Perceptual grouping in two visually reliant species: Humans (Homo sapiens) and Australian sea lions (Neophoca cinerea) (original) (raw)
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Comparative Vision Science: Seeing Eye to Eye
Comparative Cognition & Behavior Reviews, 2010
Different species possess very different eyes and nervous systems. With such biological diversity, just what do other species see and understand about the world around them? And, are there any general principles of vision to be extracted from so much biological diversity? These questions inspire researchers in the behavioral and neural sciences to study vision in nonhuman animals.
Journal of Comparative Psychology, 2009
Recent experimental results suggest that human and nonhuman primates differ in how they process visual information to assemble component parts into global shapes. To assess whether some of the observed differences in perceptual grouping could be accounted for by the prevalence of different grouping factors in different species, we carried out 2 experiments designed to evaluate the relative use of proximity, similarity of shape, and orientation as grouping cues in humans (Homo sapiens) and capuchin monkeys (Cebus apella). Both species showed similarly high levels of accuracy using proximity as a cue. Moreover, for both species, grouping by orientation similarity produced a lower level of performance than grouping by proximity. Differences emerged with respect to the use of shape similarity as a cue. In humans, grouping by shape similarity also proved less effective than grouping by proximity but the same was not observed in capuchins. These results suggest that there may be subtle differences between humans and capuchin monkeys in the weighting assigned to different grouping cues that may affect the way in which they combine local features into global shapes. and the experimental method complies with the Directive 86/609/EEC. Carlo De Lillo gratefully acknowledges a semester of study leave granted by the University of Leicester. We thank the Bioparco S.p.A. for hosting the laboratory where the experiments with monkeys were carried out, Tony Andrews for developing the software used to run the experiment with humans and Jacqueline Mizha-Murira for collecting data on human participants.
Evolutionary Constraints on Human Object Perception
Cognitive Science, 2016
Language and culture endow humans with access to conceptual information that far exceeds any which could be accessed by a non-human animal. Yet, it is possible that, even without language or specific experiences, non-human animals represent and infer some aspects of similarity relations between objects in the same way as humans. Here we show that monkeys' discrimination sensitivity when identifying images of animals is predicted by established measures of semantic similarity derived from human conceptual judgments. We used metrics from computer vision and computational neuroscience to show that monkeys' and humans' performance cannot be explained by low-level visual similarity alone. The results demonstrate that at least some of the underlying structure of object representations in humans is shared with non-human primates, at an abstract level that extends beyond low-level visual similarity. Because the monkeys had no experience with the objects we tested, the results suggest that monkeys and humans share a primitive representation of object similarity that is independent of formal knowledge and cultural experience, and likely derived from common evolutionary constraints on object representation.
2012
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.
Evidence of a Universal Perceptual Unit in Mammals
Ethology, 2010
Evidence from many studies conducted over the past century suggests that human perception is partitioned into 1-4-s units. More recently, a similar 1-4-s time constant has been found in nonperceptual phenomena, i.e. movement patterns, of both human and non-human mammalian species. Based on these findings, it appears that an evolutionarily conserved mechanism exists that segments human and non-human mammalian motor actions into 1-4-s units. This being the case, it is believed that the 1-4-s segmentation seen in human perception may also occur in mammalian perception. However, it is currently impossible to determine whether both human and non-human perception is partitioned into 1-4-s units because the paradigms used to study the 1-4-s unit in human perception cannot be applied to non-human species. This study hypothesized that vigilance postures represent a paradigm that will allow such comparative work. This is based on the fact that investigators recently found that vigilant postures in humans are partitioned into 1-4-s units, and the literature argues strongly that vigilance is largely a perceptual phenomenon. With this in mind, the current study determined whether similar vigilant postures occur in non-human mammals and whether such vigilant postures are also segmented into 1-4-s units. The study found that such postures averaged 2-3.5 s in primates (n = 1 species), carnivores (n = 2 species), artiodactyls (n = 3 species), and marsupials (n = 1 species). These findings support the hypothesis that perception in humans and other mammals is partitioned into units by a conserved mechanism. It is believed that vigilant postures will be an important quantifiable bioassay with which to conduct comparative studies of mammalian perception.
