DOI: 10.5061/dryad.stqjq2cb6
title: Data from: Isochrony in Titi Monkeys duets: Social context as a proximate cause of duets’ rhythm and regularity

description: Music and rhythm are typical features of all human cultures, but their
 biological origins remain unclear. Recent investigations suggest that
 rhythmic features of human music are shared with animal vocalizations.
 Moreover, emotions influence human speech and music, similar to what
 arousal does to the structure of animal sounds. We investigated Coppery
 titi monkeys' (Plecturocebus cupreus) duet rhythms to assess
 adherence to rhythmic patterns previously observed only in Old World
 primates and to deepen our understanding of the proximate causes of
 non-human primate song rhythm. Titis’ songs were remarkably isochronous,
 but their tempo depended on the social context: songs sung during
 territorial confrontations have a slower pace than during early morning
 singing. Songs had a faster tempo and were less regular when infants were
 present, suggesting a speed-accuracy tradeoff. Finally, we found that
 pair-mates perform isochronous songs with the same precision, suggesting
 that isochrony plays a role in boosting pair coordination, as it does in
 other singing primates. Our investigation shed light on the ultimate and
 proximate causes of primates' isochronous rhythm, confirming its
 presence for the first time in a New World monkey and highlighting the
 role of social factors in shaping its timing and regularity in the short
 term.
description: # Data from: Isochrony in Titi Monkeys duets: Social context as a
 proximate cause of duets’ rhythm and regularity DESCRIPTION OF THE DATA
 AND FILE STRUCTURE + CODE: "titi_monkeys_isochrony_code.R" A)
 DATA AND FILE STRUCTURE: 1\) RHYTHMIC PEAKS - RK COUNT (Line 5) Here, we
 count the ratios falling in the different on-off integer bins and test the
 presence of rhythmic categories in the two sexes and in the two contexts
 of emission. Dataset: **ratio_titi_ALL_check_peaks.csv** - Raw data of
 inter-onset-intervals (tk) and the corresponding rhythmic ratios (rk) on
 the titis songs sample; VARIABLES DESCRIPTION: file: name of the duet
 recording file_id: name of the TextGrid file for each individual
 contribution group: code for each titi pair date: date of the song audio
 recording context: social context in which the duet was emitted id_ind:
 the name of the individual singing sex: male/female; the sex of the
 individual singing baby: yes /no; presence or absence of a newborn in the
 group label: the label annotating the kind of temporal interval: v -&gt;
 vocalized inrtervals; u -&gt; silent duration: duration of the temporal
 interval (end-start) start: the start (seconds) of the temporal interval
 tk: inter-onset-intervals duraions n: progressive number to track the
 order of intervals rk: rhythmic ratios deriving from two successive tks
 (tk / (tk+tk+1)) 4\) REGULARITY RATE (line 317) Here we investigate
 rhythmic regularity in titi monkeys contribution. Dataset:
 **titi_all_for_RATE.csv** VARIABLES DESCRIPTION: file_id: name of the duet
 recording id_ind: name of the TextGrid file for each individual
 contribution group: code for each titi pair sex: male/female; the sex of
 the individual singing context: social context in which the duet was
 emitted baby: yes /no; presence or absence of a newborn in the group
 OFF11: number of ratios falling off integer ON11: number of ratio falling
 on integer rate2: the ratio between the count of on-integer observation
 and on- plus off-integer observations of the individual contribution
 (id_ind) 5\) Tk variation (line 449) Here we investigate the distribution
 of tk's duration. Dataset: **ratio_titi_ALL_TK.csv** VARIABLES
 DECSRIPTION: order: numbers for ordering dataset raw file: name of the
 duet recording file_id: name of the TextGrid file for each individual
 contribution group: code for each titi pair date: date of the song audio
 recording context: social context in which the duet was emitted id_ind:
 the name of the individual singing sex: male/female; the sex of the
 individual singing baby: yes /no; presence or absence of a newborn in the
 group label: the label annotating the kind of temporal interval. In this
 case: v -&gt; vocalized inervals duration: duration of the temporal
 interval "v" (end-start) start: the start (seconds) of the
 temporal interval tk: inter-onset-intervals duraions n: progressive number
 to track the order of intervals rk: rhythmic ratios deriving from two
 successive tks (tk / (tk+tk+1)) 6\) silent gap duration (line 528) Here we
 investigate the distribution of the silent gap between notes. Dataset:
 **ratio_titi_ALL_GAP_DUR.csv** VARIABLES DECSRIPTION: order: numbers for
 ordering dataset raw file: name of the duet recording file_id: name of the
 TextGrid file for each individual contribution group: code for each titi
 pair date: date of the song audio recording context: social context in
 which the duet was emitted id_ind: the name of the individual singing sex:
 male/female; the sex of the individual singing baby: yes /no; presence or
 absence of a newborn in the group label: the label annotating the kind of
 temporal interval: v -&gt; vocalized inrtervals; u -&gt; silent duration:
 duration of the temporal interval "v" (end-start) start: the
 start (seconds) of the temporal interval 7\) testing the relationship
 between tk and ratio (line 654) Here we investigate the relationship
 between of the tk and regularity of contribution the dataset used are the
 same for tk analyses and regularity ration analyses. Note: * the duet
 recordings are .wav raw files containing the sound of duet given by titi
 monkeys pairs. These raw files are uploaded as supplementary materials. *
 the TextGrid files are .Textgrid files containing information on the
 starting points of different notes, created with the "annotate"
 function through the software Praat, which once created were renamed with
 a name containing organized information on singers identity and context of
 emission. From these files are extracted the durations that are in the
 excel files. B) CODE: The file "Isochrony_titi_monkey_CODE_r1.r"
 is an annotated R script  containing: * Line 5 - the rk count for the
 rhythmic peaks * Line 120 - the testing of the peaks for the two sexes *
 Line 226 - the testing of the peaks for the contexts * Line 317 - the
 testing of the regularity rate * Line 448 - the testing of tempo variation
 * Line 528 - the analysis of silent gap duration