GENETIC AND DEVELOPMENTALGENETIC AND DEVELOPMENTALFACTORS ON FEEDINGFACTORS ON FEEDING

MAIN TOPICSMAIN TOPICS

GENETICSGENETICS

SOCIAL FACTORSSOCIAL FACTORS

ECOLOGICALECOLOGICAL

GENETICSGENETICS PAPER #IPAPER #I ““SPECIFICITY OF LEPTIN ACTION SPECIFICITY OF LEPTIN ACTION

ON ELEVATED BLOOD GLUCOSE ON ELEVATED BLOOD GLUCOSE LEVELS & HYPOTHALAMIC LEVELS & HYPOTHALAMIC NEUROPEPTIDE Y GENE NEUROPEPTIDE Y GENE EXPRESSION”EXPRESSION”

SOCIAL FACTORSSOCIAL FACTORS

PAPER #IPAPER #I ““SUSCEPTIBILITY OF ARTIFICIALLY SUSCEPTIBILITY OF ARTIFICIALLY

REARED RAT PUPS TO SOCIAL REARED RAT PUPS TO SOCIAL INFLUENCES ON FOOD CHOICE”INFLUENCES ON FOOD CHOICE”

PAPER #IIPAPER #II ““INTERACTION WITH INTERACTION WITH

DEMONSTRATORS RATS CHANGES DEMONSTRATORS RATS CHANGES OF OBSERVER RAT’S AFFECTIVE OF OBSERVER RAT’S AFFECTIVE RESPONSE TO FLAVOURSRESPONSE TO FLAVOURS””

PAPER #IIIPAPER #III ““A HISTORICAL PERSPECTIVE ON A HISTORICAL PERSPECTIVE ON

RECENT STUDIES OF SOCIAL RECENT STUDIES OF SOCIAL LEARNING ABOUT FOODS BY LEARNING ABOUT FOODS BY NORWAY RATS”NORWAY RATS”

ECOLOGICALECOLOGICAL

““FOOD SELECTION: PROBLEMS IN FOOD SELECTION: PROBLEMS IN UNDERSTANDING HOW WE UNDERSTANDING HOW WE CHOOSE WE EAT”CHOOSE WE EAT”

GENETICS: PAPER #IGENETICS: PAPER #I

INTRODUCTION:INTRODUCTION:• LEPTIN CAUSES A DECREASE IN LEPTIN CAUSES A DECREASE IN FOOD INTAKE & NPY CAUSES AN FOOD INTAKE & NPY CAUSES AN INCREASE IN FOOD INTAKE.INCREASE IN FOOD INTAKE.•STUDIES HAVE RECENTLY SHOWN STUDIES HAVE RECENTLY SHOWN THAT THAT SYSTEMATIC SYSTEMATIC ADMINISTRATION OF LEPTIN ADMINISTRATION OF LEPTIN RESULTED IN NORMALIZATION OF RESULTED IN NORMALIZATION OF FOOD INTAKE IN BODY WEIGHT OF FOOD INTAKE IN BODY WEIGHT OF OB/OB MICE.OB/OB MICE.•STUDIES HAVE ALSO SHOWN THAT STUDIES HAVE ALSO SHOWN THAT LEPTIN IN THE BRAIN & NPY IN THE LEPTIN IN THE BRAIN & NPY IN THE ARCULATE NUCLEUS ARE ARCULATE NUCLEUS ARE RESPONSIBLE FOR MEDIATING THESE RESPONSIBLE FOR MEDIATING THESE EFFECTS.EFFECTS.

PROBLEMS:PROBLEMS:

RESULTS OF PREVIOUS STUDIES HAVE SHOWN RESULTS OF PREVIOUS STUDIES HAVE SHOWN THAT THE REVERSAL OF THE OBESE THAT THE REVERSAL OF THE OBESE CONDITION OF THE OB/OB MICE RESULTS IN A CONDITION OF THE OB/OB MICE RESULTS IN A DECREASE IN HYPOTHALAMIC NPY.DECREASE IN HYPOTHALAMIC NPY.

GOAL OF THIS RESEARCH IS TO DETERMINE GOAL OF THIS RESEARCH IS TO DETERMINE THE CAUSE FOR THE ABOVE STATED RESULTS.THE CAUSE FOR THE ABOVE STATED RESULTS.

HYPOTHESIS:HYPOTHESIS:

1.1. DUE TO THE SPECIFIC ACTION OF LEPTIN DUE TO THE SPECIFIC ACTION OF LEPTIN (DIRECT EFFECT)(DIRECT EFFECT)

LEPTIN ADMINISTRATION RESULTS IN LEPTIN ADMINISTRATION RESULTS IN NORMALIZATION OF OBESITY & OVER NORMALIZATION OF OBESITY & OVER EXPRESSION OF NPY IN THE ARCULATE EXPRESSION OF NPY IN THE ARCULATE NUCLEUSNUCLEUS

2.2. DUE TO THE REVERSAL OF THE OBESE DUE TO THE REVERSAL OF THE OBESE STATE IN ITSELF (IN DIRECT EFFECT)STATE IN ITSELF (IN DIRECT EFFECT)

LEPTIN LOWERS FOOD INTAKE & BODY LEPTIN LOWERS FOOD INTAKE & BODY WEIGHT THROUGH UNRELATED WEIGHT THROUGH UNRELATED MECHANISMS.MECHANISMS.

THIS RESULTS IN A REVERSAL OF OBESITY THIS RESULTS IN A REVERSAL OF OBESITY CONDITION (LOSS OF WEIGHT)CONDITION (LOSS OF WEIGHT)

AS A RESULT OF THIS REVERSAL, NPY AS A RESULT OF THIS REVERSAL, NPY LEVELS IN THE HYPOTHALAMUS ARE LEVELS IN THE HYPOTHALAMUS ARE NORMALIZED.NORMALIZED.

HOW WILL THIS QUESTION BE HOW WILL THIS QUESTION BE ANSWERED????ANSWERED????

THE EXPERIMENTERS LOOKED AT: THE EXPERIMENTERS LOOKED AT:

- EFFECT OF LEPTIN INJECTIONS ON - EFFECT OF LEPTIN INJECTIONS ON HYPOTHALAMIC NPY LEVELS IN OB/OB HYPOTHALAMIC NPY LEVELS IN OB/OB MICE BEFORE CHANGES IN BODY MICE BEFORE CHANGES IN BODY ADIPOSITY.ADIPOSITY.- ASSESED SPECIFICITY OF LEPTIN ACTION - ASSESED SPECIFICITY OF LEPTIN ACTION BY MEASURING NPY LEVELS IN ARCULATE BY MEASURING NPY LEVELS IN ARCULATE NUCLEUS & IN TWO CONTROL SITES :NUCLEUS & IN TWO CONTROL SITES :(A) CEREBRAL CORTEX (A) CEREBRAL CORTEX (B) HIPPOCAMPUS(B) HIPPOCAMPUS

- EFFECT OF LEPTIN ON PVN LEVELS - EFFECT OF LEPTIN ON PVN LEVELS OF CRH (CONTROL MEASURE FOR NP OF CRH (CONTROL MEASURE FOR NP GENE EXPRESSION & CRH INCREASES GENE EXPRESSION & CRH INCREASES INSULIN WHICH DECREASES FOOD INSULIN WHICH DECREASES FOOD INTAKE.INTAKE.

METHODS:METHODS:

SUBJECTS:SUBJECTS: MALE OB/OB MICE N=24MALE OB/OB MICE N=24 MALE DB/DB MICE N=12MALE DB/DB MICE N=12 12 HR DAY/NIGHT SCHEDULE12 HR DAY/NIGHT SCHEDULE INDIVIDUAL CAGES WITH INDIVIDUAL CAGES WITH

CONTINUES ACCESS TO WATER. CONTINUES ACCESS TO WATER.

PROCEDURE:PROCEDURE: MICE TREATED FOR FIVE DAYS WITH INTRA MICE TREATED FOR FIVE DAYS WITH INTRA

PERITONEAL INJECTIONS OF EITHER SALINE PERITONEAL INJECTIONS OF EITHER SALINE (CONTROL) OR LEPTIN (TREATMENT)(CONTROL) OR LEPTIN (TREATMENT)

ALL INJECTIONS WERE A 150 ug.ALL INJECTIONS WERE A 150 ug. SALINE GROUP, OB GROUP, PAIR FED GROUPSALINE GROUP, OB GROUP, PAIR FED GROUP

OB/OB GROUP:OB/OB GROUP: EXPERIMENTAL GROUP: “OB” - LEPTIN EXPERIMENTAL GROUP: “OB” - LEPTIN

INJECTED, FREE FED.INJECTED, FREE FED. CONTROL GROUP: “SAL” - SALINE INJECTED CONTROL GROUP: “SAL” - SALINE INJECTED

FREE FEDFREE FED CONTROL GROUP: “PAIR FED” - SALINE CONTROL GROUP: “PAIR FED” - SALINE

INJECTED BUT PAIRED WITH MEMBERS OF THE INJECTED BUT PAIRED WITH MEMBERS OF THE OB GROUP WITH RESPECT TO THE AMOUNTS OB GROUP WITH RESPECT TO THE AMOUNTS OF FOOD EATEN.OF FOOD EATEN.

