Open-ended categorization of chick-a-dee calls by black-capped chickadees (Poecile atricapilla).
The authors trained black-capped chickadees (Poecile atricapilla) in an operant discrimination with exemplars of black-capped and Carolina chick-a-dee calls, with the goal of determining whether the birds memorized the calls of conspecifics and heterospecifics or classified the calls by species. Black-capped calls served as both rewarded (S+) and unrewarded (S-) stimuli (the within-category discrimination), whereas Carolina chick-a-dee calls served as S-s (the between-category discrimination) in the black-capped chick-a-dee call S+ group. The Carolina call S+ group had Carolina calls as S+s and S-s (within-category) and black-capped calls as S-s (between-category). Both groups discriminated between call categories faster than within a call category. In 2 subsequent experiments, both S+ groups showed transfer to novel calls and propagation back to between-category calls. The results favor the hypothesis that the acoustically similar social calls of the 2 species constitute separate open-ended categories.
D000819:Animal Communication; D000818:Animals; D001307:Auditory Perception; D003216:Conditioning, Operant; D004193:Discrimination Learning; D005260:Female; D005583:Fourier Analysis; D008297:Male; D011939:Mental Recall; D012815:Signal Processing, Computer-Assisted; D020308:Songbirds; D013018:Sound Spectrography; D013045:Species Specificity; D014163:Transfer, Psychology; D014828:Vocalization, Animal