Perceptual Evidence Research Articles

Truth, Lies and Politics: Work Experience and Judicial Perceptions of Evidence in Asylum Cases

Truth, Lies and Politics: Work Experience and Judicial Perceptions of Evidence in Asylum Cases

Explaining away temporal flow – thoughts on Prosser’s ‘Experiencing Time’

I offer some responses to Prosser’s ‘Experiencing Time’, one of whose goals is to debunk a view of temporal experience somewhat prevalent in the metaphysics literature, which I call ‘Perceptualism’. According to Perceptualism: (1) it is part of the content of perceptual experience that time passes in a metaphysically strong sense: the present has a metaphysically privileged status, and time passes in virtue of changes in which events this ‘objective present’ highlights, and moreover (2) this gives us evidence in favor of strong passage. Prosser argues that perception cannot be sensitive to whether the strong passage obtains, and therefore cannot represent strong passage in a way that gives us evidence of its truth. Although I accept this conclusion, I argue that Prosser’s argument for it is problematic. It threatens to over-generalize to rule out uncontroversial cases of perceptual knowledge, such as our knowledge that we live in a spatial world. Furthermore, a successful argument ruling out perceptual evidence for strong passage would have to give constraints on the theory/observation distinction of a kind not provided by Prosser’s discussion. I also comment on several other parts of the book.

Using oropharyngeal articulation to compensate for nasalization: Acoustic and perceptual evidence

A variety of oropharyngeal articulatory differences have been identified between oral and nasal vowel pairs in different languages, which either enhance or reduce the acoustic effects of nasalization. The aim of this study is to simulate oropharyngeal articulatory adjustment strategies to maximally compensate for the acoustic effects of nasalization. Two articulatory models were used for the simulation—one speaker-independent (SI) model and one speaker-dependent (SD) model. The results suggested that (1) the oropharyngeal articulatory strategies generated by both models effectively reduced the acoustic effects of nasalization on the low-frequency spectrum of the vowels; and (2) the oropharyngeal articulatory strategies generated by the SD model provided a better compensatory effect in the spectral region of F2 and higher formants compared to the strategies generated by the SI model. Moreover, a comparison of nasality ratings of the synthetic nasal vowels with and without oropharyngeal articulatory adjustments showed a significant reduction of nasality following oropharyngeal articulatory adjustments. These findings provide acoustic and perceptual evidence in support of motor equivalence. With further research on other speech sounds and the temporal pattern of nasalization warranted, the findings might have potential clinical implications for reducing hypernasality in persons with resonance disorders.

Neural mechanisms for hallucinations

Neuroscience Pairing a stimulus in one modality (vision) with a stimulus in another (sound) can lead to task-induced hallucinations in healthy individuals. After many trials, people eventually report perceiving a nonexistent stimulus contingent on the presence of the previously paired stimulus. Powers et al. investigated how different groups of volunteers and patients respond to this conditioning paradigm. They used behavior, neuroimaging, and computational modeling to dissect the effect of perceptual priors versus sensory evidence on such induced hallucinations. People who are more prone to hear voices were more susceptible to the induced auditory hallucinations. The network of brain regions that was active during the conditioned hallucinations resembled the network observed during clinical symptom capture in individuals who hallucinate while in a brain scanner. Science , this issue p. [596][1] [1]: /lookup/doi/10.1126/science.aan3458

The impact of counter-perceptual testimony on children’s categorization after a delay

When preschoolers are presented with a label for an entity that conflicts with its appearance, they sometimes rely on the new label rather than on the entity’s appearance to categorize the entity and to infer its properties. We examined whether children’s learning from such claims is short-lived or long-lasting and whether the persistence of their learning depends on the degree of fit between those claims and the available perceptual evidence. Children aged 3–5years (N=71) were asked to categorize hybrids. These hybrids combined 75% of the features from one animal or object with 25% of the features from a different animal or object. After categorizing each hybrid, children heard an informant provide a contrary label. Immediately after they were provided with this new label, children often recategorized the entities accordingly, especially when the label matched the hybrid’s predominant features. Children’s endorsement of the informant’s label proved to be long-lasting when it matched the hybrid’s predominant features, typically persisting even after 5weeks. In contrast, children’s endorsement often faded over time when the informant’s label did not match the hybrid’s predominant features. Overall, children were more skeptical of testimony that was more discrepant with the perceptual evidence available to them, and they were less likely to continue endorsing it after a delay. The findings have implications for our understanding of how children eventually come to represent and believe in counter-perceptual and counterintuitive concepts.

