Learning how to exploit sources of information

Representation and computation in visual working memory

The ability to sustain internal representations of the sensory environment beyond immediate perception is a fundamental requirement of cognitive processing. In recent years, debates regarding the capacity and fidelity of the working memory (WM) system have advanced our understanding of the nature of these representations. In particular, there is growing recognition that WM representations are not merely imperfect copies of a perceived object or event. New experimental tools have revealed that observers possess richer information about the uncertainty in their memories and take advantage of environmental regularities to use limited memory resources optimally. Meanwhile, computational models of visuospatial WM formulated at different levels of implementation have converged on common principles relating capacity to variability and uncertainty. Here we review recent research on human WM from a computational perspective, including the neural mechanisms that support it.

Attention with or without working memory: mnemonic reselection of attended information

Attention has been regarded as the 'gatekeeper' controlling what information gets selected into working memory. However, a new perspective has emerged with the discovery of attribute amnesia, a phenomenon revealing that people are frequently unable to report information they have just attended to moments ago. This report failure is thought to stem from a lack of consolidating the attended information into working memory, indicating a dissociation between attention and working memory. Building on these findings, a new concept called memory reselection is proposed to describe a secondary round of selection among the attended information. These discoveries challenge the conventional view of how attention and working memory are related and shed new light onto modeling attention and memory as dissociable processes.

Surprise! Draw the scene: Visual recall reveals poor incidental working memory following visual search in natural scenes

Searching within natural scenes can induce incidental encoding of information about the scene and the target, particularly when the scene is complex or repeated. However, recent evidence from attribute amnesia (AA) suggests that in some situations, searchers can find a target without building a robust incidental memory of its task relevant features. Through drawing-based visual recall and an AA search task, we investigated whether search in natural scenes necessitates memory encoding. Participants repeatedly searched for and located an easily detected item in novel scenes for numerous trials before being unexpectedly prompted to draw either the entire scene (Experiment 1) or their search target (Experiment 2) directly after viewing the search image. Naïve raters assessed the similarity of the drawings to the original information. We found that surprise-trial drawings of the scene and search target were both poorly recognizable, but the same drawers produced highly recognizable drawings on the next trial when they had an expectation to draw the image. Experiment 3 further showed that the poor surprise trial memory could not merely be attributed to interference from the surprising event. Our findings suggest that even for searches done in natural scenes, it is possible to locate a target without creating a robust memory of either it or the scene it was in, even if attended to just a few seconds prior. This disconnection between attention and memory might reflect a fundamental property of cognitive computations designed to optimize task performance and minimize resource use.

Insights on overflow from failure to report tasks

Theories of consciousness diverge on the functional requirement that a conscious state need be reportable. Some maintain that the perceptual system's capacity for consciousness exceeds that of its capacity for access. Others contend that what is accessed is all there is to consciousness. Here, we suggest a compelling case for access-free consciousness cannot be made reliant on experimental evidence where access is necessarily invoked. However, a bona fide empirical separation of consciousness and report could counter the claim that reportability, and hence access, is all there is to consciousness. We first overview recent neurophysiological findings from no-report tasks, before examining a series of studies in which participants were unable to report features of clearly visible items. These new data present a challenge for a hard "access-only" view of consciousness, as they appear to demonstrate that properties of our visual experience can remain unreportable. In so doing, we highlight the utility and underappreciated value of so-called failure to report tasks.

Using the attribute amnesia paradigm to test the automatic memory advantage of person names

Person names, which hold within them extensive meaning, such as gender and cultural information, play an essential role in our social interaction. The intentional memory advantage of person names has been proved, but whether the automatic memory advantage of them exists remains unclear. In order to explore this question, we used a paradigm called attribute amnesia that allows us to test the automatic memory of person names in a working memory task. In Experiment 1, we adopted a classic attribute amnesia paradigm including 11 pre-surprise trials requiring participants to report the location of the target (person names or animal names) among three distractors and one surprise trial requiring them to unexpectedly report the identity of the target. The results showed that the identity report accuracy of person names in the surprise test was significantly better than that of animal names that served as a control group. Experiment 2 replicated Experiment 1 but increased the number of pre-surprise trials that could reduce the report accuracy of surprise test according to previous studies. The results revealed that the accuracy of the surprise test of person names decreased significantly, and showed no significant difference from that of animal names. These results suggest that there exists an automatic memory advantage of person names in working memory; however, such an automatic memory advantage effect could be reduced after participants learn to stop automatically encoding the attended but no-need-to-report person names through experiencing sufficient trials.

