Hot years and serious and deadly assault: empirical tests of the heat hypothesis

A nationwide time-series analysis for short-term effects of ambient temperature on violent crime in South Korea

Psychological theories on heat-aggression relationship have existed for decades and recent models suggest climate change will increase violence through varying pathways. Although observational studies have examined the impact of temperature on violent crime, the evidence for associations is primarily limited to coarse temporal resolution of weather and crime (e.g., yearly/monthly) and results from a few Western communities, warranting studies based on higher temporal resolution data of modern systemic crime statistics for various regions. This observational study examined short-term temperature impacts on violent crime using national crime data for the warm months (Jun.-Sep.) across South Korea (2016-2020). Distributed lag non-linear models assessed relative risks (RRs) of daily violent crime counts at the 70th, 90th, and 99th summer temperature percentiles compared to the reference temperature (10th percentile), with adjustments for long-term trends, seasonality, weather, and air pollution. Results indicate potentially non-linear relationships between daily summer temperature (lag0-lag10) and violent crime counts. Violent crimes consistently increased from the lowest temperature and showed the highest risk at the 70th temperature (~ 28.0 °C). The RR at the 70th and 90th percentiles of daily mean temperature (lag0-lag10), compared to the reference, was 1.11 (95% CI 1.09, 1.15) and 1.04 (95% CI 1.01, 1.07), indicating significant associations. Stratified analysis showed significant increases in assault and domestic violence for increases in temperature. The lagged effects, the influences of heat on subsequent crime incidence, did not persist 21 days after the exposure, possibly due to the displacement phenomenon. We found curvilinear exposure-response relationships, which provide empirical evidence to support the psychological theories for heat and violence. Lower public safety through increased violent crime may be an additional public health harm of climate change.

Frustration-aggression hypothesis reconsidered: The role of significance quest

One of the oldest scientific theories of human aggression is the frustration-aggression hypothesis, advanced in 1939. Although this theory has received considerable empirical support and is alive and well today, its underlying mechanisms have not been adequately explored. In this article, we examine major findings and concepts from extant psychological research on hostile aggression and offer an integrative conception: aggression is a primordial means for establishing one's sense of significance and mattering, thus addressing a fundamental social-psychological need. Our functional portrayal of aggression as a means to significance yields four testable hypotheses: (1) frustration will elicit hostile aggression proportionately to the extent that the frustrated goal serves the individual's need for significance, (2) the impulse to aggress in response to significance loss will be enhanced in conditions that limit the individual's ability to reflect and engage in extensive information processing (that may bring up alternative, socially condoned means to significance), (3) significance-reducing frustration will elicit hostile aggression unless the impulse to aggress is substituted by a nonaggressive means of significance restoration, (4) apart from significance loss, an opportunity for significance gain can increase the impulse to aggress. These hypotheses are supported by extant data as well as novel research findings in real-world contexts. They have important implications for understanding human aggression and the conditions under which it is likely to be manifested and reduced.

The effects of temperature on prosocial and antisocial behaviour: A review and meta-analysis

Research from the social sciences suggests an association between higher temperatures and increases in antisocial behaviours, including aggressive, violent, or sabotaging behaviours, and represents a heat-facilitates-aggression perspective. More recently, studies have shown that higher temperature experiences may also be linked to increases in prosocial behaviours, such as altruistic, sharing, or cooperative behaviours, representing a warmth-primes-prosociality view. However, across both literatures, there have been inconsistent findings and failures to replicate key theoretical predictions, leaving the status of temperature-behaviour links unclear. Here we review the literature and conduct meta-analyses of available empirical studies that have either prosocial (e.g., monetary reward, gift giving, helping behaviour) or antisocial (self-rewarding, retaliation, sabotaging behaviour) behavioural outcome variables, with temperature as an independent variable. In an omnibus multivariate analysis (total N = 4577) with 80 effect sizes, we found that there was no reliable effect of temperature on the behavioural outcome measured. Further, we find little support for either the warmth-primes-prosociality view or the heat-facilitates-aggression view. There were no reliable effects if we consider separately the type of behavioural outcome (prosocial or antisocial), different types of temperature experience (haptic or ambient), or potential interactions with the experimental social context (positive, neutral, or negative). We discuss how these findings affect the status of existing theoretical perspectives and provide specific suggestions advancing research in this area.

