empathy and pro-social behavior in rats

EMPATHY AND PRO-SOCIAL BEHAVIOR IN RATSEmma Glanzer

Empathy

empathynoun1. The intellectual identification with or vicarious

experiencing of the feelings, thoughts, or attitudes of another.

2. The ability to understand and share the feelings of another.

3. A multilayered phenomenon that starts with automatic state matching based on motor mimicry and shared neural representations, to which cognitive perspective taking is secondary.

Russian Doll Model of Empathy

de Waal, F. B. M., “The Antiquity of Empathy”. Science. 336 (2012).

Pro-sociality and Empathy

Empathy:The capacity to recognize and share feelings experienced by another individual.

Pro-sociality:The tendency to behave so as to benefit another individual.

Hypotheses

Pro-social rescue behavior in rats is not motivated by empathic feeling.

Pro-social rescue behavior in rats is motivated by empathic feeling.

H0 HA

Bartal, I.B., Decety, J., and Mason, P. “Empathy and Pro-social Behavior in Rats”. Science. 334 (2011): 1427-1430.

Impact Factor: 31.03

Study I

Study I Hypotheses

Rats are not capable of empathically motivated helping behavior.

Rats are capable of empathically motivated helping behavior.

H0 HA

Materials and Methods: Subjects

Sprague-Dawley

3-6 months old 46 male, 12

female Housed in pairs Tails marked for

identification

Materials and Methods: Set-up

50x50 cm plexiglass arena

25x8.75 cm restrainer

Top-mounted video camera to record movement

Heterodyne recorder to detect vocalizations

Harvard Apparatus rodent restrainer.

Materials and Methods: Conditions

Trapped: n = 30Empty: n = 20Object: n = 82+ Empty: n = 12

Pre-trial Procedures

Habituation Housed in pairs 2

weeks Handled 4 days pre-

experiment Placed in arena 1

hour Returned to home

cage

Free-rat Determination Measure of

boldness Time-to-edge

latency Interesting effect

between latencies of openers and non-openers

Experimental Procedure

1. Trapped rat placed in restrainer2. Free rat marked and placed in arena3. Start sessions 90 minutes (reduce to 60)4. Record video and audio5. Rats remained in arena for duration of

session6. Repeated one session/day for 12 days.

Experimental Footage

Two Problems

Free rats didn’t open restrainer Investigator opened

door halfway Did not count as

door-opening

Trapped rat opened door from inside Plastic blocker inserted, used for remainder of

sessions Removed if free rat opened door

Alarm calls greater for trapped condition. Trapped rats were experiencing stress.

RESULTS: Alarm Calls

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Free rats in trapped condition more active in second half of sessions.

RESULTS: Activity Ratio

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Latency to door-opening shortest for rats in trapped condition.Proportion of trapped-condition rats opening door increased.

RESULTS: Door-opening

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Freezing time after door-opening decreased across sessions.

RESULTS: Freezing Time

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Females opened door at shorter latencies.Females more active in trapped condition.More female rats became openers than male rats.

RESULTS: Sex Differences

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Free rats in trapped condition spent more time at arena center.

RESULTS: Movement Distribution

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Results

Trapped rat was in distress Free rats worked to alleviate stress

Opened door at greater frequencies Opened door at shorter latencies Increased activity until door was opened

Action was deliberate Sex differences

Experiment II

To determine whether “anticipation of social interaction is necessary to motivate door-opening”.

9 pairs of rats that were openers Modified set up

Two arenas joined by restrainer Trapped rat could only egress into

separate arena Two conditions

Separated Empty Separated Cagemate

One session/day for 29 and 27 days

Rats stopped opening the door of the empty restrainer.

RESULTS: Door-opening

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Rats stopped opening the door of the empty restrainer.

RESULTS: Door-opening

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Experiment III

To examine the relative value of liberating a trapped cagemate.

New set of rats, same strain and age

Modified set up One arena with two restrainers

Two conditions Chocolate Empty Chocolate Cagemate

One session/day for 12 days

Chocolate-containing restrainer opened more quickly than empty restrainer.

RESULTS: Door-opening Latencies

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No difference in door-opening latencies for chocolate- and cagemate-containing restrainers.

