, he may need to substitute this victim of interest with one who is more available and vulnerable, like a sex worker.
Additionally, before entering a primed state, an individual may seek out ways to interact with potential victims to build his fantasy. However, in a primed state, the offender may seek victims to facilitate opportunity for action. For instance, if an individual is interested in young girls, prior to being primed, he may actively seek circumstances where he can observe or interact with young girls — like the beach or the mall — to enhance his fantasy. But when the same offender is primed, he may utilize the same locations to generate opportunity for action.
In some circumstances, what started with an individual who is not primed but actively building interest may end with the individual breaching his inhibitory threshold and becoming primed on the spot. For instance, the offender’s initial intent may have been to watch children at a bus stop to feed his fantasy, but during this activity he becomes primed (i.e., his interest overcomes action inhibitors, thereby breaching his inhibitory threshold) and acts by abducting a child.
Overall, this circumstance may appear to be an impulsive and/or poorly planned offense because the offender considered opportunity inhibitors on the fly. On the other hand, if his initial intent at a bus stop is to abduct a child, he is already primed and has had more time to consider how to defeat opportunity inhibitors. This offense may appear more methodical, or there may be indicators of offender preparedness to engage with the victim and overcome barriers to success.
Applications
In many ways, threshold-based offending is a formalization of common sense. Yet, sometimes making the obvious clear provides an opportunity to think about how a concept that was hiding in plain sight might change the way one thinks about the larger picture.
When considering that criminal behavior involves overcoming inhibitors to action, law enforcement personnel and researchers can start to develop relevant questions. For instance, what are the action inhibitors to certain types of criminal activity (e.g., rape, murder, and theft), and how do they differ among and within crime types? As an example, do some of the same inhibitors for rape also apply to theft? Are there certain types of rape that tend to involve specific inhibitors absent in other types of rape? How do certain types of offenders with certain skill sets and characteristics overcome these inhibitors?
From a prevention perspective, the presence of inhibitors is an important and intrinsic part of dissuading potential offenders from offending in the first place. Things like consequences for criminal behavior, accountability to other people, and social integration all may — according to the tenets of threshold-based offending — significantly bolster an individual’s inhibitory threshold.
From an investigative perspective, understanding how, why, and when the inhibitory threshold is breached can provide important insight into a perpetrator’s victim selection, constraints of accountable time, and the factors that go into creating a persistently primed offender. Additionally, the dynamic nature of interest in action juxtaposed with internal and external action inhibitors can help guide questions about how a specific offender cultivates interest (e.g., via fantasy) and how he consciously or subconsciously goes about reducing action inhibitors (e.g., through alcohol use or exposure to material that normalizes the action). Further, understanding when the perpetrator’s interest was not acted upon can be a significant step toward leveraging those insights during offender interviews and interactions.
From a theoretical perspective, threshold-based offending offers a simple yet comprehensive means to consider behavioral concepts within a robust context, such as differentiating between a series and a spree (see “Series and Spree Offenses,” below) and leveraging the dynamics of threshold breaches to identify types of serial offending (see “Types of Series,” below). These concepts can inform discussions about periods of significant inactivity, requirements for a sustained primed state, or even circumstances in which action inhibitors are absent or opportunity inhibitors are mitigated.
Conclusion
Threshold-based offending is not the only way to understand or explore criminal behavior, but it does offer a relatively simple way to think about it. As a behavioral model, it can be used to generate questions, hypothesize, and provide a foundation to grasp the complex nuances of an event. Understanding the dynamic relationship between interest and inhibition is the core of threshold-based offending. The usefulness of this model, then, is in highlighting the universal and dynamic nature of internal conflict and its impact on behavior.
Malamuth’s study asked an important, almost philosophical, question about criminal behavior — What is the relationship between proclivity and action? The answer is not simple because people are complicated. They have different needs and goals, and they address these needs and goals in different ways. Inhibitory goals keep individuals from acting on their basest instincts and allow them to operate within society. Society may never truly eliminate the proclivity for criminal behavior, but it can identify and create guardrails for acceptable conduct and understand what happens when those guardrails fail.
