Life-course processes
as cause and effect
of macro-level changes
in gun violence

 

Charles C. Lanfear University of Cambridge
Robert J. Sampson Harvard University

Homicide in the US

Peaked in 1990s and 2020-2021 and increasingly involves guns

Homicide in Chicago

Exaggerated in cities like Chicago, Philadelphia, Dallas

Questions

 

How have these changes in gun violence translated into personal exposure to gun violence?

 

How are these changes related to individuals’ gun behaviors?

 

How are gun behaviors driving these changes in violence?

  • Adolescent exposure high in early 1990s, low afterward
  • Adult exposure low until 2016-2021
  • Black and Hispanic males at highest risk

Question: What drove these large swings in violence and exposure?

  • One key proximal cause: gun carrying

Adolescent-onset

  • \(\frac{1}{3}\) of those ever carrying
  • Most age out
  • Associated with immediate dangerous contexts

Adult-onset

  • \(\frac{2}{3}\) of those ever carrying
  • Most still carrying today
  • Associated with insecurity and diffuse threats

 

How does this relate to macro-level changes in gun violence?

Changing age distribution of homicide

Gun homicide is increasingly committed by adults

Two similar periods of high gun violence, except…

Early 1990s

  • Concentrated in adolescence
  • Slow accumulation:
    • Deindustrialization, mass incarceration etc.
  • Context: Concentrated disadvantage, gangs, and illicit markets

 

2016-2021

  • Concentrated in adulthood
  • Rapid destabilization:
    • Trump, Ferguson, COVID-19, Floyd, etc.
  • Context: Widespread insecurity, loss of faith in institutions

Both: Legal cynicism and distrust

a cultural frame in which people perceive the law as illegitimate, unresponsive, and ill equipped to ensure public safety.

when calling the police is not a viable option to remedy one’s problems—individuals may instead resolve their grievances by their own means

… two racially differentiated beliefs promote legal gun carrying: The belief common among most carriers that police are inadequate protectors—and thus one may carry a gun as protection from crime—and the belief more common among non-white carriers that police are coercive violators of rights—and thus one may carry a gun as protection from and resistance to the oppressive state (Lanfear et al. 2024)

Linked to diffuse social and economic insecurities

Despite having much higher arrest rates, the cohort born in 1987 has greater levels of trust in police and neighbors at age twenty-five than counterparts born just nine years later, adjusting for background factors and early-life conditions (Sampson 2026)

Stroebe et al. (2017) find protective gun ownership is primarily driven by “the belief that the world is a dangerous and unstable place, populated by bad people, and that society is at the brink of collapse.”

Low trust… may increase the likelihood of interpreting others’ actions as intentional and offensive, a key antecedent of interpersonal conflict and homicide (Luckenbill 1977; Ludwig 2025).

Cynicism, distrust, and guns

legal cynicism promotes concealed gun carrying as a response to perceived insecurity.

legal cynicism in the 1990s was primarily a neighborhood phenomenon because the factors producing it were local to neighborhoods; in contrast… legal cynicism of the mid-2010s onward is rooted in macrosocial changes…

These changes were shaped by a structural legal context forged in distinctly American gun culture.

How does life-course variation in carrying impact rates of violence?

Dual process model of gun carrying and gun violence

G btitle Adolescent Process bsc1 Local instability (Risky situations) bsi Specific distrust & cynicism bsc1->bsi bsc2 Increased youth violence bsc1->bsc2 bsa Youth gun carrying bsi->bsa bsa->bsc2
G title Adult Process sc1 Societal instability (Risky world) si Diffuse distrust & cynicism sc1->si sc2 Increased adult violence sc1->sc2 sa Adult gun carrying si->sa sa->sc2

2021 was not a reprise of the 1990s; both were the result of differential activation of processes responding to macrosocial context

Some expectations

1995

  • Spatially concentrated
    • Strong disadvantage link
    • Local legal cynicism
  • Younger, more similar offender/victim
  • Group-oriented
  • Criminal contexts
    • Fewer legal guns
    • Gun policy less relevant

2021

  • More dispersed
    • Weaker disadvantage link
    • General cynicism
  • Older, less similar offender/victim
  • Individual-oriented
  • Non-criminal contexts
    • More legal guns
    • Gun policy more relevant

A research agenda

 

Gun violence

  • Changing concentrations and contexts
  • Heterogeneity, carrying, and the new decline

Cynicism, trust, and the life course

  • Legal cynicism and gun carrying across eras
  • Formative years and consequences for legal cynicism
  • Social media and unstructured socialization

A research agenda

 

National politics

  • Declining legitimacy of institutions
  • Cynicism, gun culture, and right nationalism

 

… we suggest that there is value, as initiated here, to continued theorizing on life-course processes as cause and effect of macro changes—not just in gun violence but crime more generally.

Feedback and questions

Contact:

Charles C. Lanfear
Institute of Criminology
University of Cambridge
cl948@cam.ac.uk

‍

For more about the PHDCN+:

PHDCN@fas.harvard.edu
https://sites.harvard.edu/phdcn/
https://doi.org/10.1007/s40865-022-00203-0

Appendix

Social change and the life course

 

G bsc1 Social context bsi Age-graded contexts bsc1->bsi bsc2 New social context bsc1->bsc2 bsa Situated behavior bsi->bsa bsa->bsc2 bsc1bsc2 Historical change bsabsc2 Cohort differentiation bsibsa Life course bsc1bsi Cohort dynamics

Classic concerns of demography and life course research… mostly

Not attributable to age composition

Also: Homicide nadir in 2000 but age-shift occurred in 2010

Early evidence