DB/DB GROUP:DB/DB GROUP: EXPERIMENTAL GROUP : “OB” - LEPTIN INJECTED EXPERIMENTAL GROUP : “OB” - LEPTIN INJECTED

FREE FEDFREE FED CONTROL GROUP : “ SAL” - SALINE INJECTED CONTROL GROUP : “ SAL” - SALINE INJECTED

FREE FEDFREE FED

DAILY MEASUREMENTS TAKEN OF EACH MOUSE :DAILY MEASUREMENTS TAKEN OF EACH MOUSE :

(A) BODY WEIGHT (A) BODY WEIGHT

(B) FOOD INTAKE (B) FOOD INTAKE AFTER 5 DAY TREATMENT, ANIMALS WERE AFTER 5 DAY TREATMENT, ANIMALS WERE

SACRIFICEDSACRIFICED SLIDES WERE SELECTED FROM MID REGION OF SLIDES WERE SELECTED FROM MID REGION OF

THE ARCULATE NUCLEUS IN THE PVNTHE ARCULATE NUCLEUS IN THE PVN

RESULTS:RESULTS:OB/OB GROUPOB/OB GROUP““OB” TREATMENT GROUPOB” TREATMENT GROUP DECREASE FOOD INTAKE BY 56%DECREASE FOOD INTAKE BY 56% DECREASE BODY WEIGHT BY 4.1%DECREASE BODY WEIGHT BY 4.1% DECREASE NPY LEVELS IN ARN BY 42.3%DECREASE NPY LEVELS IN ARN BY 42.3% THESE RESULTS FOR “OB” GROUP ARE THESE RESULTS FOR “OB” GROUP ARE

STATED RELATIVE TO THE “SAL” STATED RELATIVE TO THE “SAL” CONTROL CONTROL GROUPGROUP

WHICH SHOWED NO SIGNIFICANT WHICH SHOWED NO SIGNIFICANT DECREASE IN FOOD INTAKE AND NPY DECREASE IN FOOD INTAKE AND NPY LEVELS IN ARN. FURTHER MORE , “SAL” LEVELS IN ARN. FURTHER MORE , “SAL” GROUP EXPERIENCED AS INCREASE IN GROUP EXPERIENCED AS INCREASE IN BODY WEIGHT OF 1.2%.BODY WEIGHT OF 1.2%.

““PAIRED” CONTROL GROUPPAIRED” CONTROL GROUP DECREASE IN BODY WEIGHT (3.4%)DECREASE IN BODY WEIGHT (3.4%) NO CHANGE IN NPY LEVELS IN ARNNO CHANGE IN NPY LEVELS IN ARN FOR ALL GROUPS LEPTIN INJECTIONS FOR ALL GROUPS LEPTIN INJECTIONS

HAD NO AFFECT ON NPY LEVELS IN HAD NO AFFECT ON NPY LEVELS IN CEREBRAL CORTEX OR HIPPOCAMPUS CEREBRAL CORTEX OR HIPPOCAMPUS OR LEVELS OF CRH IN THE PVNOR LEVELS OF CRH IN THE PVN

DB/DB GROUPDB/DB GROUP LEPTIN ADMINISTRATION DID NOT LEPTIN ADMINISTRATION DID NOT

AFFECT FOOD INTAKE, BODY WEIGHT AFFECT FOOD INTAKE, BODY WEIGHT OR NPY LEVELS EITHER IN THE ARN, OR NPY LEVELS EITHER IN THE ARN, CEREBRAL CORTEX OR HIPPOCAMPUSCEREBRAL CORTEX OR HIPPOCAMPUS

CONCLUSIONS:CONCLUSIONS:

REMEMBER THAT: REMEMBER THAT:

NPY INCREASES FOOD INTAKE NPY INCREASES FOOD INTAKE

LEPTIN DECREASES FOOD INTAKE LEPTIN DECREASES FOOD INTAKE THUS, INCREASED NPY=DECREASED LEPTIN AND THUS, INCREASED NPY=DECREASED LEPTIN AND

INCREASED LEPTIN=DECREASED NPYINCREASED LEPTIN=DECREASED NPY FINDING HIGH LEVELS OF NPY IN OB/OB MICE IS FINDING HIGH LEVELS OF NPY IN OB/OB MICE IS

EXPECTED BECAUSE THEY DON’T PRODUCE EXPECTED BECAUSE THEY DON’T PRODUCE LEPTINLEPTIN

HOWEVER, SYSTEMATIC ADMINISTRATION OF HOWEVER, SYSTEMATIC ADMINISTRATION OF LEPTIN DECREASES NPY LEVELS IN THE ARN OF LEPTIN DECREASES NPY LEVELS IN THE ARN OF OB/OB MICEOB/OB MICE

THIS IS DIRECT EVIDENCE THAT THE THIS IS DIRECT EVIDENCE THAT THE ARN-PVN NPY SYSTEM IS ARN-PVN NPY SYSTEM IS SUPPRESSED BY CIRCULATING SUPPRESSED BY CIRCULATING LEPTINLEPTIN

EVIDENCEEVIDENCE

REDUCTION OF NPY IN ARN (43%) AFTER REDUCTION OF NPY IN ARN (43%) AFTER 4.1% WEIGHT LOSS IN “OB” GROUP CAN 4.1% WEIGHT LOSS IN “OB” GROUP CAN CONCLUDE THAT THE EFFECT OF LEPTIN CONCLUDE THAT THE EFFECT OF LEPTIN TO DECREASE NPY IN OB/OB MICE TO DECREASE NPY IN OB/OB MICE OCCURS BEFORE SIGNIFICANT CHANGES OCCURS BEFORE SIGNIFICANT CHANGES IN BODY ADIPOSITY.IN BODY ADIPOSITY.

THE PAIRFED GROUP, WHICH LOST THE PAIRFED GROUP, WHICH LOST SIMILAR AMOUNT OF WEIGHT AS “”OB” SIMILAR AMOUNT OF WEIGHT AS “”OB” GROUP DID NOT EXPERIENCE DECREASE GROUP DID NOT EXPERIENCE DECREASE IN ARN NPY LEVELS.IN ARN NPY LEVELS.

CAN CONCLUDE THAT BODY WEIGHT DOES CAN CONCLUDE THAT BODY WEIGHT DOES NOT DIRECTLY AFFECT LEVELS OF NPY, BUT NOT DIRECTLY AFFECT LEVELS OF NPY, BUT IT MUST BE DUE TO SPECIFIC ACTION OF IT MUST BE DUE TO SPECIFIC ACTION OF LEPTIN.LEPTIN.

IT APPEARS THAT A REVERSAL IN OBESE IT APPEARS THAT A REVERSAL IN OBESE CONDITION OF OB/OB MICE RESULTS IN A CONDITION OF OB/OB MICE RESULTS IN A DECREASE OF HYPOTHALAMIC NPY AS A DECREASE OF HYPOTHALAMIC NPY AS A DIRECT EFFECT O F LEPTIN AND NOT TO THE DIRECT EFFECT O F LEPTIN AND NOT TO THE INDIRECT AFFECT OF WEIGHT LOSS.INDIRECT AFFECT OF WEIGHT LOSS.

CONSEQUENTLY, REDUCED FOOD INTAKE CONSEQUENTLY, REDUCED FOOD INTAKE AND BODY WEIGHT DO NOT MEDIATE AND BODY WEIGHT DO NOT MEDIATE EFFECT OF LEPTIN TO LOWER EFFECT OF LEPTIN TO LOWER HYPOTHALAMIC NPY. RATHER LEPTIN ACTS HYPOTHALAMIC NPY. RATHER LEPTIN ACTS DIRECTLY TO DECREASE NPY.DIRECTLY TO DECREASE NPY.

3 ADDITIONAL 3 ADDITIONAL OBSERVATIONS IN OBSERVATIONS IN SUPPORT OF THIS SUPPORT OF THIS CONCLUSION.CONCLUSION.

NPY DID NOT DECREASE IN CEREBRAL NPY DID NOT DECREASE IN CEREBRAL CORTEX OR HIPPOCAMPUS SUGGESTING CORTEX OR HIPPOCAMPUS SUGGESTING THAT THE EFFECTS OF LEPTIN IS THAT THE EFFECTS OF LEPTIN IS REGIONALLY SPECIFIC TO ARN NEURONS.REGIONALLY SPECIFIC TO ARN NEURONS.

LEPTIN DID NOT ALTER NPY LEVEKS IN THE LEPTIN DID NOT ALTER NPY LEVEKS IN THE ARN OF DB/DB MICE WHICH DID NOT ARN OF DB/DB MICE WHICH DID NOT RESPOND TO LEPTINRESPOND TO LEPTIN

A. THIS SUGGESTS THAT INHERITED A. THIS SUGGESTS THAT INHERITED RESISTANCE TO LEPTIN RESULTS IN ARN RESISTANCE TO LEPTIN RESULTS IN ARN NPY NPY

NEURONS TO BE UNRESPONSIVE TO NEURONS TO BE UNRESPONSIVE TO LEPTIN, THUS LEPTIN’S AFFECT N LEPTIN, THUS LEPTIN’S AFFECT N OB/OB MICE WAS NOT DUE TO A OB/OB MICE WAS NOT DUE TO A NONSPECIFIC OR TOXIC AFFECT.NONSPECIFIC OR TOXIC AFFECT.

LEPTIN DID NOT INFLUENCE CRH LEPTIN DID NOT INFLUENCE CRH LEVELS IN PVN OF EITHER OB/OB LEVELS IN PVN OF EITHER OB/OB OR DB/DB MICE THUS INHIBITION OR DB/DB MICE THUS INHIBITION OF NPY BY LEPTIN IS NOT CAUSED OF NPY BY LEPTIN IS NOT CAUSED BY A GENERALIE HYPOTHALAMIC BY A GENERALIE HYPOTHALAMIC REACTION OF LEPTIN TO ALTER REACTION OF LEPTIN TO ALTER NEUROPEPTIDE GENE EXPRESSION.NEUROPEPTIDE GENE EXPRESSION.

MODEL: NEGATIVE MODEL: NEGATIVE FEEDBACK LOOPFEEDBACK LOOP

OB GENE EXPRESSION IN OB GENE EXPRESSION IN ADIPOSITYINCREASES WITH INCREASED ADIPOSITYINCREASES WITH INCREASED LEVELS OF ADIPOSITY.LEVELS OF ADIPOSITY.