Thermal demands and its interactions with environmental factors account for national-level variation in aggression

Literature shows that psychological phenomena, including values (e.g., individualism vs. collectivism), personality, and behaviors (e.g., prosocial and aggressive behavior), are geographically clustered. The effects of temperature on interpersonal and intergroup aggression have been studied by many social psychologists. To date the interactions between temperature and other geographical factors have not been addressed. This study is aiming to examine the effects of thermal demands and the moderating effects of natural geographical factors on aggressive behavior at national level. Data for 156 societies was obtained from publicly available databases. Consistent with the life-history theory, results of this study showed that aggressive behavior has a positive relationship with heat demands, and a negative relationship with cold demands. Aggressive behavior is also positively correlated with sunlight and altitude, and negatively correlated with coastline vicinity. Forest, coastline vicinity, and rainfall moderated the effect of thermal demands on aggressive behavior. In societies with more forests, with more rainfall, and closer to coastline, the negative effects of cold demands on aggressive behavior are stronger.

Temporal Variability of Theft Types in the Historic Centre of Porto

Criminology theories imply that time is a relevant variable, especially for the prevention and intervention of criminal occurrences. Thus, the study of criminal temporal patterns has been described as being of great relevance. The present study focuses on describing and exploring the influence of temporal and seasonal variables on the occurrence of different types of theft in the Historic Centre of Porto through the analysis of official records of the Public Security Police. Significant differences were found regarding the time of day and season of occurrence, even though it is not observed for all the types of theft analysed. Overall, theft was more prevalent at night and less frequent during winter, which is congruent with previous literature and the routine activity theory. Being the first case study in Porto city, Portugal, this research may be of extreme importance for both designing prevention and intervention policies in the area, and for inspiring future research on a criminal time analysis.

Homicide, Inequality, and Climate: Untangling the Relationships

Researchers debate the causal connections between homicide, inequality, and temperature. This study examines these relationships globally based on country-level data. A new measure of inequality is introduced that provides a more granular measure of inequality patterns than commonly used metrics. The approach allows estimation of risk sensitive decision-making that helps to explain how class impacts violence under different climate conditions. The results indicate that homicide rates are higher when poorer segments of populations are disproportionately influenced by temperature, middle class segments are influenced by inequality, and the wealthy are influenced by middle and impoverished class dynamics.

Drought and intimate partner violence towards women in 19 countries in sub-Saharan Africa during 2011-2018: A population-based study

BACKGROUND

Drought has many known deleterious impacts on human health, but little is known about the relationship between drought and intimate partner violence (IPV). We aimed to evaluate this relationship and to assess effect heterogeneity between population subgroups among women in 19 sub-Saharan African countries.