On the origin of sensory errors: Contrast discrimination under temporal constraint.

Estimation of perceptual variables is imprecise and prone to errors. Although the properties of these perceptual errors are well characterized, the physiological basis for these errors is unknown. One previously proposed explanation for these errors is the trial-by-trial variability of the responses of sensory neurons that encode the percept. In order to test this hypothesis, we developed a mathematical formalism that allows us to find the statistical characteristics of the physiological system responsible for perceptual errors, as well as the time scale over which the visual information is integrated. Crucially, these characteristics can be estimated solely from a behavioral experiment performed here. We demonstrate that the physiological basis of perceptual error has a constant level of noise (i.e., independent of stimulus intensity and duration). By comparing these results to previous physiological measurements, we show that perceptual errors cannot be due to the variability during the encoding stage. We also find that the time window over which perceptual evidence is integrated lasts no more than ∼230 ms. Finally, we discuss sources of error that may be consistent with our behavioral measurements.

Perceiving a part and the whole of narrative scenes with interactive processing between character and surroundings

ABSTRACTVisual recognition is a fast and accurate process. This study adopted a progressive revelation task which demonstrated the dynamic visual process to investigate narrative scene perception. Experiment 1 examined the recognition of character and surroundings that are presented in isolation. The results demonstrated an accumulation of perceptual evidence for recognition as a psychometric function, and character identification was found to be superior to surroundings identification (character advantage effect). Experiment 2 examined the character and surroundings identification in isolated and concurrent presentations. The results showed that less accumulated evidence was required for the concurrent condition than for the isolated condition in the surroundings identification but not in the character identification. The character advantage effect only appeared in the isolated condition. In Experiment 3, both the character and surroundings in semantically consistent or inconsistent scenes were reported. The results showed that consistency effects appeared in both character and surroundings reporting, and the character advantage effect appeared in both consistent and inconsistent conditions. Overall, the results of the present study, which have high ecological validity, supported the existence of an interactive relationship between the visual processing of character and surroundings in narrative scene perception.

The Effects of Methylphenidate on the Neural Signatures of Sustained Attention

BackgroundAlthough it is well established that methylphenidate (MPH) enhances sustained attention, the neural mechanisms underpinning this improvement remain unclear. We examined how MPH influenced known electrophysiological precursors of lapsing attention over different time scales. MethodsWe measured the impact of MPH, compared with placebo, on behavioral and electrocortical markers while healthy adults (n = 40) performed a continuous monitoring paradigm designed to elicit attentional lapses. ResultsMPH led to increased rates of target detection, and electrophysiological analyses were conducted to identify the mechanisms underlying these improvements. Lapses of attention were reliably preceded by progressive increases in alpha activity that emerged over periods of several seconds. MPH led to an overall suppression of alpha activity across the entire task but also diminished the frequency of these maladaptive pretarget increases through a reduction of alpha variability. A drug-related linear increase in the amplitude of the frontal P3 event-related component was also observed in the pretarget timeframe (3 or 4 seconds). Furthermore, during immediate target processing, there was a significant increase in the parietal P3 amplitude with MPH, indicative of enhanced perceptual evidence accumulation underpinning target detection. MPH-related enhancements occurred without significant changes to early visual processing (visual P1 and 25-Hz steady-state visual evoked potential). ConclusionsMPH serves to reduce maladaptive electrophysiological precursors of lapsing attention by acting selectively on top-down endogenous mechanisms that support sustained attention and target detection with no significant effect on bottom-up sensory excitability. These findings offer candidate markers to monitor the therapeutic efficacy of psychostimulants or to predict therapeutic responses.

Factors that impact how civil society intermediaries perceive evidence

Civil society organisations increasingly mediate the creation and exchange of evidence in their activities with policy-makers and practitioners. This article extends knowledge on evidence in policy-making settings to civil society contexts. As an exploratory and qualitative study, it shows how nine UK-based organisations working on issues including migration and social welfare hold different perceptions of evidence and its usefulness. A range of related factors involving individuals, organisations, sectors, and issue areas emerge as contingent contributors to these variations. The results suggest that researchers and practitioners seeking to engage with civil society using evidence should consider context-specific values, skills, motivations, and timeliness.