NPY ACTS IN THE HYPOTHALAMAS TO NPY ACTS IN THE HYPOTHALAMAS TO PROMOTE WEIGHT GAIN IN FAT PROMOTE WEIGHT GAIN IN FAT DEPOSITION BY INCREASING FOOD INTAKE.DEPOSITION BY INCREASING FOOD INTAKE.

BUT, BUT, HICH LEVELS OF NPY WILL EVENTUALLY LEAD TO AN INCREASE IN LEPTIN WHEN ADIPOSITY LEVELS HAVE REACHED HIGH LEVELS

•LEPTIN INHIBITS NPY SYSTEM BY LEPTIN INHIBITS NPY SYSTEM BY NEGATIVE FEEDBACK LOOP AND NEGATIVE FEEDBACK LOOP AND CAUSES A DECREASE IN NPY AND CAUSES A DECREASE IN NPY AND FOOD INTAKEFOOD INTAKE

THUS, WHEN WEIGHT LOSS HAS THUS, WHEN WEIGHT LOSS HAS OCCURRED LEPTIN LEVELS ALSO OCCURRED LEPTIN LEVELS ALSO DECREASEDECREASE

WHEN LEPTIN DECREASES NPY WHEN LEPTIN DECREASES NPY INCREASESINCREASES

NPY THEN SIGNALS EATING TO NPY THEN SIGNALS EATING TO RECOVER THE LOST WEIGHT .RECOVER THE LOST WEIGHT .

SOCIAL INFLUENCES: SOCIAL INFLUENCES: PAPER #IPAPER #I

EXPERIMENT #1EXPERIMENT #1 HYPOTHESIS: NORMALLY REARED ANIMALS

EXHIBIT A PROFOUND SOCIAL INFLUENCE OF THEIR DIET SELECTION THAN ANIMALS REARED IN SOCIAL ISOLATION.

METHODS: SUBJECTS A. OBSERVERS: THIRTY 42-DAY-OLD RAT

PUPS WHERE USED.

15 IN EXPERIMENTAL GROUP AND 15 IN 15 IN EXPERIMENTAL GROUP AND 15 IN CONTROLCONTROL

DEMONSTRATORS: THIRTY RAT PUPS 7-DEMONSTRATORS: THIRTY RAT PUPS 7-10 DAYS OLDER THAN OBSERVER PUPS10 DAYS OLDER THAN OBSERVER PUPS

APPARATUSAPPARATUS:: FOOD PREFERENCES OF INDIVIDUAL

OBSERVER RATS WERE TESTED IN LARGE , WIRE MESH HANGING CAGES THAT WERE DIVIDED INTO TWO EQUAL COMPARTMENTS BY A HARDWARE -CLOTH PARTITION.

PROCEDURE:PROCEDURE:ISOLATION REARING:

REARED IN VISUAL AND TACTILE REARED IN VISUAL AND TACTILE ISOLATIONISOLATION

15 OBSERVER RAT PUPS IN THE 15 OBSERVER RAT PUPS IN THE EXPERIMENTAL GRP.EXPERIMENTAL GRP.

TAKEN AWAY FROM THEIR MOTHERS 2-TAKEN AWAY FROM THEIR MOTHERS 2-3 DAYS AFTER THEIR BIRTH3 DAYS AFTER THEIR BIRTH

CANNULATIONCANNULATION MAINTAINED ON A POLYSTYRENE CUP MAINTAINED ON A POLYSTYRENE CUP

FLOATING IN A CONSTANT TEMP. BATHFLOATING IN A CONSTANT TEMP. BATH

UNTIL 18 DAYS OF AGE, FED ENRICHED UNTIL 18 DAYS OF AGE, FED ENRICHED MILK THROUGH CANNULAMILK THROUGH CANNULA

RAT PUPS PLACED ALONE IN SMALL, SHOE RAT PUPS PLACED ALONE IN SMALL, SHOE BOX CAGEBOX CAGE

WEANED FROM MILK TO PELLET OF WEANED FROM MILK TO PELLET OF PURINA CHOWPURINA CHOW

NORMAL REARINGNORMAL REARING 15 OBSERVER AT PUPS IN THE CONTROL 15 OBSERVER AT PUPS IN THE CONTROL

GRPGRP REARED BY THEIR MOTHERREARED BY THEIR MOTHER WEANED AT 21 DAYS OF AGEWEANED AT 21 DAYS OF AGE AD-LIB PELLETS OF PURINA CHOWAD-LIB PELLETS OF PURINA CHOW GRPS OF 3 OR 4 IN SHOE BOX CAGES GRPS OF 3 OR 4 IN SHOE BOX CAGES

AT 42 DAYS OF AGE, THE IDENTICAL AT 42 DAYS OF AGE, THE IDENTICAL PROCEDURE WAS EMPLOYED WITH ALL 30 PROCEDURE WAS EMPLOYED WITH ALL 30 OBSERVER PUPS:OBSERVER PUPS:

1. EACH OBSERVER PUP WAS INTRODUCED 1. EACH OBSERVER PUP WAS INTRODUCED TO TO

ONE COMPARTMENT OF A HANGING CAGEONE COMPARTMENT OF A HANGING CAGE

- ACCESS TO PELLETS OF PURINA CHOW- ACCESS TO PELLETS OF PURINA CHOW

- WATER - WATER

-UNDISTURBED FOR 2 DAYS-UNDISTURBED FOR 2 DAYS 2. DEMONSTRATED RAT PUPS WERE PLACED 2. DEMONSTRATED RAT PUPS WERE PLACED

IN INDIVIDUAL CAGES IN A SEPARATED IN INDIVIDUAL CAGES IN A SEPARATED ROOM. ON EACH OF 2 CONSECUTIVE DAYS ROOM. ON EACH OF 2 CONSECUTIVE DAYS

- FOOD DEPRIVED FOR 23 DAYS- FOOD DEPRIVED FOR 23 DAYS

-POWDERED PURINA CHOW FOR ONE HR.-POWDERED PURINA CHOW FOR ONE HR.

3. FOLLOWING THE THIRD, 23 HR PERIOD OF 3. FOLLOWING THE THIRD, 23 HR PERIOD OF FOOD DEPRIVATION EACH DEMONSTRATOR WAS FOOD DEPRIVATION EACH DEMONSTRATOR WAS FED EITHER ONE GRAM OF DIET ANI OR 2.4 FED EITHER ONE GRAM OF DIET ANI OR 2.4 GRAMS OF DIET MAR TO GRAMS OF DIET MAR TO

100GMS OF POWDERED PURINA CHOW FOR 1 100GMS OF POWDERED PURINA CHOW FOR 1 HR.HR.

4. IMMEDIATELY AFTER EATING EITHER DIETS 4. IMMEDIATELY AFTER EATING EITHER DIETS EACH DEMONSTRATOR RAT WAS PLACED IN A EACH DEMONSTRATOR RAT WAS PLACED IN A HANGING CAGE ON THE OTHER SIDE OF THE HANGING CAGE ON THE OTHER SIDE OF THE HARDWARE-CLOTH BARRIER FROM ITS HARDWARE-CLOTH BARRIER FROM ITS OBSERVER- INTERACTIVE FOR 30 MIN.OBSERVER- INTERACTIVE FOR 30 MIN.

5. AFTER THE 30 MIN PERIOD OF INTERACTION5. AFTER THE 30 MIN PERIOD OF INTERACTION

- DEMONSTRATORS REMOVED FROM EXPERIMENT- DEMONSTRATORS REMOVED FROM EXPERIMENT

-FOR 22 HRS OBSERVER RATS WERE OFFERED A -FOR 22 HRS OBSERVER RATS WERE OFFERED A CHOICE OF DIET ANI OR DIET MAR.CHOICE OF DIET ANI OR DIET MAR.

6. AT THE END OF THE 22HR 6. AT THE END OF THE 22HR PERIOD, EXPERIMENTERS PERIOD, EXPERIMENTERS MEASURING THE AMOUNT OF MEASURING THE AMOUNT OF EACH OF THE TWO DIETS EATEN.EACH OF THE TWO DIETS EATEN.

RESULTSRESULTS

OBSERVERS ASSIGNED TO BOTH CONTROL & OBSERVERS ASSIGNED TO BOTH CONTROL & ISOLATION REARED CONDITIONS:ISOLATION REARED CONDITIONS:

1. ATE A GREATER % OF THE DIET THAN 1. ATE A GREATER % OF THE DIET THAN THEIR RESPECTIVE DEMONSTRATORS THEIR RESPECTIVE DEMONSTRATORS HAVE EATEN.HAVE EATEN.

2. THERE WAS NOT A SIGNIFICANT 2. THERE WAS NOT A SIGNIFICANT DIFFERENCE BETWEEN THE MEAN % DIFFERENCE BETWEEN THE MEAN % EATEN OF THE OBSERVERS DIET IN EATEN OF THE OBSERVERS DIET IN COMPARISON TO WHAT THEIR COMPARISON TO WHAT THEIR DEMONSTRATORS HAD EATEN.DEMONSTRATORS HAD EATEN.

THEREFORE, RAT PUPS REARED IN THEREFORE, RAT PUPS REARED IN SOCIAL ISOLATION ARE AS SOCIAL ISOLATION ARE AS SENSITIVE TO SOCIAL INFLUENCES SENSITIVE TO SOCIAL INFLUENCES OF THEIR FOOD CHOICES AS ARE OF THEIR FOOD CHOICES AS ARE NORMALLY REARED RAT PUPS.NORMALLY REARED RAT PUPS.