METHODS AND FINDINGS

We used data from 19 Demographic and Health Surveys from 2011 to 2018 including 83,990 partnered women aged 15-49 years. Deviations in rainfall in the year before the survey date were measured relative to the 29 previous years using Climate Hazards Group InfraRed Precipitation with Station data, with recent drought classified as ordinal categorical variable (severe: ≤10th percentile; mild/moderate: >10th percentile to ≤30th percentile; none: >30th percentile). We considered 4 IPV-related outcomes: reporting a controlling partner (a risk factor for IPV) and experiencing emotional violence, physical violence, or sexual violence in the 12 months prior to survey. Logistic regression was used to estimate marginal risk differences (RDs). We evaluated the presence of effect heterogeneity by age group and employment status. Of the 83,990 women included in the analytic sample, 10.7% (9,019) experienced severe drought and 23.4% (19,639) experienced mild/moderate drought in the year prior to the survey, with substantial heterogeneity across countries. The mean age of respondents was 30.8 years (standard deviation 8.2). The majority of women lived in rural areas (66.3%) and were married (73.3%), while less than half (42.6%) were literate. Women living in severe drought had higher risk of reporting a controlling partner (marginal RD in percentage points = 3.0, 95% CI 1.3, 4.6; p < 0.001), experiencing physical violence (marginal RD = 0.8, 95% CI 0.1, 1.5; p = 0.019), and experiencing sexual violence (marginal RD = 1.2, 95% CI 0.4, 2.0; p = 0.001) compared with women not experiencing drought. Women living in mild/moderate drought had higher risk of reporting physical (marginal RD = 0.7, 95% CI 0.2, 1.1; p = 0.003) and sexual violence (marginal RD = 0.7, 95% CI 0.3, 1.2; p = 0.001) compared with those not living in drought. We did not find evidence for an association between drought and emotional violence. In analyses stratified by country, we found 3 settings where drought was protective for at least 1 measure of IPV: Namibia, Tanzania, and Uganda. We found evidence for effect heterogeneity (additive interaction) for the association between drought and younger age and between drought and employment status, with stronger associations between drought and IPV among adolescent girls and unemployed women. This study is limited by its lack of measured hypothesized mediating variables linking drought and IPV, prohibiting a formal mediation analysis. Additional limitations include the potential for bias due to residual confounding and potential non-differential misclassification of the outcome measures leading to an attenuation of observed associations.

CONCLUSIONS

Our findings indicate that drought was associated with measures of IPV towards women, with larger positive associations among adolescent girls and unemployed women. There was heterogeneity in these associations across countries. Weather shocks may exacerbate vulnerabilities among women in sub-Saharan Africa. Future work should further evaluate potential mechanisms driving these relationships.

Short-term association between ambient temperature and homicide in South Africa: a case-crossover study

BACKGROUND

Criminology research has traditionally investigated sociodemographic predictors of crime, such as sex, race, age, and socioeconomic status. However, evidence suggests that short-term fluctuations in crime often vary more than long-term trends, which sociodemographic factors cannot explain. This has redirected researchers to explore how environmental factors, such as meteorological variables, influence criminal behavior. In this study we investigate the association between daily ambient temperature and homicide incidence in South Africa, a country with one of the highest homicide rates in the world.

METHODS

Mortality data was from South Africa's civil registration system and includes all recorded deaths in the country from 1997 to 2013 (17 years). Daily temperature was from the National Oceanographic and Atmospheric Association of the United States and South Africa's Agricultural Research Council. Data were analyzed using a time-stratified case-crossover design with conditional logistic regression. We delineated cases as either "definite" (ICD-10 codes X85-Y09, n = 68,356) or "probable" homicides (ICD-10 codes W25-W26, W32-W34, W50, Y22-Y24, Y28-Y29, n = 177,873). Case periods were defined as the day on which a death occurred. Control periods were selected using a day-of-week match within the same month and district. Analyses investigated same-day and lagged effects of maximum, mean and minimum temperature.

RESULTS

A one-degree Celsius increase in same-day maximum temperature - our a priori metric of choice - was associated with a 1.5% (1.3-1.8%) increase in definite homicides and a 1.2% (1.1-1.3%) increase in total (definite + probable) homicides. Significant (p < 0.05) positive associations were also observed when applying other temperature metrics (mean, minimum) and lags (1, 0-1). The shape of the association did not display any clear non-linearities. There was no evidence of confounding by public holidays or air pollution.

CONCLUSIONS

This study suggests a positive association between daily ambient temperature and homicide in South Africa. This temperature-health relationship may be of particular concern in the context of climate change. The ability to include meteorological variables as a predictor of criminal activity and violent behavior could prove valuable in resource allocation for crime prevention efforts.

PG-13 Rated Movie Violence and Societal Violence: is there a Link?

