View-invariant object category learning, recognition, and search: how spatial and object attention are coordinated using surface-based attentional shrouds

How does the brain learn to recognize an object from multiple viewpoints while scanning a scene with eye movements? How does the brain avoid the problem of erroneously classifying parts of different objects together? How are attention and eye movements intelligently coordinated to facilitate object learning? A neural model provides a unified mechanistic explanation of how spatial and object attention work together to search a scene and learn what is in it. The ARTSCAN model predicts how an object's surface representation generates a form-fitting distribution of spatial attention, or "attentional shroud". All surface representations dynamically compete for spatial attention to form a shroud. The winning shroud persists during active scanning of the object. The shroud maintains sustained activity of an emerging view-invariant category representation while multiple view-specific category representations are learned and are linked through associative learning to the view-invariant object category. The shroud also helps to restrict scanning eye movements to salient features on the attended object. Object attention plays a role in controlling and stabilizing the learning of view-specific object categories. Spatial attention hereby coordinates the deployment of object attention during object category learning. Shroud collapse releases a reset signal that inhibits the active view-invariant category in the What cortical processing stream. Then a new shroud, corresponding to a different object, forms in the Where cortical processing stream, and search using attention shifts and eye movements continues to learn new objects throughout a scene. The model mechanistically clarifies basic properties of attention shifts (engage, move, disengage) and inhibition of return. It simulates human reaction time data about object-based spatial attention shifts, and learns with 98.1% accuracy and a compression of 430 on a letter database whose letters vary in size, position, and orientation. The model provides a powerful framework for unifying many data about spatial and object attention, and their interactions during perception, cognition, and action.     

Internal objects' or ‘chimerical monsters’?: the demonic ‘third forms’ of the internal world

The concept of 'object' whether internal or external, is a hold-over from the Enlightenment and from the positivistic certainty of nineteenth- and early twentieth-century science, Its use in current psychoanalytic theory and practice is now obsolete because of the contributions of post-modernism and their emphasis on subjectivity and relativity. In plate of the word 'object', the author favors a return to pre-Enlightenment psychology in order to address the presence and clinical manifestation of what the term 'object' screened, i.e., demons, monsters, chimerae, ghosts, spirits, etc. In terms of external 'objects', he favors such terms as 'persons' or 'subjects', which also reflects an adjustment to the post-modem emphasis on the ineffability of the Other.     

Use of phonetic specificity during the acquisition of new words: differences between consonants and vowels

The present study explores the issue of the use of phonetic specificity in the process of learning new words at 20 months of age. The procedure used follows Nazzi and Gopnik [Nazzi, T., & Gopnik, A. (2001). Linguistic and cognitive abilities in infancy: When does language become a tool for categorization? Cognition, 80, B11-B20]. Infants were first presented with triads of perceptually dissimilar objects, which were given made-up names, two of the objects receiving the same name. Then, word learning was evaluated through object selection/categorization. Tests involved phonetically different words (e.g. [pize] vs. [mora], Experiment 1), words differing minimally on their onset consonant (e.g. [pize] vs. [tize], Experiment 2a), and conditions which had never been tested before: non-initial consonantal contrasts (e.g. [pide] vs. [pige], Experiment 2b), and vocalic contrasts (e.g. [pize] vs. [pyze]; [pize] vs. [paze]; [pize] vs. [pizu], Experiments 3a-c). Results differed across conditions: words could be easily learnt in the phonetically different condition, and were learnt, though to a lesser degree, in both the initial and non-initial minimal consonant contrast; however, infants' global performance on all three vocalic contrasts was at chance level. The present results shed new light regarding the specificity of early words, and raise the possibility of different contributions for vowels and consonants in early word learning.     

Object recognition with severe spatial deficits in Williams syndrome: sparing and breakdown

Williams syndrome (WS) is a rare genetic disorder that results in severe visual-spatial cognitive deficits coupled with relative sparing in language, face recognition, and certain aspects of motion processing. Here, we look for evidence for sparing or impairment in another cognitive system-object recognition. Children with WS, normal mental-age (MA) and chronological age-matched (CA) children, and normal adults viewed pictures of a large range of objects briefly presented under various conditions of degradation, including canonical and unusual orientations, and clear or blurred contours. Objects were shown as either full-color views (Experiment 1) or line drawings (Experiment 2). Across both experiments, WS and MA children performed similarly in all conditions while CA children performed better than both WS group and MA groups with unusual views. This advantage, however, was eliminated when images were also blurred. The error types and relative difficulty of different objects were similar across all participant groups. The results indicate selective sparing of basic mechanisms of object recognition in WS, together with developmental delay or arrest in recognition of objects from unusual viewpoints. These findings are consistent with the growing literature on brain abnormalities in WS which points to selective impairment in the parietal areas of the brain. As a whole, the results lend further support to the growing literature on the functional separability of object recognition mechanisms from other spatial functions, and raise intriguing questions about the link between genetic deficits and cognition.     

