Use Of Featural Information Research Articles

Neural basis of the spatial navigation based on geometric cues

Recent studies have found that hippocampus of mammals and birds and the lateral pallium of the fish telencephalon are critical for learning the geometric properties of space. Nevertheless, other studies suggest that navigation based on geometric information is primarily supported by proximal cues near the target location. According to this hypothesis, animals could use a taxon strategy to navigate an environment where only geometric cues are available and the results from lesion studies could be masking other effects related to the use of featural information. In the present study, we examined the effects of lesions to the lateral pallium of goldfish in the encoding of geometric spatial information. Goldfish with telencephalic lesions were trained to search for a goal in a rectangular-shaped arena with either one or two possible goals. Lateral pallium lesions do not interfere with goal location when the geometric information defined the goal unambiguously. Present results suggest that the geometric information is sensitive to be encoded in taxon strategies and therefore it could not depend directly on the correct functioning of the hippocampal system.

Age and sex differences in a virtual version of the reorientation task

Previous studies on allocentric frame of reference (FoR) have shown a substantial deficit in elderly spatial navigation. (e.g. Moffat and Resnick 2002). We referred to allocentric FoR in terms of the absence of reckoning cues in solving a spatial navigation task. Although age-related effect on navigational behaviour has been already evaluated in previous studies (e.g. Driscoll et al. 2005), rarely the impact of both layout and featural information has been systematically assessed. Acquisition and use of knowledge regarding the environment are fundamental to effective everyday functioning and, consequently, have a critical impact on the quality of life, particularly for elderly adults. A general aim of this study is to investigate the different weight of layout and featural information in a virtual version of reorientation paradigm (VReor) adopting an individual difference perspective. Virtual environments have been successfully employed in research involving both children (e.g. Newhouse et al. 2007) and elderly (Moffat and Resnick 2002). Benefits in the employment of virtual reality technologies can be summed as follows: (a) improvement in experimental control, with the advantage to create realistic, interactive three-dimensional environments, and to collect a large amount of reliable data, (b) maintained ecological validity with respect to real-world settings, (c) opportunity to investigate spatial navigation strategies in samples showing different characteristics, such as aged people and people with cognitive impairments and psychopathological conditions. In line with the aforementioned theoretical framework, this paper accounted for the following ideas: first, the layout information remains stable along lifespan, because it seems to be linked to a more implicit perception of space, the use of featural information is less stable along life-span, and it tends to corrupt earlier with age. Second, males rely predominantly on layout information, while featural information is used equally by both males and females.

Object individuation and event mapping: developmental changes in infants’ use of featural information

AbstractThe present research examined the development of 4.5‐ to 7.5‐month‐old infants’ ability to map different‐features occlusion events using a simplified event‐mapping task. In this task, infants saw a different‐features (i.e. egg‐column) event followed by a display containing either one object or two objects. Experiments 1 and 2 assessed infants’ ability to judge whether the egg‐column event was consistent with a subsequent one‐column display. Experiments 3 and 4 examined infants’ ability to judge whether the objects seen in the egg‐column event and those seen in a subsequent display were consistent in their featural composition. At 7.5 and 5.5 months, but not at 4.5 months, the infants successfully mapped the egg‐column event onto the one‐column display. However, the 7.5‐ and 5.5‐month‐olds differed in whether they mapped the featural properties of those objects. Whereas the 7.5‐month‐olds responded as if they expected to see two specific objects, an egg and a column, in the final display the 5.5‐month‐olds responded as if they simply expected to see ‘two objects’. Additional results revealed, however, that when spatiotemporal information specified the presence of two objects, 5.5‐month‐olds succeeded at tagging the objects as being featurally distinct, although they still failed to attach more specific information about what those differences were. Reasons for why the younger infants had difficulty integrating featural information into their object representations were discussed.

Object individuation: infants’ use of shape, size, pattern, and color

Recent research indicates that when an event-monitoring paradigm is used, infants as young as 4.5 months of age demonstrate the ability to use featural information to individuate objects involved in occlusion events ( Wilcox & Baillargeon, 1998a, Object individuation in infancy: The use of featural information in reasoning about occlusion events. Cognitive Psychology 37, 97–155; Wilcox & Baillargeon, 1998b, Object individuation in young infants: Further evidence with an event monitoring task. Developmental Science 1, 127–142). For example, in one experiment ( Wilcox & Baillargeon, 1998b, Object individuation in young infants: Further evidence with an event monitoring task. Developmental Science 1, 127–142) 4.5-month-old infants saw a test event in which a green ball with colored dots disappeared behind one edge of a narrow or wide screen, and a red box with silver thumbtacks appeared at the other edge; the narrow screen was too narrow to hide both objects simultaneously, whereas the wide screen was sufficiently wide to hide both objects at the same time. The infants looked reliably longer at the narrow- than at the wide-screen test event. These and control results suggested that the infants had: (a) used the featural differences between the ball and box to conclude that two objects were involved in the event; (b) judged that both objects could fit simultaneously behind the wide but not the narrow screen; and hence (c) were surprised by the narrow-screen event. The present experiments build on these initial findings by investigating the features to which infants are most sensitive. Four experiments were conducted with infants 4.5–11.5 months of age using the same procedure, except that only one feature was manipulated at a time: shape, size, pattern, or color. The results indicated that 4.5-month-olds use both shape and size features to individuate objects involved in occlusion events. However, it is not until 7.5 months that infants use pattern, and 11.5 months that infants use color, to reason about object identity. It is suggested that these results reflect biases in the kind of information that infants attend to when reasoning about occlusion events. Possible sources of bias are discussed.

