Natural Scene Perception: Interactions between Semantics and Space
Open Access DepositedVisual perception of natural scenes hinges on rapidly integrating numerous spatial and semantic sources of information, making it both critical and difficult to understand the contribution of individual cues. Across three papers, this dissertation employed a diverse set of natural scenes to investigate spatial processing at brief durations, revealing immense systematicity in responses and biases directly attributable to pictorial cues. The impact of individual cues (e.g., angular declination, linear perspective) has been identified in reduced cue environments in the real world, but Chapter 2 takes an imperative step forward by characterizing egocentric distance representations in full-cue, natural pictured scenes. Across 156 novel scenes presented for brief durations in two tasks (numerical estimate, and distance discrimination) results showed a strong overall sensitivity to distance, and highly reliable differences across individual scenes that predicted performance between tasks and viewing duration. Thus, the cues within the image must consistently drive 3D spatial perception, as evidenced by the size of the ground plane significantly explaining the magnitude of scene-specific deviations in Chapter 2. Importantly, semantic information, such as the expected size of familiar objects, is abundant in natural scenes and can inform absolute distance. Chapter 3 quantifies the relative impact of object familiar size on egocentric distance estimates by manipulating the visual scale and familiarity of target objects. Results showed a distinctive bias introduced to estimates by the semantic expectation for a particular object size, which was significantly stronger for familiar versus unfamiliar objects. Given just 125 ms to view the scene, when a familiar target object (e.g., basketball) was presented larger than expected for its category, distance estimates were shorter and vice versa. Finally, given the rapid influence of familiar size, Chapter 4 tested whether expectations of familiar size modulate attention in natural scenes. Notably, violations in familiar size caused inefficient perceptual processing even when the object was task-irrelevant. Overall, this dissertation provides compelling evidence for a rapid mechanism of natural scene perception that integrates semantic knowledge and spatial cues, and puts forth a flexible framework for characterizing behavior that can be translated to other perceptual tasks and applied settings.
- All rights reserved
Notice to Authors
If you are the author of this work and you have any questions about the information on this page, please use the Contact form to get in touch with us.
| Thumbnail | Title | Date Uploaded | Visibility | Actions |
|---|---|---|---|---|
|
|
Mahableshwarkar_gwu_0075A_16788.pdf | 2024-10-02 | Open Access |
|