Nonaccidental Properties Underlie Shape Recognition in Mammalian and Nonmammalian Vision
Current Biology, 2007
An infinite number of 2D patterns on the retina can correspond to a single 3D object. How do visual systems resolve this ill-posed problem [1] and recognize objects from only a few 2D retinal projections in varied exposure conditions? Theories of object recognition rely on the nonaccidental statistics of edge properties , mainly symmetry, collinearity, curvilinearity, and cotermination. These statistics are determined by the image-formation process (i.e., the 2D retinal projection of a 3D object [4]); their existence under a range of viewpoints enables viewpoint-invariant recognition. An important question in behavioral biology is whether the visual systems of nonmammalian animals have also evolved biases to utilize nonaccidental statistics . Here, we trained humans and pigeons to recognize four shapes. With the Bubbles [10] technique, we determined which stimulus properties both species used to recognize the shapes. Both humans and pigeons used cotermination, the most diagnostic nonaccidental property of real-world objects, despite evidence from a model computer observer that cotermination was not the most diagnostic pictorial information in this particular task. This result reveals that a nonmammalian visual system that is different anatomically from the human visual system is also biased to recognize objects from nonaccidental statistics.
Pigeons and humans are more sensitive to nonaccidental than to metric changes in visual objects
Behavioural Processes, 2008
Humans and macaques are more sensitive to differences in nonaccidental image properties, such as straight vs. curved contours, than to differences in metric properties, such as degree of curvature . One-shot viewpoint invariance in matching novel objects. Vis. . Representation of regular and irregular shapes in macaque inferotemporal cortex. Cereb. Cortex 15, 1308-1321]. This differential sensitivity allows facile recognition when the object is viewed at an orientation in depth not previously experienced. In Experiment 1, we trained pigeons to discriminate grayscale, shaded images of four shapes. Pigeons made more confusion errors to shapes that shared more nonaccidental properties. Although the images in that experiment were not well controlled for incidental changes in metric properties, the same results were apparent with better controlled stimuli in Experiment 2: pigeons trained to discriminate a target shape from a metrically changed shape and a nonaccidentally changed shape committed more confusion errors to the metrically changed shape, suggesting that they perceived it to be more similar to the target shape. Humans trained with similar stimuli and procedure exhibited the same tendency to make more errors to the metrically changed shape. These results document the greater saliency of nonaccidental differences for shape recognition and discrimination in a non-primate species and suggest that nonaccidental sensitivity may be characteristic of all shape-discriminating species.
Behavioural Brain Research, 2012
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Perceptual Organization in Animal Learning: Cues or Objects?
Ethology, 2010
Chicks were trained to discriminate between two identical boxes on the basis of their position. Subsequently, the colour of parts of the positive (reinforced) box was changed and chicks were retrained. Results showed that chicks were more or less impaired during retraining depending on the spatial distribution of the changed stimuli. Chicks behaved as if a figure (a disc or a spot of dots) painted on a box was irrelevant to them, whereas they did respond to changes in the colour of a uniformly coloured box or of scattered dots painted on a box. Similar results were obtained in simultaneous discrimination learning tasks involving addition of cues (e.g. colour plus position). Addition of cues facilitated learning using boxes the same colour all over or with painted scattered dots, but not using boxes with a disc or a spot of dots. Furthermore, addition of shape and position information had different outcomes depending on the use of three-dimensional objects or of painted figures: learning facilitation occurred only using three-dimensional objects. Results are interpreted in terms of an "object hypothesis", and the validity and usefulness of traditional terms such as cues is questioned.
Wiley Interdisciplinary Reviews: Cognitive Science, 2011
Perception processes can be investigated at the physical (concerning the stimulation from the environment to the receptors), physiological (the processes taking place in the neural system), and psychological (the 'sense' of perception, the outcome produced by the physical stimulation and the physiological processes) level. The present paper focuses on visual perception, mainly from a psychological level of investigation, and revises comparative literature, highlighting both similarities and differences in the visual structures and functions in different animal classes. For this purpose, the structure of the current eyes is described in a comparative perspective, as well as perceptual organization and object recognition processes, color perception, three-dimensional structuring of the image, and motion perception. Finally, the literature about comparative susceptibility to various visual illusions will be discussed, as illusory perception has been revealed to be a most useful tool to unveil the perceptual algorithms shared by the different species. In spite of major differences between animal species in the structures in charge of perception and in the adaptations to specific ecological niches, experimental data presented here will lead to the conclusion that a number of basic perceptual principles of organization and functioning are shared between species.