Understanding spoken language demands integration of linguistic information over time. Previous work has shown that lower-level cues, like acoustic information, and higher-level cues, like semantic information, can be integrated across the course of an utterance in order to categorize words. Questions remain about how these bottom-up and top-down sources are integrated. We propose that a useful approach to this problem is to compare human behavior to normative models of cue integration, such as ideal observer models, which have been successful in other domains. We argue that ideal observer models make three key predictions about how acoustic and semantic information should be integrated during word recognition: (1) additivity: cues have additive effects on categorization; (2) transitivity: cues providing identical information should be treated identically regardless of their temporal order; and (3) reliability weighting: cues should be weighted according to their absolute and relative reliabilities. We conduct two spoken-word recognition experiments in which participants categorize a target word embedded in a sentence. We manipulate acoustic cues on the target word; semantics from the sentence; the cues’ relative timing, and the degree of noise affecting each cue. We find evidence for additivity and transitivity; we also find evidence in favor of absolute reliability driving cue reweighting, but more mixed evidence on the role of relative cue reliability. Overall, our results suggest that listeners are near-optimal in their integration of information across multiple levels of the linguistic hierarchy over time. We also discuss how these results relate to recent error-driven approaches to cue weighting.
This study explored the modulation of perceived time based on subjective visual perception, mainly focusing on object recognition. Unlike physical time, psychological time is subject to various influences, such as attention and stimulus characteristics. We conducted two experiments using images comprising dots to systematically vary stimulus clarity and visual recognizability. Experiment 1 revealed that perceived time was longer when an object was identifiable within the stimulus. Experiment 2 extended this finding by offering three response options related to object recognition and naming. The results showed that named objects further extended the perceived time in participants. These findings suggest that perceived time is influenced by subjective perceptual experiences, such as object recognition and naming, which mediate the effects of objective stimulus attributes on temporal perception.Open practices statementThe datasets generated and analyzed during the current study are available from the corresponding author upon reasonable request. The experiments were not preregistered.
Tactile sensitivity is reduced when the limb is in motion, a phenomenon known as somatosensory gating. In a previous study, we demonstrated that discrimination precision but not perceived intensity differed between active and passive movements. Here, we asked whether and how spatial attention modulates tactile precision in active and passive movements. Participants judged the relative intensity of two vibrations while the arm was still, actively moved, or passively transported by a movable platform. Visual attention was directed either to the movement start or goal position. Perceptual bias was reduced during both active and passive movement, independent of attentional allocation. In contrast, precision remained stable during active movement but declined during passive movement when attention was directed to the movement start. However, when attention was focused on the movement goals, precision was also high when doing passive movements. These findings indicate that during active movements, predictions based, likely on an efference copy, ensure tactile precision, whereas passive movements require spatial attention directed to the movement goal.
Recent work has shown that people are sensitive to coarse differences in network topology, including network features like “holes,” “crosses,” and “T-junctions.” Even children as young as 4 years old will readily distinguish between items that differ slightly in their network topology. But how robust is this sensitivity? Here, we evaluate whether people are not only sensitive to differences in the presence or absence of certain topological features, but also to their exact spatial arrangement. In a first experiment, we show that people distinguish figures which possess all the same topological features as other figures in a set if the features differ in spatial arrangement. In a second experiment, we show that people also match figures based on exact spatial arrangement. Finally, we show that memory encodes the correct relational structure of the figures: People are more likely to falsely indicate having seen an item if it shared the precise arrangement of topological features of other items they had seen (compared to a closely matched item which had the same features arranged in a different way). Combined, these results bolster the theory that people intuitively appreciate the precise spatial arrangement of topological features.
We investigated the impact of flanker size and horizontal flanker eccentricity in the reading version of the flankers task. Critical targets and the corresponding flankers were words that could either be the same or different. Target size did not change, and flankers could either be the same size as targets or larger. Flankers could be located close to targets (normal spacing - close flankers) or separated from targets by seven spaces (distant flankers). Results revealed significant effects of flanker relatedness (same word as the target or a different word) that interacted with both flanker size and flanker eccentricity in the analysis of response times. The three-way interaction was not significant. The only significant effect in the analysis of error rates was that of flanker relatedness. We replicated prior findings showing that increasing flanker eccentricity diminishes the effect of flanker relatedness, and we further demonstrated that increasing flanker size increases the magnitude of flanker effects. Crucially, an increase in flanker size was not found to compensate for the negative impact of an increase in flanker eccentricity on effects of flanker relatedness. These results suggest that eccentricity is one key visual factor influencing the spatial integration of orthographic information, and that the impact of eccentricity overrides the impact of flanker size. This provides support for the hypothesized scale-invariant gaze-centered processing of letter identities during the initial phase of orthographic processing.
