Retrospective attention: The effects on time perception.

Attention has a significant effect on time perception, as a person's perception of duration varies depending on the object of one's attention, even when the visual stimulus is consistent. This study aimed to identify the effects of directing participants' attention after a stimulus has disappeared on time perception, as prior studies have examined only pre-stimulus direction. The stimulus used comprised two overlapping figures - one large and one small. After the stimulus was removed, participants were asked to judge the length of the presentation time and shape of one of the two figures. Consequently, the participants perceived a longer presentation duration when their attention was directed to a large figure than when directed to a small figure. This finding suggests that even after an event has occurred, the time perception of the event changes depending on the feature receiving one's attention.

The perceptual timescape: Perceptual history on the sub-second scale.

There is a high-capacity store of brief time span (∼1000 ms) which information enters from perceptual processing, often called iconic memory or sensory memory. It is proposed that a main function of this store is to hold recent perceptual information in a temporally segregated representation, named the perceptual timescape. The perceptual timescape is a continually active representation of change and continuity over time that endows the perceived present with a perceived history. This is accomplished primarily by two kinds of time marking information: time distance information, which marks all items of information in the perceptual timescape according to how far in the past they occurred, and ordinal temporal information, which organises items of information in terms of their temporal order. Added to that is information about connectivity of perceptual objects over time. These kinds of information connect individual items over a brief span of time so as to represent change, persistence, and continuity over time. It is argued that there is a one-way street of information flow from perceptual processing either to the perceived present or directly into the perceptual timescape, and thence to working memory. Consistent with that, the information structure of the perceptual timescape supports postdictive reinterpretations of recent perceptual information. Temporal integration on a time scale of hundreds of milliseconds takes place in perceptual processing and does not draw on information in the perceptual timescape, which is concerned with temporal segregation, not integration.

Postdiction in Visual Awareness in Schizophrenia.

BACKGROUND: The mistiming of predictive thought and real perception leads to postdiction in awareness. Individuals with high delusive thinking confuse prediction and perception, which results in impaired reality testing. The present observational study investigated how antipsychotic medications and cognitive-behavioral therapy (CBT) modulate postdiction in schizophrenia. We hypothesized that treatment reduces postdiction, especially when antipsychotics and CBT are combined. METHODS: We enrolled patients with schizophrenia treated in a natural clinical setting and not in a randomized controlled trial. We followed up two schizophrenia groups matched for age, sex, education, and illness duration: patients on antipsychotics (n = 25) or antipsychotics plus CBT (n = 25). The treating clinician assigned the patients to the two groups. Participants completed a postdiction and a temporal discrimination task at weeks 0 and 12. RESULTS: At week 0, postdiction was enhanced in patients relative to controls at a short prediction-perception time interval, which correlated with PANSS positive symptoms and delusional conviction. At week 12, postdiction was reduced in schizophrenia, especially when they received antipsychotics plus CBT. Patients with schizophrenia were also impaired on the temporal discrimination task, which did not change during the treatment. During the 12-week observational period, all PANSS scores were significantly reduced in both clinical groups, but the positive symptoms and emotional distress exhibited a more pronounced response in the antipsychotics plus CBT group. CONCLUSION: Perceptual postdiction is a putative neurocognitive marker of delusive thinking. Combined treatment with antipsychotics and CBT significantly ameliorates abnormally elevated postdiction in schizophrenia.

Postdiction in Visual Awareness and Intrinsic Religiosity.

The mistiming and fusion of predictive thought and actual perception result in postdiction in awareness, a critical factor in the emergence of nonrational beliefs. Individuals with delusive thinking tend to experience a temporal reversal of prediction ("I guess the rain will fall.") and real perception ("I feel the rain falling."), incorrectly showing conviction that their predictions are correct. It is unknown how postdiction is related to religious cognition with a particular reference to intrinsic religiosity when religious beliefs and values are master motives and fundamental frameworks of life. Using a temporal decision-making task, we investigated a group of religiously committed individuals, atheists, and people from the general community. Results revealed higher postdiction at short thought-precept time intervals in the intrinsic religious group relative to the atheists. Intrinsic religiosity, but not delusive thinking, was predicted by postdiction in both religious individuals and the general population. These results indicate that people who display pronounced thought-percept reversal and fusion feel that they are close to a higher power and the sacred.

