Fabian Soto - Academia.edu (original) (raw)

Papers by Fabian Soto

Research paper thumbnail of Visual object categorization in birds and primates: Integrating behavioral, neurobiological, and computational evidence within a “general process” framework

Previous comparative work has suggested that the mechanisms of object categorization differ impor... more Previous comparative work has suggested that the mechanisms of object categorization differ importantly for birds and primates. However, behavioral and neurobiological differences do not preclude the possibility that at least some of those mechanisms are shared across these evolutionarily distant groups. The present study integrates behavioral, neurobiological, and computational evidence concerning the "general processes" that are involved in object recognition in vertebrates. We start by reviewing work implicating error-driven learning in object categorization by birds and primates, and also consider neurobiological evidence suggesting that the basal ganglia might implement this process. We then turn to work with a computational model showing that principles of visual processing discovered in the primate brain can account for key behavioral findings in object recognition by pigeons, including cases in which pigeons' behavior differs from that of people. These results provide a proof of concept that the basic principles of visual shape processing are similar across distantly related vertebrate species, thereby offering important insights into the evolution of visual cognition. Keywords Object categorization. Object recognition. Error-driven learning. Hierarchical model. Feedforward processing. Comparative cognition. Avian vision. Pigeon. Computational model. Animal models. Visual cortex Many species must visually recognize and categorize objects to successfully adapt to their environments. Considerable comparative research has been conducted in object recognition, especially involving pigeons and people, whose visual systems have independently evolved from a common ancestor, from which their lineages diverged more than 300 million years ago. The results of behavioral studies have sometimes disclosed striking similarities between these species, and at other times have disclosed notable disparities, especially pointing toward a lower ability of pigeons to recognize transformed versions of familiar objects (for reviews, see Kirkpatrick, 2001; Spetch & Friedman, 2006). Similarly, the results of neurobiological studies have revealed both similarities and disparities in the structures that underlie visual object processing. The overall organization of the two visual systems is quite similar, with the most notable shared feature being their subdivision into parallel pathways. All amniotes (mammals, birds, and reptiles) have two main visual pathways from retina to telencephalon: the thalamofugal and tectofugal pathways (see Fig.

Research paper thumbnail of Asymmetrical interactions in the perception of face identity and emotional expression are not unique to the primate visual system

The human visual system appears to process the identity of faces separately from their emotional ... more The human visual system appears to process the identity of faces separately from their emotional expression, whereas the human visual system does not appear to process emotional expression separately from identity. All current explanations of this visual processing asymmetry implicitly assume that it arises because of the organization of a specialized human face perception system. A second possibility is that this finding reflects general principles of perceptual processing. Studying animals that are unlikely to have evolved a specialized face perception system may shed fresh light on this issue. We report two experiments that investigated the interaction of identity and emotional expression in pigeons' perception of human faces. Experiment 1 found that pigeons perceive the similarity among faces sharing identity and emotion, and that these two dimensions are integral according to a spatial model of generalization. Experiment 2 found that pigeons' discrimination of emotion was reliably affected by irrelevant variations in identity, whereas pigeons' discrimination of identity was not reliably affected by irrelevant variations in emotion. Thus, the asymmetry previously reported in human studies was reproduced in our pigeon study. These results challenge the view that a specialized human face perception system must underlie this effect.

Research paper thumbnail of Visual object categorization in birds and primates: Integrating behavioral, neurobiological, and computational evidence within a “general process” framework

Previous comparative work has suggested that the mechanisms of object categorization differ impor... more Previous comparative work has suggested that the mechanisms of object categorization differ importantly for birds and primates. However, behavioral and neurobiological differences do not preclude the possibility that at least some of those mechanisms are shared across these evolutionarily distant groups. The present study integrates behavioral, neurobiological, and computational evidence concerning the "general processes" that are involved in object recognition in vertebrates. We start by reviewing work implicating error-driven learning in object categorization by birds and primates, and also consider neurobiological evidence suggesting that the basal ganglia might implement this process. We then turn to work with a computational model showing that principles of visual processing discovered in the primate brain can account for key behavioral findings in object recognition by pigeons, including cases in which pigeons' behavior differs from that of people. These results provide a proof of concept that the basic principles of visual shape processing are similar across distantly related vertebrate species, thereby offering important insights into the evolution of visual cognition. Keywords Object categorization. Object recognition. Error-driven learning. Hierarchical model. Feedforward processing. Comparative cognition. Avian vision. Pigeon. Computational model. Animal models. Visual cortex Many species must visually recognize and categorize objects to successfully adapt to their environments. Considerable comparative research has been conducted in object recognition, especially involving pigeons and people, whose visual systems have independently evolved from a common ancestor, from which their lineages diverged more than 300 million years ago. The results of behavioral studies have sometimes disclosed striking similarities between these species, and at other times have disclosed notable disparities, especially pointing toward a lower ability of pigeons to recognize transformed versions of familiar objects (for reviews, see Kirkpatrick, 2001; Spetch & Friedman, 2006). Similarly, the results of neurobiological studies have revealed both similarities and disparities in the structures that underlie visual object processing. The overall organization of the two visual systems is quite similar, with the most notable shared feature being their subdivision into parallel pathways. All amniotes (mammals, birds, and reptiles) have two main visual pathways from retina to telencephalon: the thalamofugal and tectofugal pathways (see Fig.

Research paper thumbnail of Asymmetrical interactions in the perception of face identity and emotional expression are not unique to the primate visual system

The human visual system appears to process the identity of faces separately from their emotional ... more The human visual system appears to process the identity of faces separately from their emotional expression, whereas the human visual system does not appear to process emotional expression separately from identity. All current explanations of this visual processing asymmetry implicitly assume that it arises because of the organization of a specialized human face perception system. A second possibility is that this finding reflects general principles of perceptual processing. Studying animals that are unlikely to have evolved a specialized face perception system may shed fresh light on this issue. We report two experiments that investigated the interaction of identity and emotional expression in pigeons' perception of human faces. Experiment 1 found that pigeons perceive the similarity among faces sharing identity and emotion, and that these two dimensions are integral according to a spatial model of generalization. Experiment 2 found that pigeons' discrimination of emotion was reliably affected by irrelevant variations in identity, whereas pigeons' discrimination of identity was not reliably affected by irrelevant variations in emotion. Thus, the asymmetry previously reported in human studies was reproduced in our pigeon study. These results challenge the view that a specialized human face perception system must underlie this effect.