Recent research has examined the selection profile—the pattern of enhancement and suppression of stimuli when allocating attention to a specific feature value. Support for several different selection profiles for simple feature dimensions (e.g., color, orientation) have been identified such as the feature-similarity gain and surround suppression effects. However, it is unclear whether the selection profile for more complex stimuli follows a similar pattern. Using a recently developed circular shape space, the current study assessed the selection profile for these simple shapes as an initial step toward the study of object-based attention. Participants attended to two target shapes while ignoring two distractors, each overlapping with one target. They performed a change identification task, reporting luminance changes of only the target shapes. We systematically varied the difference between the two targets in the shape space. In two experiments covering different ranges in the shape space, performance accuracy peaked when the two target shapes matched and then decreased in a monotonic manner as the two shapes became more different. These results align with a feature-similarity gain model and suggest that an analogous shape-similarity gain effect operates for more complex stimuli. This gain effect suggests that shape-based selection occurs in an intrinsic similarity space which can be realized by top-down attention operating on neural substrates that encode object similarity.
Ensemble processing, which allows the visual system to form summary statistical representations (e.g., the average size of a bowl of apples), can be influenced by attention. However, can such internally, statistically generated representations influence the deployment of attention? To answer this question, we conducted two experiments using a modified version of an attentional cueing paradigm with an ensemble task. Each trial began by displaying an array of eight ovals of varying sizes. Next, two ovals to the left and right of fixation were presented, where one oval was the average size of the previous set (the ensemble object), and the other oval was a distractor (the foil object). On different trials, participants reported either which oval corresponded to the average size of the previous set (ensemble task) or the location of a probe dot on one of the objects (probe task). Experiment 1 used 80% ensemble task trials and further examined effects of attentional deployment when the foil object was outside the range of ensemble size values compared to inside the ensemble range. The results revealed attentional guidance when the foil was outside the ensemble range. Experiment 2 used 20% ensemble task trials with foils outside the ensemble range and found no attentional guidance, revealing that the strength of the internal ensemble representation affects whether or not attentional guidance effects will be observed. Overall, the results provide evidence that ensemble representations can influence the deployment of spatial attention, thereby demonstrating that these two cognitive mechanisms reciprocally interact.
Spatial structure often provides information about the likely location of targets in visual search tasks and in real life. However, the extent to which spatial structure affects attention when it provides no information about target locations is less well understood. This is investigated here using a visual foraging task, whereby individuals search for many targets amongst many distractors. In six online experiments, participants foraged for multiple instances of two target types amongst two distractor types, defined by either features or conjunctions. Experiments comprised a series of manipulations of the presence, quantity, visibility, and availability of spatial structure. This was achieved via visibly segmenting displays into areas containing equal numbers of objects. These experiments assessed the effects of spatial structure on foraging using a broad range of measures and across variations including the presence of time limits and visual feedback within the display. Task-irrelevant spatial structure consistently encouraged systematic foraging, whereby participants were more likely to continue foraging within one display segment rather than to move to another. Foraging in this manner was associated with costs to foraging efficiency, and benefits to spatial memory. The general strength of the visual information about spatial structure modified the extent to which this information affected systematic foraging and foraging efficiency. Overall, spatial structure can affect individuals’ foraging patterns and strategies even when it provides no information about the potential locations of targets.
The list-wide proportion congruency effect describes how the congruency effect varies depending on the frequency of incongruent trials within a block. Specifically, the congruency effect is larger in mostly congruent (MC) blocks compared to mostly incongruent (MI) blocks. Research has shown that adaptation to these blocks does not change symmetrically when transitioning between them: moving from MC to MI leads to a rapid decrease in the congruency effect while transitioning from MI to MC results in little or no increase (Abrahamse et al., 2013). We aimed to investigate this asymmetric list shift (ALS) effect in a within-participants design where all participants experienced both transitions (MC-MI and MI-MC). Throughout Experiments 1-3 using a color-word Stroop task, we identified various forms of practice - including trial-type, stimulus-specific learning, general RT decrease, and a decrease in congruency effects over time (see Schmidt, 2016) - that can either facilitate or obscure the ALS effect, depending on the order in which participants experienced the transitions. In Experiment 4, using a face-name version of the Stroop task, where we minimized practice-related confounding factors by employing more complex stimuli and used a new stimulus set in the second transition, an ALS effect was observed regardless of the order of transition and for frequency-unbiased (i.e., 50% congruent) items. The role of practice effects and implications for the (in)-flexibility of control adaptations will be discussed.