EXPERIMENT #2EXPERIMENT #2

HYPOTHESISHYPOTHESIS: TO DETERMINE WHETHER : TO DETERMINE WHETHER SIMPLE EXPOSURE OF 42-DAY-OLD SIMPLE EXPOSURE OF 42-DAY-OLD ISOLATION REARED RATS TO THE TASTE & ISOLATION REARED RATS TO THE TASTE & SMELL OF FOOD WOULD BE ENOUGH TO SMELL OF FOOD WOULD BE ENOUGH TO ENHANCE THEIR LATER FOOD ENHANCE THEIR LATER FOOD PREFERENCES.PREFERENCES.

METHODS:METHODS:

SUBJECTS:SUBJECTS:

- 14 ISOLATION REARED RAT PUPS & 14 - 14 ISOLATION REARED RAT PUPS & 14 NORMALLY REARED RAT PUPS.NORMALLY REARED RAT PUPS.

APPARATUS:APPARATUS:- LARGE WIRE-MESH HANGING CAGES - LARGE WIRE-MESH HANGING CAGES DIVIDED INTO 2 COMPARTMENTS BY DIVIDED INTO 2 COMPARTMENTS BY HARDWARE-CLOTH COMPARTMENT- ALSO HARDWARE-CLOTH COMPARTMENT- ALSO USED IN EXP. #1USED IN EXP. #1

PROCEDURE:PROCEDURE:

SAME AS EXP. #1 EXCEPT FOR :SAME AS EXP. #1 EXCEPT FOR : NO DEMONSTRATORS WERE USEDNO DEMONSTRATORS WERE USED DURING STEP 4, RAT PUPS WERE DURING STEP 4, RAT PUPS WERE

EXPOSED FOR 30 MIN TO A SEMI-EXPOSED FOR 30 MIN TO A SEMI-CIRCULAR, STAINLESS STEEL DISH CIRCULAR, STAINLESS STEEL DISH CONTAINING EITHER DIET ANI OR CONTAINING EITHER DIET ANI OR DIET MAR. DIET MAR.

RESULTS:RESULTS:

ISOLATION REARED & NORMALLY ISOLATION REARED & NORMALLY REARED RAT PUPS WERE SIMPLY REARED RAT PUPS WERE SIMPLY EXPOSED TO A DIET:EXPOSED TO A DIET:

1. DID NOT EAT A GREATER % OF THE 1. DID NOT EAT A GREATER % OF THE DIET THEY WERE EXPOSED TODIET THEY WERE EXPOSED TO

2. DID NOT DIFFER FROM ONE 2. DID NOT DIFFER FROM ONE ANOTHER IN THE MEAN % EATEN OF ANOTHER IN THE MEAN % EATEN OF THE DIET TO WHICH THEY WERE THE DIET TO WHICH THEY WERE EXPOSED EXPOSED

THEREFORE, THE PREFERENCES BY THEREFORE, THE PREFERENCES BY RAT PUPS REARD IN ISOLATION FOR RAT PUPS REARD IN ISOLATION FOR DIET EATEN BY THEIR DIET EATEN BY THEIR DEMONSTRATORS IN EXP.#1 , DEMONSTRATORS IN EXP.#1 , CANNOT BE EXPLAINED BY SIMPLE CANNOT BE EXPLAINED BY SIMPLE EXPOSURE TO DIET ANI OR DIET MAR EXPOSURE TO DIET ANI OR DIET MAR DURING THE PERIOD OF DURING THE PERIOD OF INTERACTION BETWEEN INTERACTION BETWEEN DEMONSTRATORS & OBSERVERS.DEMONSTRATORS & OBSERVERS.

SUMMARYSUMMARY

THE SUSCEPTIBILITY TO SOCIAL THE SUSCEPTIBILITY TO SOCIAL INFLUENCE ON FOOD CHOICE IS VERY INFLUENCE ON FOOD CHOICE IS VERY RESISTANT TO AN ABNORMAL EARLY RESISTANT TO AN ABNORMAL EARLY LIFE.LIFE.

PREVIOUS SOCIAL EXPERIENCES DO NOT PREVIOUS SOCIAL EXPERIENCES DO NOT APPEAR TO PLAY A MAJOR ROLE IN THE APPEAR TO PLAY A MAJOR ROLE IN THE DEVELOPMENT TO USE DEMONSTRATORS DEVELOPMENT TO USE DEMONSTRATORS AS SOURCES OF INFORMATION ABOUT AS SOURCES OF INFORMATION ABOUT WHAT FOODS TO EAT.WHAT FOODS TO EAT.

THIS TENDENCY SEEMS TO BE A SPECIES THIS TENDENCY SEEMS TO BE A SPECIES TYPICAL BEHAVIOURTYPICAL BEHAVIOUR

SOCIAL INFLUENCES: SOCIAL INFLUENCES: PAPER #2PAPER #2

EXPERIMENT #1EXPERIMENT #1

BACKGROUND INFORMATION:BACKGROUND INFORMATION: THE GRILL & NORGENS TASTE REACTIVITY THE GRILL & NORGENS TASTE REACTIVITY

TEST MEASURES BOTH POSITIVE & TEST MEASURES BOTH POSITIVE & NEGATIVE RESPONSES TO FLAVOUR.NEGATIVE RESPONSES TO FLAVOUR.

HOW IS IT ADMINISTERED???HOW IS IT ADMINISTERED??? A FLAVOURED FLUID IS INTRODUCED A FLAVOURED FLUID IS INTRODUCED

INTO THE ORAL CAVITY OF A RAT (VIA INTO THE ORAL CAVITY OF A RAT (VIA CHRONIC CANNULA)CHRONIC CANNULA)

RATS OROFACIAL & GENERAL RATS OROFACIAL & GENERAL MOTOR RESPONSES TO THE MOTOR RESPONSES TO THE INFUSION ARE VIDEO TAPED FOR INFUSION ARE VIDEO TAPED FOR ANALYSISANALYSIS

POSITIVE RESPONSES:POSITIVE RESPONSES:

1. TONGUE PROTRUSIONS 1. TONGUE PROTRUSIONS

2. LATERAL TONGUE PROTRUSIONS2. LATERAL TONGUE PROTRUSIONS

3. PAW LICKING 3. PAW LICKING

NEGATIVE RESPONSES:NEGATIVE RESPONSES:

1. GAPING 1. GAPING

2. PASSIVE DRIPPING OF FLUID 2. PASSIVE DRIPPING OF FLUID FROM MOUTHFROM MOUTH

3. PAW FLAILING 3. PAW FLAILING

4. HEAD SHAKING 4. HEAD SHAKING

5. CHIN RUBBING 5. CHIN RUBBING

PURPOSE:PURPOSE:

TO EXAMINE WHETHER THE TO EXAMINE WHETHER THE EFFECTS OF DEMONSTRATOR EFFECTS OF DEMONSTRATOR RATS ON THE FOOD CHOICES OF RATS ON THE FOOD CHOICES OF THEIR OBSERVERS, REFLECTED THEIR OBSERVERS, REFLECTED CHANGES IN THE OBSERVERS CHANGES IN THE OBSERVERS PERCEPTION OF THE PABILITY OF PERCEPTION OF THE PABILITY OF FOODS FOODS

METHODSMETHODS

SUBJECTS:SUBJECTS: 35 OBSERVERS THAT ARE 35 OBSERVERS THAT ARE

EXPERIMENTALLY NAÏVE RATS ( BORN IN EXPERIMENTALLY NAÏVE RATS ( BORN IN CAPTIVITY ) CAPTIVITY )

35 DEMONSTRATOR RATS ( PREVIOUS 35 DEMONSTRATOR RATS ( PREVIOUS SUBJECTS IN OTHER EXPERIMENTS)SUBJECTS IN OTHER EXPERIMENTS)

APPARATUS:APPARATUS: WIRE-MESH HANGING CAGES (HOUSED WIRE-MESH HANGING CAGES (HOUSED

RATS INDIVIDUALLY )RATS INDIVIDUALLY )

CIRCULAR PLEXI GLASS TEST CHAMBER CIRCULAR PLEXI GLASS TEST CHAMBER WHICH HOUSED RATS DURING TASTE WHICH HOUSED RATS DURING TASTE REACTIVITY TESTREACTIVITY TEST

PANASONIC COLOUR VIDEO CAMERAPANASONIC COLOUR VIDEO CAMERA

TEST FLUIDS:TEST FLUIDS: 2 DISTINCT, EQUALLY PALLITABLE FLUID 2 DISTINCT, EQUALLY PALLITABLE FLUID

WERE USED IN THE EXPERIMENTWERE USED IN THE EXPERIMENT FIRST FLUID CONSISTED OF 20 GMS OF FIRST FLUID CONSISTED OF 20 GMS OF

UNSWEETENED COCOA & 50 GMS OF SUGAR UNSWEETENED COCOA & 50 GMS OF SUGAR IN 1 LITRE OF WATER (FLUID COS)IN 1 LITRE OF WATER (FLUID COS)

SECOND FLUID CONSISTED OF 20 SECOND FLUID CONSISTED OF 20 MIL LIT OF ALMONDS EXTRACTS & MIL LIT OF ALMONDS EXTRACTS & 70 GMS OF SUGAR IN 1 LITRE OF 70 GMS OF SUGAR IN 1 LITRE OF WATER ( FLUID ALS)WATER ( FLUID ALS)

PROCEDURE:PROCEDURE:

DAY 1: ALL OBSERVER RATS WERE DAY 1: ALL OBSERVER RATS WERE IMPLANTED WITH A CHRONIC CANNULAIMPLANTED WITH A CHRONIC CANNULA

DAY 2-3: RATS LEFT UNDISTURBED FOR 2 DAY 2-3: RATS LEFT UNDISTURBED FOR 2 DAYS TO RECOVER FROM SURGERYDAYS TO RECOVER FROM SURGERY