The role of shape in 4-month-old infants’ object segregation

This research examined four-month-old infants’ use of featural information ( shape or color and pattern) to segregate a display into two adjacent pieces. The infants were shown displays consisting of two objects that were the same or different in shape and that were decorated with either similar or different surface markings such that featural information could suggest that the two portions were either connected or not. Three displays were created that allowed the comparison of infants’ use of shape information and color and pattern information. The results suggest that, at four months of age, infants are more likely to use shape differences than color and pattern differences to find object boundaries. The results are discussed in the context of infants’ learning about the utility of different sources of information for predicting object boundary locations.

Object Individuation in Infancy: The Use of Featural Information in Reasoning about Occlusion Events

Recent findings by Xu and Carey (1996) indicate that, after seeing two distinct objects (e.g., a duck and a ball) emerge on the opposite sides of a screen, 10-month-olds show no surprise when the screen is removed to reveal one (e.g., a duck) as opposed to two objects (e.g., a duck and a ball). The authors took their results to mean that 10-month-olds are unable to use featural information to individuate objects. The present research examined a different interpretation of the results. This interpretation was based on a distinction betweenevent mapping,in which infants see a sequence of two distinct events and judge whether the two are consistent, andevent monitoring,in which infants see a single event and judge whether successive portions of the event are consistent. The present research contrasted infants' performances in event-mapping tasks in which they saw first an occlusion and then a no-occlusion situation (as in Xu & Carey) and in event-monitoring tasks in which they saw only an occlusion situation. It was hypothesized that infants would be more likely to give evidence of correct individuation when tested with the event-monitoring as opposed to the event-mapping tasks. Eight experiments were conducted with infants ages 7.5 to 11.5 months. These experiments yielded two main findings. First, when tested with an event-monitoring task, even 7.5-month-olds give evidence that they can use featural information to individuate the objects involved in an occlusion event. Second, when tested with an event-mapping task, even 9.5-month-olds give evidence that they can use featural information to interpret an occlusion event as long as the event is made extremely simple. These findings give weight to the distinction between event mapping and monitoring and more generally begin to shed light on the fundamental processes involved in infants' formation and use of event representations.

Infants' use of featural information in the segregation of stationary objects

Infants' use of featural information (e.g. shape, color, pattern) to segregate stationary displays was investigated in three main experiments. The first experiment showed that 7.5-month-old infants, but not younger infants, were able to form a clear interpretation of a display consisting of a curved yellow cylinder and an adjacent titled blue box as composed of two separate units. Subsequent experiments determined that infants as young as 4.5 months of age could segregate into two units a simplified version of this display consisting of a straight yellow cylinder and a straight blue box (whether the display was fully visible or boundary-occluded). These results indicate that infants as young as 4.5 months of age can use object features (at least simple ones) to determine the locations of object boundaries. The results are discussed in terms of the processes underlying object segregation in infancy, and why complex features could be difficult for younger, but not older infants to perceive.

Factors Affecting Infants' Use of Featural Information in Object Segregation

Factors Affecting Infants' Use of Featural Information in Object Segregation

On the nature and scope of featural representations of word meaning.

Behavioral experiments and a connectionist model were used to explore the use of featural representations in the computation of word meaning. The research focused on the role of correlations among features, and differences between speeded and untimed tasks with respect to the use of featural information. The results indicate that featural representations are used in the initial computation of word meaning (as in an attractor network), patterns of feature correlations differ between artifacts and living things, and the degree to which features are intercorrelated plays an important role in the organization of semantic memory. The studies also suggest that it may be possible to predict semantic priming effects from independently motivated featural theories of semantic relatedness. Implications for related behavioral phenomena such as the semantic impairments associated with Alzheimer's disease (AD) are discussed.

Infants' use of featural information in reasoning about object identity: Reconciling contradictory results

Infants' use of featural information in reasoning about object identity: Reconciling contradictory results