Fig. 1 FID procedure and measurements. This highlights the distance variables that can be measured as a function of the focal animal’s behavioral responses. Start distance (SD), visual orientation distance (VOD), VOD delay (VODD), VOD interval (VODI), flight initiation distance (FID). Adapted from (57).
Fig. 2 Conditional effect plots for interaction between observer identity and individual trial number per observer from VOD and FID models. The plot represents conditional predictions of the regression curve when all fixed effects are held constant apart from the interaction (observer × individual trial number per observer); the mean was used as the measure of central tendency, with the shaded areas displaying the relevant credible intervals (2.5 and 97.5% percent quantiles). AA represents the familiar observer, and AB represents the unfamiliar observer.
Fig. 3 Convergent validity regression. Regression relationship between visual tolerance and displacement tolerance. Estimates were derived from bivariate Bayesian model; lower values indicate greater “tolerance.” Each point represents the conditional modes of an individual baboon (n = 69) for each tolerance trait.
- Table 1 Factors hypothesized to influence VOD and FID in baboons.
Contextual variables that could be major drivers of VOD and FID responses in habituated chacma baboons (examples from relevant literature supporting the inclusion of each hypothesis can be found in table S1).
Factors Link to sensory capacity/FID/personality Response variable: VOD Observer (pseudo-predator) identity, X1 Unfamiliar observer considered a greater threat, leading to increased risk
perception and tendency to visually orient, resulting in longer VODTrial number, X2 (i) Increase or decrease in VOD with trial number indicative of habituation or
sensitization (respectively) to FID approach methodology(ii) Consistent individual VOD response through time indicates personality trait. Compatibility: Not engaged (looking/not looking),
engaged (not looking), X3Looking may enable animals to collect multiple types of information
concurrently; in addition, being “not engaged” may afford focal animals a
greater sensory capacity for detection. As a result, individuals looking as
approach commences will visually orient toward approaching observer
sooner resulting in longer VOD; engaged should yield shorter VOD.Habitat (open/closed), X4 (i) “Open” habitats may afford individuals greater visibility, increasing
likelihood of attending to approaching observer quicker, resulting in
longer VOD.(ii) Open habitats are generally considered safer for baboons, as they permit
earlier detection and avoidance of predators; therefore, risk perception
could be lower, reducing tendency to visually orient toward approaching
observer, resulting in shorter VOD.(iii) Open habitats may increase risk perception, as focal animals are less
concealed from potential threats, increasing tendency to visually orient
toward approaching observer, resulting in longer VOD.(iv) Open habitats have lower refuge availability, which may increase risk
perception, resulting in longer VOD.Height (ground/above ground), X5 “Above ground” may afford individuals greater visibility, resulting in longer
VOD. In this context, above ground is <50 cm from ground level and is
unlikely to qualify as potential refuge and therefore should not influence
risk perception.Number of neighbors within 5 m, X6 (i) As number of neighbors increase, the likelihood of a neighbor visually
orienting toward the approacher increases, i.e., collective detection, which
could result in longer VOD.(ii) As number of neighbors increase, the likelihood of predation decreases
reducing risk perception and the tendency to visually orient toward the
approach observer, resulting in shorter VOD.(iii) Increasing number of neighbors may mask both the visual and audible
cues associated with the observer’s approach, resulting in shorter VOD,
e.g., neighbors draw visual attention away from observer or noises from
neighbors mask the sounds of observer’s footsteps during approach.Neighbor flight, X7 Local conspecifics initiating flight before the focal animal will increase risk
perception and evoke vigilance. Both factors could lead to focal animals
visually orienting toward approaching observer sooner, resulting in
longer VOD.External factors (local alarms, aggressions within 5 min), X8 Localized threatening stimuli lead to increased risk perception and tendency
to visually orient, resulting in longer VOD.Localized visual and audible stimuli may reallocate some of the focal animal’s
finite attention, resulting in longer VOD.Response variable: FID VODI, X9 When visual orientation interval (distance between VOD and FID) is long,
focal animals will flee sooner, resulting in longer FID.Engaged/Not engaged, X10 FID will be higher if focal animal was engaged at the start of the approach, as
flight costs are higher because of interrupted social time (i.e., grooming)
or loss of food patch (i.e., foraging).Observer (pseudo-predator) identity, X1 Unfamiliar observer is considered a greater threat; therefore, FID should be
greater for unfamiliar observerTrial number, X2 (i) Increase or decrease in FID with trial number indicative of sensitization or
habituation (respectively) to FID approach methodology(ii) Consistent FID response through time indicates personality trait. Habitat (open/closed), X4 (i) Open habitats are generally considered safer for baboons, as they permit
earlier detection and avoidance of predators; therefore, risk perception
could be lower, resulting in shorter FID.(ii) Open habitats may increase risk perception, as focal animals are less
concealed from potential threats, resulting in longer FID.(iii) Open habitats have lower refuge availability, which may increase risk
perception, resulting in longer FID.Number of neighbors within 5 m, X6 (i) Risk diluted with greater number of neighbors; therefore, FID should
decrease as number of neighbors increases.(ii) Increasing number of neighbors increases localized visual and audible
stimuli and therefore may reallocate some of the focal animal’s finite
attention resulting in decreased FID.Neighbor flight, X7 Local conspecifics initiating flight before the focal animal will increase risk
perception and therefore increase FID.External factors (local alarms, aggressions within 5 min), X8 (i) Localized threatening stimuli leads to increased risk perception and
therefore increased FID.(ii) Localized visual and audible stimuli may reallocate some of the focal
animal’s finite attention therefore decreasing FID. - Table 2 Responses by baboons to approach and hypothesized meaning.