Fixation points are widely used in psychophysical research to stabilise gaze, yet their influence on perceptual outcomes remains underexplored. This study investigated the effects of the presence versus absence of a fixation point on monocular size-distance scaling, examining whether it functions as a fixation stabiliser, a spatial anchor (i.e., as a direct depth or location cue), or a competing visual reference. Using a widely employed fixation marker, we compared size and distance judgments for real objects and afterimages (stimuli that differ in their reliance on depth cues). Fixation points modestly improved size constancy for both stimuli, supporting their role in retinal stabilization. However, their effects on distance perception varied: real objects maintained stable distance judgments regardless of fixation, whereas afterimages exhibited greater inconsistencies when a fixation point was introduced. Therefore, fixation points appear to interfere with distance scaling for depth-ambiguous stimuli like afterimages. Additionally, correlations between accommodative abilities and errors in size perception for real objects suggest fixation points may reduce reliance on oculomotor cues by stabilizing retinal input. These findings challenge the assumption that fixation points are neutral methodological tools, highlighting their active role in shaping perceptual outcomes. Future research should critically evaluate fixation point designs and their broader impact on size and distance perception.
Human gaze behaviour provides insights into the mental processes underlying the execution of a task. As reading involves visual sampling and language processing, various studies investigate how the linguistic information of texts influences visual behaviour. However, established measures of human visual behaviour are dependent on the exact configuration of the text stimuli and the nonlinguistic stimuli used for comparison, leaving systematic stimulus-independent differences largely unknown. Here, we show that relative saccade length distributions reveal similarities and differences in gaze dynamics during reading and shape-scanning. In a within-subject design, participants read texts and scanned a spatially matched array of geometric shapes. We find that the lengths of consecutive saccades in target direction are more consistent during reading than during shape-scanning, suggesting that saccadic planning is more constrained during reading. The consistency of eye movements opposite to the target direction does not differ for the experimental conditions. These results consolidate findings from neurocognitive studies on the vision-language interface and suggest how underlying neural structures manifest themselves in observable visual behaviour. Furthermore, the results indicate that relative saccade lengths could present a new measure for investigating how linguistic processing influences human visual behaviour during reading. More broadly, the results suggest that analysing gaze behaviour dynamics via relative saccade lengths might provide novel insights into similarities and differences across tasks.
Errors rarely occur in isolation, but rather within behavioral sequences and are known to shape subsequent behavior. However, understanding the full time course of the impact of errors has been challenging given data limitations. Here, to gain key insights, two groups of precisely matched participants (n > 35,000) were compared; those who made versus did not make an error in a short object discrimination task. Linear mixed-effects models revealed error-induced effects both preceding and following errors. First, the error group showed pre-error speeding up to eight trials before the error occurred. Second, post-error slowing occurred and rapidly diminished over trials. Finally, leave-one-out cross-validation models using individual trial behavior predicted an upcoming error eight trials before the error occurred. This project highlights the systematic nature of behavioral changes around errors and demonstrates the potential for early error prediction and intervention using only simple metrics and models.
Wavelength influences multiple aspects of visual performance, yet its role in spatial resolution remains incompletely understood due to confounding factors such as luminance differences, chromatic aberration, and intraocular scatter. This study assessed how narrowband light of different wavelengths affects two-point separation thresholds under controlled stimulus and ocular conditions. Action spectra for fine spatial resolution were measured using an equal-energy approach. Sixty healthy young adults (mean age: 22.7 ± 3.3 years) with normal vision were tested in a two-point resolution task. Narrowband stimuli (420–660 nm) and a broadband white condition were produced by a 1,000-W Xenon arc lamp with interference filters. Participants were preselected for optimal acuity. Thresholds, defined as the minimum resolvable separation between two-point sources (two-point separation thresholds), were recorded using a digital micrometer, and converted to visual angle for analysis. Separation thresholds varied significantly with wavelength with short-wave light (420 nm) yielding poorer resolution compared to long-wave light (660 nm). Iris pigmentation (color, lightness, and a combination of color + lightness) also influenced performance with lighter irides associated with higher thresholds, and the largest group differences observed at short wavelengths. Two-point resolution shows systematic wavelength dependence under equal-energy conditions, with performance degraded in the short-wave range. These effects likely reflect the combined influence of chromatic aberration, optical scatter, and photoreceptor sampling, rather than scatter alone. Consideration of both optical and neural mechanisms is essential when interpreting wavelength-dependent changes in spatial vision.