DAY 4: HABITUATION DAYDAY 4: HABITUATION DAY

- RATS PLACED IN TEST APPARATUS FOR 10 - RATS PLACED IN TEST APPARATUS FOR 10 DAYS DAYS

-FOLLOWING 10 MIN. HABITUATION, RATS -FOLLOWING 10 MIN. HABITUATION, RATS WERE PLACED ON WATER DEPRIVATION WERE PLACED ON WATER DEPRIVATION SCHEDULES SCHEDULES

DEMONSTRATORS RATS DEPRIVED OF DEMONSTRATORS RATS DEPRIVED OF WATER FOR 23.5 HRS /DAY FOR 4 WATER FOR 23.5 HRS /DAY FOR 4 DAYSDAYS

OBSERVER RATS DEPRIVED OF WATER OBSERVER RATS DEPRIVED OF WATER FOR 23 HRS A DAY FOR NEXT 3 DAYS, FOR 23 HRS A DAY FOR NEXT 3 DAYS, SO THEY COULD BE TAUGHT A TASTE SO THEY COULD BE TAUGHT A TASTE AVERSION TO FLUID COS FOR DAY 8AVERSION TO FLUID COS FOR DAY 8

DURING HALF HR. DRINKING PERIODS, DURING HALF HR. DRINKING PERIODS, WATER WAS GIVEN TO 19 WATER WAS GIVEN TO 19 DEMONSTRATOR RATS (CONTROL DEMONSTRATOR RATS (CONTROL GRP.) & FLUID COS WAS GIVEN TO GRP.) & FLUID COS WAS GIVEN TO THE REMAINING 16 DEMONSTRATOR THE REMAINING 16 DEMONSTRATOR RATS (EXPERIMENTAL GRP.) RATS (EXPERIMENTAL GRP.)

DAY 5-7: TO HABITUATE RATS TO DAY 5-7: TO HABITUATE RATS TO TEST PROCEDURES TEST PROCEDURES

BEFORE EACH OBSERVER RATS 1 HR BEFORE EACH OBSERVER RATS 1 HR DRINKING PERIOD, IT WAS PLACED IN DRINKING PERIOD, IT WAS PLACED IN THE TEST CHAMBER FOR 4 MIN.THE TEST CHAMBER FOR 4 MIN.

WHILE IN CHAMBER RAT WAS WHILE IN CHAMBER RAT WAS INFUSED WITH WATER 1 MIL LIT/ MIN.INFUSED WITH WATER 1 MIL LIT/ MIN.

DAY 8: TASTE AVERSION TOOK PLACEDAY 8: TASTE AVERSION TOOK PLACE EACH OBSERVER RAT WAS GIVEN EACH OBSERVER RAT WAS GIVEN

FLUID COS. INSTEAD OF WATER 1 HR., FLUID COS. INSTEAD OF WATER 1 HR., & INJECTED WITH LITHIUM CHLORIDE & INJECTED WITH LITHIUM CHLORIDE SOLUTIONSOLUTION

DAY 9: TESTING DAY 9: TESTING FOR 30 MIN, 19 DEMONSTRATORS FOR 30 MIN, 19 DEMONSTRATORS

(ASSIGNED TO INTERACT WITH CONTROL (ASSIGNED TO INTERACT WITH CONTROL GROUP) WERE GIVEN WATER. REMAINING GROUP) WERE GIVEN WATER. REMAINING 16 DEMONSTRATORS RATS (ASSIGNED TO 16 DEMONSTRATORS RATS (ASSIGNED TO EXPERIMENTAL GROUP) WERE GIVEN FLUID EXPERIMENTAL GROUP) WERE GIVEN FLUID COSCOS

UPON COMPLETION 30 MIN PERIOD, UPON COMPLETION 30 MIN PERIOD, DEMONSTRATOR RATS WERE TRANSFERRED DEMONSTRATOR RATS WERE TRANSFERRED TO CAGES OF ASSIGNED OBSERVER RATS TO CAGES OF ASSIGNED OBSERVER RATS AND LEFT TO INTERACT FOR 30 MIN.AND LEFT TO INTERACT FOR 30 MIN.

AFTER INTERACTION, OBSERVER RATS A AFTER INTERACTION, OBSERVER RATS A TASTE REACTIVITY TEST (RECOREDE D ON TASTE REACTIVITY TEST (RECOREDE D ON VIDEOTAPE)VIDEOTAPE)

SCORING OF VIDEOTAPES WAS SCORING OF VIDEOTAPES WAS CARRIED BY AN EXPERIMENTER WHO CARRIED BY AN EXPERIMENTER WHO WAS UNAWARE OF OBSERVER RAT WAS UNAWARE OF OBSERVER RAT GROUP ASSIGNMENTGROUP ASSIGNMENT

UPON COMPLETION OF TEST RATS UPON COMPLETION OF TEST RATS WERE RETURNED TO THEIR CAGES WERE RETURNED TO THEIR CAGES AND OFFERED A CHOICE FOR 22 AND OFFERED A CHOICE FOR 22 HOURS BETWEEN 2 WEIGHED CUPS: HOURS BETWEEN 2 WEIGHED CUPS: ONE CONTAINING COS AND THE ONE CONTAINING COS AND THE OTHER ALS.OTHER ALS.

AT THE END OF THE PREFERENCE TEST AT THE END OF THE PREFERENCE TEST CUPS WERE WEIGHED AND OBSERVER CUPS WERE WEIGHED AND OBSERVER RATS INTAKE WAS DETERMINEDRATS INTAKE WAS DETERMINED

RESULTS:RESULTS:

PREFERENCE TESTPREFERENCE TEST OBSERVERS ASSIGNED TO OBSERVERS ASSIGNED TO

EXPERIMENTAL GROUP SHOWED EXPERIMENTAL GROUP SHOWED SIGNIFICANTLY WEAKER AVERSION SIGNIFICANTLY WEAKER AVERSION TO FLUID COS OVER THE 22 HR. TO FLUID COS OVER THE 22 HR. PERIOD THAN OBSERVER RATS IN PERIOD THAN OBSERVER RATS IN THE CONTROL GROUPTHE CONTROL GROUP

TASTE REACTIVITY TEST:TASTE REACTIVITY TEST: OBSERVERS IN EXPERIMENTAL AND OBSERVERS IN EXPERIMENTAL AND

CONTROL GROUPS WERE EQUALLY CONTROL GROUPS WERE EQUALLY LIKELY TO EXHIBIT POSITIVE LIKELY TO EXHIBIT POSITIVE RESPONSES (THAT IS WHEN THEY RESPONSES (THAT IS WHEN THEY WERE GIVEN WATER)WERE GIVEN WATER)

THOUGH OBSERVERS IN THE THOUGH OBSERVERS IN THE EXPERIMENTAL GROUP WERE EXPERIMENTAL GROUP WERE SIGNIFICANTLY LESS LIKELY THAN SIGNIFICANTLY LESS LIKELY THAN THE OBSERVERS ASSIGN TO THE THE OBSERVERS ASSIGN TO THE CONTROL TO EXHIBIT THE MOST CONTROL TO EXHIBIT THE MOST COMMON NEGATIVE RESPONSESCOMMON NEGATIVE RESPONSES

EXPERIMENT #2EXPERIMENT #2BACKGROUND INFORMATION:BACKGROUND INFORMATION:

IRWIN’S 2 POSSIBLE CAUSES OF IRWIN’S 2 POSSIBLE CAUSES OF DIFFERENTIAL RESPONSES EXHIBITED DIFFERENTIAL RESPONSES EXHIBITED BY ANIMALS WHEN MAKING A CHOICE:BY ANIMALS WHEN MAKING A CHOICE:

1. A REFLEXIVE RESPONSE TO THE STIMULI 1. A REFLEXIVE RESPONSE TO THE STIMULI PRESENT WHEN THE CHOICE IS MADEPRESENT WHEN THE CHOICE IS MADE

2. A MOTIVATED RESPONSE THAT 2. A MOTIVATED RESPONSE THAT REFLECTS AN ANIMALS EXPECTANCIES REFLECTS AN ANIMALS EXPECTANCIES REGARDING THE OUTCOMES OF THE REGARDING THE OUTCOMES OF THE BEHAVIOURS IT MIGHT EXHIBITBEHAVIOURS IT MIGHT EXHIBIT

IRWIN PROPOSED CHOICES MADE IN IRWIN PROPOSED CHOICES MADE IN THE PRESENCE OF THE GOAL THE PRESENCE OF THE GOAL OBJECTS WERE BIASES (NUMBER OBJECTS WERE BIASES (NUMBER 1 ABOVE), AND THAT DIFFERENCE 1 ABOVE), AND THAT DIFFERENCE RESPONSES MADE BY AN ANIMAL RESPONSES MADE BY AN ANIMAL NOT DIRECTLY EXPOSED TO GAL NOT DIRECTLY EXPOSED TO GAL OBJECTS WERE PREFERENCES OBJECTS WERE PREFERENCES (NUMBER 2 ABOVE). (NUMBER 2 ABOVE).

PURPOSEPURPOSE

TO DETERMINE WHETHER SOCIAL TO DETERMINE WHETHER SOCIAL INTERACTIONS CAUSE AN INCREASE IN INTERACTIONS CAUSE AN INCREASE IN OBSERVER MOTIVATION TO SEEK OUT FOODS OBSERVER MOTIVATION TO SEEK OUT FOODS THAT THEIR DEMONSTRATORS ATE.THAT THEIR DEMONSTRATORS ATE.

METHODSMETHODSSUBJECTSSUBJECTS:- :- EIGHT 42 DAY-OLD OBSERVER EIGHT 42 DAY-OLD OBSERVER

RATS BORN IN CAPTIVITY AND EIGHT RATS BORN IN CAPTIVITY AND EIGHT ADDITIONAL DEMONSTRATORS RATS ADDITIONAL DEMONSTRATORS RATS (PREVIOUS SUBJECTS IN OTHER (PREVIOUS SUBJECTS IN OTHER EXPERIMENTS).EXPERIMENTS).

