Target Letter Research Articles

Expecting the unexpected: Violation of expectation shifts strategies toward information exploration.

As our environment is frequently changing, it is common that our expectations are violated by unexpected stimuli or events, which leaves us uncertain about which pieces of information will be useful in the future. It is unclear how an expectation violation affects the subsequent control settings for processing of information. The current study directly addressed this issue by employing a double-surprise-trial paradigm based on the attribute amnesia task (Chen & Wyble, 2015a). In Experiment 1, participants were asked to report the location of a target letter presented among distractor digits on several trials and were then unexpectedly asked to report a different attribute (color or identity) of the target letter. In the next trial, participants were asked another unexpected question about the other attribute (identity or color respectively). The results show that, despite participants' poor performance in the first surprise trial, which replicated the attribute amnesia effect, their memory performance in the second surprise trial was dramatically improved, even when the probed attribute was different from that of the first surprise trial. This was also true in Experiment 2, where 15 trials were inserted between the two surprise trials. Experiment 3 further clarified that this effect is not triggered by the mere presence of a surprise test, but rather the violation of expectation about the nature of a surprise test. These results suggest the operation of an adaptive control mechanism that reduces the selectivity of processing in the face of unexpected events. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Contrasting episodic and template-based guidance during search through natural scenes.

Visual search through natural scenes can be guided by knowledge of where a target object has been observed previously (episodic guidance) and knowledge of that object's visual properties (template guidance). In the present experiments, we compared the relative contributions of these two sources of guidance. Episodic guidance was implemented in a contextual cuing task: participants searched multiple times through a set of scenes for a target letter that appeared in a consistent location within each scene. Template guidance was implemented by the color match between a critical distractor in each scene and a secondary visual working memory (VWM) load. There were four main findings. First, search time decreased with increasing scene repetition; episodic memory guided search. Second, the critical distractor was fixated more frequently on match compared with mismatch trials, consistent with automatic template guidance. Third, the VWM-match effect persisted in blocks with strong episodic guidance. Finally, VWM-match effects were observed from the first saccade during search, whereas episodic guidance to the target developed only later in the trial. The results support a view of natural search in which template-based mechanisms operate early during search in a manner that is not strongly constrained by scene-based forms of guidance, such as episodic knowledge. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Does attribute amnesia occur with the presentation of complex, meaningful stimuli? The answer is, "it depends".

Attribute amnesia (AA) is a recently reported phenomenon whereby participants are unable to report a salient attribute of a stimulus (e.g., the color or identity of a target letter) on which their attention has just been focused during a prior task. This counterintuitive effect has been repeatedly replicated with various simple stimuli such as digits and letters. The current study sought to explore boundaries of AA by investigating whether the phenomenon persists when participants encounter complex, meaningful stimuli (e.g., pictures) that have been shown to hold an advantage in cognitive processing and memory. In Experiments 1a-d, we examined whether AA was observed with different types of complex stimuli. In Experiments 2a-b and 3a-b, we linked the type of stimuli (simple vs. complex and meaningful stimuli) to the other two potential boundary factors of AA (i.e., repetitiveness of target stimulus and set effects of Einstellung) to see whether there were interactions between stimuli type and these two boundary factors. The results demonstrated that the AA effect was still consistently observed for complex stimuli in a typical AA paradigm wherein participants encountered many trials and the targets were repeated across trials. However, this effect only appeared for simple stimuli, but not for complex stimuli in two special cases: when target stimuli were never repeated through the experiment, or when the surprise test was placed on the first trial of the experiment. These findings have crucial implications in understanding the boundaries of the AA phenomenon.

Implicit location probability learning does not induce baseline shifts of visuospatial attention.

We tested whether implicit learning causes shifts of spatial attention in advance of or in response to stimulus onset. Participants completed randomly interspersed trials of letter search, which involved reporting the orientation of a T among Ls, and scene search, which involved identifying which of four scenes was from a target category (e.g., forest). In Experiment 1, an initial phase more often contained target letters in one screen quadrant, while the target scenes appeared equally often in all quadrants. Participants persistently prioritized letter targets in the more probable region, but the implicitly learned preference did not affect the unbiased scene task. In Experiment 2, the spatial probabilities of the scene and letter tasks reversed. Participants unaware of the probability manipulation acquired only a spatial bias to scene targets in the more probable region, with no effect on letter search. Instead of recruiting baseline shifts of spatial attention prior to stimulus onset, implicit learning of target probability yields task-dependent shifts of spatial attention following stimulus onset. Such shifts may involve attentional behaviors unique to certain task contexts.