Early and late evoked brain responses differentially reflect feature encoding and perception in the flash-lag illusion.

In the flash-lag illusion (FLI), the position of a flash presented ahead of a moving bar is mislocalized, so the flash appears to lag the bar. Currently, it is not clear whether this effect is due to early perceptual-related neural processes such as motion extrapolation or reentrant processing, or due to later feedback processing relating to postdiction, i.e., retroactively altered perception. We presented 17 participants with the FLI paradigm while recording EEG. A central flash occurred either 51 ms ("early") or 16 ms ("late") before the bar moving from left to right reached the screen center. Participants judged whether the flash appeared to the right ("no flash lag illusion") or to the left ("flash-lag illusion") of the bar. Using single-trial linear modeling, we examined the influence of timing ("early" vs. "late") and perception ("illusion" vs. "no illusion") on flash-evoked brain responses and estimated the cortical sources underlying the FLI. An earlier frontal and occipital component (200-276 ms) differentiated time-locked early vs. late stimulus presentation, indicating that early evoked brain responses reflect feature encoding in the FLI. Perception of the FLI was associated with a late window (368-452 ms) in the ERP, with larger deflections for illusion than no illusion trials, localized to the left inferior occipital gyrus. This suggests a postdiction-related reconstruction of ambiguous sensory stimulation involving late processes in the occipito-temporal cortex, previously associated with temporal integration phenomena. Our findings indicate that perception of the FLI relies on an interplay between ongoing stimulus encoding of the moving bar and feedback processing of the flash, which takes place at later integration stages.

Can prediction and retrodiction explain whether frequent multi-word phrases are accessed 'precompiled' from memory or compositionally constructed on the fly?

An important debate on the architecture of the language faculty has been the extent to which it relies on a compositional system that constructs larger units from morphemes to words to phrases to utterances on the fly and in real time using grammatical rules; or a system that chunks large preassembled, stored units of language from memory; or some combination of both approaches. Good empirical evidence exists for both 'computed' and 'large stored' forms in language, but little is known about what shapes multi-word storage/ access or compositional processing. Here we explored whether predictive and retrodictive processes are a likely determinant of multi-word storage/ processing. Our results suggest that forward and backward predictability are independently informative in determining the lexical cohesiveness of multi-word phrases. In addition, our results call for a reevaluation of the role of retrodiction in contemporary language processing accounts (cf. Ferreira and Chantavarin, 2018).

Postdiction: When Temporal Regularity Drives Space Perception through Prestimulus Alpha Oscillations.

In postdiction, the last stimulus of a sequence changes the perception of the preceding stimuli. Postdiction has been reported in all sensory modalities, but its neural underpinnings remain poorly understood. In the rabbit illusion, a sequence of nonequidistant stimuli presented isochronously is perceived as equidistantly spaced. This illusion might be driven by an internal prior favoring a constant-speed motion. Here, we hypothesized that prestimulus alpha oscillations (8-12 Hz), known to correlate with perceptual expectations and biases, would reflect the degree to which perceptual reports are influenced by a constant-speed prior. Human participants were presented with ambiguous visual sequences while being recorded simultaneously with MEG and EEG: the same sequences yielded an illusory perception in about half the trials, allowing contrasting brain responses elicited by identical sequences causing distinct percepts. As a proxy of an individual's prior, we used the percentage of perceived illusion and the detection criterion, assuming that a strong constant-speed prior would result in a higher rate of illusory percepts. We found that high frontoparietal alpha power was associated with perceiving the sequence according to the individual's prior: participants with high susceptibility to the illusion would report the illusion, while participants with low susceptibility would report the veridical sequence. Additionally, we found that prestimulus alpha phase in occipitoparietal regions dissociated illusion from no-illusion trials. We interpret our results as suggesting that alpha power reflects an individual's constant-speed prior, whereas alpha phase modulates sensory uncertainty.

Focused Review on Neural Correlates of Different Types of Motor Errors and Related Terminological Issues.