Hypothesized individual baboon behavioral response to human approaches and the threat level these responses are considered equivalent to.
Observer considered: Equivalent to
predatorEquivalent to social
threatMinimal threat No threat No. of observations
(percentage of total
observations)Response predictor Alarm bark Y – – – 0 (0%) Flight direct to refuge
(rocks, trees, or cliff)Y – – – 0 (0%) Rapid flight/sprinting
responseY Y – – 0 (0%) Displacement with geck/
grimace– Y – – 16 (0.97%) Animal passively
displaces– Y Y – 1637 (98.85%) Flinch/startled before
flight*–/* –/* –/* –/* 3 (0.18%) Animal is not displaced – –/* – Y 0 (0%) Animal is not displaced
and threatens
observer– – – Y 0 (0%) *Flinch or startled suggests that the focal animal detected observer within its usual tolerance level.
- Table 3 VOD model summary.
Parameter estimates for the model describing the relationship between VOD and the predictor variables. CI, credible interval.
Population-level effects Estimate Est. error 1–95% CI U-95% CI Rhat Bulk_ESS Tail_ESS Intercept 1.06 0.08 0.9 1.22 1.00 23,289 35,333 VODD −0.02 0.01 −0.03 0 1.00 34,760 41,624 Looking 0.21 0.02 0.17 0.25 1.00 69,337 46,658 Not engaged not looking 0.11 0.02 0.06 0.16 1.00 70,821 47,802 Open (Habitat) 0.15 0.02 0.12 0.19 1.00 73,748 46,813 Ground (Height) 0.06 0.05 −0.04 0.16 1.00 74,865 45,743 Number of neighbors −0.05 0.01 −0.06 −0.03 1.00 76,910 46,466 Neighbor flee first 0.08 0.04 0 0.16 1.00 78,003 46,586 External factors within 5 min 0.02 0.03 −0.04 0.08 1.00 79,045 47,160 Unfamiliar observer (AB) −0.04 0.07 −0.19 0.11 1.00 17,011 28,032 Trial number −0.01 0.01 −0.02 0.01 1.00 18,351 29,277 Unfamiliar observer (AB): Trial number 0.01 0.01 −0.01 0.03 1.00 17,138 26,376 Family specific (log-normal) Sigma 0.31 0.01 0.3 0.32 1.00 48,397 43,998 Group-level effects Date (58 levels) sd(Intercept) 0.14 0.02 0.1 0.18 1.00 17,027 32,825 Individual identity (69 levels) sd(Intercept) 0.24 0.03 0.18 0.31 1.00 13,558 27,638 sd(VODD) 0.04 0.01 0.02 0.05 1.00 19,663 31,617 sd(ObserverAB) 0.09 0.04 0.01 0.17 1.00 7,956 13,090 sd(TrialNo) 0.01 0 0 0.02 1.00 7,995 11,891 sd(ObserverAB:TrialNo) 0.01 0.01 0 0.02 1.00 5,454 12,200 cor(Intercept,VODD) 0.57 0.19 0.15 0.89 1.00 14,071 24,184 cor(Intercept,ObserverAB) 0.21 0.31 −0.46 0.76 1.00 25,091 33,269 cor(VODD,ObserverAB) 0.16 0.33 −0.53 0.74 1.00 20,671 33,171 cor(Intercept,TrialNo) −0.68 0.22 −0.94 −0.1 1.00 22,289 21,411 cor(VODD,TrialNo) −0.3 0.29 −0.8 0.32 1.00 17,875 27,326 cor(ObserverAB,TrialNo) −0.17 0.37 −0.81 0.57 1.00 17,569 30,321 cor(Intercept,ObserverAB:TrialNo) 0.35 0.3 −0.37 0.82 1.00 18,449 21,803 cor(VODD,ObserverAB:TrialNo) 0.29 0.31 −0.41 0.8 1.00 27,315 29,181 cor(ObserverAB,ObserverAB:TrialNo) −0.05 0.39 −0.72 0.72 1.00 17,705 33,765 cor(TrialNo,ObserverAB:TrialNo) −0.47 0.34 −0.91 0.4 1.00 9,755 21,676 - Table 4 FID model summary.
