Interplay between acoustic/phonetic and semantic processes during spoken sentence comprehension: an ERP study

When listening to speech in everyday-life situations, our cognitive system must often cope with signal instabilities such as sudden breaks, mispronunciations, interfering noises or reverberations potentially causing disruptions at the acoustic/phonetic interface and preventing efficient lexical access and semantic integration. The physiological mechanisms allowing listeners to react instantaneously to such fast and unexpected perturbations in order to maintain intelligibility of the delivered message are still partly unknown. The present electroencephalography (EEG) study aimed at investigating the cortical responses to real-time detection of a sudden acoustic/phonetic change occurring in connected speech and how these mechanisms interfere with semantic integration. Participants listened to sentences in which final words could contain signal reversals along the temporal dimension (time-reversed speech) of varying durations and could have either a low- or high-cloze probability within sentence context. Results revealed that early detection of the acoustic/phonetic change elicited a fronto-central negativity shortly after the onset of the manipulation that matched the spatio-temporal features of the Mismatch Negativity (MMN) recorded in the same participants during an oddball paradigm. Time reversal also affected late event-related potentials (ERPs) reflecting semantic expectancies (N400) differently when words were predictable or not from the sentence context. These findings are discussed in the context of brain signatures to transient acoustic/phonetic variations in speech. They contribute to a better understanding of natural speech comprehension as they show that acoustic/phonetic information and semantic knowledge strongly interact under adverse conditions.     

Chinese characters elicit face-like N170 inversion effects

Recognition of both faces and Chinese characters is commonly believed to rely on configural information. While faces typically exhibit behavioral and N170 inversion effects that differ from non-face stimuli (Rossion, Joyce, Cottrell, & Tarr, 2003), the current study examined whether a similar reliance on configural processing may result in similar inversion effects for faces and Chinese characters. Participants were engaged in an orientation judgment task (Experiment 1) and a one-back identity matching task (Experiment 2). Across two experiments, the N170 was delayed and enhanced in magnitude for upside-down faces and compound Chinese characters, compared to upright stimuli. The inversion effects for these two stimulus categories were bilateral for latency and right-lateralized for amplitudes. For simple Chinese characters, only the latency inversion effects were significant. Moreover, the size of the right-hemisphere inversion effects in N170 amplitude was larger for faces than Chinese characters. These findings show the N170 inversion effects from non-face stimuli closely parallel effects seen with faces. Face-like N170 inversion effects elicited by Chinese compound characters were attributed to the difficulty of part-whole integration as well as the disrupted regularity in relational information due to inversion. Hemispheric difference in Chinese character processing is also discussed.     

Decision Preceding Negativity in the Iowa Gambling Task: an ERP study

The present study aimed to investigate the slow negative potential (termed Decision Preceding Negativity, DPN, from the family of the Readiness Potential) which precedes a willed risky decision. To this end, evoked potentials preceding and following an economic choice were measured in a sample of 16 male students during the Iowa Gambling Task modified for ERPs recording. Statistics revealed reduced positivity/relative greater negativity (marking relative activation) in right prefrontal sites and reduced negativity (indicating relative inhibition of DPN) in central clusters over left premotor cortex, 500 ms before picking from economically disadvantageous risky decks. Analyses of the potentials elicited by the economic outcome (wins vs. losses) showed the classical frontal negativity (N260) to the economic losses. Results are consistent with the view that an economically risky decision is preceded by a relative inhibition of the planned motor response together with the activation of emotion-related right frontal sites.     

Thinking ahead or not? Natural aging and anticipation during reading

Despite growing evidence of young adults neurally pre-activating word features during sentence comprehension, less clear is the degree to which this generalizes to older adults. Using ERPs, we tested for linguistic prediction in younger and older readers by means of indefinite articles (a’s and an’s) preceding more and less probable noun continuations. Although both groups exhibited cloze probability-graded noun N400s, only the young showed significant article effects, indicating probabilistic sensitivity to the phonology of anticipated upcoming nouns. Additionally, both age groups exhibited prolonged increased frontal positivities to less probable nouns, although in older adults this effect was prominent only in a subset with high verbal fluency (VF). This ERP positivity to contextual constraint violations offers additional support for prediction in the young. For high VF older adults, the positivity may indicate they, too, engage in some form of linguistic pre-processing when implicitly cued, as may have occurred via the articles.     