The Sensed Presence Questionnaire (SenPQ): initial psychometric validation of a measure of the “Sensed Presence” experience

BackgroundThe experience of ‘sensed presence’—a feeling or sense that another entity, individual or being is present despite no clear sensory or perceptual evidence—is known to occur in the general population, appears more frequently in religious or spiritual contexts, and seems to be prominent in certain psychiatric or neurological conditions and may reflect specific functions of social cognition or body-image representation systems in the brain. Previous research has relied on ad-hoc measures of the experience and no specific psychometric scale to measure the experience exists to date.MethodsBased on phenomenological description in the literature, we created the 16-item Sensed Presence Questionnaire (SenPQ). We recruited participants from (i) a general population sample, and; (ii) a sample including specific selection for religious affiliation, to complete the SenPQ and additional measures of well-being, schizotypy, social anxiety, social imagery, and spiritual experience. We completed an analysis to test internal reliability, the ability of the SenPQ to distinguish between religious and non-religious participants, and whether the SenPQ was specifically related to positive schizotypical experiences and social imagery. A factor analysis was also conducted to examine underlying latent variables.ResultsThe SenPQ was found to be reliable and valid, with religious participants significantly endorsing more items than non-religious participants, and the scale showing a selective relationship with construct relevant measures. Principal components analysis indicates two potential underlying factors interpreted as reflecting ‘benign’ and ‘malign’ sensed presence experiences.DiscussionThe SenPQ appears to be a reliable and valid measure of sensed presence experience although further validation in neurological and psychiatric conditions is warranted.

Visuospatial Asymmetries Arise from Differences in the Onset Time of Perceptual Evidence Accumulation.

Healthy subjects tend to exhibit a bias of visual attention whereby left hemifield stimuli are processed more quickly and accurately than stimuli appearing in the right hemifield. It has long been held that this phenomenon arises from the dominant role of the right cerebral hemisphere in regulating attention. However, methods that would enable more precise understanding of the mechanisms underpinning visuospatial bias have remained elusive. We sought to finely trace the temporal evolution of spatial biases by leveraging a novel bilateral dot motion detection paradigm. In combination with electroencephalography, this paradigm enables researchers to isolate discrete neural signals reflecting the key neural processes needed for making these detection decisions. These include signals for spatial attention, early target selection, evidence accumulation, and motor preparation. Using this method, we established that three key neural markers accounted for unique between-subject variation in visuospatial bias: hemispheric asymmetry in posterior α power measured before target onset, which is related to the distribution of preparatory attention across the visual field; asymmetry in the peak latency of the early N2c target-selection signal; and, finally, asymmetry in the onset time of the subsequent neural evidence-accumulation process with earlier onsets for left hemifield targets. Our development of a single paradigm to dissociate distinct processing components that track the temporal evolution of spatial biases not only advances our understanding of the neural mechanisms underpinning normal visuospatial attention bias, but may also in the future aid differential diagnoses in disorders of spatial attention.SIGNIFICANCE STATEMENT The significance of this research is twofold. First, it shows that individual differences in how humans direct their attention between left and right space reflects physiological differences in how early the brain starts to accumulate evidence for the existence of a visual target. Second, the novel methods developed here may have particular relevance to disorders of attention, such as unilateral spatial neglect. In the case of spatial neglect, pathological inattention to left space could have multiple underlying causes, including biased attention, impaired decision formation, or a motor deficit related to one side of space. Our development of a single paradigm to dissociate each of these components may aid in supporting more precise differential diagnosis in such heterogeneous disorders.

Implementing a Public Health Objective for Alcohol Premises Licensing in Scotland: A Qualitative Study of Strategies, Values, and Perceptions of Evidence.