And like that, they were gone: A failure to remember recently attended unique faces

Attribute amnesia (AA) is a phenomenon in which participants have difficulty answering an unexpected question about an attended attribute of the most recent target stimulus. A similar situation can occur in cases of real-life eyewitness identification when the eyewitness did not explicitly try to remember the alleged perpetrator's face despite having attended to it. We found that AA is generalizable to novel faces, such that when participants were unexpectedly asked to identify a face, performance was poor, even though they had just attended to that face seconds ago (N = 40 each in an initial experiment and its replication). This finding shows that unexpected face identification is inaccurate even when the face had just been attended to and suffered minimal decay and interference, implying that AA can explain some cases of failure of eyewitness identification that cannot be attributed to a lack of attention or post-event interference.

Attribute Amnesia in the Auditory Domain

Individuals are often unable to report an attribute of an object to which they recently attended, if they expected to report a different attribute, a phenomenon known as attribute amnesia (AA). To date, all AA studies have occurred in the visual domain. The purpose of this study was to explore the boundary conditions of AA by testing if AA also occurs in the auditory domain and, if so, for which attributes. It was found that AA was present when reporting the location (p = .003) and the number of tones (p < .001) of an auditory stimulus, but not when reporting its pitch (p = .383). These findings can be understood in terms of the organisation of the primary cortical areas and help explain the differences between visual working memory and auditory working memory.

No explicit memory for individual trial display configurations in a visual search task

Previous evidence demonstrated that individuals can recall a target's location in a search display even if location information is completely task-irrelevant. This finding raises the question: does this ability to automatically encode a single item's location into a reportable memory trace extend to other aspects of spatial information as well? We tested this question using a paradigm designed to elicit attribute amnesia (Chen & Wyble, Psychological Science, 26(2) 203-210, 2015a). Participants were initially asked to report the location of a target letter among digits with stimuli arranged to form one of two or four spatial configurations varying randomly across trials. After completing numerous trials that matched their expectations, participants were surprised with a series of unexpected questions probing their memory for various aspects of the display they had just viewed. Participants had a profound inability to report which spatial configuration they had just perceived when the target's location was not unique to a specific configuration (i.e., orthogonal). Despite being unable to report the most recent configuration, answer choices on the surprise trial were focused around previously seen configurations, rather than novel configurations. Thus, there were clear memories of the set of configurations that had been viewed during the experiment but not of the specific configuration from the most recent trial. This finding helps to set boundary conditions on previous findings regarding the automatic encoding of location information into memory.

Consciousness can overflow report: Novel evidence from attribute amnesia of a single stimulus

There is a long-standing debate on whether visual consciousness is confined to cognitive access measured by reportability, or whether it is rich and overflows reportability. Much of the debate in previous studies concentrated on whether information outside attentional focus could be consciously experienced and reportable. This study sought to address the debate from a new perspective, through testing whether fully attended supraliminal information is necessarily reportable with a variation of attribute amnesia. Participants were asked to judge the parity of a single number or whether a Chinese character referred to furniture. After several trials, they were unexpectedly asked to report the stimulus identity. The results consistently showed that participants could not correctly report the identity, indicating that fully attended information that was consciously perceived could sometimes overflow report. In addition to providing novel overflow evidence, these findings also have crucial implications in understanding the relationship between consciousness and working memory.

Immediate action effects motivate actions based on the stimulus-response relationship

The theory of event coding, an influential framework for action planning, suggests that humans first integrate stimulus, response, and action effect into representation (an event file) via their contingencies, and then, the activation of expected action effects drives the associated response. While previous studies have typically examined such functions of action effects after, rather than before or during, the acquirement of the representation, Eitam et al. (Exp Brain Res 229:475-484, 2013a) demonstrated that the presence of immediate feedback to action (i.e., action effects) can instantly elicit faster responses than delayed feedback. However, the underlying mechanism of this faciliatory effect remains unclear. Specifically, while the response-effect relationship has been highlighted, the role of stimuli has not been investigated. To address this issue, the present study conducted four experiments. We first reproduced the faciliatory effects of immediate action effects with between- and within-participants design (Experiments 1 and 2, respectively). Then, we assessed whether immediate action effects facilitate response speed, when stimuli (Experiment 3) and a combination of stimuli and responses (Experiment 4) determined the delay of action effects. The identical response was executed faster when driven by stimuli associated with immediate effects than by those associated with lagged effects. This result indicates that immediate action effects do not reinforce the execution of specific motor actions itself, but facilitate actions depending on the stimulus-response relationship. We discuss the potential mechanism of the facilitation effect.