APPARATUSAPPARATUS

SHOE BOX CAGES (HOUSED RATS SHOE BOX CAGES (HOUSED RATS INDIVIDUALLY)INDIVIDUALLY)

A T-MAZE CONSTRUCTED OF PLEXIGLASS A T-MAZE CONSTRUCTED OF PLEXIGLASS WITH STAINLESS STELL GRID FLOORWITH STAINLESS STELL GRID FLOOR

2 FOOD CUPS, ONE AT EACH END OF THE 2 FOOD CUPS, ONE AT EACH END OF THE ARM MAZEARM MAZE

A LINE 5CM INSIDE THE ENTRANCE TO A LINE 5CM INSIDE THE ENTRANCE TO EACH ARM OF THE MAZE ( TO SERVE AS EACH ARM OF THE MAZE ( TO SERVE AS A BOUNDARY)A BOUNDARY)

PROCEDUREPROCEDURE

BOTH OBSERVER AND DEMONSTRATOR BOTH OBSERVER AND DEMONSTRATOR RATS WERE FED WELL BALANCED DIETSRATS WERE FED WELL BALANCED DIETS

DURING FINAL 9WKS. OF EXPERIMENT, DURING FINAL 9WKS. OF EXPERIMENT, DEMONSTRATOR RATS WERE EITHER DEMONSTRATOR RATS WERE EITHER FED BANANA OR CHOW FLAVOURED FED BANANA OR CHOW FLAVOURED PELLETS DURING THEIR ONE HOUR PELLETS DURING THEIR ONE HOUR FEEDING PERIOD (OCCURRED TUESDAY FEEDING PERIOD (OCCURRED TUESDAY AND FRIDAY OF FINAL 9 WKS.)AND FRIDAY OF FINAL 9 WKS.)

TRAININGTRAINING: OBSERVER RATS WERE TAUGHT TO : OBSERVER RATS WERE TAUGHT TO RUN FROM THE START BOX OF THE MAZE TO RUN FROM THE START BOX OF THE MAZE TO BOTH GOAL BOXESBOTH GOAL BOXES

EACH OBSERVER RAT RAN 10 TRIALS/DAY, EACH OBSERVER RAT RAN 10 TRIALS/DAY, UNTIL ALL WERE CONSISTANTLY ENTERING UNTIL ALL WERE CONSISTANTLY ENTERING THE ARM OF THE MAZE CONTAINING THE THE ARM OF THE MAZE CONTAINING THE BANANA FLAVOURED PELLETS MORE OFTEN BANANA FLAVOURED PELLETS MORE OFTEN THAN THE ARM CONTAINING THE CHOW THAN THE ARM CONTAINING THE CHOW FLAVOURED PELLETSFLAVOURED PELLETS

TESTING:TESTING: OBSERVER RATS CONTINUED TO OBSERVER RATS CONTINUED TO RUN MAZE 10 TRIALS/DAY, 7 DAY/WKS RUN MAZE 10 TRIALS/DAY, 7 DAY/WKS

TUESDAYS AND FRIDAYS OF EACH WEEK WAS TUESDAYS AND FRIDAYS OF EACH WEEK WAS ALLOWED TO INTERACT IN THEIR HOME CAGE ALLOWED TO INTERACT IN THEIR HOME CAGE WITH A DEMONSTRATOR FOR THIRTY MIN.WITH A DEMONSTRATOR FOR THIRTY MIN.

HALF OF THE DEMONSTRATOR RATS HALF OF THE DEMONSTRATOR RATS ATE BANANA FLAVOURED PELLETS ATE BANANA FLAVOURED PELLETS OR CHOW FLAVOURED PELLETS THE OR CHOW FLAVOURED PELLETS THE HOUR PROIR TO INTERACTING HOUR PROIR TO INTERACTING

EACH OBSERVER RAT WAS GIVEN 10 EACH OBSERVER RAT WAS GIVEN 10 TRIALS/DAY IN THE T-MAZE WITH TRIALS/DAY IN THE T-MAZE WITH BANANA AND CHOW FLAVOURED BANANA AND CHOW FLAVOURED PELLETS IN THEIR USUAL POSITIONS.PELLETS IN THEIR USUAL POSITIONS.

RESULTSRESULTS

EXPERIMENT REVEALED THAT 6 OF EXPERIMENT REVEALED THAT 6 OF THE 8 OBSERVER RATS WERE THE 8 OBSERVER RATS WERE SIGNIFICANTLY NORE LIKELY TO ENTER SIGNIFICANTLY NORE LIKELY TO ENTER THE ARM OF THE MAZE CONTAINING THE ARM OF THE MAZE CONTAINING BANANA FLAVOURED PELLETS ON BANANA FLAVOURED PELLETS ON DAYS THEIR DEMONSTRATORS HAD DAYS THEIR DEMONSTRATORS HAD EATEN BANANA THAN ON DAYS WHEN EATEN BANANA THAN ON DAYS WHEN DEMONSTRATORS HAD EATED CHOW DEMONSTRATORS HAD EATED CHOW FLAVOURED PELLETSFLAVOURED PELLETS

ACCORDING TO IRWIN’S ACCORDING TO IRWIN’S DEFINITION OF PREFERENCE, DEFINITION OF PREFERENCE, CHOICES OF OBSERVERS INDUCED CHOICES OF OBSERVERS INDUCED BY INTERACTION WITH BY INTERACTION WITH DEMONSTRATORS WERE DUE TO DEMONSTRATORS WERE DUE TO CHANGES IN PREFERENCE AND CHANGES IN PREFERENCE AND NOT BIASES.NOT BIASES.

SOCIAL INFLUENCES: SOCIAL INFLUENCES: PAPER#IIIPAPER#III

BACKGROUNDBACKGROUND STUDIES OF THE PAST 20 YEARS STUDIES OF THE PAST 20 YEARS

HAVE FOCUSED ON THE GOAL OF HAVE FOCUSED ON THE GOAL OF SOCIAL INTERACTION IN THE SOCIAL INTERACTION IN THE DEVELOPMENT OF ADAPTIVE DEVELOPMENT OF ADAPTIVE PATTERNS OF FOODSELECTION BY PATTERNS OF FOODSELECTION BY NORWAY RATSNORWAY RATS

THEIR IMMEDIATE GOAL OF RESEARCH: THEIR IMMEDIATE GOAL OF RESEARCH: TO DETERMINE THE BEHAVIOURAL TO DETERMINE THE BEHAVIOURAL PROCESSES THAT CAUSE ONE RAT TO PROCESSES THAT CAUSE ONE RAT TO DIRECT ITS FEEDING BEHAVIOUR DIRECT ITS FEEDING BEHAVIOUR TOWARDS THE SAME FOODS THATTOWARDS THE SAME FOODS THAT

OTHERS OF ITS SOCIAL GROUP ARE OTHERS OF ITS SOCIAL GROUP ARE EATING AND TO IGNORE POTENTIAL EATING AND TO IGNORE POTENTIAL FOODS THAT OTHERS ARE NOT EATINGFOODS THAT OTHERS ARE NOT EATING

STUDIESSTUDIES

GALEF AND CLARK (1971) STUDIED GALEF AND CLARK (1971) STUDIED THE PHENOMENON DESCRIBED BY THE PHENOMENON DESCRIBED BY STEINIGER (1950) (POISON BAIT)STEINIGER (1950) (POISON BAIT)

CONDUCTED EXPERIMENTS WITH CONDUCTED EXPERIMENTS WITH COLONIES OF WILD NORWAY RATS COLONIES OF WILD NORWAY RATS IN THE LAB.IN THE LAB.

COLONIES LIVED IN SMALL (1 X 2 COLONIES LIVED IN SMALL (1 X 2 M) ENCLOSURES.M) ENCLOSURES.

NON LETHAL, NAUSEAUTING NON LETHAL, NAUSEAUTING CONCENTRATIONS OF MILD TOXINS CONCENTRATIONS OF MILD TOXINS INTRODUCED INTO DIET B (THE MORE INTRODUCED INTO DIET B (THE MORE PALLITABLE OF THE 2 DIETS, A & B PALLITABLE OF THE 2 DIETS, A & B PRESENTED FOR 3 HRS EACH DAYPRESENTED FOR 3 HRS EACH DAY

AVERSION TO DIET B DEVELOPED AVERSION TO DIET B DEVELOPED LITTERS OF RATS BORN TO THOSE WHO LITTERS OF RATS BORN TO THOSE WHO

LEARNED AVERSION TO DIET BLEARNED AVERSION TO DIET B FOOD CHOICES OF WEANING RAT PUPS FOOD CHOICES OF WEANING RAT PUPS

OBSERVEDOBSERVED

FINDINGS:FINDINGS:

AS LONG AS YOUNG WERE LEFT IN CONTACT AS LONG AS YOUNG WERE LEFT IN CONTACT WITH ADULT MEMBERS OF THE COLONY, WITH ADULT MEMBERS OF THE COLONY, JUVENILES RAISED, ATE ONLY DIET A.JUVENILES RAISED, ATE ONLY DIET A.

ADULT WILD RATS COULD BIAS THEIR ADULT WILD RATS COULD BIAS THEIR YOUNG TO EAT A RELATIVELY UNPALLITABLE YOUNG TO EAT A RELATIVELY UNPALLITABLE SAFE FOOD (DIET A) AND TO IGNORE THE SAFE FOOD (DIET A) AND TO IGNORE THE MORE PALLITABLE POTENTIALLY MORE PALLITABLE POTENTIALLY DANGEROUS FOOD (DIET B).DANGEROUS FOOD (DIET B).

