Biology subjects

Vasas, V.

Publications and source records attributed to Vasas, V..

4 recordsLinked to original sources

bioRxiv2023

Spontaneous biases enhance generalisation in the neonate brain

The ability to use sparse evidence to produce adaptive responses in new contexts and to new stimuli (inductive generalisation) is central to biological and artificial intelligence. Young and inexperienced animals require very little evidence to generalise, raising the question of whether the neonate brain is evolutionarily prepared (predisposed) for generalisation. To understand the principles of spontaneous generalisation, we exposed neonate chicks to an artificial social partner of a specific colour, and measured generalisation by comparing responses to novel and familiar stimuli along either the red-yellow or the blue-green colour continuum. Generalisation responses were inconsistent with an unbiased model, showing biases such as asymmetrical generalisation gradients, faster learning for particular colours (red and blue over yellow and green), preferences for unfamiliar stimuli and different time courses in learning. Moreover, the chicks generalisation behaviour was consistent with a Bayesian theoretical model that explicitly incorporates predispositions as initial preferences and treats the learning process as an update of spontaneous preferences. These results show that neonate animals are evolutionarily prepared for generalisation, via biases that do not depend on experience, reinforcement or supervision. Biases that facilitate generalisation are tuned to distinctive features that are unusual in the natural environment, such as the red and blue colours. Predispositions facilitate or hinder learning in the inexperienced brain, determining how experience is used to update the likelihood of predictive models. Neonate animals use spontaneous biases to solve the problem of induction.

neuroscience↗

bioRxiv2023

Assessing preferences for adult vs juvenile features in young animals: newly-hatched chicks spontaneously approach red and large stimuli

Young precocial birds benefit from staying close to both their mother and siblings, while prioritising adults, which provide better care. Which features of the stimuli are used by young birds to prioritise attachment to adults over siblings is unknown. We started to address this question in newly hatched domestic chicks (Gallus gallus), focusing on their spontaneous preferences for visual stimuli that systematically vary between adult and juvenile chickens: size (larger in adults than in juveniles) and colour (darker and redder in adults than in juveniles). Overall, chicks at their first visual experience, that had never seen a conspecific beforehand, were most attracted to the red and large stimuli (two adult features) and interacted with red stimuli more than with yellow stimuli. When tested with red large vs. small objects (Exp. 1), chicks preferred the large shape. When tested with yellow large and small objects (Exp. 2), chicks did not show a preference. These results suggest that the combination of size and colour form the predisposition that helps chicks to spontaneously discriminate between adult and juvenile features from the first stages of life, in the absence of previous experience.

animal behavior and cognition↗

bioRxiv2022

Recording animal-view videos of the natural world

Plants, animals, and fungi display a rich tapestry of colors. Animals, in particular, use colors in dynamic displays performed in spatially complex environments. In such natural settings, light is reflected or refracted from objects with complex shapes that cast shadows and generate highlights. In addition, the illuminating light changes continuously as viewers and targets move through heterogeneous, continually fluctuating, light conditions. Although traditional spectrophotometric approaches for studying colors are objective and repeatable, they fail to document this complexity. Worse, they miss the temporal variation of color signals entirely. Here, we introduce hardware and software that provide ecologists and filmmakers the ability to accurately record animal-perceived colors in motion. Specifically, our Python codes transform photos or videos into perceivable units (quantum catches) for any animal of known photoreceptor sensitivity. We provide the plans, codes, and validation tests necessary for end-users to capture animal-view videos. This approach will allow ecologists to investigate how animals use colors in dynamic behavioral displays, the ways natural illumination alters perceived colors, and other questions that remained unaddressed until now due to a lack of suitable tools. Finally, our pipeline provides scientists and filmmakers with a new, empirically grounded approach for depicting the perceptual worlds of non-human animals.

animal behavior and cognition↗

bioRxiv2022

Newborn chicks prefer stimuli that move against gravity

At the beginning of life, inexperienced animals use evolutionary-given preferences (predispositions) to decide what stimuli attend and approach. Stimuli that contain cues of animacy, such as face-like stimuli, biological motion and changes in speed, are particularly attractive across vertebrate taxa. A strong cue of animacy is upward movement against terrestrial gravity, because only animate objects consistently move upward. To test whether upward movement is spontaneously considered attractive already at birth, we tested the early preferences of dark-hatched chicks (Gallus gallus) for upward vs downward moving visual stimuli. We found that, without any previous visual experience, chicks consistently exhibited a preference to approach upward moving stimuli, that move against gravity. A control experiment showed that these preferences are not driven by avoidance of downward stimuli. These results show that newborn animals are spontaneously attracted by upward movement, indicating that movement against gravity can be used as a cue of animacy to orient early approach responses in the absence of previous visual experience.

animal behavior and cognition↗