Recent scholarship has suggested that the frequency of violence in PG-13 rated movies has increased in recent years. Although some scholars have expressed concern that such an increase may have public health implications, this has remained untested. In the current article, trends in PG-13 movie violence are tested against trends in violence in society, including both homicides and youth violence. Raw correlations suggest that PG-13 rated movie violence is inversely related to actual violence in society. However, controlling for autocorrelations suggests that the best interpretation is that PG-13 rated movie violence is unrelated to violence in society. Caution is advised for scholars to avoid implying that PG-13 rated movie violence may have a causal effect on crime in society.

No Evidence That Experiencing Physical Warmth Promotes Interpersonal Warmth

Abstract. Williams and Bargh (2008) reported that holding a hot cup of coffee caused participants to judge a person’s personality as warmer and that holding a therapeutic heat pad caused participants to choose rewards for other people rather than for themselves. These experiments featured large effects ( r = .28 and .31), small sample sizes (41 and 53 participants), and barely statistically significant results. We attempted to replicate both experiments in field settings with more than triple the sample sizes (128 and 177) and double-blind procedures, but found near-zero effects ( r = −.03 and .02). In both cases, Bayesian analyses suggest there is substantially more evidence for the null hypothesis of no effect than for the original physical warmth priming hypothesis.

Comparing apples to apples: an environmental criminology analysis of the effects of heat and rain on violent crimes in Boston

Weather characteristics have been suggested by many social scientists to influence criminality. A recent study suggested that climate change may cause a substantial increase in criminal activities during the twenty-first century. The additional number of crimes due to climate have been ethoroughly discussed the first draft of the paper. Allstimated by associational models, which are not optimal to quantify causal impacts of weather conditions on criminality. Using the Rubin Causal Model and crime data reported daily between 2012 and 2017, this study examines whether changes in heat index, a proxy for apparent temperature, and rainfall occurrence, influence the number of violent crimes in Boston. On average, more crimes are reported on temperate days compared to extremely cold days, and on dry days compared to rainy days. However, no significant differences in the number of crimes between extremely hot days versus less warm days could be observed. The results suggest that weather forecasts could be integrated into crime prevention programs in Boston. The weather-crime relationship should be taken into account when assessing the economic, sociological, or medical impact of climate change. Researchers and policy makers interested in the effects of environmental exposures or policy interventions on crime should consider data analyses conducted with causal inference approaches.

The Influence of Interannual Climate Variability on Regional Violent Crime Rates in the United States

While the impact of climate on regional geopolitical stability and large-scale conflict has garnered increased visibility in recent years, the effects of climate variability on interpersonal violent crime have received only limited scientific attention. Though earlier studies have established a modest correlation between temperature and violent crime, the underlying seasonality in both variables was often not controlled for and spatial heterogeneity of the statistical relationships has largely been overlooked. Here a method of spatial aggregation is applied to the United States, enabling a systematic investigation into the observed relationships between large-scale climate variability and regionally aggregated crime rates. This novel approach allows for differentiation between the effects of two previously proposed mechanisms linking climate and violent crime, the Routine Activities Theory and Temperature-Aggression Hypothesis. Results indicate large and statistically significant positive correlations between the interannual variability of wintertime air temperature and both violent and property crime rates, with negligible correlations emerging from summertime data. Results strongly support the Routine Activities Theory linking climate and violent crime, with climate variability explaining well over a third of the variance of wintertime violent crime in several broad regions of the United States. Finally, results motivate the development of observationally constrained empirical models and their potential application to seasonal and potentially longer-term forecasts.

Finding the Middle Ground in Violent Video Game Research: Lessons From Ferguson (2015)

Ferguson's comprehensive meta-analysis provides convincing data that violent video games have almost no effect on children's aggression. Although this finding is unlikely to bring unity to a divided field, Ferguson's article (2015, this issue) provides important rules that should aid all researchers. First, we need to be more accepting of results that are inconsistent with our own theories. Second, extraneous variables are often responsible for the relations previous studies have found between violent media and aggression. Third, we should avoid using unstandardized assessments of important variables whenever possible. Finally, caution is warranted when generalizing laboratory research findings to severe acts of violent in the "real world." It is hoped that, by accepting these basic rules, researchers and others will adopt less extreme positions concerning the effects of violent video games.