AVOIDANCE OF DIET B IS NOT DUE TO THE AVOIDANCE OF DIET B IS NOT DUE TO THE SCENT MARKINGS BY ADULTS.SCENT MARKINGS BY ADULTS.

RESULTS:RESULTS:

DURING INTERACTION WITH DURING INTERACTION WITH ADULTS, WILD RAT PUPS WERE ADULTS, WILD RAT PUPS WERE LEARNING LEARNING ONLYONLY TO EAT THE TO EAT THE FOODS THE ADULTS WERE FOODS THE ADULTS WERE EATING, NOT TO EATING, NOT TO AVOIDAVOID FOODS FOODS THAT ADULTS WERE AVOIDINGTHAT ADULTS WERE AVOIDING

MECHANISMS FOR SOCIAL MECHANISMS FOR SOCIAL LEARNING ABOUT FOODS IN LEARNING ABOUT FOODS IN NORWAY RATSNORWAY RATS

11. PRESENCE OF ADULTS AT FEEEDING SITES e.g. . PRESENCE OF ADULTS AT FEEEDING SITES e.g.

- FOOD BOWL WITH ANAESTHESIZED FEMALE VS - FOOD BOWL WITH ANAESTHESIZED FEMALE VS FOOD BOWL WITHOUT.FOOD BOWL WITHOUT.

- PUPS ATE 4X AS MUCH FOOD FROM BOWL WITH - PUPS ATE 4X AS MUCH FOOD FROM BOWL WITH ANESTHESIZED FEMALE.ANESTHESIZED FEMALE.

-PUPS ATE FIRST MEALS OF SOLID FOOD IN -PUPS ATE FIRST MEALS OF SOLID FOOD IN PRESENCE OF ADULTPRESENCE OF ADULT

2. RESIDUAL OLFACTORY CUES e.g.2. RESIDUAL OLFACTORY CUES e.g.

- MARKING OF BOTH FOOD EATEN & AREAS - MARKING OF BOTH FOOD EATEN & AREAS AROUND FOOD.AROUND FOOD.

-70-90% OF FOOD EATEN TAKEN FROM SOILED -70-90% OF FOOD EATEN TAKEN FROM SOILED END OF CAGEEND OF CAGE

3. FLAVOUR CUES & MOTHER’S MILK e.g.3. FLAVOUR CUES & MOTHER’S MILK e.g.

- CUES IN HER MILK REFLECTING - CUES IN HER MILK REFLECTING FLAVOUR OF DIETFLAVOUR OF DIET..

-AVERSION TO MILK FED FROM FEMALE -AVERSION TO MILK FED FROM FEMALE EATING DIET OTHER THAN THEIR EATING DIET OTHER THAN THEIR MOTHERMOTHER

-SIMILARITIES TO HUMANS IN -SIMILARITIES TO HUMANS IN DEVELOPING TASTES FOR CULTURALLY DEVELOPING TASTES FOR CULTURALLY SPECIFIC FOODS; ie. SPICY FOODSSPECIFIC FOODS; ie. SPICY FOODS

4. OLFACTORY CUES ON THE BREATH OF 4. OLFACTORY CUES ON THE BREATH OF ADULT RATS e.g.ADULT RATS e.g.

- CUES FROM DIGESTIVE TRACT & FOOD - CUES FROM DIGESTIVE TRACT & FOOD CLINGING CLINGING

TO FURTO FUR SIMPLE EXPOSURE OF OBSERVERS TO THE SIMPLE EXPOSURE OF OBSERVERS TO THE

SMELL OR TASTE OF FOOD SMELL OR TASTE OF FOOD IS NOTIS NOT SUFFICIENT TO ENHANCE OBSERVERS SUFFICIENT TO ENHANCE OBSERVERS PREFERENCE FOR THAT FOOD.PREFERENCE FOR THAT FOOD.

RAT PRODUCED ODOURS RAT PRODUCED ODOURS (SEMIOCHEMICALS )& SMELL OF FOOD (SEMIOCHEMICALS )& SMELL OF FOOD PRESENTED TOGETHER INCREASES PRESENTED TOGETHER INCREASES OBSERVERS PREFERENCES FOR THAT OBSERVERS PREFERENCES FOR THAT FOOD.FOOD.

IMPLICATIONS OF SOCIAL IMPLICATIONS OF SOCIAL LEARNING FOR THE LEARNING FOR THE DEVELOPMENT OF ADAPTIVE DEVELOPMENT OF ADAPTIVE FORAGING BEHAVIOURSFORAGING BEHAVIOURS

FEEDING BEHAVIOUR OF OTHER RATS FEEDING BEHAVIOUR OF OTHER RATS INFLUENCES CHOICES OF FEEDING INFLUENCES CHOICES OF FEEDING SITES & FOODSSITES & FOODS

THIS MAY HELP OUTSIDE THE LAB. IN THIS MAY HELP OUTSIDE THE LAB. IN LOCATING NUTRITIONALLY ADEQUATE LOCATING NUTRITIONALLY ADEQUATE FOODS, IDENTIFYING TOXINS, FOODS, IDENTIFYING TOXINS, FORAGING MORE EFFICIENTLY.FORAGING MORE EFFICIENTLY.

THEY CANNOT DO THIS WITHOUT THEY CANNOT DO THIS WITHOUT SOCIAL CUES. SOCIAL CUES.

PUPS CANNOT LOCATE OR DEVELOP PUPS CANNOT LOCATE OR DEVELOP PREFERENCE FOR NUTRITIONALLY PREFERENCE FOR NUTRITIONALLY ADEQUATE FOOD ON THEIR OWNADEQUATE FOOD ON THEIR OWN

LEARNED FOR FOOD AVERSIONS LEARNED FOR FOOD AVERSIONS DUE TO TOXICOSIS CAN BE DUE TO TOXICOSIS CAN BE ABANDONED AFTER EXPOSURE TO ABANDONED AFTER EXPOSURE TO RATS THAT HAD EATEN THE RATS THAT HAD EATEN THE AVERTED FOOD.AVERTED FOOD.

ECOLOGICAL: PAPER #IECOLOGICAL: PAPER #I

FOOD SELECTIONFOOD SELECTION REQUIRES MORE THAN A NATURAL -

SCIENCE BASED, REDUCTIONIST ANALYSIS LOOKING AT THE PHYSIOLOGY & THE FEEDING BEHAVIOUR OF THE INDIVIDUAL

INVOLVES ALSO THE INTERACTION BETWEEN THE INDIVIDUAL, ECOLOGICAL & SOCIAL ENVIRONMENT.

ECOLOGY - WHICH FOODS THE ECOLOGY - WHICH FOODS THE ORGANISM EATS ORGANISM EATS

SOCIAL - FOODS AVAILABLE SOCIAL - FOODS AVAILABLE

EVOLUTION SHAPES THE HEDONIC EVOLUTION SHAPES THE HEDONIC RESPONSES TO FLAVOURS & THE RESPONSES TO FLAVOURS & THE TEXTURES TEXTURES

PROBLEMS IN FEEDING PROBLEMS IN FEEDING BEHAVIOUR- INAPPROPRIATE BEHAVIOUR- INAPPROPRIATE AMOUNTS & INAPPROPRIATE AMOUNTS & INAPPROPRIATE CHOICES OF FOOD CHOICES OF FOOD

FOOD CHOICEFOOD CHOICE

2 CLASSES OF ANIMALS :2 CLASSES OF ANIMALS :

1. DIETARY SPECIALISTS - SINGLE TYPE 1. DIETARY SPECIALISTS - SINGLE TYPE OF FOODOF FOOD

2. DIETARY GENERALISTS- VARIETY OF 2. DIETARY GENERALISTS- VARIETY OF DIFFERENT SUBSTANCES IN DIET DIFFERENT SUBSTANCES IN DIET

ONCE ASSIGNED AS A SPECIALIST, ONCE ASSIGNED AS A SPECIALIST, WRONG TO ASSUME FOOD CHOICES WRONG TO ASSUME FOOD CHOICES MADE BY MEMBERS OF THAT SPECIES IS MADE BY MEMBERS OF THAT SPECIES IS UNDERSTOODUNDERSTOOD

FEEDING STRATEGIES FEEDING STRATEGIES EVOLVED IN ANIMALS :EVOLVED IN ANIMALS :

1. FOOD SELECTORS:1. FOOD SELECTORS: CHOOSE FOOD ITEMS WITH SIMILAR CHOOSE FOOD ITEMS WITH SIMILAR

NUTRITIONALLY VALUE (SPECIALIST)NUTRITIONALLY VALUE (SPECIALIST) PREDATORS SELECT PREY THAT PREDATORS SELECT PREY THAT

WILL PROVIDE MORE ENERGY THAN WILL PROVIDE MORE ENERGY THAN WAS USED IN THEIR CAPTURE & WAS USED IN THEIR CAPTURE & CONSUMPTION, THUS MAXIMIZING CONSUMPTION, THUS MAXIMIZING THE RATE OF NET ENERGY GAIN.THE RATE OF NET ENERGY GAIN.

2. DIET COMPOSERS:2. DIET COMPOSERS:

SELECT FOOD OF VARYING NUTRITIONAL SELECT FOOD OF VARYING NUTRITIONAL VALUE (GENERALIST )VALUE (GENERALIST )

MORE COMPLEX PROCESS INVOLVED THAN MORE COMPLEX PROCESS INVOLVED THAN FOOD SELECTORSFOOD SELECTORS

OFTEN FAIL TO HAVE AN ADEQUATE DIET OFTEN FAIL TO HAVE AN ADEQUATE DIET WITH ALL THE REQUIRED NUTRIENTSWITH ALL THE REQUIRED NUTRIENTS

POSSESS BEHAVIOURAL MECHANISMS USED POSSESS BEHAVIOURAL MECHANISMS USED TO SELECT & AVOID CERTAIN TYPES OF FOOD TO SELECT & AVOID CERTAIN TYPES OF FOOD

CONGENITAL HEDONIC CONGENITAL HEDONIC RESPONSESRESPONSES

OLFACTORY & GUSTATORY SYSTEMS OLFACTORY & GUSTATORY SYSTEMS DISCRIMINATE & RESPOND TO DISCRIMINATE & RESPOND TO CHEMICAL STIMULI OF FOOD. CHEMICAL STIMULI OF FOOD.

