Age-of-acquisition effects in semantic processing tasks

In two experiments, we examined whether word age-of-acquisition (AoA) is a reliable predictor of processing times in semantic tasks. In the first task, participants were asked to say the first associate that came to mind when they saw a stimulus word; the second task involved a semantic categorisation between words with a definable meaning and first names. In both tasks, there were significantly faster responses to earlier-acquired than to later-acquired words. On the basis of these results, we argue that age-of-acquisition effects do not originate solely from the speech output system, but from the semantic system as well.     

The dependence of semantic relatedness effects upon prime processing

The semantic relationship between a prime and a target word has been shown to affect the speed at which the target word is processed. This series of experiments investigated how the semantic priming effect is influenced by the nature of the task performed on the prime word. Subjects were asked to perform either a naming or a letter-search task on the prime word and either a lexical-decision or color-naming task on the target word. When the primes were named, response times for the target words were facilitated in the lexical-decision task and inhibited in the color-naming task. However, these effects were eliminated or reduced to an insignificant level when the primes were searched for letters. We suggest that in order to produce the usual priming effect, the primes have to be processed for meaning rather than probed for constituents.     

The effects of perceptual load on semantic processing under inattention

Inattentional blindness refers to a failure to consciously detect an irrelevant object that appears without any expectation when attention is engaged with another task. The perceptual load theory predicts that task-irrelevant stimuli will reach awareness only when the primary task is of low load, which allows processing resources to spill over to processing task-irrelevant stimuli as well. We studied whether perceptual load has an effect on inattentional blindness for a task-irrelevant stimulus whose meaning is or is not relevant to the attentional goals of the observer. In the critical trial, a word appeared without any expectation in the center of a display of attended pictures. The results showed that, under both high and low load, unexpected words belonging to the attended semantic category were detected more often than semantically unrelated words. These results imply that task-irrelevant stimuli, whose meanings are relevant to the observer’s task, enter awareness irrespective of perceptual load.     

Age of acquisition effects in the semantic processing of pictures

In two experiments, we investigated the role of age of acquisition (AoA) in the categorizing of objects in semantic tasks that do not require access to the object names. In both a found inside or outside the house (Experiment 1A) and a smaller or larger than a loaf of bread (Experiment 2A) classification task, objects with earlier-acquired names were categorized more quickly than those with later-acquired names. Experiments 1B and 2B also showed AoA effects on object-naming times for the same pictures. We conclude that AoA operates within the identification process in a fashion not simply restricted to name retrieval. These effects may be better explained in terms of the connectionist model proposed by Ellis and Lambon Ralph (2000) or by accounts that locate AoA within the semantic system (e.g., Brysbaert, Van Wijnendaele, & De Deyne, 2000; van Loon-Vervoorn, 1989).     

Emotional speech processing: disentangling the effects of prosody and semantic cues

To inform how emotions in speech are implicitly processed and registered in memory, we compared how emotional prosody, emotional semantics, and both cues in tandem prime decisions about conjoined emotional faces. Fifty-two participants rendered facial affect decisions (Pell, 2005a), indicating whether a target face represented an emotion (happiness or sadness) or not (a facial grimace), after passively listening to happy, sad, or neutral prime utterances. Emotional information from primes was conveyed by: (1) prosody only; (2) semantic cues only; or (3) combined prosody and semantic cues. Results indicated that prosody, semantics, and combined prosody-semantic cues facilitate emotional decisions about target faces in an emotion-congruent manner. However, the magnitude of priming did not vary across tasks. Our findings highlight that emotional meanings of prosody and semantic cues are systematically registered during speech processing, but with similar effects on associative knowledge about emotions, which is presumably shared by prosody, semantics, and faces.     

Emotional speech processing: Disentangling the effects of prosody and semantic cues

To inform how emotions in speech are implicitly processed and registered in memory, we compared how emotional prosody, emotional semantics, and both cues in tandem prime decisions about conjoined emotional faces. Fifty-two participants rendered facial affect decisions (Pell, 2005a), indicating whether a target face represented an emotion (happiness or sadness) or not (a facial grimace), after passively listening to happy, sad, or neutral prime utterances. Emotional information from primes was conveyed by: (1) prosody only; (2) semantic cues only; or (3) combined prosody and semantic cues. Results indicated that prosody, semantics, and combined prosody–semantic cues facilitate emotional decisions about target faces in an emotion-congruent manner. However, the magnitude of priming did not vary across tasks. Our findings highlight that emotional meanings of prosody and semantic cues are systematically registered during speech processing, but with similar effects on associative knowledge about emotions, which is presumably shared by prosody, semantics, and faces.     