Visual attention is suppressed for targets that are located close to the attended location, but recovered for more distant targets, which is known as the location-based surround suppression. This study aimed to investigate whether the location-based surround suppression is modulated by the color salience or presentation time of features at these locations. Participants discriminated whether two targets on a circle were identical or different after one of them was cued. Low-salience with a short-time condition (i.e., baseline), low-salience with a long-time condition, and high-salience cue with a short-time condition were employed in Experiments 1-3. High-salience cue-targets with a long-time condition, no-cue control condition, and high-salience targets with a short-time condition were employed in Experiments 4-6. Discrimination accuracy gradually increased with increasing inter-target distance under the low-salience with short-time condition, indicating that nearby targets might fall within the cued target's suppressive surround, but distant targets might not. Not only accuracy but also reaction time evidence for surround suppression was found under the long-time condition or high-salience cue condition in Experiments 2-3, revealing that surround suppression is more pronounced under these two conditions. However, surround suppression disappeared once the high-salience targets were employed in Experiments 4-6, even under the long-time condition. These findings demonstrated that location-based surround suppression is dynamically modulated by the interaction of three factors: top-down control (cue salience), bottom-up competition (target salience), and availability of feedback-processing resources (stimulus presentation time).
Holistic processing is a fast, efficient, and seemingly effortless processing style typically linked with perceiving faces and objects of expertise—where observers appear unable to selectively attend to features within a stimulus. Holistic face processing is disrupted when the top and bottom halves are vertically separated by a substantial amount. This was attributed to the biological implausibility of the elongated faces—a domain-specific explanation. However, more recent findings of face-like holistic processing of stimuli with strong perceptual grouping cues suggest that such cues support holistic processing more generally. If so, the breakdown of holistic processing with vertical separation may reflect a disruption to perceptual grouping mechanisms rather than to face-specific mechanisms. We tested this hypothesis across three experiments. Experiment 1 used a modified composite part matching paradigm to replicate previous results—vertically separating the halves in a composite face paradigm disrupted holistic face processing. Experiment 2 demonstrated that vertical part displacement similarly disrupted holistic processing of non-face stimuli rich in perceptual grouping cues, which are not constrained by biological plausibility. Experiment 3 revealed that horizontal misalignment—a standard method of disrupting holistic processing—does not further diminish holistic processing of vertically displaced non-face stimuli, consistent with the interpretation that holistic processing was already disrupted for these stimuli. These findings support a disrupted perceptual grouping, rather than biological implausibility, account of the disruption to face holistic processing with vertical part misalignment. This has implications for understanding face processing and, given the role of holistic perception in supporting perceptual expertise, skilled perception more broadly.
Listeners use information in the speech signal as well as linguistic and real-world knowledge to tackle the immense variability of speech. Here, we focus on the use of contextual and talker-bound fundamental frequency (F0) cues during the perception of voiceless fricatives’ center of gravity (CoG). In Experiment 1, Dutch participants heard the sentence Nu komt het woord ?ok (“Now comes the word ?ok”) where “?” denotes a fricative from a synthetic /s-ʃ/ continuum in three carrier F0 conditions (low, mid, high), and indicated whether they heard the high-CoG /sɔk/ “sock” or the low-CoG /ʃɔk/ “(to) trudge.” We found a contrastive effect of context F0 on CoG perception whereby hearing a high F0 carrier sentence led to a lower fricative CoG perception. In Experiments 2a and b, an exposure phase was added where participants either heard a low or a high F0-shifted talker. At test, all participants heard fixed-F0 words /?ɔk/ and indicated whether they heard sok or sjok. Talker F0 guided participants’ responses in both experiments, but across more trials in Experiment 2b than in Experiment 2a. In Experiment 3, combining context and talker manipulations, two groups of participants heard either a low or a high F0 talker in exposure, and both low and high F0-shifted carrier sentences at test. There was a large context F0 effect, but crucially, no talker F0 effect. Overall, we found evidence that both contextual and talker-bound F0 cues have contrastive effects on fricative perception, and that contextual cues, when present and sufficiently reliable, can outweigh talker cues.