The Error-related negativity (Ne/ERN) and the feedback-related negativity (FRN), two event-related potentials in electroencephalogram tracings, have been used to examine error processing in conscious actions. In the classical terminology the Ne/ERN and the FRN are differentiated with respect to whether internal (Ne/ERN) or external (FRN) error information is processed. In motor tasks, however, errors of different types can be made: A wrong action can be selected that is not adequate to achieve the task goal (or action effect), or the correctly selected action can be mis-performed such that the task goal might be missed (movement error). Depending on the motor task and the temporal sequences of these events, internal and external error information can coincide. Hence, a clear distinction of the information source is difficult, and the classical terminology that differentiates the Ne/ERN and the FRN with respect to internal and external error information becomes ambiguous. But, a stronger focus on the characteristics of the definition of "task" and the cause of "errors", as well as on temporal characteristics of event-related potentials with respect to the task action allows separate examination of the processing of movement errors, the processing of the prediction of action effect errors, or the processing of the detection of action effect errors. The present article gives an overview of example studies investigating the Ne/ERN and the FRN in motor tasks, classifies them with respect to action effect errors or movement errors, and proposes updated terminology.

All in Good Time: Long-Lasting Postdictive Effects Reveal Discrete Perception.

Is consciousness a continuous stream of percepts or is it discrete, occurring only at certain moments in time? This question has puzzled philosophers, psychologists, and neuroscientists for centuries. Both hypotheses have fallen repeatedly in and out of favor. Here, we review recent studies exploring long-lasting postdictive effects and show that the results favor a two-stage discrete model, in which substantial periods of continuous unconscious processing precede discrete conscious percepts. We propose that such a model marries the advantages of both continuous and discrete models and resolves centuries old debates about perception and consciousness.

The interplay of predictive and postdictive components of experienced selfhood.

Objects that we affect by our body movements can be experienced as being controlled by (agency) and belonging to the own body (ownership). Such impressions of minimal selfhood arise when objects move as predicted prior to the action (predictive component). But they can also arise when otherwise unpredictable object movements turn out to be consistent with (e.g. spatially compatible to) preceding actions (postdictive component). Here we studied how the impact of postdictive components of inferred minimal selfhood in terms of action-object compatibility is shaped by different levels of predictability of these object movements. We found that compatibility between actions and object movements, and to a lesser extent predictability of object movements, affected reported agency while only compatibility affected reported ownership. Importantly, predictive and postdictive factors influenced these measures in an independent manner. We discuss these results against the background of models that assume multiple components of experienced minimal selfhood.

Compress global, dilate local: Intentional binding in action-outcome alternations.

Intentional binding refers to subjective temporal attraction between an action and its outcome. However, the nature of intentional binding in multiple actions remains unclear. We examined intentional binding in alternated action-outcome dyads. Participants actively or passively pressed a key, followed by a tone, and they again pressed the key; resulting in four keypress-tone dyads in a trial. Participants reproduced the duration of alternated keypress-tone dyads or the temporal interval between a dyad embedded in the alternations. The reproduced duration was shorter in the active than in the passive condition, suggesting the intentional binding in action-outcome alternations. In contrast, the reproduced interval between a dyad was longer in the active condition and did not correlate with the reproduced duration. These results suggest that subjective time during actions relies not only on an internal clock but also on postdictive biases that are switched based on what we recall.

Practicing metacognition through the use of repeated posttest predictions.

BACKGROUND: Development of metacognitive skills is one method to increase self-awareness of pharmacy students. This study sought to assess students' posttest prediction (postdiction) of performance on a series of multiple-choice examinations to determine if feedback regarding predicted and actual performance could improve personal predictive abilities over time. IMPACT: While there was a statistically significant change in the students' predictive abilities from examination one to examination three, lower scores in examination two disrupted the trend we had hoped to see. When broken down by overall course score, the highest performing students rarely overestimated their score (5-21% of the time, depending on examination), while the lowest performing students were more varied (22-56% over prediction, depending on examination). RECOMMENDATIONS: This study used a novel assessment method of postdictions without additional data points such as predictions or grade point average (GPA), which could have helped confirm the value of the method. Additionally, we realized assessing the impact of the qualitative feedback students received could elucidate why and recommend this for future studies. DISCUSSION: While students were generally poor predictors of their performance, repeated use of this skill helped them to reduce the number of over predictions made by the end of the course. This change was greatest for the lowest performing students indicating that they may receive more benefit from this exercise than higher performing students. This method of using postdictions adds to the collection of tools that can be used to measure student metacognitive skills.