Opposite ERP effects for conscious and unconscious semantic processing under continuous flash suppression

We examined whether semantic processing occurs without awareness using continuous flash suppression (CFS). In two priming tasks, participants were required to judge whether a target was a word or a non-word, and to report whether the masked prime was visible. Experiment 1 manipulated the lexical congruency between the prime-target pairs and Experiment 2 manipulated their semantic relatedness. Despite the absence of behavioral priming effects (Experiment 1), the ERP results revealed that an N4 component was sensitive to the prime-target lexical congruency (Experiment 1) and semantic relatedness (Experiment 2) when the prime was rendered invisible under CFS. However, these results were reversed with respect to those that emerged when the stimuli were perceived consciously. Our findings suggest that some form of lexical and semantic processing can occur during CFS-induced unawareness, but are associated with different electrophysiological outcomes.     

Differential interference effects of negative emotional states on subsequent semantic and perceptual processing

Past studies have revealed that encountering negative events interferes with cognitive processing of subsequent stimuli. The present study investigates whether negative events affect semantic and perceptual processing differently. Presentation of negative pictures produced slower reaction times than neutral or positive pictures in tasks that require semantic processing, such as natural or man-made judgments about drawings of objects, commonness judgments about objects, and categorical judgments about pairs of words. In contrast, negative picture presentation did not slow down judgments in subsequent perceptual processing (e.g., color judgments about words, size judgments about objects). The subjective arousal level of negative pictures did not modulate the interference effects on semantic or perceptual processing. These findings indicate that encountering negative emotional events interferes with semantic processing of subsequent stimuli more strongly than perceptual processing, and that not all types of subsequent cognitive processing are impaired by negative events.     

The effects of different types of noise on semantic processing and syntactic reasoning

The results of four experiments showed that there was no effect of continuous noise on semantic processing and syntactic reasoning tests. However, performance on both tests was impaired when conglomerate noise, consisting of typewriting, music and unattended speech was played. It is suggested that this represents a distraction effect similar to those already reported in the literature, and this result also emphasises the importance of considering the effects of meaningful noise rather than just examining white noise of different intensities. Performance on the semantic processing test was impaired by intermittent, unpredictable noise, but this noise had no effect on the syntactic reasoning test. Possible reasons for the different effects of the intermittent noise on the two tests are put forward.     

义符的类别一致性和家族大小影响形声字的语义加工

采用行为实验和眼动技术考察义符的类别一致性和家族大小对形声字语义加工的影响。结果发现：(1) 在一致性判断和视觉选择中均存在着字词水平的类别一致性效应, 义符同整字类别一致的字容易认知。(2) 义符的家族大小影响形声字的语义加工, 义符家族大, 汉语母语者对形声字的加工更容易采用形旁推理策略。(3) 义符家族的类别一致性影响形声字的语义加工。(4) 义符家族的类别一致性和家族大小效应受义符与整字的类别一致性调节。     

Psychopathy and cerebral asymmetry in semantic processing

A divided visual field (DVF) procedure was used to investigate the cerebral organization of language processes in psychopaths. The subjects consisted of four groups of 13 right-handed males: noncriminals (NC), and criminals with high (H), medium (M), and low (L) scores on the Psychopathy Checklist (Hare, 1980). The subject had to decide if a concrete noun, tachistoscopically presented in either the left (LVF) or the right visual hemifield (RVF), matched a pretrial work (SR task), or was an exemplar of a specific category (SC task) or an abstract category (AC task). There were no group differences in reaction time. As predicted, group differences in errors were confined to the AC task; Groups L and NC made fewer RVF than LVF errors (thus showing the sort of RVF advantage expected with semantic categorization), whereas the opposite was true of Group H. The results, along with those obtained in a recent dichotic listening study, lead us to speculate that psychopathy may be associated with weak or unusual lateralization of language function, and that psychopaths may have fewer left hemisphere resources for processing language than do normal individuals.     

Congruity effects evoked by subliminally presented primes: automaticity rather than semantic processing

In a size judgment task on words denoting concrete objects, subliminally presented stimuli that preceded the targets influenced response times and were dependent on whether responses to the prime and the target were congruent or incongruent (Experiment 1). These findings, mirroring S. Dehaene et al. (1998), imply that primes are unconsciously categorized and processed to the response stage. However, the effect does not generalize to primes that are not in the response set (Experiment 2), and even exposure to primes not in the response set in an interleaved naming-size judgment task fails to induce it (Experiment 3). However, the effect generalizes from lowercase primes to the same set of uppercase targets (Experiment 4), suggesting an abstract level of operation. The findings suggest that rather than resulting from unconscious prime categorization, the congruity effect results from automatized stimulus-response mappings. Potential differences between the number and the word domain are discussed.     

