Titi monkey neophobia and visual abilities allow for fast responses to novel stimuli

Abstract

The Snake Detection Theory implicates constricting snakes in the origin of primates, and venomous snakes for differences between catarrhine and platyrrhine primate visual systems. Although many studies using different methods have found very rapid snake detection in catarrhines, including humans, to date no studies have examined how quickly platyrrhine primates can detect snakes. We therefore tested in captive coppery titi monkeys (Plecturocebus cupreus) the latency to detect a small portion of visible snake skin. Because titi monkeys are neophobic, we designed a crossover experiment to compare their latency to look and their duration of looking at a snake skin and synthetic feather of two lengths (2.5 cm and uncovered). To test our predictions that the latency to look would be shorter and the duration of looking would be longer for the snake skin, we used survival/event time models for latency to look and negative binomial mixed models for duration of looking. While titi monkeys looked more quickly and for longer at both the snake skin and feather compared to a control, they also looked more quickly and for longer at larger compared to smaller stimuli. This suggests titi monkeys’ neophobia may augment their visual abilities to help them avoid dangerous stimuli.

The Saliency of Snake Scales and Leopard Rosettes to Infants: Its Relevance to Graphical Patterns Portrayed in Prehistoric Art

“…These researchers exposed a narrow section of gopher snake skin to foraging monkeys and noted their enhanced wariness and memory of where they last saw the apparent snake. Follow-up research with captive titi monkeys ( Plecturocebus cupreus ) demonstrated a similar effect of sustained attention, comparing a small (2.5cm length) segment of gopher snake skin with a same-length feather ( Lau et al, 2021 ).…”

Niche expansion of capuchin monkeys to forest floor on guild‐reduced islands increases interspecific spatio‐temporal overlap

“…We used survival analyses to test differences in visit latency of both species at the tool‐use and non‐tool‐use areas, and compared, respectively, each species' “waiting times” (Lau et al., 2021; Swinkels et al., 2023). The waiting time is the time interval between consecutive detections of the alternative species at a camera trap location (Figure 1).…”

Familiarity mediates apes' attentional biases toward human faces

“…As our data were strictly positive (latencies can only be greater than 0 ms) and right-censored (i.e. we excluded all responses with a latency greater than 1000 ms), we ran a survival analysis for the response variable latency (ms) to touch as our measure of attentional bias ( sensu [ 53 ], see also [ 54 , 55 ]). For all experiments, we fitted Cox proportional hazards regression mixed-effects models using the coxph function of the survival library [ 56 ] in R v. 4.1.0 [ 57 ] to explore the relative importance of Species and Stimuli Type on the subjects' response latencies ( sensu [ 53 ]).…”

“…we excluded all responses with a latency greater than 1000 ms), we ran a survival analysis for the response variable latency (ms) to touch as our measure of attentional bias ( sensu [ 53 ], see also [ 54 , 55 ]). For all experiments, we fitted Cox proportional hazards regression mixed-effects models using the coxph function of the survival library [ 56 ] in R v. 4.1.0 [ 57 ] to explore the relative importance of Species and Stimuli Type on the subjects' response latencies ( sensu [ 53 ]). This class of model is a form of survival analysis [ 58 ] that allows the incorporation of categorical variables under a regression modelling framework, making it an ideal choice for our data and research questions.…”