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arxiv: 2606.13463 · v1 · pith:GCXNUANZnew · submitted 2026-06-11 · 🧬 q-bio.OT

Begging with a Purpose? Testing Behavioural Hallmarks of First-Order Intentionality in Free-ranging Hanuman Langurs

Dishari Dasgupta , Shriparna Chattopadhyay , Sruti Banerjee , Pratyusha Adhikary , Akash Dutta , Manabi Paul , Anindita Bhadra This is my paper

Pith reviewed 2026-06-27 05:08 UTC · model grok-4.3

classification 🧬 q-bio.OT
keywords Hanuman langursintentional communicationfirst-order intentionalitygestural communicationfood solicitationprimatesbehavioral markersfree-ranging
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The pith

Free-ranging Hanuman langurs display multiple behavioral hallmarks of first-order intentionality in their human-directed gestures.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper tests whether the human-directed food-solicitation gestures of Hanuman langurs show signs of intentional communication. Researchers ran 360 experimental and control trials at six sites in India, recording behaviors such as audience checking, recipient-directed orientation, rapid approaches, gesture use and flexibility. These markers appeared frequently during food presentations but rarely or not at all in controls, with significant differences at every site. Gesturing also stopped once food was obtained. The results indicate that first-order intentionality is present in this non-ape primate species living near humans.

Core claim

Experimental trials elicited audience checking, recipient-directed orientation, rapid approach responses, food-solicitation gestures and gestural flexibility, whereas these behaviours were rare or absent in control trials. Differences between experimental and control conditions were significant across all six study sites. Signalling also ceased following food acquisition, consistent with the stopping rule associated with an Apparently Satisfactory Outcome. Our findings demonstrate the presence of multiple behavioural hallmarks linked to first-order intentionality in the human-directed gestural communication of free-ranging Hanuman langurs.

What carries the argument

The set of behavioural markers used to operationalize first-order intentionality: audience checking, recipient-directed orientation, rapid approach responses, food-solicitation gestures, gestural flexibility, and the stopping rule after an Apparently Satisfactory Outcome.

If this is right

  • Intentional communication occurs in free-ranging non-ape primates.
  • The evolutionary distribution of intentionality-related traits extends across primates beyond apes.
  • Human-directed gestures in wild langurs can be tested experimentally for cognitive markers.
  • The observed patterns remain consistent across multiple anthropogenic sites.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Similar experiments could test for these markers in other monkey species that interact with humans.
  • The results suggest that proximity to humans may influence how primates develop intentional signaling.
  • Future comparisons between free-ranging and captive groups could clarify environmental effects on these behaviors.

Load-bearing premise

The quantified markers validly capture first-order intentionality rather than reflexive or learned responses without mental-state attribution.

What would settle it

If audience checking, flexible gesturing, and the stopping rule after food acquisition appeared at similar rates in control trials without food presentation.

Figures

Figures reproduced from arXiv: 2606.13463 by Akash Dutta, Anindita Bhadra, Dishari Dasgupta, Manabi Paul, Pratyusha Adhikary, Shriparna Chattopadhyay, Sruti Banerjee.

Figure 1
Figure 1. Figure 1: Field site map of the six study sites located in the southern part of the state of West Bengal, India. The study sites are as follows: A. Habibpur, B. Kalyani, C. Sarenga D. Nungi E.Dakshineswar F. Chandannagar A total of 360 trials were conducted, consisting of 180 trials separately for experimental and control conditions (30 trials per condition, per site). Following established protocols for testing Com… view at source ↗
Figure 2
Figure 2. Figure 2: Experimental and control trial protocol for assessing intentional gestural communication in free-ranging Hanuman langurs. (a) Experimental Cue 1: the experimenter raised one arm while visibly displaying bread for 10 s. (b) Concealment phase: the bread was hidden from the langur for 10 s. (c) If the focal langur produced a begging gesture, the food reward was delivered immediately. If no response occurred, … view at source ↗
Figure 4
Figure 4. Figure 4: Hallmark 2: Desire Criterion (goal-directedness). (a) Operationalization of the hallmark. (b-i) Box-and-jitter plot of LO (Look) duration for the experimental (E0 and control (C) trials across all six sites. (b-ii) Violin-and-jitter plot of approach (AP) latency during experimental trials across all six sites. (b–iii) Bar plot showing the percentage of ASO (BG Stop) events after the focal langur received b… view at source ↗
Figure 5
Figure 5. Figure 5: Hallmark 3 : Social Use. (a) Operationalization of the hallmark. (b) P [PITH_FULL_IMAGE:figures/full_fig_p017_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Hallmark – Volitional control (behaviour change after cue).(ia & iia) Operationalization of hallmark. (ib) Percentage of Approach events (AP = 1) by focal langurs during experimental (dark blue circle) versus control (light green triangle) trials across all six field sites. (ic) Stacked bar plots showing the proportion of behavioural changes exhibited by focal langurs after receiving the cu, for experiment… view at source ↗
read the original abstract