Parameter estimates for the model describing the relationship between FID and the predictor variables.
Population-level effects Estimate Est. Error 1–95% CI U-95% CI Rhat Bulk_ESS Tail_ESS Intercept 0.67 0.1 0.47 0.87 1.00 13,556 28,565 VODI −0.04 0.01 −0.07 −0.01 1.00 45,436 45,243 Engaged 0.14 0.02 0.1 0.18 1.00 97,776 46,015 Open (Habitat) 0.12 0.02 0.08 0.16 1.00 91,775 47,949 Ground (Height) 0.12 0.06 0 0.23 1.00 100,351 48,107 Number of neighbors −0.08 0.01 −0.09 −0.06 1.00 98,909 47,398 Neighbor flee first 0 0.05 −0.09 0.09 1.00 94,500 45,544 External factors within 5 min 0.01 0.04 −0.06 0.08 1.00 94,487 45,998 Unfamiliar observer (AB) −0.14 0.08 −0.3 0.03 1.00 19,463 30,667 Trial number −0.02 0.01 −0.04 −0.01 1.00 21,542 34,353 Unfamiliar observer (AB): Trial
number0.02 0.01 0 0.05 1.00 17,996 27,736 Family specific (log-normal) Sigma 0.36 0.01 0.34 0.37 1.00 55,469 45,557 Group-level effects Date (58 levels) sd(Intercept) 0.14 0.02 0.11 0.19 1.00 17,300 31,725 Individual identity (69 levels) sd(Intercept) 0.49 0.05 0.4 0.6 1.00 13,780 25,841 sd(VODI) 0.06 0.02 0.02 0.09 1.00 10,338 13,826 sd(ObserverAB) 0.18 0.04 0.1 0.26 1.00 17,276 16,843 sd(TrialNo) 0.01 0 0 0.02 1.00 11,643 13,855 sd(ObserverAB:TrialNo) 0.01 0.01 0 0.02 1.00 8,880 18,037 cor(Intercept,VODI) 0.26 0.22 −0.16 0.7 1.00 22,518 25,743 cor(Intercept,ObserverAB) 0.04 0.2 −0.33 0.44 1.00 34,506 35,920 cor(VODI,ObserverAB) 0.16 0.28 −0.39 0.68 1.00 10,048 18,984 cor(Intercept,TrialNo) −0.46 0.25 −0.84 0.15 1.00 43,028 29,416 cor(VODI,TrialNo) −0.25 0.33 −0.81 0.45 1.00 17,519 28,304 cor(ObserverAB,TrialNo) −0.39 0.29 −0.86 0.26 1.00 21,982 31,250 cor(Intercept,ObserverAB:TrialNo) −0.12 0.33 −0.73 0.56 1.00 45,303 39,936 cor(VODI,ObserverAB:TrialNo) −0.36 0.35 −0.88 0.47 1.00 26,569 34,646 cor(ObserverAB,ObserverAB:TrialNo) −0.05 0.37 −0.7 0.69 1.00 31,439 41,766 cor(TrialNo,ObserverAB:TrialNo) −0.13 0.39 −0.77 0.67 1.00 19,037 35,675
Supplementary Materials
Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/6/28/eaaz0870/DC1
Additional Files
Supplementary Materials
Habituation is not neutral or equal: Individual differences in tolerance suggest an overlooked personality trait
Andrew T. L. Allan, Annie L. Bailey, Russell A. Hill
This PDF file includes:
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- Texts S1 and S2
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