Edwin P Willems
Biographic Data
| ID | 2535784 |
|---|---|
| NAME | Edwin P Willems |
| GIVEN NAMES | Edwin P |
| FAMILY NAME | Willems |
| SIGNATURE | WILLEMS E P |
| AFFILIATIONS | University of Kansas |
| ORCID | 0000-0001-7555-3484 |
| VERIFIED | Yes |
| TOTAL WORKS | 21 |
| TOTAL CITATIONS | 58 |
| AUTHOR COUNT | 21 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1953 |
| LATEST PUBLICATION YEAR | 2026 |
| H-INDEX | 5 |
Hair Steroid Signatures of Cooperative Breeding in Male and Female Common Marmosets (Callithrix jacchus)
Alternative reproductive tactics of unflanged and flanged male orangutans revisited
In many slowly developing mammal species, males reach sexual maturity well before they develop secondary sexual characteristics. Sexually mature male orangutans have exceptionally long periods of developmental arrest. The two male morphs have been associated with behavioral alternative reproductive tactics, but this interpretation is based on cross‐sectional analyses predominantly of Northwest Sumatran populations. Here we present the first longi…
To drum or not to drum: Selectivity in tree buttress drumming by chimpanzees ( Pan troglodytes verus ) in the Nimba Mountains, Guinea
Chimpanzees live in fission‐fusion social organizations, which means that party size, composition, and spatial distribution are constantly in flux. Moreover, chimpanzees use a remarkably extensive repertoire of vocal and nonvocal forms of communication, thought to help convey information in such a socially and spatially dynamic setting. One proposed form of nonvocal communication in chimpanzees is buttress drumming, in which an individual hits a …
The slow ape: High infant survival and long interbirth intervals in wild orangutans
The social organization of Homo ergaster: Inferences from anti-predator responses in extant primates
Validation of an acoustic location system to monitor Bornean orangutan ( Pongo pygmaeus wurmbii ) long calls
The long call is an important vocal communication signal in the widely dispersed, semi-solitary orangutan. Long calls affect individuals' ranging behavior and mediate social relationships and regulate encounters between dispersed individuals in a dense rainforest. The aim of this study was to test the utility of an Acoustic Location System (ALS) for recording and triangulating the loud calls of free-living primates. We developed and validated a d…
Endocrinological correlates of male bimaturism in wild Bornean orangutans
Among primates, orangutans are unique in having pronounced male bimaturism leading to two fully adult morphs that differ in both physical appearance and behavior. While unflanged males have a female-like appearance, flanged males have the full suite of secondary sexual characteristics, including cheek flanges and a large throat sac. So far, hormonal correlates of arrested development in unflanged males and the expression of secondary sexual chara…
Determinants of Paternity Success in a Group of Captive Vervet Monkeys (Chlorocebus aethiops sabaeus)
Toward an Explicit Rationale for Naturalistic Research Methods
Demography and life history of Thomas langurs ( Presbytis thomasi )
Life history data from wild primate populations are necessary to explain variation in primate social systems and explain differences between primates and other mammals. Here we report life history data from a 12.5‐year study on wild Thomas langurs. Mean age at first reproduction was 5.4 years and the sex ratio at birth was even. The mean interbirth interval (IBI) after a surviving infant was 26.8 mo, after nonsurviving infants 17.7 mo, and combin…
The myth of the typical baboon
The external validity of papers on external validity
The external validity of papers on external validity
Two interpretations of Brown's hypothesis for the risky shift
Shift toward risk and heterogeneity of groups
Risk is a Value
Data supported the assumption that persons tend to view themselves as moderately risky vis-a-vis their peers. Ss tended to ascribe positions to their peers that were equal to or more cautious than their own and participation in group discussion enhanced the probability of this relative judgment
Risk Preferences as Related to Judged Consequences of Failure
In order to explore why the most widely used measure of risk proneness (Choice-dilemmas Questionnaire) yields so much internal variation, its items were filled out in the usual manner and then in terms of how serious the consequences of failure would be in each case. Correlations between the usual risk recommendations, consequences of failure, and national norms for magnitude of risky shift suggested a positive relationship between risk preferenc…
Dependence of the Risky Shift on Instructions: A Replication
An earlier study of group-induced shift toward risk was replicated by varying usual (risk-oriented) and neutral instructions orthogonally against 2 group conditions to induce shift toward risk. In agreement with the earlier study, (a) usual (risk-oriented) instructions produced a shift toward risk while neutral instructions did not and (b) the differential effect of experimental instructions was found to be located in the group process because “b…
Where is the risky shift? Dependence on instructions
Behavioral Validity of a Test for Measuring Social Anxiety
A portion of the Tavistock Self-assessment Inventory has been proposed as a measure of social anxiety, which is postulated as a personal disposition to avoid public, visible, complex, socially evaluated behavior. 80 high school students' participation in school activities, rated on a 5-point scale from passive audience participation up to the most singular, focal leadership, was the criterion of validity, under the assumption that Ss scoring high…
The Structure of the Brazilian Family
Journal Article The Structure of the Brazilian Family Get access Emilio Willems Emilio Willems Vanderbilt University Search for other works by this author on: Oxford Academic Google Scholar Social Forces, Volume 31, Issue 4, May 1953, Pages 339-345, https://doi.org/10.2307/2573069 Published: 01 May 1953
The Structure of the Brazilian Family
Journal Article The Structure of the Brazilian Family Get access Emilio Willems Emilio Willems Vanderbilt University Search for other works by this author on: Oxford Academic Google Scholar Social Forces, Volume 31, Issue 4, May 1953, Pages 339-345, https://doi.org/10.2307/2573069 Published: 01 May 1953
