Spatial cognition
Saturday, October 01st, 2011 [17:20 - 19:20]
PS_2.071 - Spatial representation and grasping: the role of distance and sensory feedback
Renzi, C. 1, 2 , Ricciardi, E. 2 , Bonino, D. 2 , Handjaras, G. 2 , Vecchi, T. 1 & Pietrini, P. 2
1 Department of Psychology, University of Pavia, Pavia, Italy
2 Laboratory of Clinical Biochemistry and Molecular Biology, University of Pisa, Pisa, Italy
In the presence of vision, aimed motor acts can trigger remapping into peripersonal space. However, it is yet unclear how the space is coded and remapped depending on the availability of visual feedback and on the target position within the subject’s peripersonal space, and which cerebral areas subserve such processes. We used fMRI in right-handed volunteers to examine neural activity during reach-to-grasp movements with and without visual feedback and at different distances of the target (near vs far reachable space). Brain response in the superior parietal lobules (SPL), in the dorsal premotor cortex (dPM) and in the anterior part of the inferior parietal lobule (IPL) was significantly higher during visually-guided grasping towards the far targets compared to the closer ones. Moreover, IPL exhibited the opposite pattern when grasping in the absence of visual feedback. We argue that in the presence of visual feedback, a visuo-motor circuit (dPM-SPL) intervenes to remap space, possibly to support online control of movement. Conversely, IPL seems to be involved in coding/remapping peripersonal space.
PS_2.072 - Spatial reasoning about remote environments encoded through narratives
Avraamides, M. 1 , Galati, A. 1 , Meneghetti, C. 2 , Pazzaglia, F. 2 & Denis, M. 3
1 University of Cyprus
2 University of Padua
3 LIMSI-CNRS Orsay
In two experiments we investigated how spatial information described in narratives is organized in memory. Participants read short stories describing themselves at remote settings (e.g., an opera house) and were asked to memorize the locations of objects in them. Subsequently, they physically rotated to the left or right to match a change of orientation described in the narrative and then pointed towards memorized objects from imagined perspectives. Performance was faster and more accurate when participants pointed to objects from the imagined perspective that was aligned with the initial orientation described in the narrative than any other orientation. This finding suggests that (1) participants maintained spatial information in memory from a preferred direction that was determined by the initial orientation introduced in the narrative, and (2) they did not update this initial spatial memory when physically rotating. Therefore, spatial updating in environments encoded through language vs. through perceptual experience may differ.
PS_2.073 - Developmental trajectories of mental rotation abilities across adolescence
Conson, M. , Mazzarella, E. & Trojano, L.
Dept. of Psychology, Second University of Naples, Italy
Developmental studies on mental rotation have focused their attention on childhood or early adolescence, but did not compare different adolescent stages. In the present paper we present a cross-sectional study to clarify the effect of adolescence-related brain maturation processes on different imagery abilities. To this aim, three groups of adolescents with typical development were required to mentally rotate letters, objects and hands. Results showed that 11-12 year-old participants were slower and less accurate than both 14-15 and 17-18 year-old individuals in all the three tasks. Moreover, the effect of body anatomical constraints on mental rotation of hands emerged in 14-15 year-old participants, and fully matured in 17-18 year-old participants. These findings demonstrate that brain developmental changes in the age range between early and middle adolescence are crucial for increasing general efficiency of mental imagery abilities. Visuospatial imagery is fully effective by middle adolescence, whereas only late adolescent automatically activate motor, body-related, information to mentally simulate actions.
PS_2.074 - Multisensory processing during spatial navigation
van der Ham, I. , van der Kuil, M. & Delogu, F.
Experimental Psychology, Helmholtz Institute, Utrecht University, the Netherlands
Finding your way is undoubtedly a necessity in everyday life. Although numerous studies have addressed navigation ability based on performance in purely visual tasks, hardly any have focused on the contribution of auditory sensory processing. In this study we have specifically examined how both visual and auditory cues are used to navigate through virtual environments. The main goal was to assess to what extent auditory information, in isolation and in combination with visual information, contributes to navigation ability. Virtual, interactive, three-dimensional mazes were used, consisting of rooms that were only discernable by visual cues, auditory cues, or a combination of visual and auditory cues. After memorizing the environment with one set of cues, participants were placed at a random room in the maze with the same set of cues and were instructed to find their way to the exit. Results indicate that visual cues lead to better navigation performance, compared to auditory cues. Notably, performance did not improve when combining visual and auditory cues, compared to visual cues in isolation. These findings indicate that auditory information can be used to navigate through a virtual environment, but they do not contribute to performance when visual information is also available.