RESULTS: Door-opening Latencies

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Discussion

Desire for social contact Free rats liberated cagemate even when

contact was prevented Stop alarm calls

Alarm calls occurred too infrequently Curiosity

Curiosity extinguishes within trial time frame

Coincidence with activity levels Door-opening was hard, could not occur

accidentally

Study I Hypotheses

Rats are not capable of empathically motivated helping behavior.

Rats are capable of empathically motivated helping behavior.

H0 HA

Critique

Experiment conducted during rat’s light cycle

Opening door halfway

No data tables

Poorly explained procedures

Silberberg, A., Allouch, C., Sandfort, S., Kearns, D., Karpel, H., and Slotnick, B. “Desire for social contact, not empathy, may explain rescue behavior in rats”. Animal Cognition. (2013).

Impact Factor: 2.71

Study II

Study II Hypotheses

Pro-social behaviors are motivated by social contact, as free rats will not learn to liberate a trapped rat when absence of social contact is the outcome of behaviors.

Pro-social behaviors are not motivated by social contact, as free rats will learn to liberate a trapped rat when absence of social contact is the outcome of behaviors.

H0 HA

Materials and Methods: Subjects

Sprague-Dawley 3-6 months old 12 females, 6 pairs Housed in pairs Habituated as in

Study I

Materials and Methods: Set-up

Two plastic arenas 41x58 cm each Joined by restrainer

25x8.75 cm restrainer Doors recessed 2.1 cm Opened by rat contact

with metal strip sensor on free rat’s side

Materials and Methods: Conditions All 12 rats participated in each condition sequentially Condition 1

Free rat contact opens distal door 30 minute sessions, 15 sessions

Condition 2 Free rat contact opens near door, permitting social

contact 30 minute sessions, 15 sessions

Condition 3 Free rat contact opens distal door 30 minute sessions, 27 sessions

Experimental Procedure1. Trapped rat placed in restrainer2. Free rat placed in arena3. Session duration 30 minutes4. Investigators observe rat behavior5. Repeated one session/day for 15 days,

then move to next condition6. End with 27 sessions of Condition 3

Latencies increased across Condition 1.Latencies decreased between Conditions 1 and 2.

RESULTS: Door-opening Latencies

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Response rate decreased across Condition 1.Response rate increased between Conditions 1 and 3.

RESULTS: Door-opening Frequencies

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Experiment II

To determine if frequent door-sensor contacts are due to free rat’s motivation to be near cagemate.

Same subjects and materials

Continue Condition 3 for 1 session Quantify:

Return time in restrainer Free rat contact with restrainer

Introduce Condition 4 Fifteen 30-minute sessions No action by free rat will

release trapped rat

3 of 6 free rats spend majority of time in contact with restrainer.4 of 6 trapped rats spend majority of time after door opening in restrainer.

RESULTS: Video Scores

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No decrease in response rate.

RESULTS: Latency and Frequency

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RESULTS: Experiments I and II

Result Empathy

Social Contac

tCondition 1: Latencies increased and frequencies decreased ✓

Condition 2: Latencies decreased across sessions ✓ ✓

Condition 3: Response latency remained short ✓

Condition 3: Response frequency remained high ✓

Condition 4: Free rat responses did not decrease ✓

Discussion

Difference in trapped rat behavior between Conditions 1 and 2

Free rat’s responses are not outcome-dependent.

Study II Hypotheses

Pro-social behaviors are motivated by social contact, as free rats will not learn to liberate a trapped rat when absence of social contact is the outcome of behaviors.

Pro-social behaviors are not motivated by social contact, as free rats will learn to liberate a trapped rat even when absence of social contact is the outcome of behaviors.

H0 HA

Critique Graphs hard to interpret No frequency data for Condition 2 Video scoring

Snout contacts not counted Trapped rat position not scored when free rat was

on top of restrainer Poor analysis

Poor design for opening mechanism Analysis of Condition 4

Is pro-social behavior in rats motivated by empathy?

Hypotheses

Pro-social rescue behavior in rats is not motivated by empathic feeling.

Pro-social rescue behavior in rats is motivated by empathic feeling.

H0 HA