Strategies to effectively implement self-assessment techniques using multiple methods.

BACKGROUND: This commentary accompanies a companion article that used post-test predictions or postdictions as a self-assessment strategy to help third-year pharmacy students evaluate and understand their test performance. IMPACT: In addition to providing constructive critiques to the companion article, two educational studies using different self-assessment techniques are highlighted. TEACHABLE MOMENT: To help improve the design and implementation of self-assessment strategies in the future, the goal of this teachable moments matter is to unpack the relationship between self-assessment and metacognition. Specifically, this commentary will address the consequences of using singular self-assessments as well as provide strategies on how to appropriately utilize self-assessments through the triangulation of multiple methods.

Metaphorical Action Retrospectively but Not Prospectively Alters Emotional Judgment.

Metaphorical association between vertical space and emotional valence is activated by bodily movement toward the corresponding space. Upward or downward manual movement "following" observation of emotional images is reported to alter the perceived valence as more positive or negative. This study aimed to clarify this retrospective emotional modulation. Experiment 1 investigated the effects of temporal order of emotional stimuli and manual movements. Participants performed upward, downward, or horizontal manual movements immediately before or after observation of emotional images; they then rated the valence of the image. The images were rated as more negative in downward- than in horizontal-movement conditions only when the movements followed the image observation. Upward movement showed no effect. Experiment 2 examined the effects of temporal proximity between images, movements, and ratings. The results showed that a 2-s interval either between image and movement or movement and rating nullified the retrospective effect. Bodily movement that corresponds to space-valence metaphor retrospectively, but not prospectively, alters the perceived valence of emotional stimuli. This effect requires temporal proximity between emotional stimulus, the subsequent movement, and rating of the stimulus. With respect to the lack of effect of upward-positive correspondence, anisotropy in effects of movement direction is discussed.

Back from the future: Volitional postdiction of perceived apparent motion direction.

Among physical events, it is impossible that an event could alter its own past for the simple reason that past events precede future events, and not vice versa. Moreover, to do so would invoke impossible self-causation. However, mental events are constructed by physical neuronal processes that take a finite duration to execute. Given this fact, it is conceivable that later brain events could alter the ongoing interpretation of previous brain events if they arrive within this finite duration of interpretive processing, before a commitment is made to what happened. In the current study, we show that humans can volitionally influence how they perceive an ambiguous apparent motion sequence, as long as the top-down command occurs up to 300ms after the occurrence of the actual motion event in the world. This finding supports the view that there is a temporal integration period over which perception is constructed on the basis of both bottom-up and top-down inputs.

Mistiming of thought and perception predicts delusionality.

The timing of thoughts and perceptions plays an essential role in belief formation. Just as people can experience in-the-moment perceptual illusions, however, they can also be deceived about how events unfold in time. Here, we consider how a particular type of temporal distortion, in which the apparent future influences "earlier" events in conscious awareness, might affect people's most fundamental beliefs about themselves and the world. Making use of a task that has been shown to elicit such reversals in the temporal experience of prediction and observation, we find that people who are more prone to think that they predicted an event that they actually already observed are also more likely to report holding delusion-like beliefs. Moreover, this relationship appears to be specific to how people experience prediction and is not explained by domain-general deficits in temporal discrimination. These findings may help uncover low-level perceptual mechanisms underlying delusional belief or schizotypy more broadly and may ultimately prove useful as a tool for identifying those at risk for psychotic illness.

Keeping postdiction simple.