PS_2.075 - Both perceptual and personal factors drive visuospatial planning in the TSP
Basso, D.
Faculty of Education, Free University of Bozen-Bolzano
Visuospatial planning is a particular kind of planning, studied using the Traveling Salesperson Problem (TSP). In this 2D task, perceptual data are expected to heavily influence the choice of the trajectory in order to visit all the locations using the shortest path. However, personal traits such as egocentrism and allocentrism were not considered yet into computational models that tried to explain human performance. In this study, 30 trials (representing an open version of the TSP) were administered to 60 healthy participants, which were required to connect 5 up to 10 points within a 2D square by finding the shortest path. Each trial was built placing the dots according to a mathematical function except for one dot, which was far away from the other ones. Results showed that the external dots were included into the figures by using either a horizontal or a vertical heuristic (as described in Basso, 2005). This performance was mainly dependent on their ego-allocentric score, while the real shortest path was partially relevant for the choice of allocentric people only. These results may not be explained by purely syntactic models (such as crossing-avoidance or pyramid approaches) but could be interpreted within the 4-stages planning model.
PS_2.076 - So far so good: affective content in reaching distance perception
Valdes-Conroy, B. 1 , Shorkey, S. P. 2 , Román, F. J. 3 & Hinojosa, J. A. 4
1 Universidad Complutense de Madrid (UCM)
2 University of North Carolina at Chapel Hill.
3 Universidad Autónoma de Madrid
4 Instituto Pluridisciplinar, UCM
Substantial growth of interest about the interactions between perceptual and motor systems has provided extensive evidence of the multimodality of the peripersonal neural system. Such multimodality has been proposed to underlie basic action planning mechanisms. Surprisingly, little attention has been devoted to the role of affective attributes of objects in reaching distance perception and action. We present a real scenario experiment in which we manipulated both physical and psychological attributes of stimuli (e.g. desirability, familiarity) in order to test their influence on distance perception. Using a proximity judgment task participants were asked to indicate when an object was near enough to reach. Participant’s estimations measured in centimetres showed a tendency to perceive undesirable objects (e.g., “used condom”) as closer than desirable or familiar objects (e.g., 50€ note, own mobile phone). Individual differences taken with the Revised Eysenck Personality Questionnaire (EPQ-R) showed a significant correlation between extraversion and the estimation of reaching distances. These results are contrasted with a computer-based experiment in which digital objects (controlled for arousal and affect) were presented on a horizontal display surface. Together, our data highlight the relevance of emotional attributes and individual differences in the representation of objects and motor actions within peripersonal space.
PS_2.077 - Similarity and number of alternatives in the random-dot motion paradigm
Van Maanen, L. 1 , Grasman, R. 1 , Forstmann, B. U. 1 , Keuken, M. 1, 2 , Brown, S. 3 & Wagenmakers, E. 1
1 Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands
2 Max-Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
3 School of Psychology, University of Newcastle, Callaghan, Australia
The popular random-dot motion (RDM) task has recently been applied to multiple-choice perceptual decision-making. In this task, participants have to decide on a direction of motion of a cloud of moving dots. The response alternatives typically surround the stimulus in a circular way. However, this means that changes in the number of alternatives on an RDM display lead to changes in the angular distance between the response alternatives, complicating the study of multiple-choice effects with this paradigm. To disentangle the effects of angular distance and number of alternatives we analyzed behavior in the RDM task using a neurally-inspired optimal observer model. The model applies Bayesian principles to give an account of how changes in the stimulus influence the decision-making process. In addition to an analysis of optimal behavior, we applied a Linear Ballistic Accumulator (LBA, Brown & Heathcote, 2008) model to verify the predictions of the optimal model. The results show that (a) there is a natural interaction in the RDM task between angular distance and the number of alternatives, (b) the number of alternatives is encoded by the "response caution" parameter, and (c) behavior in the RDM task is near optimal when handling multiple choices.