Laura A. Carlson

Grounding spatial language in perception: an empirical and computational investigation.

The present paper grounds the linguistic cdategorization of space in aspects of visual perception; specifically, the structure of projective spatial terms such as above are grounded in the process of attention and in vector-sum coding of overall direction. This is formalized in the attentional vector-sum (AVS) model. This computational model accurately predicts linguistic acceptability judgments for spatial terms, under a variety of spatial configurations. In 7 experiments, the predictions of the AVS model are tested against those of 3 competing models. The results support the AVS model and disconfirm its competitors. The authors conclude that the structure of linguistic spatial categories can be partially explained in terms of independently motivated perceptual processes.

Getting Lost in Buildings

People often get lost in buildings, including but not limited to libraries, hospitals, conference centers, and shopping malls. There are at least three contributing factors: the spatial structure of the building, the cognitive maps that users construct as they navigate, and the strategies and spatial abilities of the building users. The goal of this article is to discuss recent research on each of these factors and to argue for an integrative framework that encompasses these factors and their intersections, focusing on the correspondence between the building and the cognitive map, the completeness of the cognitive map as a function of the strategies and individual abilities of the users, the compatibility between the building and the strategies and individual abilities of the users, and complexity that emerges from the intersection of all three factors. We end with an illustrative analysis in which we apply this integrative framework to difficulty in way-finding.

Using spatial terms to select an object.

Our interactions with the world often involve selecting one object from a cluttered array of objects. One way to accomplish this is with language. For example, spatial terms, such as above, guide selection by specifying the position of one object (the located object) with respect to a second object (the reference object). Most of the work on the apprehension of spatial terms has examined displays that contain only these two objects. In the present paper, we examine how the presence of an extra object (a distractor) in the display impacts apprehension. Consistent effects of distractor presence were obtained across acceptability-rating and speeded sentence/picture verification tasks. Importantly, these effects were independent of the placement of the distractor. These results suggest that the distractor has its influence during processes that spatially index and identify the located and reference objects and that processes involved in computing the spatial term operate only on these objects.

When What You Hear Influences When You See Listening to an Auditory Rhythm Influences the Temporal Allocation of Visual Attention

The three experiments reported here demonstrated a cross-modal influence of an auditory rhythm on the temporal allocation of visual attention. In Experiment 1, participants moved their eyes to a test dot with a temporal onset that was either synchronous or asynchronous with a preceding auditory rhythm. Saccadic latencies were faster for the synchronous condition than for the asynchronous conditions. In Experiment 2, the effect was replicated in a condition in which the auditory context stopped prior to the onset of the test dot, and the effect did not occur in a condition in which auditory tones were presented at irregular intervals. Experiment 3 replicated the effect using an accuracy measure within a nontimed visual task. Together, the experiments’ findings support a general entrainment perspective on attention to events over time.

Selecting landmarks in novel environments.

People use salient landmarks when learning a route through a novel environment. However, it is not clear what makes a given landmark salient. In two experiments, subjects learned a route through a virtual museum, performed a recognition memory test for objects in the museum, and provided spatial descriptions and drew maps of the learned route. Objects with strong perceptual features occurred at decision points or at non-decision points along the route. Objects with both of these features were recognized faster and were included more often in the maps and written directions. When these features were separated, perceptual features maintained a strong influence on the recognition task, but had no influence on the spatial tasks, which were influenced only by spatial features. These findings challenge the idea that either a recognition task or descriptive task alone provides a complete account of landmark representation.

Neural correlates of spatial term use.

The current research used event-related brain potentials (ERPs) to assess the processes underlying online apprehension of the spatial term above. Constituent steps defined within G. D. Logan and D. D. Sadlers (1996) computational theory of apprehension were associated with distinct modulations of ERPs. Specifically, finding the relevant objects was associated with an amplitude modulation of P3; competition in assigning directions to space was associated with modulation of a frontal slow wave; and computing and comparing the spatial relation was associated with modulation of a parietal slow wave. These modulations were differentially influenced by the type of reference frame used to define the spatial term and by the participants response. The current study supports this decompositional approach to apprehension and provides a means of assessing each step independently.

Inhibition of attended processing during saccadic eye movements.

People are unable to perform some, but not all, cognitive tasks while moving their eyes. A possible common denominator among disrupted processes is the use of attention. The present research proposes and tests anattentional suppression hypothesis to evaluate this claim. This hypothesis states that because attention is obligatorily allocated to a to-be-fixated location prior to the onset of a saccade, during saccadic events attentional resources are unavailable to direct processing associated with higher order cognitive tasks. Subjects were engaged in a task that combined saccades and shifts of attention across global and local levels of hierarchical figures. When the eyes did not move, this shift took place between stimulus presentations. When saccades intervened between the stimuli, the global-local shifts of attention were interrupted, suggesting that saccades suppress cognitive processes requiring attention.

How far is near? Inferring distance from spatial descriptions

A word may mean different things in different contexts. The current study explored the changing denotations of spatial terms, focusing on how the distance inferred from a spatial description varied as a function of the size of the objects being spatially related. We examined both terms that explicitly convey distance (i.e., topological terms such as near), and terms not traditionally associated with distance (i.e., projective terms such as left).The critical finding was that estimates of distance associated with both classes of terms were systematically influenced by the size of the objects, generalising an effect observed by Morrow and Clark (1988) with approach. The effect was replicated using an indirect scaling method, and centre-to-centre and edge-to-edge estimates. The results support the idea that dimensions relevant to the processing of spatial terms are not limited to information explicitly conveyed by the spatial terms.

Interpreting spatial terms involves simulating interactions

Recent research in spatial language has demonstrated that the interpretation of a spatial term depends not only on the geometry of the configuration of the objects being spatially related, but also on extrageometric information, including information about the objects and their interaction. Such effects could emerge from activation of general knowledge of the association between the objects; thus, they should be widely observed. In contrast, they could be more restricted, emerging only in situations in which the spatial language task positions objects in a manner that is consistent with a simulation of their interaction. In two experiments, we test each of these ideas and demonstrate that extrageometric information augments geometric information in the interpretation of spatial terms only when the situation enables the interaction.

Selecting a Reference Object.

One way to describe the location of an object is to relate it to another object. Often there are many nearby objects, each of which could serve as a candidate to be the reference object. A common theoretical assumption is that features that make a given object salient relative to the candidate set are instrumental in determining which is selected. The current research tests this assumption, assessing the relative importance of spatial, perceptual, and functional-interactive features. Three experiments demonstrated that spatial features have the strongest influence on reference object selection, with the perceptual feature of color playing no significant role. Functional-interactive features were shown to be spatially dependent, having an influence only when the spatial configuration enabled an interaction between the located object and the reference object. These findings challenge the common perspective that salience in and of itself dictates reference object selection and argue for a reliance on spatial features.