Ryan Schacht
Biographic Data
| ID | 132331 |
|---|---|
| NAME | Ryan Schacht |
| GIVEN NAMES | Ryan |
| FAMILY NAME | Schacht |
| SIGNATURE | SCHACHT R |
| AFFILIATIONS | East Carolina University |
| ORCID | 0000-0002-4606-7345 |
| VERIFIED | Yes |
| TOTAL WORKS | 11 |
| TOTAL CITATIONS | 21 |
| AUTHOR COUNT | 11 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 2015 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 3 |
In Utero Selection Echoes Across a Lifetime
The sex ratio at birth in 19th and early 20th century cohorts gauges important demographic selection processes that appear detectable well into older age
The Secondary Sex Ratio and Male Mortality at Pre‐Reproductive Ages
OBJECTIVES: The secondary sex ratio (i.e., the ratio of male to female live births; hereafter referred to as the SSR) falls in populations encountering ambient stressors. Much theory and some empirical work indicates that males born to low SSR cohorts may be "positively selected" in that excess culling in utero may correspond with greater than expected survival among live-born males in that cohort. We extend prior work by testing, in historical U…
Historical Mortality Dynamics on the Baja California Peninsula
Decision-making under climate shocks and economic insecurity
Patterning of Sexual Violence against Women across US Cities and Counties
Sexual violence against women is a global public health concern; yet, determining its patterning is still largely understudied. An excess of males has emerged as a central concern given that men are the primary perpetrators of violent behavior, particularly against women. However, it is increasingly unclear as to whether an excess or, rather, a shortage of men drives purported negative social outcomes. To address these conflicting expectations, w…
NDVI predicts birth seasonality in historical Baja California Sur, Mexico
Birth seasonality is a phenomenon whereby populations can be characterized by a single month or season in which births peak. While non-human animal research suggests that seasonal birth-pulses are related to variation in climate and local energy availability, social scientists debate the mechanisms responsible for it in humans. Here we investigate the role of precipitation, temperature, and energy availability on seasonal conception and birth pul…
Frail Males on the American Frontier
While sex ratios at birth (SRB) have been shown to vary within and across populations, after over a century of research, explanations have remained elusive. A variety of ecological, demographic, economic, and social variables have been evaluated, yet their association with SRB has been equivocal. Here, in an attempt to shed light on this unresolved topic within the literature, we approach the question of what drives variation in SRB using detaile…
Marriage dynamics in old Lower California
It is commonly expected that natural selection will favor earlier reproduction, yet ecological constraints can force people to delay marriage. Furthermore, humans demonstrate sex-specific preferences in marriage partners - with grooms normally a few years older than their brides; however, the age at which individuals marry can influence the spousal age gap. We investigate factors influencing age at first marriage and age difference at marriage us…
Sex ratios and life tables
The male/female sex ratio (SR) and its age-specific patterns vary considerably across time and place. The SR generally begins male-biased at birth and becomes female-biased later in life, but this relationship should respond to historical trends and events. Temporal trends in SRs remain largely unstudied and formal demographic relationships are not well defined. We (1) define SRs in a life table framework, (2) estimate the age at which the number…
Marriage Markets and Male Mating Effort
Partner choice decision making and the integration of multiple cues
Marriage Markets and Male Mating Effort
NDVI predicts birth seasonality in historical Baja California Sur, Mexico
Birth seasonality is a phenomenon whereby populations can be characterized by a single month or season in which births peak. While non-human animal research suggests that seasonal birth-pulses are related to variation in climate and local energy availability, social scientists debate the mechanisms responsible for it in humans. Here we investigate the role of precipitation, temperature, and energy availability on seasonal conception and birth pul…
Frail Males on the American Frontier
While sex ratios at birth (SRB) have been shown to vary within and across populations, after over a century of research, explanations have remained elusive. A variety of ecological, demographic, economic, and social variables have been evaluated, yet their association with SRB has been equivocal. Here, in an attempt to shed light on this unresolved topic within the literature, we approach the question of what drives variation in SRB using detaile…
Marriage dynamics in old Lower California