On the Relative Contribution of Deep Convolutional Neural Networks for SSVEP-Based Bio-Signal Decoding in BCI Speller Applications.

Brain-computer interfaces (BCI) harnessing steady state visual evoked potentials (SSVEPs) manipulate the frequency and phase of visual stimuli to generate predictable oscillations in neural activity. For BCI spellers, oscillations are matched with alphanumeric characters allowing users to select target numbers and letters. Advances in BCI spellers can, in part, be accredited to subject-specific optimization, including; 1) custom electrode arrangements; 2) filter sub-band assessments; and 3) stimulus parameter tuning. Here, we apply deep convolutional neural networks (DCNNs) demonstrating cross-subject functionality for the classification of frequency and phase encoded SSVEP. Electroencephalogram (EEG) data are collected and classified using the same parameters across subjects. Subjects fixate forty randomly cued flickering characters ( 5 ×8 keyboard array) during concurrent wet-EEG acquisition. These data are provided by an open source SSVEP dataset. Our proposed DCNN, PodNet, achieves 86% and 77% offline accuracy of classification across-subjects for two data capture periods, respectively, 6-seconds (information transfer rate = 40 bpm) and 2-seconds (information transfer rate = 101 bpm). Subjects demonstrating sub-optimal (<70%) performance are classified to similar levels after a short subject-specific training period. PodNet outperforms filter-bank canonical correlation analysis for a low volume (3-channel) clinically feasible occipital electrode configuration. The networks defined in this study achieve functional performance for the largest number of SSVEP classes decoded via DCNN to date. Our results demonstrate PodNet achieves cross-subject, calibrationless classification and adaptability to sub-optimal subject data, and low-volume EEG electrode arrangements.

Visual Crowding in Glaucoma.

PurposeCrowding refers to the phenomenon in which objects that can be recognized when viewed in isolation are unrecognizable in clutter. Crowding sets a fundamental limit to the capabilities of the peripheral vision and is essential in explaining performance in a broad array of daily tasks. Due to the effects of glaucoma on peripheral vision, we hypothesized that neural loss in the disease would lead to stronger effects of visual crowding.MethodsSubjects were asked to discriminate the orientation of a target letter when presented with surrounding flankers. The critical spacing value (scritical), which was required for correct discrimination of letter orientation, was obtained for each quadrant of the visual field. scritical values were correlated with standard automated perimetry (SAP) mean sensitivity (MS) and optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) thickness measurements.ResultsThe study involved 13 subjects with mild glaucomatous visual field loss and 13 healthy controls. Glaucomatous eyes had significantly greater (worse) scritical than controls (170.4 ± 27.1 vs. 145.8 ± 28.0 minimum of visual angle, respectively; P = 0.007). scritical measurements were significantly associated with RNFL thickness measurements (R2 = 26%; P < 0.001) but not with SAP MS (P = 0.947).ConclusionsIn glaucoma patients, a pronounced visual crowding effect is observed, even in the presence of mild visual field loss on standard perimetry. scritical was associated with the amount of neural loss quantified by OCT. These results may have implications for understanding how glaucoma patients are affected in daily tasks where crowding effects may be significant.

Anticipation of cognitive conflict is reflected in microsaccades: Evidence from a cued-flanker task.

Microsaccade frequency has recently been shown to be sensitive to high-level cognitive processes such as attention and memory. In the present study we explored the effects of anticipated cognitive conflict. Participants were administered a variant of the flanker task, which is known to elicit cognitive interference. At the beginning of each trial, participants received a colour cue providing information about the upcoming target frame. In two thirds of the trials, the cue reliably informed the participants that in the upcoming trial the flankers either matched the central target letter or not. Hence, participants could accurately anticipate whether cognitive conflict would arise or not. On neutral trials, the cue provided no useful information. The results showed that microsaccadic rate time-locked to cue onset was reduced on trials in which an upcoming cognitive conflict was expected. These findings provide new insights about top-down modulations of microsaccade dynamics.