Human action control relies on the close interconnection of action and perception. This is possible through a binding mechanism that integrates distributed features of perceptual and action-related events within sensorimotor representations (event files). Encountering any one of these features later on can retrieve previously integrated features from memory and influence current action. Since actions are represented as their sensory consequences rather than their motor pattern, previous studies suggest that actions can be integrated into and retrieved from event representations even without being executed. However, it is still unclear whether binding and retrieval processes for omitted actions are highly automatic processes or if they can be influenced by higher-order strategies. Here we used sequential tasks to investigate whether binding and retrieval regarding omitted responses is affected by the time to prepare a response and by the likelihood of response omissions. Results indicate that binding and retrieval are highly adaptive processes that rely on the action planning of responses but operate beyond immediate action contingencies, facilitating efficient action control in future behavior.
During conversations in the presence of other competing talkers, multiple speech streams compete for listeners' attentional focus. Listeners must segregate speech streams, and selectively attend to the target talker while filtering out irrelevant speech. Research on value-driven attention suggests that perceptual and attentional processes are biased by prior rewarding experi-ences with stimuli-that is, high-valued stimuli win attentional competition. However, it remains unknown whether such effects generalize to speech perception in multitalker environments. Here, the present study investigated whether listeners can better understand speech spoken by talkers associated with higher versus lower values in challenging listening conditions. In three experiments, we used reward-based training paradigms to either explicitly or implicitly induce listeners to associate talkers' voices with varying magnitudes of rewards. Subsequently, listeners performed a speech-on-speech intelligibility task in which the exposed voices were either the target or distractor. We found that explicit talker-reward learning did not influence speech intelligibility. In contrast, we observed that implicitly acquired talker-reward associations improved the intelligibility of high-reward talkers, but only in the most adverse listening condition. However, this effect did not replicate when we further imposed greater attentional demands by presenting target and masker talkers' speech without spatial sepa-ration. Instead, listeners relied primarily on acoustic cues other than reward-associated talkers' voices. Furthermore, the reward values associated with the distractor talker had no effect on interference. These findings suggest that value associ-ated with talkers' voices do not reliably bias listeners' attention to overcome the complex, acoustic constraints imposed in speech-on-speech perception.
The present study provides a test of the influence of bottom-up visual cues on transposed-word effects. In a speeded grammatical decision task, two adjacent transposed words in an ungrammatical sequence of words were presented either in the same case (e.g., the white was cat big) or in different cases (e.g., the white WAS cat big). By comparing transposed-word sequences with the corresponding ungrammatical control sequences (e.g., the white was/WAS cat slowly), a significantly smaller transposed-word effect was found in the different-case condition. We take this result as further evidence for the role played by bottom-up positional noise in driving transposed-word effects. Changing case across the transposed-words provides additional bottom-up cues for word-order, hence diminishing transposed-word effects.
Feature integration across perception and action is a crucial aspect of cognitive processing, creating retrievable episodic representations known as stimulus-response episodes or event files. While some studies suggest that attention is unnecessary for stimulus-response binding and retrieval, others argue its importance in these processes. To reconcile this contradiction, the current study proposed an attentional threshold for feature integration in event files and tentatively tested this assumption. Since active suppression has been documented to down-regulate attention allocation toward certain stimuli, the current study set out to test the influence of active suppression on stimulus-response binding and retrieval. More specifically, we employed a modified distractor-response binding (DRB) paradigm with a search-and-identification task. Participants searched for targets defined by either a positive feature (Experiment 1, e.g., red when the target is a red letter) or a negative feature (Experiment 2, e.g., blue when the target is a non-blue letter). Distractors were unattended in Experiment 1 but were actively suppressed in Experiment 2, when they carried negative features. Significant DRB effects were observed in Experiment 1 but not in Experiment 2, suggesting that active suppression may reduce attention allocation toward distractors below a critical threshold for feature integration in event files. The current findings support the notion of an attentional threshold which determines what can be involved in the stimulus-response binding and retrieval processes.
