1. SUBMISSIVE AND AGGRESSIVE
PERSONALITIES IN FEMALE
SPOTTED HYENAS
• 1Wangui G. Hymes, 2S. Kevin McCormick, 2Kay E. Holekamp
1Department of Chemistry and Biochemistry, Spelman College, Atlanta, GA
2Department of Integrative Biology, Michigan State University, East Lansing, MI
1Wangui G. Hymes, 2S. Kevin McCormick, 2Kay E. Holekamp
2. Animal vs. Human Personalities
Humans:
Consistent individual
variation of emotion and
behavioral patterns
• (Mitchel et al, 2004)
Animals:
Consistent, among-
individual variation in
behavior and state
• (Sih et al, 2014)
3. Behavior Research
Research in the field…
Grueling, taxing process
Focus on more observable
traits
• Lean towards more
aggressive acts
Lack of available research
on submissiveness
• Due in part to:
a) Above reasons
b) Traditional
hypothesis
6. Spotted Hyenas as an Animal Model
Largest of the 4 living
hyena species
Matrilineal linear
dominance hierarchies
Highly social (similar to
cercopithecine primates)
All photos courtesy of Mara Hyena Project
8. Procedure
Used behavioral data field
notes collected by personnel
from the Michigan State
University Mara Hyena Project
1. Selected adult females (>2
y/o) from two clans that
survived to at least 5 years of
age
2. Coded for aggressive and
submissive interaction rates
over 2 years
3. Utilized Access queries to
create dataset.
1.Controlled for age and rank
9. Analysis
Prediction 1: Submissiveness vs. aggressiveness
Pearson’s linear correlation
• (R Base Package)
• lm(Submissiveness ~ Aggressiveness)
Prediction 2: Is submissiveness a personality trait
Controlling for:
• Direction up or down the hierarchy
Linear mixed effects model
• (R Lme4 Package)
• lmer(Rate ~ ID (random) + Rank (Fixed) + Year (Fixed))
10. Prediction 1: Rate of submissive and
aggressive interactions will not be a simple
negative correlation
Prediction 2: Unsolicited submissiveness will be individually
consistent through repeated measures across time and
context.
Hypothesis: Submissiveness is its own
personality trait
13. Prediction 1: Rate of submissive and aggressive interactions
will not be a simple negative correlation
Prediction 2: Unsolicited submissiveness will be
individually consistent through repeated
measures across time and context.
Hypothesis: Submissiveness is its own
personality trait
17. Conclusions
Our results, suggest that our hypothesis is supported.
Prediction 1
• Not negatively correlated, actually positively correlated when
accounting for the hierarchy
Prediction 2
• Submissiveness appears to not vary significantly across time, which is
comparable to aggressiveness
However, more data and sophisticated analyses need
to be conducted.
Sampling effort: More years included
Pseudo-personality: Missing environmental variables
18. Discussion
Findings suggest that submissiveness may be its
own personality trait
Submissiveness was positively correlated with
aggression
Future Questions:
What is the function of submissiveness?
• Does it alleviate aggression received?
How does the submissive trait develop?
21. Animal vs Human Personalities
Animals:
Aggressiveness
Boldness
Sociability
Activity
Neuroticism
• (Reale, 2007)
Humans:
Agreeableness
Openness to new
experiences
Conscientiousness
Extraversion
Emotional stability
• (Gosling, 2001)
22. Behaviors
Table of Critical Incidences
Aggressive Behavior Submissive Behavior
Bite Shake Bite Carpal Crawl Grovel
Push Chase Submissive
Posture
Squeal/Yell
Lunge Snap Open Mouth
Appease
Grin
Point Look/Glare Head Bob Ears Back
Stand Over Displace Approach/ Avoid Back Off
Editor's Notes
Good morning, my name is Wangui Hymes….(spelman intro)…I’m studying the behavior of spotted hyenas in the Holekamp lab under the direction of Phd candidate Kevin McCormick…who is studying the development of behavioral traits through gene transcription modifications, aka epigenetics
and today I’m going to talk to you about submissive and aggressive personalities in female spotted hyenas
Since my research revolves around the behavior of hyenas , I will first give you an overview of the field of animal behavior (specifically the study of animal personalities) as well as why we use spotted hyenas as our animal model…then, I will explain exactly what question I was trying to answer this summer as well as our hypothesis and two predictions
behavior of animals has been studied for a long time
recently society and scientists have started to accept animal personalities and this information can be used to better understand human personalities.
To emphasize the potential of studying animal behavior…
Sih et al defines animal personalities as “consistent, among-individual variation in behavior and state,” and this is almost identical to
Mitchel et al’s definition of human personalities “consistent individual variation of emotion and behavioral patterns.”
Add the five personality types in animals and humans
*add hyena pics showcasing the different behaviors
Keep using hyenas, start describing aggressiveness and submissiveness
n the field, very hard to id behaviors
so scientists have focused on the ones that are easier to identify.
aggressive acts
literature review on behavior articles (none earlier than 2005)
6/30 mentioned submissive behavior independent of aggression
This focus on dominant behavior is due to 1) again, aggressive acts are a lot easier to id in the field and 2…
2) mainly because scientists have assumed that submission and aggression are the two extremes of one personality trait.
Nelson (2000) postulated that submission and aggression may actually be two separate traits,
backed up by psychological research
aggressiveness and submissiveness = independently or positively correlated.