The public health objective for alcohol premises licensing, established in Scotland in 2005, is unique globally. We explored how public health practitioners engaged with the licensing system following this change, and what helped or hindered their efforts. Semi-structured interviews were conducted with 13 public health actors, audio-recorded, and analysed using an inductive framework approach. Many interviewees viewed the new objective as synonymous with reducing population-level alcohol consumption; however, this view was not always shared by licensing actors, some of whom did not accept public health as a legitimate goal of licensing, or prioritised economic development instead. Some interviewees were surprised that the public health evidence they presented to licensing boards did not result in their hoped-for outcomes; they reported that licensing officials did not always understand or value health data or statistical evidence. While some tried to give “impartial” advice to licensing boards, this was not always easy; others were clear that their role was one of “winning hearts and minds” through relationship-building with licensing actors over time. Notwithstanding the introduction of the public health objective, there remain significant, and political, challenges in orienting local premises licensing boards towards decisions to reduce the availability of alcohol in Scotland.

Complementary length in vowel–consonant sequences: Acoustic and perceptual evidence for a sound change in progress in Bavarian German

This study is concerned with the Bavarian German dialect feature of complementary length in vowel plus consonant sequences according to which tense (long) vowels always precede lenis stops (short closure) and lax (short) vowels always precede fortis stops (long closure). The study investigates whether a vowel length contrast is developing before fortis stops due to dialect leveling. We measured vowel and consonant duration in trochaic words differing only in vowel length which were read by 40 older and younger Bavarian and Saxon (control group) German speakers. Older Bavarians distinguished tense and lax vowels by means of vowel to vowel plus consonant ratios that indicate an inverse timing pattern. Saxons and younger Bavarians signal the tense–lax distinction independently of the following stop length. A perception test showed that this sound change in progress also affects perception. We argue for a contact-induced change which is triggered by external as opposed to internal factors.

Information Order Shifts Criterion Placement in Perceptual Decisions

Facing perceptual decisions with asymmetric stakes, individuals exhibit a conservative criterion placement. This bias prevents them from reaching the optimal decision process defined as the one which maximizes their expected payoffs. We propose in the present experimental study a non-invasive method to correct behaviors toward more optimality. We manipulate the information order between payoff information and perceptual evidence for three different incentive levels invariant regarding Signal Detection Theory predictions. Our results support the effectiveness of such manipulation: the decision strategy shifts toward optimality when payoff information is displayed last. The shift toward optimality is more pronounced for higher payoff contrasts. These results, which cannot be explained within the Signal Detection Theory framework, give new insights on the cognitive processes responsible for the conservative criterion placement.

The interdependence of perceived confession voluntariness and case evidence.

The current research investigated the mechanisms by which perceptions of confession evidence both influence and are influenced by perceptions of other case evidence using the theoretical framework of coherence-based reasoning (CBR). CBR posits that ambiguity and uncertainty are eschewed by artificially imposing consistency between pieces of evidence through bidirectional reasoning: Inferences about evidence lead to a preferred verdict, which in turn radiates backward to influence the perception of evidence. Two studies tested the CBR account with regard to confessions. An online sample of participants evaluated confession and nonconfession evidence at pretest and posttest. Study 1 revealed that, during pretest, participants (N = 119) deemed the evidence independent and nonprobative and the confession to be voluntary. However, at posttest, in the context of a criminal trial, participants considered the same evidence interrelated and highly inculpatory or exculpatory, depending on their verdict. Moreover, participants who voted to convict deemed the confession substantially voluntary, whereas participants who voted to acquit deemed it involuntary. Study 2 experimentally manipulated the strength of the nonconfession evidence in an effort to push participants (N = 127) toward a particular verdict. The same patterns of results emerged but were conditional on the strength of the nonconfession evidence: Strong case evidence caused the confession to be perceived as more voluntary, despite the fact that the confession was held constant. These findings replicate the coherence effect in a new domain and suggest that judges conducting harmless error analysis or making admissibility decisions might underappreciate the impact of confession evidence on jurors' verdicts. (PsycINFO Database Record

Tablet Technology and Cloud Storage as Evidence of Pedagogic Development in Pre-service Teacher Education

INCREASINGLY, EDUCATORS AND PRE-SERVICE teachers studying to become educators are called to present evidence of their teaching practice and the development of their pedagogic skills. Traditionally this evidence was likely to be printed, with pen and paper notes or typed examples. However, technology such as mobile and tablet devices and cloud storage is enabling new forms of evidence. This study was designed to examine how pre-service teachers develop a digital teaching portfolio incorporating multi-modal evidence linked to accreditation standards. This paper examines survey data, focus group responses and work samples to explore how 213 pre-service teachers use technology to document their work and pedagogic engagement. In examining the nature of ‘evidence’ we have adapted Bronfenbrenner's ecological framework (1979, 1993) to investigate pre-service teachers' perceptions of evidence of learning and explore their concerns with using technology to document learning and facilitate teacher accreditation.

