Showing papers by "Carel ten Cate published in 2017"

Spontaneous generalization of abstract multimodal patterns in young domestic chicks

Abstract: From the early stages of life, learning the regularities associated with specific objects is crucial for making sense of experiences. Through filial imprinting, young precocial birds quickly learn the features of their social partners by mere exposure. It is not clear though to what extent chicks can extract abstract patterns of the visual and acoustic stimuli present in the imprinting object, and how they combine them. To investigate this issue, we exposed chicks (Gallus gallus) to three days of visual and acoustic imprinting, using either patterns with two identical items or patterns with two different items, presented visually, acoustically or in both modalities. Next, chicks were given a choice between the familiar and the unfamiliar pattern, present in either the multimodal, visual or acoustic modality. The responses to the novel stimuli were affected by their imprinting experience, and the effect was stronger for chicks imprinted with multimodal patterns than for the other groups. Interestingly, males and females adopted a different strategy, with males more attracted by unfamiliar patterns and females more attracted by familiar patterns. Our data show that chicks can generalize abstract patterns by mere exposure through filial imprinting and that multimodal stimulation is more effective than unimodal stimulation for pattern learning.

Assessing the uniqueness of language: Animal grammatical abilities take center stage.

Abstract: Questions related to the uniqueness of language can only be addressed properly by referring to sound knowledge of the relevant cognitive abilities of nonhuman animals. A key question concerns the nature and extent of animal rule-learning abilities. I discuss two approaches used to assess these abilities. One is comparing the structures of animal vocalizations to linguistic ones, and another is addressing the grammatical rule- and pattern-learning abilities of animals through experiments using artificial grammars. Neither of these approaches has so far provided unambiguous evidence of advanced animal abilities. However, when we consider how animal vocalizations are analyzed, the types of stimuli and tasks that are used in artificial grammar learning experiments, the limited number of species examined, and the groups to which these belong, I argue that the currently available evidence is insufficient to arrive at firm conclusions concerning the limitations of animal grammatical abilities. As a consequence, the gap between human linguistic rule-learning abilities and those of nonhuman animals may be smaller and less clear than is currently assumed. This means that it is still an open question whether a difference in the rule-learning and rule abstraction abilities between animals and humans played the key role in the evolution of language.

Selective auditory grouping by zebra finches: testing the iambic–trochaic law

Abstract: Humans have a strong tendency to spontaneously group visual or auditory stimuli together in larger patterns. One of these perceptual grouping biases is formulated as the iambic/trochaic law, where humans group successive tones alternating in pitch and intensity as trochees (high-low and loud-soft) and alternating in duration as iambs (short-long). The grouping of alternations in pitch and intensity into trochees is a human universal and is also present in one non-human animal species, rats. The perceptual grouping of sounds alternating in duration seems to be affected by native language in humans and has so far not been found among animals. In the current study, we explore to which extent these perceptual biases are present in a songbird, the zebra finch. Zebra finches were trained to discriminate between short strings of pure tones organized as iambs and as trochees. One group received tones that alternated in pitch, a second group heard tones alternating in duration, and for a third group, tones alternated in intensity. Those zebra finches that showed sustained correct discrimination were next tested with longer, ambiguous strings of alternating sounds. The zebra finches in the pitch condition categorized ambiguous strings of alternating tones as trochees, similar to humans. However, most of the zebra finches in the duration and intensity condition did not learn to discriminate between training stimuli organized as iambs and trochees. This study shows that the perceptual bias to group tones alternating in pitch as trochees is not specific to humans and rats, but may be more widespread among animals.

Bridging the gap: Learning of acoustic nonadjacent dependencies by a songbird.

Abstract: Many animal species can detect dependencies between adjacent visual or auditory items in a string. Compared with adjacent dependencies, detecting nonadjacent dependencies, as present in linguistic constructions, is more challenging as this requires detecting a relation between items irrespective of the number and nature of the intervening items. There is limited evidence that nonhuman animals can detect such dependencies. An animal group in which such abilities might be expected is songbirds, which have learned songs consisting of a series of vocal elements given in specific sequences. So far no songbird (or other bird species) has been tested for its ability to detect nonadjacent dependencies. We examined whether zebra finches can detect the dependencies between items at the edges of artificially arranged strings of song elements. Zebra finches were trained to discriminate 2 sets of dependent song elements that always appeared in the same order (A and B; C and D), from other element combinations (AD, AC, BD, CB, CA, DB). The element combinations were separated by intervening (I) elements. Subsequent tests revealed that the finches could generalize the learned dependencies over different numbers and types of intervening items. Our findings show that the ability for detecting nonadjacent dependencies is not limited to humans or primates, and lend support to theories that suggest that nonadjacent dependencies can be learned by a nonlinguistic associative learning process. (PsycINFO Database Record