Significant, researchers have been excluding an entire trait.
From this….
*stress that its spotted hyenas, not all hyenas are the same
Before I go into my procedure…A little info on the animal model we used to test out our hypotheses on this summer…the spotted hyena.
highly social carnivore
most abundant of the 4 living species of hyena
most importantly (for this study at least) is one of, if not, the most social carnivores.
Social meaning that it lives in very large groups and has very complex social behaviors
similarity to the structure of the Old World Primates (baboons, macaques, vervet monkeys
spotted hyena = ideal species to test various hypotheses
on to research the various factors that may be shaping the evolution of social behavior in animals.
The lab collected by previous members
*simplify..focused on adult females (2-5) and controlled for..;.
For this study, we utilized…
In order to construct the dataset for the analysis, we extracted behavioral data for adult females 2-5 years of age in the talek and North Serena Clan, coding the aggressions and unsolicited appeasements.
After our dataset was constructed, we applied a simple linear correlation to determine the relationship between aggressiveness and submissiveness within and individual (R-Base package)
Used linear mixed-effects models to determine if submissive and aggressive rates presented consistent individual variation over time and across contexts (R: lme4-package)
Now, that I’ve shown you a bit of how we ran our experiment and analyzed our data…here is what we found.
Hypothesized that…Submissiveness outside of aggressive interactions is its own personality trait
We predicted that:
rate of submissive and aggressive behaviors would not be a simple negative correlation
unprovoked (unsolicited) submission in an individual would be consistent across time and context (as per Sih and Mitchel et al’s definitions of animal/human personality)
Note…In conducting this study, we are filling in some of the holes that exist in past research and creating a more solid foundation from which future studies on animal behavior can build.
Transition: Now that I have introduced you to my project, the subjects I’m using and my hypotheses & predictions I am going to now go over how exactly we went about testing out our hypotheses
Note for all graphs always explain the X and Y axis, and anything else on the graph (make sure the audience can read the axies)
After log transforming the Rates to account for a lack of normality, we ran a simple correlation between an individuals rate of aggressions and submissions over 2 years. Here we found a complete lack of correlation.
R2 = knowing x does not predict y – uncorrelated
P = large, not significant
Sample size 53
Prettify it by changing axes…low aggression - high aggression (same for submission)
When we stripped the data down to control for rank where individuals were both submissive and aggressive at least once over two years (NOTE: that means only including observational sessions with individuals of lower rank [For aggressions] or individual of higher rank [For submissions].
*pause*
Here we see and incredibly strong positive correlation between aggressiveness and submissiveness.
Sample size 23
Hypothesized that…Submissiveness outside of aggressive interactions is its own personality trait
We predicted that:
rate of submissive and aggressive behaviors would not be a simple negative correlation
unprovoked (unsolicited) submission in an individual would be consistent across time and context (as per Sih and Mitchel et al’s definitions of animal/human personality)
Note…In conducting this study, we are filling in some of the holes that exist in past research and creating a more solid foundation from which future studies on animal behavior can build.
Transition: Now that I have introduced you to my project, the subjects I’m using and my hypotheses & predictions I am going to now go over how exactly we went about testing out our hypotheses
Note for all graphs always explain the X and Y axis, and anything else on the graph (make sure the audience can read the axies)
Overall, most of our individuals are fairly stable across time when rank is accounted for. Though you can see the amount of variance can get fairly large, and some individuals did differ between year, but not a lot. Neither year or rank significantly influenced the rate of aggressiveness suggesting that aggressiveness is consistent across time, which is what we expected
Sample size: 21
This is similar to what we observed with aggressiveness. Again few individuals had significantly different submissive rates between years, and what differences there were could not be accounted for by rank. Therefore, this appears to suggest that submissiveness is its own trait.
Sample 22
2) mainly because scientists have assumed that submission and aggression are the two extremes of one personality trait.
Nelson (2000) postulated that submission and aggression may actually be two separate traits,
backed up by psychological research
aggressiveness and submissiveness = independently or positively correlated.
Significant, researchers have been excluding an entire trait.
From this….
Remind audience of variables in prediction..
Aggressiveness (positive control): As expected, based off prior studies, aggressiveness fits the definition of a personality trait.
Submissiveness: our results suggest that submissiveness is a personality trait. However, more data needs to be pulled and more sophisticated analysis need to be conducted in order to reinforce our findings and determine whether or not this is truly a personality trait and not pseudo-personality (can occur due to artifacts in the data).
I’d like to thank..
The SROP and BEACON programs, specifically Mr Steven Thomas & Dr Judi Brown Clarke for…
Phd Candidate Nora Lewin for….
Our lab manager Hadley Courad for…
Emily Weigel who was my Animal Behavior professor at Spelman last semester and, if it were not for her assistance, I would not be here
And, Maggie Sawdy for double checking and correcting all of the mistakes I made while inputting the thousands of different behaviors for this study
*replace table with pictures
Inc pics of aggressive acts (t3 – t1)
pics of submissive acts (didn’t rate them but..here they are)
The hyenas exhibit aggressive and submissive behavior by…*list of the various behaviors*
An unsolicited submissive appeasement is one that is not preceded by an aggressive act towards/on the appeasing individual.
We don’t record every single behavior, we only record those that we can observe and quantify – critical incidence. (Ex. How long they’ve been walking/sleeping)