Global gain modulation generates time-dependent urgency during perceptual choice in humans.

Decision-makers must often balance the desire to accumulate information with the costs of protracted deliberation. Optimal, reward-maximizing decision-making can require dynamic adjustment of this speed/accuracy trade-off over the course of a single decision. However, it is unclear whether humans are capable of such time-dependent adjustments. Here, we identify several signatures of time-dependency in human perceptual decision-making and highlight their possible neural source. Behavioural and model-based analyses reveal that subjects respond to deadline-induced speed pressure by lowering their criterion on accumulated perceptual evidence as the deadline approaches. In the brain, this effect is reflected in evidence-independent urgency that pushes decision-related motor preparation signals closer to a fixed threshold. Moreover, we show that global modulation of neural gain, as indexed by task-related fluctuations in pupil diameter, is a plausible biophysical mechanism for the generation of this urgency. These findings establish context-sensitive time-dependency as a critical feature of human decision-making.

How the perception of evidence can affect the use of evidence-based practice in day-to-day practice

Relevance: Health systems across the world are concerned with the quality and safety of patient care and urged to ensure that they are delivering care that is based on the best current research evidence, known as evidence based practice (EBP). Even if many physiotherapists hold positive attitudes towards EBP, they seem to have difficulty to break through different barriers such as lack of time, inability to understand statistics and misconceptions of the concept. If there occurs misconceptions about the concept of evidence, there is reason to believe that it affects the day-to-day practice. Little work has been undertaken previously in exploring what lies behind physiotherapists’ actions relating to evidence. To understand how EBP is carried out and how decisions are made in day-to-day practice, it is important to grasp how the concept of evidence is perceived. One method for addressing this problem could be to improve therapists’ knowledge of how to promote integration of research evidence into clinical decision-making.

Disrupted latent decision processes in medication-free pediatric OCD patients

BackgroundDecision-making in Obsessive Compulsive Disorder has typically been investigated in the adult population. Computational approaches have recently started to get integrated into these studies. However, decision-making research in pediatric OCD populations is scarce. MethodsWe investigated latent decision processes in 21 medication-free pediatric OCD patients and 23 healthy control participants. We hypothesized that OCD patients would be more cautious and less efficient in evidence accumulation than controls in a two alternative forced choice (2AFC) task. ResultsPediatric OCD patients were less efficient than controls in accumulating perceptual evidence and showed a tendency to be more cautious. In comparison to post-correct decisions, OCD patients increased decision thresholds after erroneous decisions, whereas healthy controls decreased decision thresholds. These changes were coupled with weaker evidence accumulation after errors in both groups. LimitationsThe small sample size limited the power of the study. ConclusionsOur results demonstrate poorer decision-making performance in pediatric OCD patients at the level of latent processes, specifically in terms of evidence accumulation.

The phonetic origins of /s/-retraction: Acoustic and perceptual evidence from Australian English

In contemporary spoken English, /s/ can resemble a post-alveolar fricative when it occurs in /str/ clusters e.g. street. /s/-retraction in /str/ is known to be widespread in North American English, but the question of how this sound change comes about has attracted only a very small amount of empirical research. This paper investigates the phonetic pre-conditions for /s/-retraction based on the results of two experiments conducted with Australian English. Study 1 shows that the first spectral moment (M1) for /s/ is lower in /spr, str, skr/ and slightly lower in /sp, st, sk/ than in pre-vocalic position. Temporal variation in first spectral moment trajectories suggests that the articulatory movements associated with the rhotic are timed relatively earlier in /str/ vs. /spr, skr/ clusters. Study 2 tested native listener categorization of sibilants produced by multiple talkers. Results show that sibilants originally produced in stream and steam elicit /ʃ/ responses when spliced into pre-vocalic contexts. There was an interaction with talker gender, with male voices eliciting more /ʃ/ responses. Thus, the conditions for sound change to occur by which /s/ becomes /ʃ/ originate in a synchronic bias for /s/ produced in /sC(r)/ clusters to show increased auditory similarity to /ʃ/. Australian English shows the pre-conditions for /s/-retraction but is not currently undergoing this sound change.