A relationship between temperature and aggression in NFL football penalties

BACKGROUND

Increased ambient temperature has been implicated in increased physical aggression, which has important practical consequences. The present study investigates this established relationship between aggressive behavior and ambient temperature in the highly aggressive context of professional football in the National Football League (NFL).

METHODS

Using a publicly available dataset, authors conducted multiple hierarchical regression analyses on game-level data (2326 games).

RESULTS

The analysis revealed that temperature positively predicted aggressive penalties in football, and that this relationship was significant for teams playing at home but not for visiting teams.

CONCLUSION

These results indicate that even in the aggressive context of football, warmer weather contributes to increased violence. Further, the presence of the heat-aggression relationship for the home team suggests that the characteristics of interacting groups may influence whether heat would have an adverse effect on the outcome of those interactions.

Aggression and violence around the world: A model of CLimate, Aggression, and Self-control in Humans (CLASH)

Worldwide there are substantial differences within and between countries in aggression and violence. Although there are various exceptions, a general rule is that aggression and violence increase as one moves closer to the equator, which suggests the important role of climate differences. While this pattern is robust, theoretical explanations for these large differences in aggression and violence within countries and around the world are lacking. Most extant explanations focus on the influence of average temperature as a factor that triggers aggression (The General Aggression Model), or the notion that warm temperature allows for more social interaction situations (Routine Activity Theory) in which aggression is likely to unfold. We propose a new model, CLimate, Aggression, and Self-control in Humans (CLASH), that helps us to understand differences within and between countries in aggression and violence in terms of differences in climate. Lower temperatures, and especially larger degrees of seasonal variation in climate, call for individuals and groups to adopt a slower life history strategy, a greater focus on the future (vs. present), and a stronger focus on self-control. The CLASH model further outlines that slow life strategy, future orientation, and strong self-control are important determinants of inhibiting aggression and violence. We also discuss how CLASH differs from other recently developed models that emphasize climate differences for understanding conflict. We conclude by discussing the theoretical and societal importance of climate in shaping individual and societal differences in aggression and violence.

Mortality during a Large-Scale Heat Wave by Place, Demographic Group, Internal and External Causes of Death, and Building Climate Zone

Mortality increases during periods of elevated heat. Identification of vulnerable subgroups by demographics, causes of death, and geographic regions, including deaths occurring at home, is needed to inform public health prevention efforts. We calculated mortality relative risks (RRs) and excess deaths associated with a large-scale California heat wave in 2006, comparing deaths during the heat wave with reference days. For total (all-place) and at-home mortality, we examined risks by demographic factors, internal and external causes of death, and building climate zones. During the heat wave, 582 excess deaths occurred, a 5% increase over expected (RR = 1.05, 95% confidence interval (CI) 1.03-1.08). Sixty-six percent of excess deaths were at home (RR = 1.12, CI 1.07-1.16). Total mortality risk was higher among those aged 35-44 years than ≥ 65, and among Hispanics than whites. Deaths from external causes increased more sharply (RR = 1.18, CI 1.10-1.27) than from internal causes (RR = 1.04, CI 1.02-1.07). Geographically, risk varied by building climate zone; the highest risks of at-home death occurred in the northernmost coastal zone (RR = 1.58, CI 1.01-2.48) and the southernmost zone of California's Central Valley (RR = 1.43, CI 1.21-1.68). Heat wave mortality risk varied across subpopulations, and some patterns of vulnerability differed from those previously identified. Public health efforts should also address at-home mortality, non-elderly adults, external causes, and at-risk geographic regions.

