chapter 1 exploratory behavior profiles

What behavioral syndrome? Individual differences and multiple exploratory behavioral profiles in

prairie voles

Danielle N. Lee* & Zuleyma Tang-MartínezDepartment of Biology

University of Missouri-St. Louis

Animal personality research

Behavioral Syndromes: Suites of related behaviors across situations or contexts

– Correlation of behaviors– Behavioral plasticity limited

• Context• Stability

Behavioral Stability

• Broad– Correlations of behavior

across different contexts or functional categories

• Domain specific– Correlations of behavior

within a single context or functional behavioral category

• Trait response (Stable)– Behavioral responses that

are consistent from one situation to another

• State response (Unstable)– Behavioral responses that

occur in a specific situation (not consistent from one situation to another)

Behavioral Context

Kopp, Voge & Misslin 1999

Behavioral Stability

• Broad– Correlations of behavior

across different contexts or functional categories

• Domain specific– Correlations of behavior

within a single context or functional behavioral category

• Trait response (Stable)– Behavioral responses that

are consistent from one situation to another

• State response (Unstable)– Behavioral responses that

occur in a specific situation (not consistent from one situation to another)

Behavioral Context

Broad behavioral SyndromeCorrelations of behavior across different contexts or functional categories

• Wilson et al. 1993• Pumpkin-seed sunfish,

Lepomis gibbosus• Multiple Contexts

(Exploration & Social)Bold fish were more likely to

approach novel objects and swim in closer proximity to other fish compared to shy fish Image credit: Encyclopaedia

Brittanica

Domain-specific Behavioral SyndromeCorrelations of behavior within a single context or functional behavioral category

• Verbeek et al. 1994• Great tits, Parus major• Single Context

(Exploration)Fast novel room explorers

are also fast novel object explorers

Image credit: http://www.thebirdsofsussex.co.uk/

Behavioral Stability

• Broad– Correlations of behavior

across different contexts or functional categories

• Domain specific– Correlations of behavior

within a single context or functional behavioral category

• Trait response (Stable)– Behavioral responses that

are consistent from one situation to another

• State response (Unstable)– Behavioral responses that

occur in a specific situation (not consistent from one situation to another)

Behavioral Context

Behavioral Syndromes Hypotheses Hierarchy

• H0: no correlations of behavior responses across situations or contexts = no syndrome = STATE RESPONSE

• H1: correlations of behavior response across situations or contexts = syndrome = TRAIT RESPONSE

• H1a: correlations of behavior responses within one context = DOMAIN SPECIFIC

• H1b: correlations of behavioral responses across two or more contexts = BROAD

OBJECTIVE• To examine individual variation in a single

context – EXPLORATION

QUESTIONS• Is variation in individual behavior consistent

across different tests?• If so, then do these consistent differences in

behavior contribute to a behavioral syndrome?

Exploratory behavior

• Functional behavior category widely studied• Tendency to investigate novel environments

and/or objects• Spontaneous behavioral responses• Indicates how animals might gather

information about local environment and its resources

Microtus ochrogasterprairie vole

Methods

• Three Exploratory tests– Open-field with novel objects – Exploratory maze– Two-way novel choice apparatus

Open-field with Novel Objects TestDependent Variables:

1)Latency

2)Time in the novel environment

3)Time with novel objects

4)Returns

5)Instantaneous scan of location

a) Total squaresb) Visits to each section

Exploratory Maze Test

Dependent Variables:

1)Latency

2)Number of times each arm was entered

3)Returns to the start box

Novel Choice Test

Dependent Variables:

1)Latency

2)Time to reach the first terminal

3)Time to reach the second terminal

4)Total time to complete the test

Overall Predictions

• Lower latency • More time spent

interacting with novel stimuli

• Higher spatial scores

less exploratory more exploratory

•Higher latency •Less time spent interacting with novel stimuli•Lower spatial scores

