Extended Data Figure 2. Pup call ISIs drive retrieval and approach behavior in experienced females.

a, Retrieval in cold pup assay from Fig. 1c across dams and experienced virgins (‘EVs’). Dams and EVs did not differ in their retrieval behavior. Warm pups: dams (85.2%, n=27 trials) vs. EVs (77.0%, n=26), p=0.50; prototypes (‘proto’): dams (91.7%, n=12) vs. EVs (66.7%, n=18), p=0.19; cold pups: dams (25.0%, n=12) vs. EVs (38.5%, n=13), p=0.67 (two-tailed Fisher’s test). Retrieval rate±95% binomial CIs. b, Latency to retrieve on successful retrieval trials from Fig. 1c. Latencies were binned based on whether ISIs elicited retrieval at similar rates to warm pups. Latencies to retrieve cold pups and cold pups dubbed over with slow morphs (single syllables (‘SS’) and 575 ms ISIs) were longer than for warm pups (p=0.02) or cold pups dubbed over with morphs containing ISIs between 75:375 ms (p=0.001) (Kruskal–Wallis H-test with Dunn’s correction). Median±95% CIs. c, A y-maze was used to assess approach towards speakers playing pup calls versus temporal morphs in the absence of a live pup. A speaker in one room played a prototypical pup call, while a competing speaker in the other room played its spectrally-matched, temporal morph. Mice were given two minutes to enter a room. Data from dams and experienced virgins were pooled. d, When competing morphs contained ISIs between 25:149 ms (62.5 ms: 44.2%, n=52 total trials) or 201:350 ms (275 ms: 55.6%, n=45), experienced females showed no significant preference between the prototype and morph (compared to chance (0.50) using two-tailed binomial test; 62.5 ms, p=0.49; 275 ms, p=0.46). Mice showed a significant preference to approach prototypes when ISIs were slower than 350 ms. 425 ms (25.0%, n=20), p=0.04; 575+ ms (15.8%, n=19), p=0.005. Data binned ±75 ms except 575+. Retrieval rate±95% binomial CIs. Stats: *p<0.05, **p<0.01