Ecologic factors relating to firearm injuries and gun violence in Chicago

BACKGROUND

Firearm violence is a major burden on Chicago with greater than 1500 gunshot injuries occurring annually. Identifying ecologic variables related to the incidence of firearm-related injuries and crime could prove useful for developing new strategies for reducing gun-related injuries.

METHODS

The Illinois Trauma Registry (ITSR) and the Chicago Police Department's CLEAR (Citizen Law Enforcement Analysis and Reporting) dataset were retrospectively analyzed to investigate group-level factors potentially related to the incidence of gun-related injuries and crime in Chicago from 1999 through 2012. Multivariate linear regression was used to evaluate the effects of day of the week, daily maximum temperature, precipitation, and snow on the incidence of firearm-related injuries and crime.

RESULTS

A total of 18,655 gunshot wounds occurred during the study period (ITSR, 1999-2009). There were 156,866 acts of gun violence identified in the CLEAR dataset (2002-2012). Day of the week, daily maximum temperature, and precipitation were associated with differential risks of gun injury and violence. Rain decreased firearm-related injuries by 9.80% [RR: 0.902, 95% CI: 0.854-0.950] and crime by 7.00% [RR: 0.930, 95% CI: 0.910-0.950]. Gunshot wounds were 33% [RR: 1.33, 95% CI: 1.29-1.37] more frequent on Fridays and Saturdays and gun crime was 18% [RR: 1.18, 95% CI: 1.16-1.20] more common on these days. Snow was not associated with firearm-related injuries or crime.

CONCLUSIONS

Day of the week, daily maximum temperature, and rain are associated with the incidence of firearm-related injuries and crime. Understanding the effects of these variables may allow for the development of predictive models and for risk-adjusting injury and crime data.

Climate change and levels of violence in socially disadvantaged neighborhood groups

The current study examines the link between climate change and neighborhood levels of violence using 20 years of monthly climatic and crime data from St. Louis, MO, USA. St. Louis census tracts are aggregated in neighborhood groups of similar levels of social disadvantage, after which each group is subjected to time series analysis. Findings suggest that neighborhoods with higher levels of social disadvantage are very likely to experience higher levels of violence as a result of anomalously warm temperatures. The 20 % of most disadvantaged neighborhoods in St. Louis, MO, USA are predicted to experience over half of the climate change-related increase in cases of violence. These results provide further evidence that the health impacts of climate change are proportionally higher among populations that are already at high risk and underscore the need to comprehensively address climate change.

An Analysis of the Relationship between Weather and Aggressive Crime in Cleveland, Ohio

This study investigated the relationship between weather and aggressive crime for the period from 1999 through 2004 for the city of Cleveland, Ohio. The majority of the analysis focused on meteorological summer (June–August), because this is the time when the most oppressive conditions occur. Citywide analysis (nonspatial) was performed for many temporal variations, which accounted for season, time of day, and day of week (weekend or weekday). The linear regression model explored the relationship between apparent temperature and aggressive crime counts. Results show that summer has the highest aggressive crime counts, while winter has the lowest crime counts. Aggressive crime generally increases linearly as apparent temperature increases, with nonaggravated assaults and domestic violence assaults having the largest response as the weather becomes hotter. The midday and early night hours (i.e., 0300–1200 LT) have the greatest significant findings relating apparent temperature to aggressive crime.

Further analysis was performed at the subcity level. A threshold of mean apparent temperature of 24°C was used in order to investigate spatial patterns of aggressive crime when it is “hot” compared to when it is “cold.” Overall, the spatial patterns of crime counts are minimally influenced by hotter weather. Despite the numerous different spatial analyses that were performed, there was no significant evidence suggesting that spatial patterns of aggressive crime are greatly affected by hotter weather. Rather, it appears that warmer weather brings relatively similar percentage increases in aggressive crime activity citywide. Further exploration and analysis of the weather–crime relationship could be of significant benefit to law enforcement officials and emergency response personnel, who increasingly use geographic information system (GIS)-based tools in their work to assist in determining where and when intervention is most beneficial.