The social organization of Homo ergaster: Inferences from anti-predator responses in extant primates
Where is the risky shift? Dependence on instructions
The slow ape: High infant survival and long interbirth intervals in wild orangutans
Shift toward risk and heterogeneity of groups
The Structure of the Brazilian Family
Journal Article The Structure of the Brazilian Family Get access Emilio Willems Emilio Willems Vanderbilt University Search for other works by this author on: Oxford Academic Google Scholar Social Forces, Volume 31, Issue 4, May 1953, Pages 339-345, https://doi.org/10.2307/2573069 Published: 01 May 1953
Behavioral Validity of a Test for Measuring Social Anxiety
A portion of the Tavistock Self-assessment Inventory has been proposed as a measure of social anxiety, which is postulated as a personal disposition to avoid public, visible, complex, socially evaluated behavior. 80 high school students' participation in school activities, rated on a 5-point scale from passive audience participation up to the most singular, focal leadership, was the criterion of validity, under the assumption that Ss scoring high…
Risk is a Value
Data supported the assumption that persons tend to view themselves as moderately risky vis-a-vis their peers. Ss tended to ascribe positions to their peers that were equal to or more cautious than their own and participation in group discussion enhanced the probability of this relative judgment
Risk Preferences as Related to Judged Consequences of Failure
In order to explore why the most widely used measure of risk proneness (Choice-dilemmas Questionnaire) yields so much internal variation, its items were filled out in the usual manner and then in terms of how serious the consequences of failure would be in each case. Correlations between the usual risk recommendations, consequences of failure, and national norms for magnitude of risky shift suggested a positive relationship between risk preferenc…
Dependence of the Risky Shift on Instructions: A Replication
An earlier study of group-induced shift toward risk was replicated by varying usual (risk-oriented) and neutral instructions orthogonally against 2 group conditions to induce shift toward risk. In agreement with the earlier study, (a) usual (risk-oriented) instructions produced a shift toward risk while neutral instructions did not and (b) the differential effect of experimental instructions was found to be located in the group process because “b…
Where is the risky shift? Dependence on instructions
Shift toward risk and heterogeneity of groups
Two interpretations of Brown's hypothesis for the risky shift
The external validity of papers on external validity
The external validity of papers on external validity
The myth of the typical baboon
Demography and life history of Thomas langurs ( Presbytis thomasi )
Life history data from wild primate populations are necessary to explain variation in primate social systems and explain differences between primates and other mammals. Here we report life history data from a 12.5‐year study on wild Thomas langurs. Mean age at first reproduction was 5.4 years and the sex ratio at birth was even. The mean interbirth interval (IBI) after a surviving infant was 26.8 mo, after nonsurviving infants 17.7 mo, and combin…
Toward an Explicit Rationale for Naturalistic Research Methods
Determinants of Paternity Success in a Group of Captive Vervet Monkeys (Chlorocebus aethiops sabaeus)
Validation of an acoustic location system to monitor Bornean orangutan ( Pongo pygmaeus wurmbii ) long calls
The long call is an important vocal communication signal in the widely dispersed, semi-solitary orangutan. Long calls affect individuals' ranging behavior and mediate social relationships and regulate encounters between dispersed individuals in a dense rainforest. The aim of this study was to test the utility of an Acoustic Location System (ALS) for recording and triangulating the loud calls of free-living primates. We developed and validated a d…
Endocrinological correlates of male bimaturism in wild Bornean orangutans
Among primates, orangutans are unique in having pronounced male bimaturism leading to two fully adult morphs that differ in both physical appearance and behavior. While unflanged males have a female-like appearance, flanged males have the full suite of secondary sexual characteristics, including cheek flanges and a large throat sac. So far, hormonal correlates of arrested development in unflanged males and the expression of secondary sexual chara…
The social organization of Homo ergaster: Inferences from anti-predator responses in extant primates
The slow ape: High infant survival and long interbirth intervals in wild orangutans
To drum or not to drum: Selectivity in tree buttress drumming by chimpanzees ( Pan troglodytes verus ) in the Nimba Mountains, Guinea
Chimpanzees live in fission‐fusion social organizations, which means that party size, composition, and spatial distribution are constantly in flux. Moreover, chimpanzees use a remarkably extensive repertoire of vocal and nonvocal forms of communication, thought to help convey information in such a socially and spatially dynamic setting. One proposed form of nonvocal communication in chimpanzees is buttress drumming, in which an individual hits a …
Alternative reproductive tactics of unflanged and flanged male orangutans revisited
In many slowly developing mammal species, males reach sexual maturity well before they develop secondary sexual characteristics. Sexually mature male orangutans have exceptionally long periods of developmental arrest. The two male morphs have been associated with behavioral alternative reproductive tactics, but this interpretation is based on cross‐sectional analyses predominantly of Northwest Sumatran populations. Here we present the first longi…
Hair Steroid Signatures of Cooperative Breeding in Male and Female Common Marmosets (Callithrix jacchus)
Psychology (11 works) · Biology (9 works) · Social Psychology (9 works) · Ecology (8 works) · Primate Behavior and Ecology (8 works) · Social Psychology (5 works) · Wildlife Ecology and Conservation (5 works) · Zoology (5 works) · Animal Behavior and Reproduction (4 works) · Animal Vocal Communication and Behavior (4 works)