Shuyao Wang

We investigated how visual cognitive processes unfold under temporal constraints using the rapid serial visual presentation (RSVP) paradigm. In a typical RSVP task, stimuli are presented sequentially at the same spatial location, usually at a rate of 10 items per second. This paradigm imposes high temporal pressure on the visual system while effectively controlling other variables, such as spatial confounds. Therefore, RSVP is a suitable tool to investigate how cognitive resources are allocated to process items in quick succession. An interesting phenomenon that emerges in the dual-target RSVP paradigm is the attentional blink (AB). The AB refers to the impairment in reporting a second target (T2) when it appears shortly after the first target (T1), usually between 200 and 500 ms. The AB provides an ideal platform to examine processing limitations because it allow for a direct comparison between two time interval conditions: 1) short intervals, during which the identification of T2 is significantly impaired; 2) longer intervals, during which no ‘blink’ occurs and T2 is reported normally. This dissertation hence utilizes the RSVP and AB paradigms to examine the visual cognition under temporal constraints with regard to three specific aspects: 1. Whether working memory consolidation failure during the AB is a discrete, all-or-none process, or a gradual loss of representational quality (Chapter 2). 2. If spatial attention can be flexibly adjusted under time pressure and how this adjustment influences the discrete or graded nature of conscious awareness (Chapter 3). 3. How internal memory representations guide attention and whether this process can be captured by physiological signals for covert information detection (Chapter 4). In Chapter 2, we analyzed data derived from continuous report tasks embedded in the AB paradigm to investigate the nature of working memory failures. The analysis included four distinct datasets: three obtained from different laboratories (Asplund et al., 2014; Karabay et al., 2022; Tang et al., 2020) and one from a new experiment conducted for this study. We conducted a systematic comparison of seven computations models, including “slot” models (standard mixture, slot, slots plus resource models) and variable precision models. Our results consistently showed that models incorporating a discrete guessing component (“slot” models) provided the best fit at both group and individual levels. Simulation analyses confirmed that these models accurately reproduce the “blink” pattern. In contrast, the standard VP model failed to capture impaired representations during the blink window, unless a guessing parameter was added. These findings support the view that working memory (WM) consolidation in the tested tasks is a capacity-limited process where targets either enter memory successfully or fail entirely, with failures resulting in pure guessing. In Chapter 3, we investigated whether participants can adaptively control their attentional scale under temporal constraints. In this study, we assumed that changes in the nature of T2 awareness, specifically indexed by its representational precision, would indicate whether attentional scaling had been successfully implemented. We manipulated the T1 location using session-wise, trial-wise, or statistical regularities. We then analyzed T2 performance using mixture modeling to dissociate the probability of conscious access from representational precision. Our results showed that precision decreased when session-wise cues and statistical regularities were implemented, indicating that a broad attentional scale was successfully induced in these contexts. In contrast, trial-wise cues failed to modulate precision, suggesting that immediate, trial-by-trial adaptation is not possible in this condition. These findings demonstrate that while spatial attention can be adjusted to influence the nature of conscious awareness, such spatial control depends on stable explicit cues or implicit learning of regularities rather than immediate adjustments. In Chapter 4, we applied the RSVP paradigm to the practical domain of concealed information detection to investigate how internal memory representations influence temporal attention. Specifically, we embedded personally familiar faces as task-irrelevant probes within the RSVP streams within a gender- based target detection task. We then utilized four physiological measures: ERP (P3) amplitude, theta-band power, pupil size, and pupil size change to assess covert recognition. We found that all indicators successfully distinguished familiar probes from neutral control stimuli at the group level. However, at the individual level, although ERP and theta-band power signals provided reliable detection for most participants, pupillary responses were less effective. This is likely due to the difficulty of isolating relatively slow-developing pupillary signals in high-speed RSVP paradigms. Furthermore, by integrating neural and pupillary signals, we found that combined inference compensated to some extent for limitations of single measures. In sum, these chapters explore how the human cognitive system processes information under temporal constraints using computational modeling, behavioral performance, and physiological measures. Across three empirical studies, we demonstrate that the cognitive system regulates information flow via reactive gating, proactive spatial scaling, and memory-driven priority signals. Specifically, our findings show that while working memory and conscious access in typical AB tasks are primarily governed by discrete, all-or-none capacity limits, the nature of awareness remains flexible and can be proactively configured by adjusting the attentional scale. Furthermore, internal memory representations can automatically capture processing resources even without overt report, a process that can be reliably tracked through neural signals. Overall, this work suggests that temporal constraints provide a window into the dynamic nature of human cognition, illustrating how this system adaptively manages information processing under such pressure.