The following two passages explore the evolutionary origins of human rhythmic entrainment.
Passage A
The human capacity for entrainment—the ability to physically synchronize to an external auditory beat—is remarkably rare among mammals. While some evolutionary theorists posit that this capacity emerged as a direct adaptation for social bonding, a more parsimonious explanation views human rhythm as an evolutionary byproduct, or spandrel, of bipedal locomotion. The transition to upright walking was a biomechanical revolution that demanded complex, highly regular neurological timing mechanisms simply to maintain physical balance and coordinate alternating limb movements. Over millions of years, as these crucial oscillatory neural networks became deeply established in the hominid motor cortex, they were subsequently co-opted by the auditory system. This cross-wiring allowed early humans to process and physically respond to periodic acoustic patterns. Thus, under this framework, our profound physiological response to a musical beat is not a specialized adaptation for group cohesion, but essentially a neurological echo of our ancestors' adaptation to walking. The ability to keep a beat was never selected for its own sake; rather, it hitched a ride on the crucial evolutionary imperative of navigating the savanna on two feet.
Passage B
In attempting to locate the evolutionary origins of human rhythm, biomechanical reductionists often overlook the severe communicative necessities and intense survival pressures of early hominid societies. Shared rhythmic behavior cannot be adequately explained without recognizing its immense adaptive value in group survival. Long before the development of complex syntax, synchronized group vocalizations and percussive movements served as early forms of 'social glue.' These communal rhythmic rituals functioned to lower intragroup aggression, coordinate collective labor, and signal group strength to rival bands. Furthermore, if rhythmic capabilities were merely an incidental mechanical byproduct of locomotion, we would not expect to see the intense neurochemical rewards—such as the release of oxytocin and endorphins—that humans universally experience during synchronized group drumming or dancing. These dedicated, deeply embedded neurological reward pathways strongly indicate that rhythmic synchronization was directly and selectively favored for its socially cohesive properties. Natural selection actively shaped the human brain to reward synchronous rhythmic behavior because groups that danced and drummed together were substantially more likely to survive, cooperate, and reproduce than those that did not.
Statement: Based on the argument in Passage A, Author A would evaluate the "intense neurochemical rewards" cited by Author B as compelling evidence that rhythmic entrainment was selectively favored for its adaptive value in social bonding.
Answer: Answer