“When considering that criminal behavior involves overcoming inhibitors to action, law enforcement personnel and researchers can start to develop relevant questions.”
Series and Spree Offenses
Threshold-based offending offers an interesting glimpse into the dynamics of repetitive criminal activity and can help better define what constitutes a series of offenses versus a spree. While the difference between a series and spree may seem only semantic, there are significant structural differences that can be highlighted by applying a threshold-based perspective.
A series is defined as multiple offenses committed by the same individual (or co-offenders) separated by significant time and space. In serial killings, the offender kills and then after a significant period of inactivity kills again.
On the other hand, a spree involves continuous criminal offending extended over time and space. In spree killings, the offender kills in one location and then follows up with additional killings in other locations in quick succession.
Using threshold-based offending, one can better refine the concepts of series and sprees predicated on the absence or presence, respectively, of a sustained primed state between offenses. In a series, after the offender commits the offense, interest transitions to below the inhibitory threshold. This may mean the offender has satisfied the underlying acquisitional goal or there has been an increase in action inhibitors. To reoffend, this offender must once again overcome the inhibitory threshold (figure 8).
Figure 8: In a series, the offender drops below the inhibitory threshold between offenses.
In a spree, the offender remains primed between offenses (figure 9). This implies he has not sufficiently satisfied his acquisitional goal or his action inhibitors are significantly and consistently low. In this state, he must only overcome opportunity inhibitors. As a result, he more quickly engages in action and capitalizes on emerging opportunity.
Figure 9: In a spree, the offender remains in a primed state between offenses.
Types of Series
Threshold-based offending can highlight that in some series, the offender’s interest in offending is the driving factor, while in others, action inhibitors have a more pronounced impact. For instance, figure 10 illustrates two offenses in a series driven by an individual’s interest in offending. In this example, action inhibitors remain relatively consistent. However, the offender generates an increasing level of interest. Eventually, he becomes primed and offends because this interest overcomes his action inhibitors. Following action, the offender’s interest drops below the inhibitory threshold.
Figure 10: In a series of criminal offenses (e.g., serial murder or serial rape), the offender drops below the inhibitory threshold between offenses. Pictured is a dynamic interest with a consistent inhibitory threshold.
In this series, action is highly dependent on the offender’s dynamic and emerging interest. This may be due to periodic spikes in fantasy or grievance that, upon successful action, are followed by significant decreases in interest.
In comparison, figure 11 shows an inhibitor-driven series. The perpetrator maintains a relatively consistent level of interest in offending. Those instances in which he becomes primed and eventually offends are based on periodic absences of action inhibitors that create pockets of primed opportunities for action.
Figure 11: In a series of criminal offenses (e.g., serial murder or serial rape), the offender’s interest may be consistent, but the application of action inhibitors involves periods of significantly lowered thresholds.
These pockets of action may be generated through a lack (or reduction) of action inhibitors. For instance, his work schedule or living circumstances may offer periods when he is not accountable to someone else, reducing his action inhibitors and giving him opportunity to pursue action in a primed state.
Dr. Dover serves as a crime analyst with the FBI’s Behavioral Analysis Unit-5 and instructs on topics pertaining to behavioral analysis for the FBI National Academy. He can be reached at tjdover@fbi.gov.
Endnotes
1 Neil M. Malamuth, “Rape Proclivity Among Males,” Journal of Social Issues 37, no. 4 (1981): 138-157, https://doi.org/10.1111/j.1540-4560.1981.tb01075.x. Malamuth measured likelihood as 2 or above on a scale ranging from 1 (“not at all likely”) to 5 (“very likely”). Approximately 20% of respondents indicated a 3 or above on the same scale.
2 It is important to consider that there may have been some respondents who did offend but remained undetected. However, Malamuth attributed his findings, in part, to several myths (at the time) that desensitized males to the emotional and physical realities of rape. He postulated that this made it easier for some of the study subjects to hypothetically consider rape under certain circumstances. Many of these myths persist today and revolve around the context of the rape (e.g., if it involves an intimate relationship between the victim and offender), level of violence in the rape (e.g., if coercion is used versus physical violence), and reputation of the victim (e.g., if they are considered “sexually promiscuous”).
3 Threshold-based offending was first referred to as “needs accumulation” in T. Dover, “Implementing a Complex Social Simulation of the Violent Offending Process: The Promise of a Synthetic Offender” (PhD diss., George Mason University, 2016). In this work, the process of overcoming inhibitors to pursue goals is represented through an accumulator that relies on threshold-based rules. Using an accumulator as a driven threshold system is based on John B. Rundle et al., “Probabilities for Large Events in Driven Threshold Systems,” Physical Review E 86, no.2 (2012), https://doi.org/10.1103/PhysRevE.86.021106, and also draws from work in affect accumulation in marital processes (J.M. Gottman, “Psychology and the Study of Marital Processes,” Annual Review of Psychology 49, no. 1 (1998): 169-197, https://doi.org/10.1146/annurev.psych.49.1.169; and John Gottman et al., “Behavior Exchange Theory and Marital Decision Making,” Journal of Personality and Social Psychology 34, no.1 (1976): 14-23, https://doi.org/10.1037/0022-3514.34.1.14); models of stimulus onset during cognition (Leendert Van Maanen and Hedderik Van Rijn, “An Accumulator Model of Semantic Interference,” Cognitive Systems Research 8, no. 3 (2007): 174-181, https://doi.org/10.1016/j.cogsys.2007.05.002); and models of self-regulation in sex offenders (D.L.L. Polaschek et al., “Rapists’ Offense Processes: A Preliminary Descriptive Model,” Journal of Interpersonal Violence 16, no. 6 (2001): 523-544, https://doi.org/10.1177/088626001016006003; and Tony Ward, Stephen M. Hudson, and Thomas Keenan, “A Self-Regulation Model of the Sexual Offense Process,” Sexual Abuse: A Journal of Research and Treatment 10, no. 2 (1998): 141-157, https://doi.org/10.1023/A:1022071516644). The concept has since been refined and developed as threshold-based offending in the FBI National Academy course “Behavioral Analysis as Decision-Support: Theory and Application in Law Enforcement Investigations,” where it is presented as a viable and useful way to conceptually model behavior.
4 A.H. Maslow, “A Theory of Human Motivation,” Psychological Review 50, no. 4 (1943): 370-396, https://doi.org/10.1037/h0054346.
5 Roger C. Schank and Robert P. Abelson, “Scripts, Plans, and Knowledge,” in IJCAI ’75: Proceedings of the 4th International Joint Conference on Artificial Intelligence (San Francisco: Morgan Kaufmann Publishers, 1975): 151-157; Roger Schank and Robert Abelson, Scripts, Plans, Goals and Understanding: An Inquiry into Human Knowledge Structures (Hillsdale, NJ: Lawrence Erlbaum Associates, 1977); Stephen Slade, Goal-Based Decision Making: An Interpersonal Model (Hillsdale, NJ: Lawrence Erlbaum Associates, 1994); and R. Sun, “Motivational Representations Within a Computational Cognitive Architecture,” Cognitive Computation 1 (2009): 91-103, https://doi.org/10.1007/s12559-009-9005-z.
6 Another method to address hunger might be to ignore it because the individual’s goal is not to end it (e.g., dieting or fasting).
7 Maslow.
8 Dover, 2016.
9 Male pronouns are used throughout this article when referring to an offender/potential offender for illustrative purposes.
10 Ibid.
11 Malamuth.
12 However, it is important to note that for other men, these same victim statements may feed rape fantasies and have the opposite effect by increasing interest.
13 Alternatively, if this feeds into the offender’s fantasy, it may intensify interest for that individual.
14 Or, this may enrage a different offender and, thereby, weaken his action inhibitors.
15 The issues of opportunity and tactical viability are the subject of significant discussion in T.J. Dover, “The Offender Interaction Process Model,” The Forensic Examiner 19, no. 3 (2010): 28-40. This discussion focuses on what happens when an offender moves from strategic interest toward tactical planning and dynamic action.