Variables and Methods for Studying Primates (Overview)

Transcription

1 Variables and Methods for Studying Primates (Overview) History of Field Primatology Variables: the traits you measure when you do research Examples of variables from primatology Ethograms and methods for recording behaviors The goal of research: To understand relationships among quantifiable variables by hypothesizing these relationships, and then testing them Science: using theories to come up with hypothesized relationships among variables, then collecting and analyzing data on those variables to see if that predicted relationship exists, then replicating

2 History of Field Primatology Scientific studies of primates in their natural environments ( in the field ) Before 1929: no scientific studies psychologists interested Captive vs. wild Cognitive comparisons to humans : Washburn wanted to understand human origins by incorporating evolutionary theory newly-acquired hominid record fossil data knowledge of living people : descriptive primatological studies monkey sociality depends on kinship monkeys display protocultural behavior focal follow -style studies Leaky 1975 to NOW: scientific, theory-driven primatology (J. Altmann)

3 A variable is any property that we can quantify and measure

4 Some Variables Studied by Primatologists Physical, Ecological, Behavioral, Social Can be measured at different levels: individual, group, or species Age, sex, size Anatomy Hormones Parasite load Genetic factors Feeding rates Locomotion Dominance rank Mating frequency Grooming rates Threats (e.g., eye flashes) Group composition (e.g., 10 males, 15 females, 8 infants) Territory size Day range Birth rate Sex ratio Age ratios Habitat Average age at first reproduction Vulnerability to predation Diet (folivore, insectivore) Philopatry vs. dispersal Activity patterns Hierarchical vs. egalitarian Parity

5 Variable: Thumb Presence or Absence Spider monkey with four fingers (not pentadactylism)

6 Variable: Locomotion Type Vertical clinging and leaping

7 Variable: Canine Length Female human Male drill

8 Variable: Sex

9 Variable: Grooming Rate (and groomer vs. groomee)

10 Variable: Egalitarian vs. Hierarchical Egalitarian muriqui Hierarchical hamadryas

11 Variable: Philopatry vs. Dispersal

12 Variable: Philopatry vs. Dispersal

13 Variable: Activity Pattern Nocturnal owl monkey

14 Variable Features There are often different ways to measure a variable in which you are interested Variables can be measured at different levels, such as intraindividual, inter-individual, group, population, or species levels Variables can be quantified or categorical Variables can be discreet or continuous Operationalize: to define a concept or variable so that it can be measured or expressed quantitatively Choose variables with high variance! In the end, ALL variables are quantified, even categorical ones like sex

15 The behavioral repertoire exhibited by a species Different species, different ethogram Helps you quantify an animal s behaviors Checklists and codes Well-established for many species Ethogram

16 Common Marmoset

17 Common Marmoset Ethogram: Agonism Tufts-flick (TF) Frown (FR) Cuff (CU) Chase (CH) Fight (FI) Attack (AT) Snap bite (SB) Submit (SU) Continuous submit (CS) Retreat (RE) rapid back-and-forth movement of ear tufts lower eyebrows, furl brow, and turn down corners of mouth while staring swift, superficial blow or scratch performed aggressively pursue partner, with one or both animals exhibiting aggression and/ or submission (not play) grapple aggressively with partner(s), involving biting, clawing, and wrestling lunge at or pounce on partner aggressively; may or may not result in fight direct a single short, sharp bite at partner flatten ear tufts and/or facial grimace (partially open mouth with corners of mouth retracted, exposing lower and sometimes upper teeth) and/or slit eyes (eyelids half closed) continuous submit; start scoring after 5 sec starting from a stationary position, move at lest one body length away from another animal within 1 sec of the other animal establishing proximity (within 10 cm)

18 Common Marmoset Ethogram: Play Play (PL) two or more animals lunge, grapple, wrestle or chase for at lest 1 sec in absence of aggression or intense submission; play face may or may not be present Solicit play (SP) Play face (PF) Join play (JP) End play (EP) Social play (SO) direct play face toward, pounce on, or initiate grapple with partner, in absence of ongoing play with partner open mouth without retraction of the lips join ongoing play bout between two or more partners discontinue all social play for _> 3 sec social interactions involving non-aggressive physical contact with other individuals; high activity

19 Common Marmoset Ethogram: Infant-Associated behaviors Climb on (ON) climb onto any part of partner's body so that all four limbs are on partner Solicit climb on (SC) position body directly above infant and/or pull infant onto body; may or may not result in infant climbing onto partner's body Climb off (OF) Push off/ reject (PO) voluntary climb off partner's body after having all four limbs on partner prevent juvenile from climbing onto body, or rub or otherwise force juvenile off body Nurse (NU) have mouth on female's nipple for _> 1 sec End nursing (EN) discontinue nursing posture

20 Common Marmoset Ethogram: Other Social Behaviors Sniff/nuzzle (SN) Anogenital inspect (AI) Groom (GR) Sexual solicit (SS) Mount (MO) Initiate huddle (IH) Leave huddle (LH) orient face against or toward partner, excluding anogenital region orient face against or toward anogenital region of partner, or use hands or mouth to investigate anogenital region of partner; includes anogenital groom use hands and/or mouth to pick through fur and/or mouth of partner, excluding anogenital region stare at partner with ear tufts flattened and eyes slit climb on partner's back from behind and grip partner around waist and legs; may be accompanied by pelvic thrusting establish passive, torso-torso body contact with partner, with both animals remaining stationary and in passive contact for at least 3 sec terminate huddle after at least 3 sec of passive, torso-torso body contact during which both partners remained stationary Object steal (OS) Attempt object steal (AO) take any non-food object from hands or mouth of partner attempt but fail to take non-food object from hands or mouth of partner

