Attention, predictive learning, and the inverse base-rate effect: Evidence from event-related potentials

We report the first electrophysiological investigation of the inverse base-rate effect (IBRE), a robust non-rational bias in predictive learning. In the IBRE, participants learn that one pair of symptoms (AB) predicts a frequently occurring disease, whilst an overlapping pair of symptoms (AC) predicts a rarely occurring disease. Participants subsequently infer that BC predicts the rare disease, a non-rational decision made in opposition to the underlying base rates of the two diseases. Error-driven attention theories of learning state that the IBRE occurs because C attracts more attention than B. On the basis of this account we predicted and observed the occurrence of brain potentials associated with visual attention: a posterior Selection Negativity, and a concurrent anterior Selection Positivity, for C vs. B in a post-training test phase. Error-driven attention theories further predict no Selection Negativity, Selection Positivity or IBRE, for control symptoms matched on frequency to B and C, but for which there was no shared symptom (A) during training. These predictions were also confirmed, and this confirmation discounts alternative explanations of the IBRE based on the relative novelty of B and C. Further, we observed higher response accuracy for B alone than for C alone; this dissociation of response accuracy (B>C) from attentional allocation (C>B) discounts the possibility that the observed attentional difference was caused by the difference in response accuracy

Syntactic anomaly elicits a lexico-semantic (N400) ERP effect in the second but not in the first language

Recent brain potential research into first versus second language (L1 vs. L2) processing revealed striking responses to morphosyntactic features absent in the mother tongue. The aim of the present study was to establish whether the presence of comparable morphosyntactic features in L1 leads to more similar electrophysiological L1 and L2 profiles. ERPs were acquired while German-English bilinguals and native speakers of English read sentences. Some sentences were meaningful and well formed, whereas others contained morphosyntactic or semantic violations in the final word. In addition to the expected P600 component, morphosyntactic violations in L2 but not L1 led to an enhanced N400. This effect may suggest either that resolution of morphosyntactic anomalies in L2 relies on the lexico-semantic system or that the weaker/slower morphological mechanisms in L2 lead to greater sentence wrap-up difficulties known to result in N400 enhancement

Predictive learning, prediction errors, and attention: evidence from event-related potentials and eye tracking

Prediction error (‘‘surprise’’) affects the rate of learning: We learn more rapidly about cues for which we initially make incorrect predictions than cues for which our initial predictions are correct. The current studies employ electrophysiological measures to reveal early attentional differentiation of events that differ in their previous involvement in errors of predictive judgment. Error-related events attract more attention, as evidenced by features of event-related scalp potentials previously implicated in selective visual attention (selection negativity, augmented anterior N1). The earliest differences detected occurred around 120 msec after stimulus onset, and distributed source localization (LORETA) indicated that the inferior temporal regions were one source of the earliest differences. In addition, stimuli associated with the production of prediction errors show higher dwell times in an eyetracking procedure. Our data support the view that early attentional processes play a role in human associative learning

A change of task prolongs early processes: evidence from ERPs in lexical tasks.

PublishedJournal ArticleSwitching tasks costs time. Allowing time to prepare reduces the cost, but usually leaves an irreducible "residual cost." Most accounts of this residual cost locate it within the response-selection stage of processing. To determine which processing stage is affected, we measured event-related potentials (ERPs) as participants performed a reading task or a perceptual judgment task, and examined the effect of a task switch on early markers of lexical processing. A task cue preceding a string of blue and red letters instructed the participant either to read the letter string (for a semantic classification in Experiment 1, and a lexical decision in Experiment 2) or to judge the symmetry of its color pattern. In Experiment 1, having to switch to the reading task delayed the evolution of the effect of word frequency on the reading task ERP by a substantial fraction of the effect on reaction time (RT). In Experiment 2, a task switch delayed the onset of the effect of lexical status on the ERP by about the same extent that it prolonged the RT. These effects indicate an early locus of (most of) the residual switch cost: We propose that this reflects a form of task-related attentional inertia. Other findings have implications for the automaticity of lexical access: Effects of frequency, lexicality, and orthographic familiarity on ERPs in the symmetry task indicated involuntary, but attenuated, orthographic and lexical processing even when attention was focused on a nonlexical property.Economic and Social Research Counci

Self-paced preparation for a task switch eliminates attentional inertia but not the performance switch cost

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.This article may not exactly replicate the final version published in the APA journal. It is not the copy of record.The performance overhead associated with changing tasks (the "switch cost") usually diminishes when the task is specified in advance but is rarely eliminated by preparation. A popular account of the "residual" (asymptotic) switch cost is that it reflects "task-set inertia": carry-over of task-set parameters from the preceding trial(s). New evidence for a component of "task-set inertia" comes from eye-tracking, where the location associated with the previously (but no longer) relevant task is fixated preferentially over other irrelevant locations, even when preparation intervals are generous. Might such limits in overcoming task-set inertia in general, and "attentional inertia" in particular, result from suboptimal scheduling of preparation when the time available is outside one's control? In the present study, the stimulus comprised 3 digits located at the points of an invisible triangle, preceded by a central verbal cue specifying which of 3 classification tasks to perform, each consistently applied to just 1 digit location. The digits were presented only when fixation moved away from the cue, thus giving the participant control over preparation time. In contrast to our previous research with experimenter-determined preparation intervals, we found no sign of attentional inertia for the long preparation intervals. Self-paced preparation reduced but did not eliminate the performance switch cost-leaving a clear residual component in both reaction time and error rates. That the scheduling of preparation accounts for some, but not all, components of the residual switch cost, challenges existing accounts of the switch cost, even those which distinguish between preparatory and poststimulus reconfiguration processes. (PsycINFO Database Recor