Exploring the role of expectations and stimulus relevance on stimulus-specific neural representations and conscious report.

Subjective experience can be influenced by top-down factors, such as expectations and stimulus relevance. Recently, it has been shown that expectations can enhance the likelihood that a stimulus is consciously reported, but the neural mechanisms supporting this enhancement are still unclear. We manipulated stimulus expectations within the attentional blink (AB) paradigm using letters and combined visual psychophysics with magnetoencephalographic (MEG) recordings to investigate whether prior expectations may enhance conscious access by sharpening stimulus-specific neural representations. We further explored how stimulus-specific neural activity patterns are affected by the factors expectation, stimulus relevance and conscious report. First, we show that valid expectations about the identity of an upcoming stimulus increase the likelihood that it is consciously reported. Second, using a series of multivariate decoding analyses, we show that the identity of letters presented in and out of the AB can be reliably decoded from MEG data. Third, we show that early sensory stimulus-specific neural representations are similar for reported and missed target letters in the AB task (active report required) and an oddball task in which the letter was clearly presented but its identity was task-irrelevant. However, later sustained and stable stimulus-specific representations were uniquely observed when target letters were consciously reported (decision-dependent signal). Fourth, we show that global pre-stimulus neural activity biased perceptual decisions for a ‘seen’ response. Fifth and last, no evidence was obtained for the sharpening of sensory representations by top-down expectations. We discuss these findings in light of emerging models of perception and conscious report highlighting the role of expectations and stimulus relevance.

Emotional real-world scenes impact visual search

Research shows that emotional stimuli can capture attention, and this can benefit or impair performance, depending on the characteristics of a task. Additionally, whilst some findings show that attention expands under positive conditions, others show that emotion has no influence on the broadening of attention. The current study investigated whether emotional real-world scenes influence attention in a visual search task. Participants were asked to identify a target letter embedded in the centre or periphery of emotional images. Identification accuracy was lower in positive images compared to neutral images, and response times were slower in negative images. This suggests that real-world emotional stimuli have a distracting effect on visual attention and search. There was no evidence that emotional images influenced the spatial spread of attention. Instead, it is suggested that findings may provide support for the argument that positive emotion encourages a global processing style and negative emotion promotes local processing.

Comparing Effects of Instruction on Word Meaning and Word Form on Early Literacy Abilities in Kindergarten

ABSTRACTResearch Findings: The present study compared effects of explicit instruction on and practice with the phonological form of words (form-focused instruction) versus explicit instruction on and practice with the meaning of words (meaning-focused instruction). Instruction was given via interactive storybook reading in the kindergarten classroom of children learning Dutch. We asked whether the 2 types of instruction had different effects on vocabulary development and 2 precursors of reading ability—phonological awareness and letter knowledge—and we examined effects on these measures of the ability to learn new words with minimal acoustic-phonetic differences. Learners showed similar receptive target-word vocabulary gain after both types of instruction, but learners who received form-focused vocabulary instruction showed more gain in semantic knowledge of target vocabulary, phonological awareness, and letter knowledge than learners who received meaning-focused vocabulary instruction. Level of ability to learn pairs of words with minimal acoustic-phonetic differences predicted gain in semantic knowledge of target vocabulary and in letter knowledge in the form-focused instruction group only. Practice or Policy: A focus on the form of words during instruction appears to have benefits for young children learning vocabulary.

Alphabet books: The nature of parents’ shared reading between and across books

This study examined the nature of parents’ shared reading with their preschoolers between and across two different alphabet trade books. The “busy” book contains more sentences and words per page, more complex illustrations per page, and the target letter takes up less of the page and appears in the same colour as the text. The “less busy” book contains fewer sentences and words per page, simpler, more monochromatic illustrations, and the target letter takes up more of the page and appears in a different colour from the text. Participants included 46 parent–child dyads from middle SES homes. The children (13 boys, 33 girls) ranged from 4-years-old to 6.8-years-old (M = 5.63, SD = 0.6). Results revealed that parents made more references to the writing system and to more narrative elements when reading the “less busy” book. They also requested their children’s responses more when reading this book. Parents made more references to the illustrations and regulation of behaviour when reading the “busy” book. These results went beyond the child’s language level and the parent’s education level, controlling for the overall number of utterances. Findings also showed that parents seem to have a consistent style across both alphabet books, such that the more characteristics of the shared reading appeared during one book, the more they featured in the shared reading of the other book. Parents may benefit from exposure to different types of alphabet books and how their varying characteristics can impact on discourse style.

Reward elicits cognitive control over emotional distraction: Evidence from pupillometry

Attention is biased toward emotional stimuli, even when they are irrelevant to current goals. Motivation, elicited by performance-contingent reward, reduces behavioural emotional distraction. In emotionally neutral contexts, reward is thought to encourage use of a proactive cognitive control strategy, altering anticipatory attentional settings to more effectively suppress distractors. The current preregistered study investigates whether a similar proactive shift occurs even when distractors are highly arousing emotional images. We monitored pupil area, an online measure of both cognitive and emotional processing, to examine how reward influences the time course of control. Participants (n = 110) identified a target letter flanking an irrelevant central image. Images were meaningless scrambles on 75% of trials; on the remaining 25%, they were intact positive (erotic), negative (mutilation), or neutral images. Half the participants received financial rewards for fast and accurate performance, while the other half received no performance-contingent reward. Emotional distraction was greater than neutral distraction, and both were attenuated by reward. Consistent with behavioural findings, pupil dilation was greater following emotional than neutral distractors, and dilation to intact distractors (regardless of valence) was decreased by reward. Although reward did not enhance tonic pupil dilation (an index of sustained proactive control), exploratory analyses showed that reward altered the time course of control-eliciting a sharp, rapid, increase in dilation immediately preceding stimulus onset (reflecting dynamic use of anticipatory control), that extended until well after stimulus offset. These findings suggest that reward alters the time course of control by encouraging proactive preparation to rapidly disengage from emotional distractors.

Dissociating between the N2pc and attentional shifting: An attentional blink study

The N2pc is routinely used as an electrophysiological index of attentional shifting. Its absence is thus taken as evidence that no shift of attention occurred. We provide evidence in contrast to this notion using a variant of the attentional blink (AB) paradigm. Two target letters, embedded in two streams of distractor letters and defined by their color, were separated by either 300 or 800 ms. The second target was preceded by a distractor frame of the same color (cue). As expected, identification of the second target was poorer at the short than at the long lag (the AB effect). The AB did not affect attentional capture by the cue, but suppressed and delayed the N2pc associated with it. This result suggests that the N2pc does not reflect attentional shifting. Instead, we conclude that the N2pc indexes the transient enhancement that occurs at the spatial focus of attention and promotes high-level processing such as identification. This conclusion calls for a reinterpretation of findings from the attentional capture literature that relied on the N2pc as an index of attentional shifting. Our results also inform contemporary models of the AB.

Exogenous attention and memory for faces following contextual behavioral immune system activation

The behavioral immune system (BIS) is characterized by affective, cognitive and behavioral processes that work in an articulated manner to prevent the occurrence of infections. Attention and memory evolved to enhance the organism's chances of survival and have been proposed to play an important role in the BIS. The present study investigated the effects of attention and memory for neutral faces after a contextual activation of the BIS. Participants were primed, by the use of film clips, either with infectious disease concerns or non-infectious disease concerns. They performed an exogenous attentional task involving the discrimination of target letters, with face stimuli presented as distractors, which was then followed by a surprise recognition task for the faces. The results showed that participants in the infectious disease condition were more accurate in the attentional task than participants in the control condition. No significant difference between groups was found in the response times during the attention task nor in memory performance. Overall, these results suggest that the BIS might be associated with a hypervigilant state towards cues in general and that BIS activation through this type of priming may not be sufficient to clearly activate mnemonic mechanisms.

Synesthesia improves sensory memory, when perceptual awareness is high

Empirical evidence suggests that synesthesia is associated with enhanced sensory processing. A separate body of empirical literature suggests that synesthesia is linked to a specific profile of enhanced episodic and working memory performance. However, whether sensory (iconic) memory performance is also affected by synesthesia remains unknown. Therefore, we tested 22 grapheme-color synesthetes and compared their performance in a partial-report paradigm with 22 individually matched non-synesthete controls. Participants were briefly presented with a circular-letter array and required to report the identity of the letter at a probed target location after various delays. Furthermore, they were required to indicate the subjective clarity of the target letter after every trial. The results suggest that sensory memory performance is enhanced in synesthesia, but only when subjective clarity of the target letter is high. Additional exploratory analyses revealed that synesthetic consistency, which is widely used to confirm the genuineness of synesthesia, correlated significantly with performance in the partial report paradigm. We conclude that synesthesia does not generally enhance sensory memory performance, but that synesthetic experiences may enhance sensory memory performance when perceptual awareness of the target is high. Furthermore, the stability of synesthetic associations may be linked to sensory memory performance.

"Two Minds Don't Blink Alike": The Attentional Blink Does Not Occur in a Joint Context.

Typically, when two individuals perform a task together, each partner monitors the other partners’ responses and goals to ensure that the task is completed efficiently. This monitoring is thought to involve a co-representation of the joint goals and task, as well as a simulation of the partners’ performance. Evidence for such “co-representation” of goals and task, and “simulation” of responses has come from numerous visual attention studies in which two participants complete different components of the same task. In the present research, an adaptation of the attentional blink task was used to determine if co-representation could exert an influence over the associated attentional mechanisms. Participants completed a rapid serial visual presentation task in which they first identified a target letter (T1) and then detected the presence of the letter X (T2) presented one to seven letters after T1. In the individual condition, the participant identified T1 and then detected T2. In the joint condition, one participant identified T1 and the other participant detected T2. Across two experiments, an attentional blink (decreased accuracy in detecting T2 when presented three letters after T1) was observed in the individual condition, but not in joint conditions. A joint attentional blink may not emerge because the co-representation mechanisms that enable joint action exert a stronger influence at information processing stages that do not overlap with those that lead to the attentional blink.

The Power of Negative Thinking: Paradoxical but Effective Ignoring of Salient-but-Irrelevant Stimuli by a Spatial Cue

It is often assumed that a uniquely colored singleton among other uniformly colored stimuli can function as a powerful attractor of attention (Theeuwes, 1992). However, top-down attentional mechanisms are also powerful and can suppress distractors when a pre-cue is given (Cunningham & Egeth, 2016; Munneke, Van der Stigchel, & Theeuwes, 2008). The current study tested whether an endogenous spatial cue indicating the location of a salient color singleton distractor can eliminate involuntary attentional allocation to such a stimulus. On each trial, either a capital "B" or "F" was randomly presented as the target letter. On ignore trials, an arrow cue indicated a to-be-ignored location that would never contain a target but would contain a color singleton distractor. Neutral trials provided no useful spatial information. Target-distractor compatibility was manipulated with a lowercase 'b' or 'f' distractor to test processing of the cued location. The results showed that a significant singleton capture effect was eliminated on ignore trials regardless of the consistency of the singleton color (Experiments 1 & 2). Significant compatibility effects were observed on both ignore and neutral trials, suggesting that participants adopted the strategy of selecting the cued location followed by rapid disengagement from that location on ignore trials. Overall, a spatial cue produces paradoxical but effective ignoring of salient-but-irrelevant stimuli; with a spatial cue, participants inhibited a cued location by first selecting the location and then rapidly disengaging from it. To explore whether participants could learn to ignore the color singleton in the absence of a spatial cue (Gaspelin & Luck, 2017; Vatterott & Vecera, 2012), in Experiment 3, only neutral trials were used with a consistent color singleton. Participants were not able to suppress singleton distractors, although the magnitude of singleton capture effects was reduced compared to that of neutral trials in Experiments 1 and 2. Meeting abstract presented at VSS 2018

Direct gaze, eye movements, and covert and overt social attention processes.

The present study is a replication and extension of previous research examining the effects of others' gaze direction and gaze shifts on both participants' (N = 32) manual responses, as an indicator of covert processes, and their visual attention, as an indicator of overt processes, within an experimental response time (RT) paradigm, under both fixed- and free-viewing instructions. Participants viewed arrays of faces displaying direct or averted gaze, which shifted or held their gaze, concurrent with the presentation of a target letter that participants had to identify overlaid on one face, all while their gaze was recorded with an eye-tracking system. Participants' RTs and eye movements both revealed faster responses when the target face displayed either direct or shifted gaze, and especially when its gaze had shifted from averted to direct, though these effects were modulated by the viewing instructions. Thus, the findings replicate and extend previous research by revealing that direct gaze and dynamic motion onset affect both covert and overt attention.

Attention capture during visual search: The consequences of distractor appeal, familiarity, and frequency

ABSTRACTVisual distractions can lure our attention and impede our everyday performance, especially if they are highly meaningful and appealing to the observer. The current research assessed how semantically rich, personally relevant distractors (i.e., cartoon characters), either appealing or neutral, capture attention and whether the frequency with which we encounter these distractors can impact the effects. Participants were slower to identify a target letter in the presence of a neutral distractor relative to an appealing distractor, reflecting covert attentional capture. However, this effect reversed when appealing distractors appeared less frequently than neutral distractors. Collectively, the evidence suggests that the amount of capture observed overall likely depends on the interplay between a distractor’s semantic salience (i.e., the amount of meaningful knowledge an observer has about the distractor), its affective salience (i.e., how the observer feels about the distractor), and how frequently it is encountered.

Gender Differences in the Automatic Attention to Romantic Vs Sexually Explicit Stimuli

IntroductionGender differences in sexual responses and cognitive and emotional processing to romantic and sexually explicit stimuli have been reported. However, these differences seem to depend on the automaticity of the task that is being used, thus suggesting that gender differences may be the result of specific mechanisms rather than a generalized effect. AimTo expand previous basic processes research on gender differences to romantic vs sexually explicit stimuli, focusing on potential differentiating mechanisms influencing male and female sexual responses, we aim to investigate gender differences on automatic attention to sexual stimuli, and to test its relationship with sexual excitation proneness. Methods26 women and 30 men (heterosexual) performed an automatic attention task, in which romantic and sexually explicit stimuli were presented as distractors, that is, stimuli to be ignored, while a concurrent letter discrimination task was performed, followed by a self-report task assessing subjective sexual and emotional responses to the stimuli. Main Outcome MeasuresPercentage of accuracy and response times (RTs) to discriminate the target letters were used as markers of automatic attention, with lower accuracy and longer RTs reflecting a higher degree of attentional capture by the distractor stimuli (romantic and sexually explicit). Participants completed self-report ratings on emotional valence, general arousal, and sexual arousal toward romantic and sexually explicit stimuli. They further reported on their sexual excitation proneness. ResultsFindings revealed that sexually explicit pictures yielded more automatic attention capture. However, this effect was superseded by pornography consumption, which likely reflects a habituation mechanism. Also, data revealed gender-x type of picture interaction effects only at the self-report task, with men rating sexually explicit stimuli as more sexually exciting, and women rating these stimuli as less pleasant. No relationship was found between automatic attention proxies and sexual excitation proneness. Clinical TranslationWhile therapeutic strategies are used as tools to improve attention to sexual stimuli (and, hence, increase sexual arousal), the current findings suggest that the specific pathways by which attention influences sexual response are still to be established. Also, gender differences on the subjective appraisal of sex stimuli suggest that therapeutic approaches, consisting on exposure techniques, must recognize gender specificities. Strengths & LimitationsTo our knowledge, this is the first study applying an automatic attention task to the field of sex research, thus adding new inputs to the topic of attention, gender differences, and sexual response. However, there is very limited research in the field of automatic attention, which may limit the interpretation of our findings, at the moment. ConclusionWhereas both genders do not seem to differ in automatic attention toward romantic and sexually explicit stimuli, their responses do differ in their subjective appraisal of the stimuli. Furthermore, despite theoretical assumptions on the relationship between attention and sexual response, automatic attention seemed not to be related to sexual excitation proneness. Carvalho J, Czop O, Rocha M, et al. Gender differences in the automatic attention to romantic vs sexually explicit stimuli. J Sex Med 2018;15:1083–1092.