Intentional communication has been studied extensively in primates, yet evidence from free-ranging non-ape species remains limited. Human-directed food-solicitation gestures in Hanuman langurs (Semnopithecus entellus) have recently been described, but whether these behaviours exhibit behavioural hallmarks associated with first-order intentionality remains unknown. Here, we experimentally investigated the presence of these hallmarks in free-ranging Hanuman langurs across six anthropogenic sites in southern West Bengal, India. We conducted 360 experimental and control trials and quantified behavioural markers commonly used to operationalize intentional communication. Experimental trials elicited audience checking, recipient-directed orientation, rapid approach responses, food-solicitation gestures and gestural flexibility, whereas these behaviours were rare or absent in control trials. Differences between experimental and control conditions were significant across all six study sites. Signalling also ceased following food acquisition, consistent with the stopping rule associated with an Apparently Satisfactory Outcome. Our findings demonstrate the presence of multiple behavioural hallmarks linked to first-order intentionality in the human-directed gestural communication of free-ranging Hanuman langurs. These results extend the study of intentionality beyond apes and provide new insights into the evolutionary distribution of intentionality-related traits across primates.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 1 minor

Summary. The manuscript reports results from 360 experimental and control trials across six anthropogenic sites in India testing whether human-directed food-solicitation gestures by free-ranging Hanuman langurs exhibit behavioral hallmarks of first-order intentionality. Markers quantified include audience checking, recipient-directed orientation, rapid approach responses, food-solicitation gestures, gestural flexibility, and cessation of signaling after an Apparently Satisfactory Outcome (food acquisition). The authors report these behaviors occur significantly more often in experimental (food-present) than control trials at all sites and conclude that the data demonstrate first-order intentionality in a non-ape primate species.

Significance. If the central interpretation holds, the multi-site empirical design would extend the documented distribution of intentional-communication markers beyond apes to colobines and strengthen comparative claims about the evolutionary history of these traits. The use of free-ranging subjects and a stopping-rule test are positive features of the study.

major comments (2)
  1. [Methods / Experimental Design] The experimental contrast (food-present vs. food-absent) does not include controls capable of dissociating first-order intentional signaling from associative learning or reflexive orientation to salient human cues (e.g., non-social food cues, habituation trials, or non-communicative goal-directed actions). Because the same behavioral sequence is predicted by simpler reinforcement mechanisms at anthropogenic sites, this omission is load-bearing for the claim that the quantified markers specifically operationalize first-order intentionality.
  2. [Abstract / Results] The abstract states that differences were significant across all six sites and consistent with the stopping rule, yet reports no statistical tests, effect sizes, inter-observer reliability coefficients, or controls for site or individual identity. These details are required to evaluate whether the data support the cross-site consistency claim.
minor comments (1)
  1. [Methods] The operational definitions of each behavioral marker (audience checking, gestural flexibility, etc.) should be stated explicitly with reference to prior literature so that readers can assess their validity independent of the intentionality interpretation.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their detailed and constructive comments on our manuscript. We address each major point below and outline planned revisions where appropriate.

read point-by-point responses

  1. Referee: [Methods / Experimental Design] The experimental contrast (food-present vs. food-absent) does not include controls capable of dissociating first-order intentional signaling from associative learning or reflexive orientation to salient human cues (e.g., non-social food cues, habituation trials, or non-communicative goal-directed actions). Because the same behavioral sequence is predicted by simpler reinforcement mechanisms at anthropogenic sites, this omission is load-bearing for the claim that the quantified markers specifically operationalize first-order intentionality.

    Authors: We agree that additional controls could further isolate intentionality from associative or reflexive processes. However, our design follows standard protocols used in ape intentionality studies (e.g., audience checking and stopping-rule tests), and the food-absent condition controls for baseline human-directed behaviors at the same sites. The observed patterns—particularly gestural flexibility, recipient-directed orientation, and cessation after food acquisition—are less parsimoniously explained by simple reinforcement alone. We will add an explicit discussion of this limitation and its implications for interpretation in the revised manuscript. revision: partial

  2. Referee: [Abstract / Results] The abstract states that differences were significant across all six sites and consistent with the stopping rule, yet reports no statistical tests, effect sizes, inter-observer reliability coefficients, or controls for site or individual identity. These details are required to evaluate whether the data support the cross-site consistency claim.

    Authors: The full manuscript reports the relevant statistical tests (including site-level comparisons), effect sizes, inter-observer reliability (Cohen’s kappa), and mixed-effects models controlling for site and individual identity in the Results and Statistical Analysis sections. The abstract is a concise summary and does not include these values due to length constraints. To improve clarity, we will revise the abstract to reference the key statistical support for cross-site consistency while retaining the word limit. revision: yes

Circularity Check

0 steps flagged

No circularity: empirical comparison of pre-defined markers across conditions

full rationale

The paper reports an experimental study that applies established behavioral markers (audience checking, recipient-directed orientation, etc.) drawn from prior primate communication literature to new data from controlled food-present vs. food-absent trials. These markers are treated as operational definitions imported from external sources rather than derived or fitted within the paper itself. No equations, parameter estimation, or self-citation chains are used to generate the central claim; the result is a straightforward frequency comparison that stands or falls on the external validity of the imported markers. No load-bearing step reduces to a self-definition or fitted input by construction.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The central claim rests on the domain assumption that the listed behavioral markers reliably indicate first-order intentionality; no free parameters or invented entities are introduced.

axioms (1)
  • domain assumption Behavioral markers such as audience checking, recipient-directed orientation, gestural flexibility, and the stopping rule after food acquisition operationalize first-order intentionality.
    Invoked throughout the abstract as the basis for interpreting the experimental results.

pith-pipeline@v0.9.1-grok · 5781 in / 1087 out tokens · 24879 ms · 2026-06-27T05:08:37.369846+00:00 · methodology

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Reference graph

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