Is motion extrapolation employed in multiple object tracking? Tracking as a low-level, non-predictive function

In a series of five experiments, we investigated whether visual tracking mechanisms utilize prediction when recovering multiple reappearing objects. When all objects abruptly disappeared and reappeared mid-trajectory, it was found that (a) subjects tracked better when objects reappeared at their loci of disappearance than when they reappeared in their extrapolated trajectories, (b) disappearance episodes ranging from 150 to 900 ms had virtually no differential effect on performance, (c) tracking deteriorated monotonically as a function of displacement magnitude during disappearance, and (d) tracking did not depend on whether objects moved in predictable paths. Even objects that reappeared backward in their trajectories were tracked dramatically better than objects that reappeared in their extrapolated trajectories. When all objects disappeared and reappeared in ways that implicated the presence of an occluder (i.e., with occlusion and disocclusion cues along fixed contours), tracking again was not predictive, and performance deteriorated with increased displacement. When objects reappeared predictably in 75% of trials, they were still tracked better when they reappeared at their points of disappearance. Theoretical implications of a non-predictive multiple object tracking mechanism are discussed.     

Object individuation using property/kind information in rhesus macaques (Macaca mulatta)

Around 1 year of age, infants develop the ability to individuate objects in the absence of spatiotemporal information. Some have proposed that this capacity relies on the emergence of language and, in particular, that comprehending an object's label is required to individuate it as a particular kind. One approach to testing this hypothesis is to conduct experiments on pre-linguistic human infants. A second is to test non-linguistic animals. We followed the second approach, exploring whether semi-free-ranging rhesus macaques can individuate objects using property/kind information. To make the results most directly comparable, we adapted a reaching paradigm used to examine property/kind individuation in infants. Results from three experiments demonstrate that, like 12-month-old infants, adult rhesus macaques can use both spatiotemporal and property/kind information to individuate food objects. In a fourth experiment designed to examine which properties are used to individuate food objects, results revealed that rhesus use color, but not shape. These results, together with experiments involving different procedures, provide support for the conclusion that in the absence of linguistic abilities, some non-human primates spontaneously use property/kind information to individuate objects.     

Motion and edge sensitivity in perception of object unity

Although much evidence indicates that young infants perceive unitary objects by analyzing patterns of motion, infants' abilities to perceive object unity by analyzing Gestalt properties and by integrating distinct views of an object over time are in dispute. To address these controversies, four experiments investigated adults' and infants' perception of the unity of a center-occluded, moving rod with misaligned visible edges. Both alignment information and depth information affected adults' and infants' perception of object unity in similar ways, and infants perceived object unity by integrating information about object features over time. However, infants perceived a moving, misaligned, three-dimensional object as indeterminate in its connectedness, whereas adults perceived it as connected behind the occluder. These findings indicate that the effectiveness of common motion in specifying unified surfaces across an occluder is reduced by misalignment of edges. Alignment information enhances perception of object unity either by serving directly as information for unity or by optimizing the detectability of motion-carried information for unity. In addition, young infants are able to retain information about edge orientation over short intervals in determining connectedness via a process of spatiotemporal integration.     

Do you remember where sounds,pictures and words came from? The role of the stimulus format in object location memory

Contrasting results in visual and auditory spatial memory stimulate the debate over the role of sensory modality and attention in identity-to-location binding. We investigated the role of sensory modality in the incidental/deliberate encoding of the location of a sequence of items. In 4 separated blocks, 88 participants memorised sequences of environmental sounds, spoken words, pictures and written words, respectively. After memorisation, participants were asked to recognise old from new items in a new sequence of stimuli. They were also asked to indicate from which side of the screen (visual stimuli) or headphone channel (sounds) the old stimuli were presented in encoding. In the first block, participants were not aware of the spatial requirement while, in blocks 2, 3 and 4 they knew that their memory for item location was going to be tested. Results show significantly lower accuracy of object location memory for the auditory stimuli (environmental sounds and spoken words) than for images (pictures and written words). Awareness of spatial requirement did not influence localisation accuracy. We conclude that: (a) object location memory is more effective for visual objects; (b) object location is implicitly associated with item identity during encoding and (c) visual supremacy in spatial memory does not depend on the automaticity of object location binding.     

What kinds of alternative possibilities are required of the folk concept(s) of choice?

Our concept of choice is integral to the way we understand others and ourselves, especially when considering ourselves as free and responsible agents. Despite the importance of this concept, there has been little empirical work on it. In this paper we report four experiments that provide evidence for two concepts of choice—namely, a concept of choice that is operative in the phrase having a choice and another that is operative in the phrase making a choice. The experiments indicate that the two concepts of choice can be differentiated from each other on the basis of the kind of alternatives to which each is sensitive. The results indicate that the folk concept of choice is more nuanced than has been assumed. This new, empirically informed understanding of the folk concept of choice has important implications for debates concerning free will, responsibility, and other debates spanning psychology and philosophy.