Sources of bias and uncertainty in a visual temporal individuation task

Abstract

Despite a clear ability to detect temporal modulations of visual stimuli in excess of 50 Hz, temporal individuation and serial order judgment tasks can be performed only when stimuli alternate at much slower rates, and the nature of such sluggishness remains unclear. One example of a task with a slow temporal limit is the individuation of a cued letter in a rapid serial visual presentation (RSVP) stream. The present study investigates the nature of the code used to perform such a slow temporal individuation task and the sources of uncertainty involved. The results demonstrate that temporal, rather than ordinal, position in the RSVP stream is critical in serial order estimation, suggesting the involvement of a noisy temporal code. In addition to variability in temporal coding, observers' choices are also limited by a number of other factors, such as categorical errors and biases related to the position of the cue in the letters' stream. Attentional filtering improves categorization, but crucially, it does not seem to increase the temporal precision of judgment. Generalizing the present results, I suggest that perception of order is limited by an internal temporal sampling instability that is distinct and independent from attention and that, similarly to temporal jitter in a clock, acts as a low-pass filter that hinders the judgment of the order of events that unfold too quickly.

Sleep after practice reduces the attentional blink

“…The result seems consistent with previous suggestions that training improves T2 reports owing to increased attentional control (Choi et al, 2012). It is also consistent with the notion that training improves temporal expectation (Tang et al, 2014; Willems et al, 2014), in as much as temporal expectation improves efficacy of selection, as reported by Martini (2013).…”

“…In addition, we computed efficacy, latency and precision of selection using a method similar to that used by Vul, Nieuwenstein, and Kanwisher (2008) and Martini (2013). The method is based on the analysis of serial position error of the reported letters at different lags.…”

Splitting attention reduces temporal resolution from 7 Hz for tracking one object to <3 Hz when tracking three

“…Processing of the first target in attentional blink tasks may be limited by the temporal imprecision of attentional selection, but unfortunately it is rarely studied. The evidence available is that the precision of selection of the first target in a rapid serial visual presentation (RSVP) stream (Martini, 2012;Vul, Nieuwenstein, & Kanwisher, 2008) has a standard deviation of approximately 70 ms. Approximately the same figure is found for judging the instantaneous position of a moving object at the time of a cue (Murakami, 2001;Linares, Holcombe, & White, 2009).…”

Holcombe Nguyen Goodbourn (in press). Implied reading direction and prioritization of letter encoding. Journal of Experimental Psychology: General

“…One might expect that the appearance of the cues would trigger sampling from the stream, resulting in the reported letters being either simultaneous with the cue or from some time after the cue-a positively skewed distribution of serial-position errors. Instead, the distribution of positions is symmetric, with many coming from before the time of the cue (Botella, Suero, & Barriopedro, 2001;G&H;Martini, 2013). Based on these findings, G&H theorized that even the letters presented before the cue activate orthographic representations, that the activation of these representations persists, and that subsequently the cue is bound to one of them (for a related model that anticipates some of these ideas, see Botella, Suero, & Barriopedro, 2001).…”