Water regulation in the rat: III. The artificial control of thirst with stomach loads of water and sodium chloride.

382

560

The relationships between spatial attention and conscious perception are currently the object of intense debate. Recent evidence of double dissociations between attention and consciousness cast doubt on the time-honored concept of attention as a gateway to consciousness. Here we review evidence from behavioral, neurophysiologic, neuropsychological, and neuroimaging experiments, showing that distinct sorts of spatial attention can have different effects on visual conscious perception. While endogenous, or top-down attention, has weak influence on subsequent conscious perception of near-threshold stimuli, exogenous, or bottom-up forms of spatial attention appear instead to be a necessary, although not sufficient, step in the development of reportable visual experiences. Fronto-parietal networks important for spatial attention, with peculiar inter-hemispheric differences, constitute plausible neural substrates for the interactions between exogenous spatial attention and conscious perception.

Section: Discussionmentioning

confidence: 99%

Attentional Routes to Conscious Perception

Chica¹,

Bartolomeo²

2012

382

560

“…It is important to note that presentation time (either 250 or 450 ms in this experiment) does not seem to influence performance (see results). In fact, iconic memory is thought to be independent of the duration of stimulus presentation (Sperling, 1960; Dick, 1974), at least within our time range of 200–400 ms (Di Lollo and Dixon, 1992). …”

Section: Methodsmentioning

confidence: 99%

“…Choosing the right answer to such questions could have a significant behavioral impact. This early visual memory can be split into two primary components: a high-capacity, short-lived iconic memory (Sperling, 1960; Coltheart, 1980) followed by a limited-capacity visual working memory that can last many seconds (Pasternak and Greenlee, 2005; Fukuda et al, 2010; Keogh and Pearson, 2011). …”

Section: Introductionmentioning

confidence: 99%

The Sensory Components of High-Capacity Iconic Memory and Visual Working Memory

Bradley¹,

Pearson²

2012

Early visual memory can be split into two primary components: a high-capacity, short-lived iconic memory followed by a limited-capacity visual working memory that can last many seconds. Whereas a large number of studies have investigated visual working memory for low-level sensory features, much research on iconic memory has used more “high-level” alphanumeric stimuli such as letters or numbers. These two forms of memory are typically examined separately, despite an intrinsic overlap in their characteristics. Here, we used a purely sensory paradigm to examine visual short-term memory for 10 homogeneous items of three different visual features (color, orientation and motion) across a range of durations from 0 to 6 s. We found that the amount of information stored in iconic memory is smaller for motion than for color or orientation. Performance declined exponentially with longer storage durations and reached chance levels after ∼2 s. Further experiments showed that performance for the 10 items at 1 s was contingent on unperturbed attentional resources. In addition, for orientation stimuli, performance was contingent on the location of stimuli in the visual field, especially for short cue delays. Overall, our results suggest a smooth transition between an automatic, high-capacity, feature-specific sensory-iconic memory, and an effortful “lower-capacity” visual working memory.

“…Could the short-lasting memory for pictures be iconic memory (e.g., Sperling, 1960) or very short-term memory (VSTM) as described by Phillips and his colleagues (Phillips, 1983; Potter and Jiang, 2009)? The answer is no.…”

Section: Rapid Serial Visual Presentationmentioning

confidence: 99%

Recognition and Memory for Briefly Presented Scenes

Potter¹

2012

Three times per second, our eyes make a new fixation that generates a new bottom-up analysis in the visual system. How much is extracted from each glimpse? For how long and in what form is that information remembered? To answer these questions, investigators have mimicked the effect of continual shifts of fixation by using rapid serial visual presentation of sequences of unrelated pictures. Experiments in which viewers detect specified target pictures show that detection on the basis of meaning is possible at presentation durations as brief as 13 ms, suggesting that understanding may be based on feedforward processing, without feedback. In contrast, memory for what was just seen is poor unless the viewer has about 500 ms to think about the scene: the scene does not need to remain in view. Initial memory loss after brief presentations occurs over several seconds, suggesting that at least some of the information from the previous few fixations persists long enough to support a coherent representation of the current environment. In contrast to marked memory loss shortly after brief presentations, memory for pictures viewed for 1 s or more is excellent. Although some specific visual information persists, the form and content of the perceptual and memory representations of pictures over time indicate that conceptual information is extracted early and determines most of what remains in longer-term memory.