Postdiction effects are phenomena in which a stimulus influences the appearance of events taking place before it. In metacontrast masking, for instance, a masking stimulus can render a target stimulus shown before the mask invisible. This and other postdiction effects have been considered incompatible with a simple explanation according to which (i) our perceptual experiences are delayed for only the time it takes for a distal stimulus to reach our sensory receptors and for our neural mechanisms to process it, and (ii) the order in which the processing of stimuli is completed corresponds with the apparent temporal order of stimuli. As a result, the theories that account for more than a single postdiction effect reject at least one of these theses. This paper presents a new framework for the timing of experiences-the non-linear latency difference view-in which the three most discussed postdiction effects-apparent motion, the flash-lag effect, and metacontrast masking-can be accounted for while simultaneously holding theses (i) and (ii). This view is grounded in the local reentrant processes, which are known to have a crucial role in perception. Accordingly, the non-linear latency difference view is both more parsimonious and more empirically plausible than the competing theories, all of which remain largely silent about the neural implementation of the mechanisms they postulate.

Post-determined emotion: motor action retrospectively modulates emotional valence of visual images.

Upward and downward motor actions influence subsequent and ongoing emotional processing in accordance with a space-valence metaphor: positive is up/negative is down. In this study, we examined whether upward and downward motor actions could also affect previous emotional processing. Participants were shown an emotional image on a touch screen. After the image disappeared, they were required to drag a centrally located dot towards a cued area, which was either in the upper or lower portion of the screen. They were then asked to rate the emotional valence of the image using a 7-point scale. We found that the emotional valence of the image was more positive when the cued area was located in the upper portion of the screen. However, this was the case only when the dragging action was required immediately after the image had disappeared. Our findings suggest that when somatic information that is metaphorically associated with an emotion is linked temporally with a visual event, retrospective emotional integration between the visual and somatic events occurs.

Postdiction: its implications on visual awareness, hindsight, and sense of agency.

There are a few postdictive perceptual phenomena known, in which a stimulus presented later seems causally to affect the percept of another stimulus presented earlier. While backward masking provides a classical example, the flash lag effect stimulates theorists with a variety of intriguing findings. The TMS-triggered scotoma together with "backward filling-in" of it offer a unique neuroscientific case. Findings suggest that various visual attributes are reorganized in a postdictive fashion to be consistent with each other, or to be consistent in a causality framework. In terms of the underlying mechanisms, four prototypical models have been considered: the "catch up," the "reentry," the "different pathway" and the "memory revision" models. By extending the list of postdictive phenomena to memory, sensory-motor and higher-level cognition, one may note that such a postdictive reconstruction may be a general principle of neural computation, ranging from milliseconds to months in a time scale, from local neuronal interactions to long-range connectivity, in the complex brain. The operational definition of the "postdictive phenomenon" can be applicable to such a wide range of sensory/cognitive effects across a wide range of time scale, even though the underlying neural mechanisms may vary across them. This has significant implications in interpreting "free will" and "sense of agency" in functional, psychophysical and neuroscientific terms.

Spatial warping by oriented line detectors can counteract neural delays.

The slow speed of neural transmission necessitates that cortical visual information from dynamic scenes will lag reality. The "perceiving the present" (PTP) hypothesis suggests that the visual system can mitigate the effect of such delays by spatially warping scenes to look as they will in ~100 ms from now (Changizi, 2001). We here show that the Hering illusion, in which straight lines appear bowed, can be induced by a background of optic flow, consistent with the PTP hypothesis. However, importantly, the bowing direction is the same whether the flow is inward or outward. This suggests that if the warping is meant to counteract latencies, it is accomplished by a simple strategy that is insensitive to motion direction, and that works only under typical (forward-moving) circumstances. We also find that the illusion strengthens with longer pulses of optic flow, demonstrating motion integration over ~80 ms. The illusion is identical whether optic flow precedes or follows the flashing of bars, exposing the spatial warping to be equally postdictive and predictive, i.e., peri-dictive. Additionally, the illusion is diminished by cues which suggest the bars are independent of the background movement. Collectively, our findings are consistent with a role for networks of visual orientation-tuned neurons (e.g., simple cells in primary visual cortex) in spatial warping. We conclude that under the common condition of forward ego-motion, spatial warping counteracts the disadvantage of neural latencies. It is not possible to prove that this is the purpose of spatial warping, but our findings at minimum place constraints on the PTP hypothesis, demonstrating that any spatial warping for the purpose of counteracting neural delays is not a precise, on-the-fly computation, but instead a heuristic achieved by a simple mechanism that succeeds under normal circumstances.