Is preparing for a language switch like preparing for a task switch? (article)

This is the author accepted manuscript. The final version is available from APA via the DOI in this recordThe dataset associated with this article is located in ORE at https://doi.org/10.24378/exe.403There is another ORE record for this publication: http://hdl.handle.net/10871/36569A key index of top-down control in task switching-preparation for a switch-is underexplored in language switching. The well-documented EEG "signature" of preparation for a task switch-a protracted positive-polarity modulation over the posterior scalp-has thus far not been reported in language switching, and the interpretation of previously reported effects of preparation on language switching performance is complicated by confounding factors. In an experiment using event-related potentials (ERPs) and an optimized picture-naming paradigm that addressed these confounds the language was specified by an auditory cue on every trial and changed unpredictably. There were two key manipulations. First, the cue-stimulus interval allowed either generous (1,500 ms) or little (100 ms) opportunity for preparation. Second, to explore the interplay between bottom-up and top-down language selection, we compared a highly transparent and familiar "supercue"-the name of the language spoken in that language to a relatively opaque cue (short speeded-up fragment of national anthem). Preparation for a switch elicited a brain potential strongly reminiscent of the posterior switch positivity documented in task switching. As previously shown in task switching, its amplitude inversely predicted the performance "switch cost," demonstrated by our ERP analyses contingent on reaction time (RT). This overlap in the electrophysiological correlates of preparing to switch tasks and languages suggests domain-general processes for top-down selection of task-set and language for production. But, the surprisingly small language switch cost following the supercue in the short CSI suggests that rapid and (possibly automatic) bottom-up selection-not typically observed in task switching-may also occur. (PsycINFO Database RecordThe research described in this paper was supported by a PhD scholarship to the second author from the Economic and Social Research Council (ESRC, UK)

Single-Loop Opto-Electronic Oscillator at 10.4 GHz with a Cascaded Microstrip Bandpass Filter Configuration

The opto-electronic oscillator is a well-known microwave photonic device that produces high-frequency signals in the microwave range. One of the main advantages of the opto-electronic oscillator is that it produces high-frequency signals with low phase noise thanks to the resonator's properties. In most cases the opto-electronic oscillator faces the problem of generating side modes besides the oscillation signal due to non-ideal filtering. In this paper we propose a solution for the additional suppression of these undesired harmonics using a combination of two slightly detuned bandpass microstrip filters. We report an improvement for the side-mode suppression ratio about 8.3 dB with a single-loop 90-m-long opto-electronic oscillator at 10.4 GHz

Processing differences across regular and irregular inflections revealed through ERPs

Research strongly suggests that printed words are recognized in terms of their constituent morphemes, but researchers have tended to consider the recognition of derivations and inflections in separate theoretical debates. Recently, Crepaldi et al. (2010) proposed a theory that claims to account for the recognition of both derivations and inflections. We investigated brain potentials in the context of masked priming to test two key predictions of this theory: (a) that regular inflections should prime their stems to a greater degree than irregular inflections should prime their stems; and (b) that priming for regular inflections should arise earlier in the recognition process than priming for irregular inflections. Significant masked priming effects were observed for both regular and irregular inflections, though these effects were greater for regular inflections. ERP data further suggested that masked priming effects for regular and irregular inflections had different time courses. Priming for regular but not irregular inflections emerged in a time window reflecting processing up to 250 ms post target onset, and while priming for regular and irregular inflections was observed in a time window reflecting processing 400-600 ms post target onset, these effects arose earlier and were of greater magnitude for the regular inflections. These findings support a form-then-meaning characterisation of the visual word processing system such as that proposed by Crepaldi et al. (2010) and raise challenges for alternative approache

Nodular Posterior Scleritis: Clinico-Sonographic Characteristics and Proposed Diagnostic Criteria

Purpose: To report the clinical and ultrasound features and outcomes of a series of nodular posterior scleritis. / Methods: Retrospective medical record review of 11 consecutive patients with nodular posterior scleritis. Patient demographics, ocular and systemic findings, ultrasound features, and final anatomical and visual outcomes were recorded. / Results: There were 9 females and 2 males (11 eyes) with mean age at presentation of 57 years (range, 30-84 years). Underlying systemic inflammatory disease was present in 73%. Symptoms included pain in 73% and blurred vision in 45%. A solitary amelanotic mass without the presence of lipofuscin was found in all cases. Associated ocular features included retinal pigment epithelial changes (67%), intraocular inflammation (55%), subretinal fluid (50%), macular edema (50%), and choroidal folds (30%). B-mode ultrasound showed a sclerochoroidal mass with high internal reflectivity (100%) of mean elevation of 4.1 mm. There was nodular thickening of the sclera (100%) and fluid in Tenon space or "T" sign (36%). A complete regression of the nodule after the treatment was observed only in 1 patient (11%) and partial regression in 4 patients (44%). / Conclusion: Nodular posterior scleritis should be considered in the differential diagnosis of a single amelanotic choroidal mass showing high internal reflectivity on ultrasound B-scan. It can produce intraocular inflammation in 50% of the cases and may be painless in 25%. It has a high association with a systemic underlying disease