Logan S. James

Diverse approaches to understand how acoustic communication systems function, evolve, and develop across species

Research

Birds Biases in Vocal Patterning

Songbirds and humans share striking similarities in how they organize vocal sequences. My work has found that learning biases, systematic tendencies in how vocal patterns are acquired, shape song structure in zebra finches in ways that parallel universal patterns in human speech and music. Through expansive comparative analyses across songbird species, I've discovered the prevalence of hierarchical patterning rules like Menzerath's law, and pervasive patterns in sequencing that are also found in human music. Surprisingly, I have found that vocal learning ability does not strongly predict sequence patterning.

Learning biases underlie “universals” in avian vocal sequencing (2017) Mechanisms underlying vocal learning biases (2020) Phylogeny and mechanisms of shared hierarchical patterns in birdsong (2021)

Spectrograms showing positional biases in zebra finch syllables, with bar charts of syllable duration, frequency, and amplitude across song positions — Learning biases shape where zebra finches place syllables within their songs, producing systematic patterns in duration and frequency.

Comparative analysis of Menzerath's law across songbird families, showing spectrograms and regression plots for multiple species — Menzerath's law (longer songs have shorter syllables) appears across diverse songbird families.

Frogs Mechanisms of Communication

Túngara frogs produce multimodal courtship displays involving acoustic calls, vocal sac inflation, and surface water ripples. I study the production and perception of these displays, including how dopamine modulates call complexity and social decision-making. Using robotic frogs and laser vibrometry, I've mapped how different signal components covary and how receivers integrate multimodal information to make mate choice decisions.

Dopamine affects social decision-making in calling male túngara frogs (2025) Covariation among multimodal components in courtship display (2021) Cross-modal facilitation of auditory discrimination (2022)

Graphical abstract showing dopamine agonist effects on túngara frog calling behavior, with dose-dependent changes in chuck numbers and call timing — Dopamine modulates call complexity in túngara frogs, causing dose-dependent increases in chuck number and changes in call timing.

Experimental setup for robotic frog playback experiments, showing the arena, robofrog with inflatable vocal sac, and mechanical apparatus — A robotic frog with an inflatable vocal sac allows controlled manipulation of multimodal courtship signals.

Bats Auditory Decision-Making

Fringe-lipped bats are remarkable eavesdroppers: they locate prey by listening to the mating calls of frogs and insects. But how do young bats learn which calls mean a safe meal versus a toxic one? By testing wild-caught bats across development, I found that juvenile bats begin with broad, exploratory predatory responses that appear to be refined through experience, documenting a developmental trajectory for acoustic cognition in the wild.

The ontogeny of decision-making in an eavesdropping predator (2025)

In the press:

Fringe-lipped bat predatory responses to frog calls across species, showing palatable versus unpalatable prey sorted by predatory response score — Juvenile fringe-lipped bats show broad predatory responses to diverse frog calls, narrowing their preferences as they mature.

Humans Shared Acoustic Preferences

Do humans and other animals find the same sounds appealing? Using a large-scale online experiment through The Music Lab, I presented thousands of human listeners with pairs of animal calls and asked which they preferred. Remarkably, human preferences aligned with those of the animals themselves across birds, frogs, insects, and mammals, suggesting that some aspects of acoustic aesthetics may be rooted in shared auditory biases in processing.

Humans share acoustic preferences with other animals (preprint)

Calls of the Wild experiment from The Music Lab, showing human preference alignment with animal preferences across 18 species — Human listeners preferred the same calls that animals preferred, with agreement across birds, frogs, insects, and mammals.

Zebra finches · AI Vocal Interactions

Vocal exchanges are common across species, yet the principles underlying the interaction dynamics are often poorly understood. In collaboration with Earth Species Project, I use comprehensive analysis pipelines to examine the interactions of female zebra finches and measure their response dynamics. Moreover, using AI-driven acoustic interaction models, I can simulate real-time interactions with live animals and identify the importance of key features to elicit naturalistic behavior from a bird.

Zebra finch females flexibly communicate with each other and with AI-driven acoustic interaction models (2026)

In the press: