Stimulus Onset Asynchrony Research Articles

Modulations of response activation contribute to block-wide control: Evidence from proportion congruency effects in the prime-probe task.

Distractor-related congruency effects are smaller in blocks of mostly incongruent (vs. mostly congruent) trials. It remains unclear, though, how control processes produce this proportion congruency effect (PCE). The attentional shift account posits that experiencing conflict more frequently in mostly incongruent (vs. mostly congruent) blocks biases control processes to shift attention away from the distractor. The response modulation account posits that, if participants identify the distractor before the target, control processes use the distractor's identity to prepare a congruent response in mostly congruent blocks and/or an incongruent response in mostly incongruent blocks. We conducted four experiments (N = 192) to investigate whether a modulation of response activation contributes to the PCE in the prime-probe task. We observed a larger PCE when the prime/distractor appeared 166 ms before (vs. simultaneously with) the probe/target (Experiment 1) and a PCE without an overall congruency effect at a longer, 933-ms stimulus onset asynchrony (SOA; Experiment 2). Critically, the latter PCE was associated with a negative congruency effect in mostly incongruent blocks, consistent with a modulation of response activation but not a shift of attention. Finally, in a modified prime-probe task, wherein participants respond to each stimulus before the next one appears (1,133 ms SOA), we observed analogous PCEs and negative congruency effects (Experiment 3) and a PCE-like effect in response force just before the probe appeared (Experiment 4). These findings indicate an independent contribution of control processes that modulate response activation to the PCE at long prime-probe SOAs, which extends beyond minimizing distraction from irrelevant stimuli. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Human olfactory perception embeds fine temporal resolution within a single sniff.

A sniff in humans typically lasts one to three seconds and is commonly considered to produce a long-exposure shot of the chemical environment that sets the temporal limit of olfactory perception. To break this limit, we devised a sniff-triggered apparatus that controls odorant deliveries within a sniff with a precision of 18 milliseconds. Using this apparatus, we show through rigorous psychophysical testing of 229 participants (649 sessions) that two odorants presented in one order and its reverse become perceptually discriminable when the stimulus onset asynchrony is merely 60 milliseconds (Cohen's d = 0.48; 95% confidence interval, (55, 59); 120-millisecond difference). Discrimination performance improves with the length of stimulus onset asynchrony and is independent of explicit knowledge of the temporal order of odorants or the relative amount of odorant molecules accumulated in a sniff. Our findings demonstrate that human olfactory perception is sensitive to chemical dynamics within a single sniff and provide behavioural evidence for a temporal code of odour identity.

Comparison of Virtual Reality Exergames and Nature Videos on Attentional Performance: A Single-Session Study.

This study aimed to investigate the acute effects of a single session of a VR exergame (Beat Saber) and a VR nature video (Ireland 4K) on attentional performance, using the Flanker and Attentional Blink (AB) tasks. The objective was to assess whether these VR interventions could enhance attentional control, as measured by improvements in response times and accuracy. A total of 39 psychology students, aged 19-25, were randomly assigned to one of three groups: VR exergame, VR nature video, or control. Participants completed the Flanker and AB tasks before and after the intervention. A repeated measures design was employed to analyze changes in response times and accuracy across pre- and post-test sessions. The study revealed significant improvements in response times and accuracy across all groups in the post-test measures, indicating a strong training effect. In the AB task, shorter stimulus onset asynchrony (SOA) led to decreased accuracy and slower response times, emphasizing the difficulty in processing closely spaced targets. The interaction between Type and Group in response times for target stimuli suggested that the intervention types differentially influenced processing speed in specific conditions. The findings suggest that while brief VR interventions did not produce significant differences between groups, the training effect observed highlights the influence of task-specific factors such as SOA and target presence. Further research is needed to explore whether longer or repeated VR sessions, as well as the optimization of task-specific parameters, might lead to more pronounced cognitive benefits.

Dissociable Effects of Endogenous and Exogenous Attention on Crowding: Evidence from Event-Related Potentials.

Crowding is a common visual phenomenon that can significantly impair the recognition of objects in peripheral vision. Two recent behavioral studies have revealed that both exogenous and endogenous attention can alleviate crowding, but exogenous attention seems to be more effective. The present study employed the event-related potential (ERP) technique to explore the electrophysiological characteristics of the influence of these two types of attention on crowding. In the experiment, participants were required to judge whether the letter "T" was upright or inverted, which may be preceded by an exogenous cue or an endogenous cue indicating the location of the target letter. The behavioral results showed that while exogenous cues reduced crowding in all stimulus onset asynchronies (SOAs), endogenous attention took effects only in long SOA. The ERP results indicated that both endogenous and exogenous cues significantly alleviated the inhibition of visual crowding on the N1 component. However, the endogenous cue was effective only under long SOA, while the exogenous cue was effective only under short SOA conditions. In addition, invalid exogenous cues induced a larger P3 wave amplitude than valid ones in the short SOA condition, but endogenous attention did not show such a difference. These results indicate that both endogenous and exogenous attention can alleviate the effects of visual crowding, but they differ in effect size and temporal dynamics.

Conceptual masking disrupts change-detection performance.

The present study investigated the effects of long-term knowledge on backward masking interference in visual working memory (VWM) by varying the similarity of mask stimuli along categorical dimensions. To-be-remembered items and masks were taken from categories controlled for perceptual distinctiveness and distinctiveness in kinds (e.g., there are many kinds of cars and few kinds of coffee mugs). Participants completed a change-detection task in which the memory array consisted of exemplars from either a similar or distinctive category, followed by a mask array of items from the same category (conceptually similar versus conceptually distinct categories), a different category, or no mask. The results over two experiments showed greater interference from conceptually similar masks as compared with the other conditions across stimulus onset asynchrony (SOA) conditions, suggesting masking with conceptually similar categories leads to more interference even when masks are shown well after the stimulus. These results have important implications for both the nature and time course of long-term conceptual knowledge influencing VWM, particularly when using complex real-world objects.

The phase coherence of cortical oscillations predicts dynamic changes in perceived visibility.

The phase synchronization of brain oscillations plays an important role in visual processing, perceptual awareness, and performance. Yet, the cortical mechanisms underlying modulatory effects of post-stimulus phase coherence and frequency-specific oscillations associated with different aspects of vision are still subject to debate. In this study, we aimed to identify the post-stimulus phase coherence of cortical oscillations associated with perceived visibility and contour discrimination. We analyzed electroencephalogram data from two masking experiments where target visibility was manipulated by the contrast ratio or polarity of the mask under various onset timing conditions (stimulus onset asynchronies, SOAs). The behavioral results indicated an SOA-dependent suppression of target visibility due to masking. The time-frequency analyses revealed significant modulations of phase coherence over occipital and parieto-occipital regions. We particularly identified modulations of phase coherence in the (i) 2-5Hz frequency range, which may reflect feedforward-mediated contour detection and sustained visibility; and (ii) 10-25Hz frequency range, which may be associated with suppressed visibility through inhibitory interactions between and within synchronized neural pathways. Taken together, our findings provide evidence that oscillatory phase alignments, not only in the pre-stimulus but also in the post-stimulus window, play a crucial role in shaping perceived visibility and dynamic vision.

The celebrity effect on gaze following in older and young adults

BackgroundIn daily life, people often follow others’ gaze direction to infer their attention and mental state. This phenomenon is known as gaze following.ObjectiveThis study aimed to explore whether gaze following in different age groups is influenced by celebrity identity.MethodsWe recruited 70 participants, including 35 older adults and 35 young adults. The experimental materials consisted of three faces with different identity information (a political leader, a movie star, and an ordinary person). Each face had left and right gaze conditions. Targets and cues were presented with both longer and shorter stimulus onset asynchrony (SOA) conditions.ResultsBoth older adults and young adults exhibited similar gaze following behaviors. Importantly, the celebrity effect on gaze following was observed in both groups, with stronger effects induced by the leader’s and star’s gazes compared to the ordinary person’s gaze. Older adults showed a larger facilitation effect under the longer SOA condition compared to the shorter SOA, while no such SOA-related facilitation effect was found for young adults.ConclusionThese findings suggest that older adults can integrate social information from others’ faces (celebrity identity) into the process of gaze following as effectively as young adults.

The role of semantic information in Chinese word segmentation

ABSTRACT Word segmentation is crucial for reading in Chinese, where the absence of explicit word boundaries poses a distinct challenge. Previous studies in Chinese have examined how lexical and sub-lexical variables affect word segmentation. The present study investigated whether higher-level semantic information affects word segmentation using a primed word segmentation task with Overlapping Ambiguous Strings (OAS). An OAS is a three-character string in Chinese (e.g. ABC [in Latin letters]) where the middle character can constitute a word with both the left (word AB) and right (word BC) characters. The OAS was preceded by a semantic or repetition prime (presented for 42, 83, or 200 ms, across participants), priming either AB or BC. The semantic priming effect occurred at the 200-ms Stimulus Onset Asynchrony (SOA), whereas the repetition priming effect occurred at both 83 and 200-ms SOAs. These findings demonstrate that semantic information can affect word segmentation in Chinese within 200 ms.

Investigating acoustic startle habituation and prepulse inhibition with silent functional MRI and electromyography in young, healthy adults.

Startle habituation and prepulse inhibition (PPI) are distinct measures of different sensory information processes, yet both result in the attenuation of the startle reflex. Identifying startle habituation and PPI neural mechanisms in humans has mostly evolved from acoustic-focused rodent models. Human functional magnetic resonance imaging (fMRI) studies have used tactile startle paradigms to avoid the confounding effects of gradient-related acoustic noise on auditory paradigms and blood-oxygen-level-dependent (BOLD) measures. This study aimed to examine the neurofunctional basis of acoustic startle habituation and PPI in humans with silent fMRI. Using silent fMRI and simultaneous electromyography (EMG) to measure startle, the neural correlates of acoustic short-term startle habituation and PPI [stimulus onset asynchronies (SOA) of 60 ms and 120 ms] were investigated in 42 healthy adults (28 females). To derive stronger inferences about brain-behaviour correlations at the group-level, models included EMG-assessed measures of startle habituation (regression slope) or PPI (percentage) as a covariate. A linear temporal modulator was modelled at the individual-level to characterise functional changes in neural activity during startle habituation. Over time, participants showed a decrease in startle response (habituation), accompanied by decreasing thalamic, striatal, insula, and brainstem activity. Startle habituation was associated with the linear temporal modulation of BOLD response amplitude in several regions, with thalamus, insula, and parietal lobe activity decreasing over time, and frontal lobe, dorsal striatum, and posterior cingulate activity increasing over time. The paradigm yielded a small amount of PPI (9-13%). No significant neural activity for PPI was detected. Startle habituation was associated with the thalamus, putamen, insula, and brainstem, and with linear BOLD response modulation in thalamic, striatal, insula, parietal, frontal, and posterior cingulate regions. These findings provide insight into the mediation and functional basis of the acoustic primary startle circuit. Instead, whilst reduced compared to conventional MRI, scanner noise may have disrupted prepulse detection and processing, resulting in low PPI and impacting our ability to map its neural signatures. Our findings encourage optimisation of the MRI environment for acoustic PPI-based investigations in humans. Combining EMG and functional neuroimaging methods shows promise for mapping short-term startle habituation in healthy and clinical populations.

Luminance and chromaticity discrimination sensitivities right after an abrupt decrease in background luminance

AbstractWhen we enter a dark place, such as a tunnel, from a bright exterior, our visual sensitivities take some time to adapt to lower light levels. However, there have been few reports on how quickly luminance and chromaticity discrimination sensitivities recover in this situation. This study aims to quantify the time course of discrimination sensitivity for luminance and chromaticity directions after an abrupt decrease in background luminance. In each trial, the background luminance was decreased from 100 to 1 cd/m2. Subsequently, one target and three reference stimuli of different colors were presented under four stimulus‐onset asynchrony (SOA) conditions. The participants discriminated the target stimulus from reference stimuli. The results showed that discrimination sensitivity was the lowest right after the background luminance changed and gradually improved with SOAs. The sensitivity decreases differed across color directions, with the greatest decrease in luminance, a moderate decrease in S−(L + M), and a negligible change in L−M. However, statistically significant differences were observed only between luminance and L−M, suggesting that the sensitivity decrease after the abrupt decrease in background luminance did not significantly differ between the chromaticity directions. We speculate that these results stem from the interaction between chromatic perception and luminance adaptation, and possibly from rod intrusions.

How large are root and affix priming effects in visual word recognition? Estimation from original data and a Bayesian meta-analysis

ABSTRACT Priming effects for morphological roots support theories that grant them a unique representational status in visual word recognition. However, effects for other morphemes, including inflectional affixes, have been inconsistent. In a large-N experiment, we test the reliability of inflectional affix priming and add a meta-analysis to quantify priming effect size for roots and affixes. Study 1 probes priming for the English past tense suffix –ed at short (34 ms) and long (150 ms) stimulus-onset asynchrony; pure morphological priming is not obtained that is statistically distinguishable from form-based priming effects. A Bayesian meta-analysis (Study 2) demonstrates priming for roots and prefixes, but not suffixes, that are statistically larger than form-based priming effects. Taken together the absence of suffix priming contrasts with robust root and prefix effects, which may reflect the left-to-right nature of visual word recognition in the languages studied in this work.

Sustained attention can be measured using a brief computerized attention task

The Continuous Visual Attention Test (CVAT) is a test that detects visuomotor reaction time (RT, alertness), variability of reaction time (VRT, sustained attention), omission errors (OE, focused attention), and commission errors (CE, response inhibition). The standard test takes 15 min, while the ultrafast version only 90 s. Besides overall task length, the two versions differ by target probability (20% and 80% in the 15-min vs. only 80% in the 90-s test) and stimulus-onset asynchrony (SOA) (1, 2, and 4 s in the 15-min vs. only 1 s in the 90-s test. We aimed to analyze the effect of target probability, SOA, and time length on the CVAT variables across the 15-min task and to verify correlations and agreements between the 15-min and the 90-s CVATs. 205 healthy participants performed the two CVATs on the same day. Considering the 15-min task, RT and CE were strongly affected by target probability. Conversely, VRT was not affected. When the 15-min task was compared to the 90-s task, we found no significant difference in the VRT variable. Additionally, a significant agreement between the two tasks was found for the VRT variable. We concluded that sustained attention can be measured with the 90-s CVAT.

Effects of stimulus onset asynchrony on cognitive control in healthy adults.

The efficiency of cognitive control in healthy adults can be influenced by various factors, including the stimulus onset asynchrony (SOA) effect and strategy training. To address these issues, our study aims to investigate the impact of SOA on single-mode cognitive control using the Go/No-Go task, as well as the manifestation of proactive control within dual mechanisms of cognitive control through the AX-CPT task. In single-mode cognitive control, extending SOA led to significantly enhanced reaction times (RTs) during Go trials, suggesting improved task performance with increased preparation time. Moreover, the analysis revealed consistently higher accuracy rates in No-Go trials than to Go trials across all SOA levels, indicating robust inhibition processes unaffected by SOA variations. In the dual mechanisms of cognitive control, significant variations in RT and accuracy were observed among different trial types. Notably, participants exhibited superior performance in detecting targets during BY trials and shorter RTs in BX trials, indicative of efficient processing of target stimuli. Conversely, prolonged RTs in AY trials suggest proactive control strategies aimed at maintaining task-relevant information and inhibiting irrelevant responses. Overall, these findings highlight the effect of SOA on single-mode cognitive control and the emergence of proactive control within dual mechanisms of cognitive control in healthy adults.

Development of emergent processes and threshold of consciousness with levels of processing.

The transition of experience from unconscious to conscious, the emergent process, is a crucial topic in consciousness studies. Three frameworks exist to explain the process: (1) consciousness arises in an all-or-none manner; (2) consciousness arises gradually; (3) consciousness arises either all at once or gradually, depending on the level of stimulus processing (low- vs. high-level). However, the development of emergent processes of consciousness remains unclear. This study examines the development of emergent processes of consciousness based on the level of stimulus processing framework. Ninety-nine children (5-12 year-olds) and adults participated in two online discrimination tasks. These tasks involved color discrimination as lower-level processing and number magnitude discrimination as higher-level processing, as well as backward masking with stimulus onset asynchronies (SOAs) varying from 16.7 to 266.7 ms. We measured objective discrimination accuracy and used a 4-scale Perceptual Awareness Scale (PAS) to assess subjective awareness. We fit the data to a four-parameter nonlinear function to estimate the center of the slope (threshold) and the range of the slope (gradualness, the measure of emergent process of consciousness) of the model. The results showed the threshold of objective discrimination was significantly higher in 5-6 year-olds than in 7-12 year-olds, but not of subjective awareness. The emergent process of objective discrimination in the number task was more gradual than in the color task. The findings suggest that the thresholds of subjective awareness in 5-6 year-olds and objective discrimination in 7-9 year-olds are similar to those in adults. Moreover, the emergent processes of subjective awareness and objective discrimination in 5-6 year-olds are also similar to those in adults. Our results support the level of processing hypothesis but suggest that its effects may differ across developmental stages.

Effect of additional tasks on the reaction time of braking responses in simulated car driving: beyond the PRP effect.

The presentation of one task increases the reaction time on a subsequent task, if stimulus onset asynchrony (SOA) between tasks is short. This psychological refractory period (PRP) effect is typically leveling off as SOA approaches 1 s, which has been documented both in classical laboratory paradigms and in simulated car driving. Here we report a more persistent effect on the subsequent task that goes well beyond the typical duration of the PRP effect. In a driving simulator, 120 healthy older participants followed a lead car that mostly drove at a constant speed. They had to maintain a regular distance from the lead car and had to brake when the lead car braked. Participants also engaged in several additional tasks during driving (two types of tasks: typing three-digit numbers, stating arguments on public issues). SOA between the braking task and the last preceding additional task was 11.49 s ± 1.99 (mean and standard deviation). In a control condition, the braking task was administered without additional tasks. Main performance outcome was Braking Reaction Time (RT, in s), as the interval between onset of brake lights of the lead car and the moment participants released the gas pedal. Additionally, foot movement time (MT, in s), i.e., the difference between gas pedal release and brake pedal onset, was considered for possible compensation behavior. Inter-vehicle distance to the lead car (in m) was taken into account as a moderator. We found that RT averaged 0.77 s without additional tasks, but averaged 1.45 s with additional tasks. This RT difference was less pronounced at smaller inter-vehicle distances, and was not compensated for by faster MT from the gas pedal to the brake pedal. We conclude that detrimental effects of additional tasks on subsequent braking responses can be more persistent than suggested by the PRP effect, possibly because of maintaining multiple task sets, requiring increased executive control. We further conclude that potential detrimental effects can be ameliorated at small inter-vehicle distances by mobilizing extra cognitive resources when response urgency is higher. As a practical implication of our study, distracting stimuli can have persisting detrimental effects on traffic safety.

Decoding the task specificity of post-error adjustments: Features and determinants

Errors typically trigger post-error adjustments aimed at improving subsequent reactions within a single task, but little work has focused on whether these adjustments are task-general or task-specific across different tasks. We collected behavioral and electrophysiological (EEG) data when participants performed a psychological refractory period paradigm. This paradigm required them to complete Task 1 and Task 2 separated by a variable stimulus onset asynchrony (SOA). Behaviorally, post-error slowing and post-error accuracy exhibited task-general features at short SOAs but some task-specific features at long SOAs. EEG results manifest that task-general adjustments had a short-lived effect, whereas task-specific adjustments were long-lasting. Moreover, error awareness specifically conduced to the improvement of subsequent sensory processing and behavior performance in Task 1 (the task where errors occurred). These findings demonstrate that post-error adjustments rely on both transient, task-general interference and longer-lasting, task-specific control mechanisms simultaneously, with error awareness playing a crucial role in determining these mechanisms. We further discuss the contribution of central resources to the task specificity of post-error adjustments.

Impacts of audiovisual simultaneity perception on single-task and dual-task gaits in middle-aged and older adults

BackgroundWhile dual-task walking requires the ability to integrate sensory information from multiple ongoing sources, it remains unknown whether dual-task walking is more affected than single-task walking by the multisensory integration ability. Research questionHow does the audiovisual temporal integration ability affect single-task and dual-task gaits in the aging population? MethodsOne hundred and thirty healthy middle-aged and older adults (age = 64.7 ± 6.4 years) completed an audiovisual simultaneity judgment (AVSJ) task and underwent single-task, motor dual-task, and cognitive dual-task gait assessments. In the AVSJ task, participants judged whether a flash and an auditory stimulus presented at different stimulus onset asynchronies were simultaneous. The accuracy and precision of the AVSJ performance were assessed using the point of subjective simultaneity (PSS) and the temporal binding window (δ), respectively. A lower absolute PSS and δ indicated better performance. Participants held a cup of water and performed serial-7 subtraction for motor and cognitive dual-task gait assessments, respectively. The spatiotemporal gait parameters and their variability were calculated. The influences of PSS and δ on the gait parameters of the three gaits were examined with multiple hierarchical regressions. ResultsOnly the cognitive dual-task gait was significantly affected by PSS and δ. Greater PSS predicted a longer single support time (β = 0.195, p = 0.024) and its variability (β = 0.224, p = 0.011). Greater δ predicted greater step time variability (β = 0.198, p = 0.022). SignificanceDeclined perception of audiovisual simultaneity particularly degrades temporal control of cognitive dual-task walking, highlighting the importance of assessing and training this ability after midlife.

Emotional attention: Time course and effects of agonistic and antagonistic overlay of intrinsic and goal relevances.

Emotional attention can be explained within a goal-directed theory framework according to which attention is captured by the goal relevance of stimuli, that is, their conduciveness nature to a momentarily important goal. However, such an explanation does not consider the attentional impact of intrinsic relevance of stimuli, that is, their general pleasantness. This problem could be resolved by appraisal theories, suggesting that attention is captured by intrinsic relevance and goal relevance of stimuli, whether the relevance overlay is agonistic (e.g., pleasant and goal-conducive) or antagonistic (e.g., unpleasant and goal-conducive). Moreover, appraisal theories suggest that early and late attentional capture would be more impacted by intrinsic relevance and goal relevance, respectively. In the present study, we confronted the predictions of appraisal theories with that of goal-directed theory. To this end, 120 participants performed parallelly an induction task to induce different relevance values to three colored squares, and a dot-probe task with two different stimulus onset asynchrony, to measure early and late attentional captures. This paradigm allowed us to measure attentional capture between a neutral stimulus, a goal-relevant stimulus, and an overlay stimulus. The overlay stimulus was agonistic in one group, while it was antagonistic in the other group. Our results showed evidence in favor of appraisal theories. Namely, the overlay stimulus captured more attention than the goal-relevant and the neutral stimulus, regardless of whether the overlay was agonistic or antagonistic. However, our results were mixed regarding the effects of intrinsic relevance and goal relevance on attentional capture as a function of temporality. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Beyond alpha band: prestimulus local oscillation and interregional synchrony of the beta band shape the temporal perception of the audiovisual beep-flash stimulus

Objective. Multisensory integration is more likely to occur if the multimodal inputs are within a narrow temporal window called temporal binding window (TBW). Prestimulus local neural oscillations and interregional synchrony within sensory areas can modulate cross-modal integration. Previous work has examined the role of ongoing neural oscillations in audiovisual temporal integration, but there is no unified conclusion. This study aimed to explore whether local ongoing neural oscillations and interregional audiovisual synchrony modulate audiovisual temporal integration. Approach. The human participants performed a simultaneity judgment (SJ) task with the beep-flash stimuli while recording electroencephalography. We focused on two stimulus onset asynchrony (SOA) conditions where subjects report ∼50% proportion of synchronous responses in auditory- and visual-leading SOA (A50V and V50A). Main results. We found that the alpha band power is larger in synchronous response in the central-right posterior and posterior sensors in A50V and V50A conditions, respectively. The results suggested that the alpha band power reflects neuronal excitability in the auditory or visual cortex, which can modulate audiovisual temporal perception depending on the leading sense. Additionally, the SJs were modulated by the opposite phases of alpha (5–10 Hz) and low beta (14–20 Hz) bands in the A50V condition while the low beta band (14–18 Hz) in the V50A condition. One cycle of alpha or two cycles of beta oscillations matched an auditory-leading TBW of ∼86 ms, while two cycles of beta oscillations matched a visual-leading TBW of ∼105 ms. This result indicated the opposite phases in the alpha and beta bands reflect opposite cortical excitability, which modulated the audiovisual SJs. Finally, we found stronger high beta (21–28 Hz) audiovisual phase synchronization for synchronous response in the A50V condition. The phase synchrony of the beta band might be related to maintaining information flow between visual and auditory regions in a top-down manner. Significance. These results clarified whether and how the prestimulus brain state, including local neural oscillations and functional connectivity between brain regions, affects audiovisual temporal integration.

Emotional salience modulates the forward-flow of memory.

As we navigate our day-to-day lives, we regularly adapt our behaviour according to what we predict may happen next in a given context. When an unexpected event occurs, our predictions about the world are disrupted and must be updated. Unexpected, isolated events, particularly with high emotionality, are also better recalled. In the present work, we investigated how oddballs affect recall dynamics. Seventy young, healthy participants encoded word lists containing either emotional or perceptual oddballs at varying stimulus onset asynchronies followed by free recall. It is well established that after recalling an item, we have a higher probability of recalling items encoded nearby, particularly those that were encoded after the item was recalled, a phenomenon known as forward contiguity of recall. We tested how novelty (oddballs versus control words) modulated forward contiguity as a function of salience type (emotional versus perceptual). The present results provide empirical evidence of forward contiguity modulation selectively by emotional salience and suggest that recall patterns after presenting emotional and perceptual oddballs are mediated by different mechanisms.