No description available.

No description available.

People need to know where objects are located in order to be able to interact with the world, and spatial language provides the main linguistic means of facilitating this. However, the information contained in the description about objects locations is not the only message conveyed; there is evidence in fact that people carry out inferences that go beyond the simple geometric relation specified (Coventry & Garrod, 2004; Tyler & Evans, 2003). People draw inferences about objects dynamic and objects interaction, and these information become critical for the apprehension of spatial language. Among the inferences people draw from spatial language the property of the converseness is particularly appealing; this principle states that given the description "A is above B" one can also infers "B is below A" (Leveit, 1984, 1996). Thus if the speaker says "the book is above the telephone" implicitly the listener also knows that the telephone is below the book. However this extra information does not necessary facilitate the apprehension of spatial descriptions. If it is true that inferences increase the amount of information the description conveys (Johnson-Laird & Byrne, 1991), it is also true that this "extra-information" can be a disadvantage. In fact the spatial preposition used in the description can end up in being ambiguous because it suits more than one interpretation: The consequence is a reduction of the informativeness (Bar-Hillel, 1964). Tyler and Evans (2003) called this inferential process Best Fit. Speakers choose the spatial preposition which offers the best fit between the conceptual spatial relation and the speaker's communicative needs. This principle can be considered a logical extension of the notion of relevance (Grice. 1975; Sperber & Wilson, 1986) and an integration for the Q-Principle (Asher & Lascarides, 2003; Levinson, 2000a) according to which speakers have the duty to avoid statements that are informationally weaker than their knowledge of the world allows. This dissertation explores whether the inferences people draw on spatial representations, in particular those based on the converseness principle (Levelt, 1996), will affect the process that drive the speaker to choose the most informative description, that is the description that best fit spatial relations and speaker needs (Tyler & Evans, 2003). Experiment 1 and 2 study whether converseness, tested by manipulating the orientation of the located object, affects the extent to which a spatial description based on the preposition over, under, above, below is regarded as a good description of those scenes. Experiment 3 shows that the acceptability for a projective spatial preposition is affected by the orientation of both the object presented in the scene. Experiment 4 and 5 replicate the results achieved in the previous experiments using polyoriented objects (Leek, 1998b) in order to exclude the possibility that the decrease of acceptability was due to the fact that one object was shown in a non-canonical orientation. Experiment 6, 7 and 8 will provide evidence that converseness generates ambiguous descriptions also with spatial prepositions such as in front of, behind, on the left and to the right. Finally Experiment 9 and 10 show that for proximity terms such as near and far informativeness is not that relevant, but rather it seems that people simply use contextual information to set a scale for their judgments.

One of the important and unsolved questions in vision research is how space is represented. Despite extensive research from a variety of disciplines this topic is still poorly understood and, at present, there is no theory that can provide a complete explanation. The traditional view on space representation is a geometric one that assumes a one-to-one mapping between physical and perceived space, but much of the current evidence points towards other solutions. For example, it has been proposed that there may be no single visual representation of a 3D scene that can account for performance in all tasks, suggesting that space representation may take a looser form without a globally consistent map of space. The studies described in this thesis provide evidence that challenges the idea of a single internal representation of space by exploring size and distance judgements under a range of different conditions in a virtual expanding room. In this environment, participants viewed the scene binocularly through a wide field of view head mounted display. They were allowed to move and were consequently provided with veridical information about the scene also from their own movements. Importantly, the scene expanded or contracted four-fold during experiments, giving a unique opportunity to explore how different distance cues contribute to size and distance judgements when biases in both judgements were very large. The available cues were set in conflict: one type of cue, based on stereopsis and motion parallax, gave a veridical signal of the change in the scene, whereas another type of cue was unaffected by the expansion of the scene and, hence, signalled that the room remained constant. The most striking result is that the perceived location of objects does not always follow a transitive ordering with respect to physical space, which is incompatible with a one-to-one mapping between perceived and physical space. Instead, the results can be better explained by a cue combination model. This approach has not previously been used for object location, but was here successfully applied for a range of conditions even when there was a large conflict between the distances signalled by the contributing cues. Further, it appears that perceived size and perceived distance are not based on a single estimate of distance, demonstrating the lack of internal consistency from a different angle. Overall, these experiments provide results that are difficult to reconcile with a model based on geometric reconstruction and suggest that the visual system does not have a single internal representation of space.