Statistical Analysis

• PCA analysis for each exploratory test• Identified the key dependent variables

– PC1 accounted for the highest % of variance– All dependent variables that scored above .80 that

explained PC1 – called Key Dependent Variables

• Ranked each Key DV• Computed the overall Exploratory Score for each

individual in each test• Correlate Exploratory scores across tests

Exploratory Scores Continuum

• Open-field with novel objects test• Exploratory Maze test• Two-way novel choice test

lower exploratory scores higher exploratory scores

Open-field with novel objects test

1 2 3

Latency to depart start box -.353 -.243 .866

Total squares visited .638 .656 -.046

Returns -.711 .303 -.250

Time in novel environment .820 .476 .166

Time with novelties .675 .015 .235

Visits to center squares -.624 .603 .288

Visits to edge squares .945 .005 .106

Ratio of visits to center: edge squares

.553 -.573 -.105

Components

PC 1 explains 46.9% of the variancePC 2 explains 18.7 %PC 3 explains 12.5 %

N = 10258 females44 males

Exploratory maze test

PC 1 explains 58% of the variancePC 2 explains 19%

1 2

Latency to depart start box -.593 .526

Returns .306 -.857

Visits to arm 1 .787 .139

Visits to arm 2 .818 .279

Visits to arm 3 .888 .069

Sum of visits to all arms .979 .179

N = 9853 females45 males

Components

Novel choice apparatus test

1 2 3

Latency to depart start box .753 -.316 .154

Time to reach 1st terminal .860 -.316 .103

Time to reach 2nd terminal .821 -.323 -.038

Total test time (minus latency)

.906 -.347 .017

Components

PC 1 explains 54% of the variancePC 2 explains18%PC3 explains 13 %

N = 14183 females58 males

Correlations of Exploratory Scores across all three tests

Open-field testExploratory Score

Novel choice testExploratory Score

Novel choice test Exploratory Score

r = .075

p = .602------

Maze test Exploratory Score

r = -.052

p = .717

r = -.265

p = .060

N = 5126 females25 males

No correlated suites of behavior across test situations.

Discussion

• Behavior in one situation did not correlate or predict behavior in a different situation

• Behavioral responses are distinct and stand alone

• Animals interpret context differently• Null hypothesis in hierarchy

Behavioral Syndromes Hypotheses Hierarchy

• H0: no correlations of behavior responses across situations or contexts = no syndrome = STATE RESPONSE

• H1: correlations of behavior response across situations or contexts = syndrome = TRAIT RESPONSE

• H1a: correlations of behavior responses within one context = DOMAIN SPECIFIC

• H1b: correlations of behavioral responses across two or more contexts = BROAD

• Fox et al. (2009). Mountain chickadees, Poecile gambeli, – Exploration in a novel room and with novel objects

• Nelson et al. (2008). Roosters, Gallus gallus domesticus– calling behavior in three different contexts: anti-

predator, territoriality, and foraging in both a real and a virtual environment

• Dingemanse (2008). Sticklebacks, Gasterosteus aculeatus • Adriaenssens & Johnsson (2008). Brown trout, Salmo trutta • Milderman (2008) Starlings, Sturnus vulgaris• Snekser et al. (2008). Damselfish, Stegastes leucostictus

Historical accounts

• Context – Learning ability and congition

• Selected lines of “bright” and “dull” rats

• Various labyrinth mazes

• No two trials of the exact same test correlated with any degree of reliability. Tolman (1924)

• Learning ability is specific to the apparatus. Tryon (1940), Searle (1949)

Take home messages

• No single test can serve as a proxy for an entire domain

• Test domain-specific syndromes first, then broad

• Do not assume evidence of broad behavioral syndromes means domain-specific behavioral syndromes also exist

ACKNOWLEDGEMENTS• Fritz Trillmich & Robyn Hudson• The Tang Gang

Gena Sbeglia, Laura Kent, Elizabeth Congdon, Javier Hernandez

• Blog readers and SM supporters• Jasmine Clayton, Robert Clayton,

Allison Clayton• Stan Braude, Karen Norberg, Lon

Wilkens, George Taylor• David Chisholm• Lab Assistants

– Meital Laks, Dominique Craven, Evynn Craven, AnnaLynn Harris, Dianne Voorhis

• American Society of Mammalogists GIAR

• TWA Scholarship for Environmental Science

• Dr. John P. Rier Biology Student Travel Award

• Animal Behavior Society Young Scientist International Travel Award (ABS-NSF)