It is commonly expected that natural selection will favor earlier reproduction, yet ecological constraints can force people to delay marriage. Furthermore, humans demonstrate sex-specific preferences in marriage partners - with grooms normally a few years older than their brides; however, the age at which individuals marry can influence the spousal age gap. We investigate factors influencing age at first marriage and age difference at marriage us…
Sex ratios and life tables
The male/female sex ratio (SR) and its age-specific patterns vary considerably across time and place. The SR generally begins male-biased at birth and becomes female-biased later in life, but this relationship should respond to historical trends and events. Temporal trends in SRs remain largely unstudied and formal demographic relationships are not well defined. We (1) define SRs in a life table framework, (2) estimate the age at which the number…
Patterning of Sexual Violence against Women across US Cities and Counties
Sexual violence against women is a global public health concern; yet, determining its patterning is still largely understudied. An excess of males has emerged as a central concern given that men are the primary perpetrators of violent behavior, particularly against women. However, it is increasingly unclear as to whether an excess or, rather, a shortage of men drives purported negative social outcomes. To address these conflicting expectations, w…
Partner choice decision making and the integration of multiple cues
Marriage Markets and Male Mating Effort
Sex ratios and life tables
The male/female sex ratio (SR) and its age-specific patterns vary considerably across time and place. The SR generally begins male-biased at birth and becomes female-biased later in life, but this relationship should respond to historical trends and events. Temporal trends in SRs remain largely unstudied and formal demographic relationships are not well defined. We (1) define SRs in a life table framework, (2) estimate the age at which the number…
Marriage dynamics in old Lower California
It is commonly expected that natural selection will favor earlier reproduction, yet ecological constraints can force people to delay marriage. Furthermore, humans demonstrate sex-specific preferences in marriage partners - with grooms normally a few years older than their brides; however, the age at which individuals marry can influence the spousal age gap. We investigate factors influencing age at first marriage and age difference at marriage us…
NDVI predicts birth seasonality in historical Baja California Sur, Mexico
Birth seasonality is a phenomenon whereby populations can be characterized by a single month or season in which births peak. While non-human animal research suggests that seasonal birth-pulses are related to variation in climate and local energy availability, social scientists debate the mechanisms responsible for it in humans. Here we investigate the role of precipitation, temperature, and energy availability on seasonal conception and birth pul…
Frail Males on the American Frontier
While sex ratios at birth (SRB) have been shown to vary within and across populations, after over a century of research, explanations have remained elusive. A variety of ecological, demographic, economic, and social variables have been evaluated, yet their association with SRB has been equivocal. Here, in an attempt to shed light on this unresolved topic within the literature, we approach the question of what drives variation in SRB using detaile…
Patterning of Sexual Violence against Women across US Cities and Counties
Sexual violence against women is a global public health concern; yet, determining its patterning is still largely understudied. An excess of males has emerged as a central concern given that men are the primary perpetrators of violent behavior, particularly against women. However, it is increasingly unclear as to whether an excess or, rather, a shortage of men drives purported negative social outcomes. To address these conflicting expectations, w…
Decision-making under climate shocks and economic insecurity
Historical Mortality Dynamics on the Baja California Peninsula
The Secondary Sex Ratio and Male Mortality at Pre‐Reproductive Ages
OBJECTIVES: The secondary sex ratio (i.e., the ratio of male to female live births; hereafter referred to as the SSR) falls in populations encountering ambient stressors. Much theory and some empirical work indicates that males born to low SSR cohorts may be "positively selected" in that excess culling in utero may correspond with greater than expected survival among live-born males in that cohort. We extend prior work by testing, in historical U…
In Utero Selection Echoes Across a Lifetime
The sex ratio at birth in 19th and early 20th century cohorts gauges important demographic selection processes that appear detectable well into older age
Demographic Trends and Gender Preferences (8 works) · Demography (7 works) · Population (7 works) · Sociology (7 works) · Biology (6 works) · Geography (6 works) · Demography (5 works) · Ecology (5 works) · Evolutionary Psychology and Human Behavior (4 works) · Demographic economics (3 works)