Warming increases the risk of civil war in Africa

Armed conflict within nations has had disastrous humanitarian consequences throughout much of the world. Here we undertake the first comprehensive examination of the potential impact of global climate change on armed conflict in sub-Saharan Africa. We find strong historical linkages between civil war and temperature in Africa, with warmer years leading to significant increases in the likelihood of war. When combined with climate model projections of future temperature trends, this historical response to temperature suggests a roughly 54% increase in armed conflict incidence by 2030, or an additional 393,000 battle deaths if future wars are as deadly as recent wars. Our results suggest an urgent need to reform African governments' and foreign aid donors' policies to deal with rising temperatures.

Is the Curve Relating Temperature to Aggression Linear or Curvilinear? Assaults and Temperature in Minneapolis Reexamined

Using archival data from Minneapolis recorded in 3-hr time intervals, E. G. Cohn and J. Rotton concluded that there is an inverted U-shaped relationship between temperature and assault, with the maximum assault rate occurring at 74.9 degrees F. They depicted this relationship by plotting temperature against assault. This plot, however, fails to take into account time of day. Time of day was strongly related to both temperature and assault, but in opposite directions. Between 9:00 p.m. and 2:59 a.m. of the next day, when most assaults occurred, there was a positive linear relationship between temperature and assault. The Minneapolis data actually provide stronger support of a positive linear (or monotonic) relationship between temperature and assault than of an inverted U-shaped relationship.

Human ecology, crime, and crime control: linking individual behavior and aggregate crime

The paper extends previous research published by Cohen, Machalek, Vila, and others on the evolutionary-ecological paradigm for understanding criminal behavior. After reviewing literature related to human ecology and crime, the paper focuses on elements relevant to human ecology-biology, development, and ecological factors--and their role in criminal behavior. Major emphasis is placed on the linkages between individual factors and macro-level crime using chronic offending as a case in point. The principles of evolutionary ecology then are used to discuss counterstrategies to crime, and the prospects for protection/avoidance, deterrent, and nurturant strategies in light of evidence on chronic offending.

Cyclical changes of homicide rates: a reanalysis of Brearley's 1932 data

The objective of this analysis is to explore the possibility that Brearley's failure to detect a coherent pattern of seasonal variation in his well-known study of homicide in the United States was due to a lack of statistical refinement. The original data on homicides in the United States between 1923 and 1928 (N = 51,798) were reanalyzed using spectral analysis. The results show a significant seasonal dependency with a peak in the homicide rate in August. The seasonal dependency explains between 23% and 30% of the total homicide variance. The importance of this finding is the degree of explained variance and the location of the peak, which is remarkably consistent with more contemporary studies using similar methods despite substantial sociodemographic changes, suggesting an endogenous etiology.

Chronic nonmalignant pain and violent behavior

Research suggests that violence has entered the medical setting to a remarkable degree, causing medical professionals to be at the highest risk for becoming the victims of assaults and violent acts. This article reviews general theories of aggression and research on these theories, and uses them to assess risk factors in patients with chronic pain. There are data to suggest that pain may increase the risk of aggressiveness in some patients. However, it may decrease the risk in others paradoxically. The research available underscores the need for evaluating patients with pain for the risk of violent or aggressive behavior; specific recommendations are made in this regard.

Human aggression

Research on human aggression has progressed to a point at which a unifying framework is needed. Major domain-limited theories of aggression include cognitive neoassociation, social learning, social interaction, script, and excitation transfer theories. Using the general aggression model (GAM), this review posits cognition, affect, and arousal to mediate the effects of situational and personological variables on aggression. The review also organizes recent theories of the development and persistence of aggressive personality. Personality is conceptualized as a set of stable knowledge structures that individuals use to interpret events in their social world and to guide their behavior. In addition to organizing what is already known about human aggression, this review, using the GAM framework, also serves the heuristic function of suggesting what research is needed to fill in theoretical gaps and can be used to create and test interventions for reducing aggression.