21 Common Marmoset Ethogram: Food-Associated Behaviors Food steal (ST) take any food from hands or mouth of partner Attempt food steal (AF) attempt but fail to take food from hands or mouth of partner Share food (SH) eat from a food source from which partner is simultaneously eating or occupying without removing any food from partner's mouth or hands New food (NF) eat from a food source which no other animal is currently holding, eating from, or occupying

22 Common Marmoset Ethogram: Individual Behaviors Bristle strut (BS) arching posture and/or strut locomotion and/or general Piloerection Scentmark (SM) rub or drag anogenital, suprapubic, or sternal region along substrate, object, or partner Genital present (GP) raise tail to expose genitals Object manipulation (OM) sniff, bite, chew, gouge, handle, pounce on, grapple with, or otherwise manipulate inanimate object, excluding food items and water bottle, for at least 1 sec

23 Overview Variables: the traits you measure when you do research Examples of variables from primatology Ethograms and methods for recording behaviors The goal of research: To understand relationships among quantifiable variables by hypothesizing these relationships, and then testing them Science: using theories to come up with hypothesized relationships among variables, then collecting and analyzing data on those variables to see if that predicted relationship exists, then replicating

24 The goal of our research: To understand relationships among quantifiable variables by hypothesizing these relationships, and then testing them

25 Height and Weight Y Person Height (inches) A B C D E F G H I Y X J Weight (pounds ) Height Weight X

26 Height and Weight Y Positive, Linear Height Weight X

27 Hours Since Breakfast and Fullness Y Person Hours since breakfast A 1 10 B 2 8 C 4 3 D 1 9 E F 3 6 G 3 4 H 4 4 I 6 2 J 3 5 Y Fullness (1-10 scale) Fullness: 1 = famished 5 = just right 10 = stuffed X Hours Fullness X

28 Hours Since Breakfast and Fullness Y Hours Negative, Linear Fullness X

29 Height and Age Y Person Height (inches) A 18 1 B 24 2 C D E 40 8 F G H I J Y Age (years) X Height Age X

30 Height and Age Y Positive, Curvilinear Height Age X

31 Height and Sex Y Person Height (inches) A 65 0 B 60 0 C 68 1 D 72 1 E 70 1 F 60 0 G 64 0 H 69 1 I 62 0 J 70 1 Y Sex: 0 = female, 1 = male Sex X Height 0 Sex 1 X

32 Height and Sex 68 Height (inches) 64 Bars represent averages Female (0) Male (1) Sex

33 Relationships Between Variables Lots of kinds of relationships Relationships are also called associations, correlations When there is a relationship, one variable predicts or explains the other variable Can be more than two variables ( multivariate ; 3D graph instead of 2D) Categorical variables okay too Graphing is a tool to help you visually understand mathematical relationships between variables

34 Primate Variables: Relationships? Age Sex Size Anatomy Hormones Parasite load Genetic factors Feeding rates Locomotion Dominance rank Mating frequency Grooming rates Threats Group composition Territory size Day range Birth rate Sex ratio Age ratios Habitat Age at first reproduction Vulnerability to predation Diet Activity patterns Hierarchical vs. egalitarian Parity Thumbs Canine Length

35 Good hypothesis are scientific: Testable Falsifiable Replicable Based on Theories

36 Testable Is it possible to collect data relevant to your variables? Is the data you intend to collect welloperationalized?

37 Falsifiability Karl Popper advocated empirical falsifiability as the criterion for distinguishing scientific theory from nonscience/pseudoscience (17 minutes audio) v=ztmvtklur7i Freud Einstein Oprah Is the predicted relationship between your variables falsifiable? "falsifiable" does not mean "false"

38 Replicability If other people do your study, do they get the same results? If not, your conclusion about your hypothesis was probably wrong This leads to the progression of science Not perfect in primatology (different monkeys, different times, different places), but researchers try to recreate the environment of an original test

39 Theory-Based What is a theory? Not a hunch Self-consistent Supported by prior evidence Predictive Testable Subject to corrections Broader than hypotheses Is your hypothesis consistent with relevant theories? In the case of this Primate Behavioral Ecology, one of the main relevant theories is Evolutionary Theory

40 Scientists in Action They observe natural process until they think they see a pattern in the events they are observing. They define questions to investigate based on their observations. These questions often arise from findings of earlier research or even research done by other scientists (and citizen scientists). They develop hypotheses (testable guesses) to try to answer their questions. They systematically collect and then analyze information (data) to test the hypotheses. They look at the results, then come to conclusions about whether their hypotheses are correct (supported or not supported). Replicability: usually people don t try to falsify their own hypotheses, but other scientists do, and this leads to a progression in science Often, they ask even more questions based on what they have observed; theories become refined and approach trueness over time

41 End