Resolving the associative learning paradox by category learning in pigeons

A sequence bottleneck for animal intelligence and language?

We discuss recent findings suggesting that non-human animals lack memory for stimulus sequences, and therefore do not represent the order of stimuli faithfully. These observations have far-reaching consequences for animal cognition, neuroscience, and studies of the evolution of language and culture. This is because, if non-human animals do not remember or process information about order faithfully, then it is unlikely that non-human animals perform mental simulations, construct mental world models, have episodic memory, or transmit culture faithfully. If this suggested sequence bottleneck proves to be a prevalent characteristic of animal memory systems, as suggested by recent work, it would require a re-examination of some influential concepts and ideas.

"Distribution of dominant wavelengths predicts jackdaw (Corvus monedula) color discrimination performance"

Color vision is an important perceptual ability in most species and a crucial capacity underlying any cognitive task working with color stimuli. Birds are known for their outstanding vision and tetrachromacy. Two jackdaws were trained to indicate whether they perceive two colors as same or different. The dominant wavelengths of the experimental colors were assessed to relate the birds' performance to the physical qualities of the stimuli. The results indicate that the differences or similarities in dominant wavelengths of the colors had a strong influence on the behavioral data. Colors related to a reduced discriminatory performance were colors of particularly close wavelengths, whereas differences in saturation or brightness were less relevant. Overall, jackdaws mostly relied on hue to discriminate color pairs, and their behavior strongly reflected the physical composition of the color set. These findings show that when working with color stimuli, not only the perceptual abilities of the particular species, but also the technical aspects concerning the color presentation have to be considered carefully.

Cost does not prevent pigeons from investing in the future

One of the simplest forms of behavior, operant behavior, appears fundamentally prospective, implying potential similarity to 'sophisticated' prospective behaviors like planning in terms of underlying mechanisms. But differences between paradigms for studying behavior resulting from 'simple' versus 'sophisticated' mechanisms prevent true comparison of underlying mechanisms. To aid development of an operant paradigm with more similarity to 'sophisticated' prospective paradigms, we replicated and extended Cowie and Davison's (2021) investing task. Pigeons were required to emit an investing response to ensure food at a different time and different response location. We asked if investing depended on whether the behavior was a single, discrete key peck (typical in operant paradigms) or an extended sequence of pecks (echoing behaviors in planning paradigms), and whether facilitative effects of an immediate stimulus change persisted when the stimulus change no longer occurred. Pigeons invested successfully whether investing required one or more responses, and for extended investing responses, performance did not worsen significantly with increasing response requirements. Experience investing with an immediate stimulus change did not enhance subsequent investing without the stimulus change. Findings show simple learning mechanisms can support extended activities with no immediate consequences. Further, they support the investing paradigm as a potential tool for investigations of overlap in mechanisms controlling 'simple' and 'sophisticated' behavior.

Simplified Visual Stimuli Impair Retrieval and Transfer in Audiovisual Equivalence Learning Tasks

BACKGROUND

The visually guided Rutgers Acquired Equivalence Test (RAET) and the various visual and audiovisual versions of the test with the same structure involve rule acquisition, retrieval, and generalization and is based on learning stimulus pairs (antecedents and consequents). In an earlier study we have found no difference in the acquisition learning and only slight enhancement in retrieval and generalization in the audiovisual learning compared to the visual one if complex readily verbalizable visual stimuli (cartoon faces and color fish) were used. In this study, we sought to examine whether similar phenomena can be observed with feature-restricted, less verbalizable visual stimuli (geometric shapes).

METHODS

A total of 119 healthy adult volunteers completed two computer-based test paradigms: Polygon (PO) and SoundPolygon (SP). PO is a visual test where the antecedents are shaded circles, and the consequents are geometric shapes. SP is an audiovisual test where the antecedents are sounds and the consequents are the same geometric shapes as in PO.

RESULTS

There were no significant differences in the performances and the reaction times in the acquisition phase between the PO (visual) and SP (audiovisual) tests. However, the performances in retrieval and generalization were significantly poorer in the audiovisual test and the reaction times were also longer.

CONCLUSION

The acquisition phase seems to be independent from the stimulus modality if the simple geometric shapes were visual stimuli. However, feature-restricted, less verbalizable visual stimuli make more difficult to retrieve and generalize the already acquired audiovisual information.

Artificial intelligence-based prediction of pathogen emergence and evolution in the world of synthetic biology

The emergence of new techniques in both microbial biotechnology and artificial intelligence (AI) is opening up a completely new field for monitoring and sometimes even controlling the evolution of pathogens. However, the now famous generative AI extracts and reorganizes prior knowledge from large datasets, making it poorly suited to making predictions in an unreliable future. In contrast, an unfamiliar perspective can help us identify key issues related to the emergence of new technologies, such as those arising from synthetic biology, whilst revisiting old views of AI or including generative AI as a generator of abduction as a resource. This could enable us to identify dangerous situations that are bound to emerge in the not-too-distant future, and prepare ourselves to anticipate when and where they will occur. Here, we emphasize the fact that amongst the many causes of pathogen outbreaks, often driven by the explosion of the human population, laboratory accidents are a major cause of epidemics. This review, limited to animal pathogens, concludes with a discussion of potential epidemic origins based on unusual organisms or associations of organisms that have rarely been highlighted or studied.

