Spontaneous Learning of Visual Structures in Domestic Chicks

Abstract

Simple SummaryOur aim is to investigate the recognition of the structure of multi-element configurations; one mechanism that supports communicative functions in different species. Cognitive mechanisms involved in this ability might not have evolved specifically for communicative use, but derive from other functions. Thus, it is crucial to study these abilities in species that are not vocal learners and with stimuli from other modalities. We know already that domestic chicks can learn the temporal statistical structure of sequences of visual shapes, however their abilities to encode the spatial structure of visual patterns (configurations composed of multiple visual elements presented simultaneously side-by-side) is much less known. Using filial imprinting learning, we showed that chicks spontaneously recognize the structure of their imprinting stimulus, preferring it to one composed of the same elements in different configurations. Moreover, we found that in their affiliative responses chicks give priority to information located at the stimulus edges, a phenomenon that was so far observed only with temporal sequences. This first evidence of a spontaneous edge bias with spatial stimuli further stresses the importance of studying similarities and differences between the processing of linguistic and nonlinguistic stimuli and of stimuli presented in various sensory modalities.AbstractEffective communication crucially depends on the ability to produce and recognize structured signals, as apparent in language and birdsong. Although it is not clear to what extent similar syntactic-like abilities can be identified in other animals, recently we reported that domestic chicks can learn abstract visual patterns and the statistical structure defined by a temporal sequence of visual shapes. However, little is known about chicks’ ability to process spatial/positional information from visual configurations. Here, we used filial imprinting as an unsupervised learning mechanism to study spontaneous encoding of the structure of a configuration of different shapes. After being exposed to a triplet of shapes (ABC or CAB), chicks could discriminate those triplets from a permutation of the same shapes in different order (CAB or ABC), revealing a sensitivity to the spatial arrangement of the elements. When tested with a fragment taken from the imprinting triplet that followed the familiar adjacency-relationships (AB or BC) vs. one in which the shapes maintained their position with respect to the stimulus edges (AC), chicks revealed a preference for the configuration with familiar edge elements, showing an edge bias previously found only with temporal sequences.

Statistical learning in domestic chicks is modulated by strain and sex

“…As in 28 , this could be achieved only by encoding either the co-occurrence frequencies of the sequence elements (i.e., how often two shapes appear together), or the predictive relations within pair elements (i.e., the transitional probabilities between the two shapes) 50 . Overall, these results are consistent with previous infant research 6,9 as well as studies on chicks and other species (e.g., 22,[24][25][26][27] ) highlighting the importance of imprinting research for the uncovering of animals' spontaneous abstraction abilities. www.nature.com/scientificreports/ Importantly, our evidence confirms the pivotal role of sex in determining familiarity or novelty preferences in this species, and its interaction with the chicks' strain.…”

“…Thanks to the prominent learning mechanism of filial imprinting, species as domestic chicks (Gallus gallus) offer the opportunity to study unsupervised forms of statistical learning, like it is done in human adults and infants. Using imprinting procedures, it has been possible to demonstrate spontaneous sensitivity to spatial arrangements of visual and audiovisual displays [24][25][26][27] . However, chicks' implicit learning capabilities are not limited to spatial regularities.…”

Positional encoding in cotton-top tamarins (Saguinus oedipus)

“…It is not clear, though, which representations and computational mechanisms different species use to encode positional relationships. Comparative studies have just started to address this issue in primates (Grainger et al 2012; Sonnweber et al 2015), rodents (Murphy et al 2004), and avian species (Chen and ten Cate 2017; Chen et al 2014; Ravignani et al 2015; Rosa-Salva et al 2018; Scarf et al 2016). While some studies have shown successful mastery of the intended pattern, others suggest that animals sometimes focus on a different level of granularity (Ravignani et al 2015; Wakita 2019).…”

“…These results suggest that computations operating on serial stimuli can be available also for visual configurations. Along this line, Rosa-Salva et al (2018) have tested the spontaneous abilities of domestic chicks in visual imprinting, showing a preferential encoding for the position of items located at the edges. The similarities and differences in processing visual and acoustic regularities have just started to be explored (review in Milne et al 2018).…”

Conserved abilities of individual recognition and genetically modulated social responses in young chicks (Gallus gallus)

“…Thanks to these features, imprinting has become a model system for memory, learning and social behaviour (Bateson, 1966; Bolhuis, 1991; Horn, 1985, 2004; McCabe, 2013, 2019). In the laboratory, imprinting is studied using well controlled artificial stimuli such as balls, cubes, cylinders or two-dimensional stimuli presented on cardboards or computer screens (Rosa-Salva et al, 2018; Versace, Schill, Nencini, & Vallortigara, 2016; Versace, Spierings, Caffini, ten Cate, & Vallortigara, 2017; Wood & Wood, 2015). These experiments have shown that chicks discriminate subtle differences of the imprinting objects, such as rotation of the features located inside the imprinting object (Vallortigara & Andrew, 1991), the configuration of items that compose the imprinting stimulus (Rosa-Salva et al, 2018) and even the underlying structure of the stimuli independent of their physical appearance (Martinho & Kacelnik, 2016; Versace, Regolin, & Vallortigara, 2006; Versace, Spierings, et al, 2017).…”