SOA对Stroop启动效应的影响:行为和ERP研究

在Stroop启动范式中,启动刺激是灰色的色词,目标刺激是颜色块,被试的任务是命名颜色块的颜色。本研究通过行为实验和事件相关电位(ERP)实验的方法,研究SOA(Stimulus Onset Asynchrony)对Stroop启动效应的影响。当SOA为107ms时,在行为数据(反应时)和ERP数据(N300成分)上均表现出明显的启动效应;当SOA为1040ms时,行为上和ERP上的启动效应消失。该结果提示了在Stroop启动效应中,启动刺激对目标刺激的影响很可能是发生在对目标刺激的知觉加工晚期。     

Semantic categorization and event-related potentials

The N400 component of the event-related brain potential (ERP) was examined by presenting subjects with a series of words belonging to the same category and a series of declarative sentences. Half of the word series ended with a semantically unrelated word, while half of the sentences ended with a semantically inappropriate word. In the first experiment, subjects were instructed to read the word series and sentences, while in the second experiment they were instructed to indicate whether the word series or sentences ended appropriately or not with a button-press response. Word series and sentences with semantically incongruous endings produced a robust negative component at 400 msec followed by a positive-going wave for both the reading and decision tasks. When the subjects were required to categorize the word series and sentences endings, the negative component was followed by a robust P3 in both conditions. Analysis of scalp amplitude distributions for each task taken in conjunction with previous findings suggests that the semantically induced N400 component is most likely a "generic" N2. The relationship between the N2, N400, and P3 is discussed.     

One answer to the demand for accountability: Selection utility as an investment decision

An examination of selection utility models demonstrates that they bear a considerable resemblance to capital budgeting models well established in the finance literature. Five applications of capital budgeting to selection utility are suggested and discussed. Capital budgeting concepts are recommended as a rich source of further practical and theoretical development of selection Utility models.     

Sign-tracking behavior in aversive conditioning: Its acquisition via a Pavlovian mechanism and its suppression by operant contingencies

When rats are presented with Pavlovian backward pairings in which shock is the unconditioned stimulus (US) and an elevated platform the conditioned stimulus (CS), they show a strong tendency to approach the platform. Attempts were made at evaluating the nature of the associative mechanisms responsible for the acwuisition and maintenance of the approach behavior. In Experiment 1, following a baseline period when platform presentations were given in the absence of shocks, first (training I), approach to the platform was prevented and subjects were exposed to either backward, forward, or random presentations of shock and platform: this procedure attempted to minimize the effects of response learning on the acquisition of approach behavior. Then (training II), all subjects received backward shock-platform pairings and had access to the platform. Approach to the platform was stronger in animals previously exposed to backward pairings than in the animals of the other two groups. Also, animals preexposed to forward platform-shock pairings showed suppression of approach behavior on the first trial of training II relative to their performance on the last trial of baseline. These data suggest that a stimulus-reinforcer learning mechanism alone is sufficent for the acquisition of approach. Experiments 2a and 2b evaluated the effects of “punishing” operant contingencies on Pavlovian-produced approach behavior. The results showed that approach can be eliminated, but only after repeated exposure to an operant contingency which consisted of the immediate closure of the platform upon approach responding. These data suggest that approach behavior produced by Pavlovian contingencies can be modified by operant contingencies. Taken together, these data provide additional support for a sign-tracking notion in aversive conditioning.     

On ad hoc personality scales: A reply to Burisch

Two recent articles by M. Burisch (1984, American Psychologist, 37, 214–227; 1984, Journal of Research in Personality, 18, 81–98) have presented data bearing on the traditional methods by which personality is assessed. Based on a review of selected empirical studies and analyses of new data, Burisch has concluded that (a) single-item global self-ratings generally yield greater coefficients of criterion validity than questionnaire measures of the same traits, and (b) most existing personality questionnaires can be shortened considerably without any consequent loss in validity. These conclusions stand in direct contrast to previous appeals by Epstein and others for the use of extensive aggregate measures of personality derived according to the axioms of psychometric theory. In response to Burisch, we describe measurement artifacts and strategies of test item selection that account for some of his conclusions and we reiterate the need for the application of conventional construct-based questionnaires in the assessment of personality.