In visual images, we perceive both space (as a continuous visual medium) and objects (that inhabit space). Similarly, in dynamic visual experience, we perceive both continuous time and discrete events. What is the relationship between these units of experience? The most intuitive answer may be similar to the spatial case: time is perceived as an underlying medium, which is later segmented into discrete event representations. Here we explore the opposite possibility--that our subjective experience of time itself can be influenced by how durations are temporally segmented, beyond more general effects of change and complexity. We show that the way in which a continuous dynamic display is segmented into discrete units (via a path shuffling manipulation) greatly influences duration judgments, independent of psychophysical factors previously implicated in time perception, such as overall stimulus energy, attention and predictability. It seems that we may use the passage of discrete events--and the boundaries between them--in our subjective experience as part of the raw material for inferring the strength of the underlying "current" of time.

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Selective attention not only influences which objects in a display are perceived, but also directly changes the character of how they are perceived--for example, making attended objects appear larger or sharper. In studies of multiple-object tracking and probe detection, we explored the influence of sustained selective attention on where objects are seen to be in relation to each other in dynamic multi-object displays. Surprisingly, we found that sustained attention can warp the representation of space in a way that is object-specific: In immediate recall of the positions of objects that have just disappeared, space between targets is compressed, whereas space between distractors is expanded. These effects suggest that sustained attention can warp spatial representation in unexpected ways.

The underlying units of attention are often discrete visual objects. Perhaps the clearest form of evidence for this is the same-object advantage: Following a spatial cue, responses are faster to probes occurring on the same object than they are to probes occurring on other objects, while equating brute distance. Is this a fundamentally spatial effect, or can same-object advantages also occur in time? We explored this question using independently normed rhythmic temporal sequences, structured into phrases and presented either visually or auditorily. Detection was speeded when cues and probes both lay within the same rhythmic phrase, compared to when they spanned a phrase boundary, while equating brute duration. This same-phrase advantage suggests that object-based attention is a more general phenomenon than has been previously suspected: Perceptual structure constrains attention, in both space and time, and in both vision and audition.

Violations of spatiotemporal continuity disrupt performance in many tasks involving attention and working memory, but experiments on this topic have been limited to the study of moment-by-moment on-line perception, typically assessed by passive monitoring tasks. We tested whether persisting object representations also serve as underlying units of longer-term memory and active spatial navigation, using a novel paradigm inspired by the visual interfaces common to many smartphones. Participants used key presses to navigate through simple visual environments consisting of grids of icons (depicting real-world objects), only one of which was visible at a time through a static virtual window. Participants found target icons faster when navigation involved persistence cues (via sliding animations) than when persistence was disrupted (e.g., via temporally matched fading animations), with all transitions inspired by smartphone interfaces. Moreover, this difference occurred even after explicit memorization of the relevant information, which demonstrates that object persistence enhances spatial navigation in an automatic and irresistible fashion.