ANIMALS IN NEW ENVIRONMENT - ANIMALS IN NEW ENVIRONMENT - GUSTATORY SYSTEM PROVIDES NO GUSTATORY SYSTEM PROVIDES NO PROTECTION AGAINST INGESTING PROTECTION AGAINST INGESTING TOXINS.TOXINS.

FOOD PYRAMID - HEDONIC SCALE OF FOOD PYRAMID - HEDONIC SCALE OF PALATABILITIES OF VARIOUS FOODS.PALATABILITIES OF VARIOUS FOODS.

MOTIVATED TO EAT - BODY NOT MOTIVATED TO EAT - BODY NOT DESIGNED TO COPE WITH THE DESIGNED TO COPE WITH THE HEDONICALLY DRIVEN SELECTION OF HEDONICALLY DRIVEN SELECTION OF FOODS.FOODS.

RESULTS IN DISEASES- e.g.RESULTS IN DISEASES- e.g.

-TOOTH DECAY, OBESITY, CANCER OF -TOOTH DECAY, OBESITY, CANCER OF GASTROINTESTINAL SYSTEM GASTROINTESTINAL SYSTEM ASSOCIATE TO HIGH LEVELS OF FAT ASSOCIATE TO HIGH LEVELS OF FAT INTAKE.INTAKE.

SUMMARYSUMMARY

ALTHOUGH A CONGENITAL PATTERN ALTHOUGH A CONGENITAL PATTERN OF HEDONIC RESPONSES EVOLVED OF HEDONIC RESPONSES EVOLVED TO GUIDE US IN FOOD SELECTION TO GUIDE US IN FOOD SELECTION YOU CANNOT RELY ON “WISDOM YOU CANNOT RELY ON “WISDOM OF THE BODY” FOR THESE CHOICES.OF THE BODY” FOR THESE CHOICES.

EXPOSURE TO DIFFERENT FOODS EXPOSURE TO DIFFERENT FOODS INCREASED DIFFERING FROM THOSE INCREASED DIFFERING FROM THOSE EATEN BY OUR ANCESTORS EATEN BY OUR ANCESTORS

THEREFORE NOT VERY RELIABLE IN THEREFORE NOT VERY RELIABLE IN IDENTIFYING BETWEEN DESIRABLE IDENTIFYING BETWEEN DESIRABLE OR TOXIC FOODS BASED ON THEIR OR TOXIC FOODS BASED ON THEIR SENSORY QUALITIESSENSORY QUALITIES

HARD TO SELECT HEALTHY FOOD HARD TO SELECT HEALTHY FOOD DUE TO THE LARGE MARKET DUE TO THE LARGE MARKET DEVOTED TO ADVERTISING JUNK DEVOTED TO ADVERTISING JUNK FOOD.FOOD.

SELECTING FOODSSELECTING FOODS

PROLONG EXPOSURE TO AN UNPALATABLE PROLONG EXPOSURE TO AN UNPALATABLE FLAVOUR WILL PRODUCE AN EXCEPTANCE FLAVOUR WILL PRODUCE AN EXCEPTANCE & A PERVERSE PREFERENCE FOR THAT & A PERVERSE PREFERENCE FOR THAT FLAVOUR.FLAVOUR.

HOWEVER, FREQUENTLY EXPOSED TO A HOWEVER, FREQUENTLY EXPOSED TO A FOOD DURING A MEAL CAN LEAD TO A FOOD DURING A MEAL CAN LEAD TO A DECREASED LIKING TO THE FOOD.DECREASED LIKING TO THE FOOD.

PREFERENCE FOR A FLAVOUR WILL BE PREFERENCE FOR A FLAVOUR WILL BE ENHANCED WHEN PAIRED WITH A POSITIVE ENHANCED WHEN PAIRED WITH A POSITIVE EVENT. EVENT.

PREFERENCE FLAVOUR WILL PREFERENCE FLAVOUR WILL CAUSE A TASTE AVERSION IF CAUSE A TASTE AVERSION IF PAIRED WITH A NEGATIVE EVENT PAIRED WITH A NEGATIVE EVENT

AN INDIVIDUAL IS MOST LIKELY TO AN INDIVIDUAL IS MOST LIKELY TO INGEST CERTAIN FOODS IF INGEST CERTAIN FOODS IF AFFECTED BY THE INTERACTION AFFECTED BY THE INTERACTION WITH CONSPECIFICS EATING THAT WITH CONSPECIFICS EATING THAT FOOD.FOOD.

CONCLUSIONCONCLUSION

ENVIRONMENTAL INFLUENCES AN ENVIRONMENTAL INFLUENCES AN INDIVIDUALS’ BIAS SELECTION OF INDIVIDUALS’ BIAS SELECTION OF FOOD - EXTERNAL CUESFOOD - EXTERNAL CUES

NEED TO EXAMINE FOOD SELECTION NEED TO EXAMINE FOOD SELECTION ACCORDING TO THE BIOLOGICAL & ACCORDING TO THE BIOLOGICAL & SOCIAL ENVIRONMENT THE SOCIAL ENVIRONMENT THE INDIVIDUAL IS EATING IN - NOT JUST INDIVIDUAL IS EATING IN - NOT JUST THE PHYSIOLOGY OF FOOD INTAKE.THE PHYSIOLOGY OF FOOD INTAKE.

SUMMARYSUMMARY

GENETICS: PAPER #1GENETICS: PAPER #1 NPY INCREASES FOOD INTAKE AND NPY INCREASES FOOD INTAKE AND

LEPTIN DECREASES FOOD INTAKELEPTIN DECREASES FOOD INTAKE HIGH LEVELS OF NPY IN OB/OB MICE IS HIGH LEVELS OF NPY IN OB/OB MICE IS

EXPECTED BECAUSE THEY DO NOT EXPECTED BECAUSE THEY DO NOT PRODUCE LEPTINPRODUCE LEPTIN

HOWEVER, SYSTEMIC ADMINISTRATION HOWEVER, SYSTEMIC ADMINISTRATION OF LEPTIN DECREASES NPY LEVELS IN OF LEPTIN DECREASES NPY LEVELS IN ARN OF OB/OB MICEARN OF OB/OB MICE

ARCULATE PVN-NPY SYSTEM IS ARCULATE PVN-NPY SYSTEM IS SUPPRESSED BY CIRCULATING SUPPRESSED BY CIRCULATING LEPTINLEPTIN

SOCIAL INFLUENCES: PAPER #1SOCIAL INFLUENCES: PAPER #1 SOCIAL INFLUENCE ON FOOD

CHOICE IS RESISTANT TO AN ABNORNAL EARLY LIFE

SOCIAL INFLUENCES ON FOOD INTAKE SEEMS TO BE A SPECIES TYPICAL BEHAVIOUR.

SOCIAL INFLUENCES: PAPER #2SOCIAL INFLUENCES: PAPER #2 OBSERVERS IN THE EXPERIMENTAL AND OBSERVERS IN THE EXPERIMENTAL AND

CONTROL GROUP ARE EQUALLY LIKELY TO CONTROL GROUP ARE EQUALLY LIKELY TO EXHIBIT POSITIVE RESPONSE (TASTE EXHIBIT POSITIVE RESPONSE (TASTE REACTIVITY TEST)REACTIVITY TEST)

IRWIN’S DEFINITION OF PREFERENCE SHOWS IRWIN’S DEFINITION OF PREFERENCE SHOWS THAT CHOICES OF OBSERVERS INDUCED BY THAT CHOICES OF OBSERVERS INDUCED BY INTERACTION WITH DEMONSTRATORS WERE INTERACTION WITH DEMONSTRATORS WERE DUE TO CHANGES IN PREFERENCE AND NOT DUE TO CHANGES IN PREFERENCE AND NOT BIASBIAS

SOCIAL INFLUENCES: PAPER #3SOCIAL INFLUENCES: PAPER #3 4 MECHANISMS FOR SOCIAL LEARNING 4 MECHANISMS FOR SOCIAL LEARNING

ABOUT FOODS IN NORWAY RATS ARE:ABOUT FOODS IN NORWAY RATS ARE: 1. PRESENCE OF ADULTS AT FEEDING 1. PRESENCE OF ADULTS AT FEEDING

SITESSITES 2. RESIDUAL OLFACTORY CUES2. RESIDUAL OLFACTORY CUES 3. FLAVOUR CUES IN MOTHER’S MILK3. FLAVOUR CUES IN MOTHER’S MILK 4. OLFACTORY CUES ON THE BREATH OF 4. OLFACTORY CUES ON THE BREATH OF

ADULT RATSADULT RATS

ECOLOGICAL: PAPER #1ECOLOGICAL: PAPER #1 FOOD INTAKE OR SELECTION OF FOOD INTAKE OR SELECTION OF

FOOD INTAKE DEPENDS ON FOOD INTAKE DEPENDS ON ENVIRONMENTAL INFLUENCES, ENVIRONMENTAL INFLUENCES, BIOLOGICAL, AND SOCIAL BIOLOGICAL, AND SOCIAL ENVIRONMENT THE INDIVIDUAL ENVIRONMENT THE INDIVIDUAL IS EATING IN.IS EATING IN.