Limits of flexibility and associative learning in pigeons

In a recent study, Wasserman, Kain, and O'Donoghue (Current Biology, 33(6), 1112-1116, 2023) set out to resolve the associative learning paradox by showing that pigeons can solve a complex category learning task through associative learning. The present Outlook paper presents their findings, expands on this paradox, and discusses implications of their results.

Why birds are smart

Many cognitive neuroscientists believe that both a large brain and an isocortex are crucial for complex cognition. Yet corvids and parrots possess non-cortical brains of just 1-25 g, and these birds exhibit cognitive abilities comparable with those of great apes such as chimpanzees, which have brains of about 400 g. This opinion explores how this cognitive equivalence is possible. We propose four features that may be required for complex cognition: a large number of associative pallial neurons, a prefrontal cortex (PFC)-like area, a dense dopaminergic innervation of association areas, and dynamic neurophysiological fundaments for working memory. These four neural features have convergently evolved and may therefore represent 'hard to replace' mechanisms enabling complex cognition.

The Pigeon as a Model of Complex Visual Processing and Category Learning

Over the past 30 years, behavioral, computational, and neuroscientific investigations have yielded fresh insights into how pigeons adapt to the diverse complexities of their visual world. A prime area of interest has been how pigeons categorize the innumerable individual stimuli they encounter. Most studies involve either photorealistic representations of actual objects thus affording the virtue of being naturalistic, or highly artificial stimuli thus affording the virtue of being experimentally manipulable. Together those studies have revealed the pigeon to be a prodigious classifier of both naturalistic and artificial visual stimuli. In each case, new computational models suggest that elementary associative learning lies at the root of the pigeon's category learning and generalization. In addition, ongoing computational and neuroscientific investigations suggest how naturalistic and artificial stimuli may be processed along the pigeon's visual pathway. Given the pigeon's availability and affordability, there are compelling reasons for this animal model to gain increasing prominence in contemporary neuroscientific research.

Assembly and annotation of 2 high-quality columbid reference genomes from sequencing of a Columba livia × Columba guinea F1 hybrid

Pigeons and doves (family Columbidae) are one of the most diverse extant avian lineages, and many species have served as key models for evolutionary genomics, developmental biology, physiology, and behavioral studies. Building genomic resources for columbids is essential to further many of these studies. Here, we present high-quality genome assemblies and annotations for 2 columbid species, Columba livia and Columba guinea. We simultaneously assembled C. livia and C. guinea genomes from long-read sequencing of a single F1 hybrid individual. The new C. livia genome assembly (Cliv_3) shows improved completeness and contiguity relative to Cliv_2.1, with an annotation incorporating long-read IsoSeq data for more accurate gene models. Intensive selective breeding of C. livia has given rise to hundreds of breeds with diverse morphological and behavioral characteristics, and Cliv_3 offers improved tools for mapping the genomic architecture of interesting traits. The C. guinea genome assembly is the first for this species and is a new resource for avian comparative genomics. Together, these assemblies and annotations provide improved resources for functional studies of columbids and avian comparative genomics in general.

The pigeon as a machine: Complex category structures can be acquired by a simple associative model

Never known for its smarts, the pigeon has proven to be a prodigious classifier of complex visual stimuli. What explains its surprising success? Does it possess elaborate executive functions akin to those deployed by humans? Or does it effectively deploy an unheralded, but powerful associative learning mechanism? In a series of experiments, we first confirm that pigeons can learn a variety of category structures - some devised to foil the use of advanced cognitive processes. We then contrive a simple associative learning model to see how effectively the model learns the same tasks given to pigeons. The close fit of the associative model to pigeons' categorization behavior provides unprecedented support for associative learning as a viable mechanism for mastering complex category structures and for the pigeon's using this mechanism to adapt to a rich visual world. This model will help guide future neuroscientific research into the biological substrates of visual cognition.

Assembly and annotation of two high-quality columbid reference genomes from sequencing of a Columba livia x Columba guinea F1 hybrid

Pigeons and doves (family Columbidae) are one of the most diverse extant avian lineages, and many species have served as key models for evolutionary genomics, developmental biology, physiology, and behavioral studies. Building genomic resources for colubids is essential to further many of these studies. Here, we present high-quality genome assemblies and annotations for two columbid species, Columba livia and C. guinea. We simultaneously assembled C. livia and C. guinea genomes from long-read sequencing of a single F1 hybrid individual. The new C. livia genome assembly (Cliv_3) shows improved completeness and contiguity relative to Cliv_2.1, with an annotation incorporating long-read IsoSeq data for more accurate gene models. Intensive selective breeding of C. livia has given rise to hundreds of breeds with diverse morphological and behavioral characteristics, and Cliv_3 offers improved tools for mapping the genomic architecture of interesting traits. The C. guinea genome assembly is the first for this species and is a new resource for avian comparative genomics. Together, these assemblies and annotations provide improved resources for functional studies of columbids and avian comparative genomics in general.

Animal cognition: Wild mountain chickadees follow the abstract rules

concept formation is a cognitive skill that nonhuman animals have been shown to possess. Most often, this ability has been shown in laboratory tasks; a new study sheds light on what role abstract concept formation may play in the wild.

Cognition: The power of simple associative learning

Associative learning is traditionally considered to be slow and inefficient compared to 'smarter' rule-based learning. New research reveals the remarkable ability of associative learning in acquiring exceedingly complex categories.