No description available.

No description available.

The present thesis examines the processing of numerical magnitude using a series of Stroop variants existing paradigms are modified and new ones devised. The Stroop effect, observed when numerical magnitude is the task-irrelevant dimension, has been widely used as an indicator for autonomous processing. However, it is argued that this effect does not provide a sensitive enough measure for the degree of information processing. Instead, current findings have demonstrated that the reversed numerical distance effect observed during physical size comparison of digits (when numerical magnitude is the task- irrelevant dimension) can be used as a reliable measure for refined autonomous processing. Neuroimaging data are consistent with this proposal. Others factors which influence numerical magnitude processing, such as effects of writing system and familiarity, are also examined. Findings are discussed with respect to existing theoretical accounts. In addition to the relative strength and speed of processing, stimulus discriminability and familiarity also contribute to a more comprehensive understanding of number comparison. The autonomous property of numerical magnitude processing during parity judgement and numerosity matching is also investigated. Current findings indicate that numerical magnitude processing is, in most cases, refined. Experimental designs have significant contributions as to whether refined processing can be elicited. Moreover, the present thesis provides evidence supporting the ideas that (1) representations of numerical magnitude follow the principle of cardinality and are therefore linear, and (2) numbers evoke discrete representations which are distinct from continuous presentations evoked by other quantitative dimensions such as physical size. Future research directions are suggested, with an emphasis on non-symbolic stimuli which can potentially be used as diagnostic tools for dyscalculia with young children, on the assumption that the aetiology of this developmental condition rests on a more general quantity processing deficit.

This research explores the dynamic fabric of experienced space in acousmatic music. The topology of spatial texture is a network of concepts treating music as a flexible, textural space, which deforms, shapes, and transforms in time. A comprehensive terminology is introduced, along with five fixed-media electroacoustic compositions, which exemplify a manifestation of spatial texture in composition and musical thinking. The theory draws from research on the cross-modality of texture perception, philosophical discourse on embodied meaning, physics, psychology of visual art, and discourse on space in acousmatic music. Several different structural perspectives are discussed, which reveal how spatial texture incorporates lower sound-structural levels, materiality, states and processes, motion, global networks and terrains, and relationships between space and time. Emphasis is put on visual and physical connections with spatiality in the acousmatic experience: cogency in spatial structure and dynamics reinforces links among modalities. The concepts and terminology are intended as a contribution to theory in the acousmatic medium, relevant to composition, analysis, and listening. The music represents an aesthetic orientation which emphasises materiality and morphology in texture, transformative processes, spatial design, and spatiotemporal polyvalence.

This thesis examines the context effects on retrieval, and the influence of action on the representation of distance in cognitive maps. It is proposed that bias in distance estimation is a function of the contexts of retrieval that trigger the representation of action in memory during evaluation tasks. The proposal is consistent with embodied cognition evidence that suggests that actions are implicitly a part of the representation, and will be naturally extracted as part of the retrieval process. The experimental work presented examines two different contextual cues; the frequency of visitation to landmarks, and the importance of activity performed at landmarks. Each cue primes differently the conceptualisation of landmarks prior to making distance estimation. This priming facilitates memory access, which fleshes out relevant spatial information from cognitive maps that are used in distance estimation and route description. This proposal was examined in a series of four experiments that employed structured interviews. Participants had to rate landmarks based on frequency of visitation criteria or importance of activity criteria, or both. They then made verbal distance estimations and route descriptions. The results found implicate the involvement of action representation. The involvement of action in cognitive process was empirically investigated in three further experiments. A new methodology was developed featuring the use of a blindfold, linguistic descriptions, and control of actual movements. Blindfolded participants learned new environments through verbal descriptions by imagining themselves walking in time with the metronome beats. During turns, they were carefully moved. Following instructions, they performed an action at mid-route. Their memories for the newly learned environments were tested through recalls and measured again with the metronome beats. The results found were consistent with explanations based on network-map theory. They implicate attentional processes as an intrinsic part of the cognitive mechanism, and the strings of the network-map as the actual motor program that executes the movement. These results are discussed in relation to the nature of cognitive maps.