A connectivity model for semantic processing

Summary A connectivity model for semantic processing, based on two major assumptions, is proposed and tested. The representation assumption states that semantically related features are represented by an interconnected structure of features. A network is termed interconnected if each node is linked to at least two other nodes. According to the processing assumption, indirect activation becomes increasingly effective as the number of interconnected nodes increases. The connectivity model thus predicts that more complex concepts will be processed faster than less complex concepts. Experiment 1 was performed to determine the number of features for a set of 72 words and to show that subordinate concepts share common features with their natural superordinate concept. In Experiments 2 and 3 subjects had to judge whether or not a word belonged to a previously defined natural superordinate concept. The results confirm the connectivity model and show that concepts with many features can be classified faster than concepts with only a few features.This research was supported by a Grant of the Max Kade Foundation     

Automatic and volitional semantic processing in aphasia.

The present study investigated the status of semantic information in aphasia by comparing the performances of aphasic and nonaphasic subjects on two tasks: an automatic semantic facilitation task and a volitional task of relatedness judgment. Both the aphasic and nonaphasic groups evidenced a semantic facilitation effect, in an on-line task of semantic processing. However, those aphasics with severe comprehension and naming disturbances (termed low comprehension aphasics) demonstrated considerable difficulty in judging the relatedness between a pictured object and members of that object's semantic field, the severity of the impairment being greater for those pictures that the low comprehension aphasics were unable to name. The pattern of results can best be explained by supposing the structural integrity of the store of semantic information in aphasia, and in particular in low comprehension aphasia: information that is retrieved and manipulated in judgment-mediated tasks with considerable difficulty.     

The role of verb argument structure in sentence processing: Distinguishing between syntactic and semantic effects

This paper describes an ongoing research program designed to investigate how syntactic and semantic aspects of lexical information become available to the sentence processing system. The two experiments described here distinguished between syntactic and semantic representations by using cross-modal naming and lexical decision in a new way. The relationship between the main verb and the probe word was varied such that the probe word met either the syntactic criteria to be an argument, the semantic criteria, neither, or both the syntactic and semantic criteria. Lexical decision times were sensitive to both syntactic and semantic congruity, while naming times were sensitive only to syntactic congruity. The two tasks were then used to investigate syntactic and semantic representations when verb argument structure was ambiguous. Subcategorized structures were constructed without regard for biasing context, but the contextually inappropriate thematic frame was ruled out while the inappropriate syntactic frame was still available.     

Activation states and semantic processing: A comparison of the effects of noise and time of day

Results from six experiments comparing the effects of noise and time of day on semantic processing led to the following conclusions. First, time of day influenced the speed of verification of semantic information. In contrast to this, noise had no effect on this task, nor did it change the diurnal variation associated with it. Second, studies of retrieval of category instances and of clustering in free recall confirmed that noise and time of day have different effects on other aspects of semantic processing. These results have strong implications for the development of the performance profiles associated with different activation states.     

Parafoveal semantic processing of emotional visual scenes

The authors investigated whether emotional pictorial stimuli are especially likely to be processed in parafoveal vision. Pairs of emotional and neutral visual scenes were presented parafoveally (2.1 degrees or 2.5 degrees of visual angle from a central fixation point) for 150-3,000 ms, followed by an immediate recognition test (500-ms delay). Results indicated that (a) the first fixation was more likely to be placed onto the emotional than the neutral scene; (b) recognition sensitivity (A') was generally higher for the emotional than for the neutral scene when the scenes were paired, but there were no differences when presented individually; and (c) the superior sensitivity for emotional scenes survived changes in size, color, and spatial orientation, but not in meaning. The data suggest that semantic analysis of emotional scenes can begin in parafoveal vision in advance of foveal fixation.     

Electrophysiological evidence of automatic early semantic processing

This study investigates the automatic-controlled nature of early semantic processing by means of the Recognition Potential (RP), an event-related potential response that reflects lexical selection processes. For this purpose tasks differing in their processing requirements were used. Half of the participants performed a physical task involving a lower-upper case discrimination judgement (shallow processing requirements), whereas the other half carried out a semantic task, consisting in detecting animal names (deep processing requirements). Stimuli were identical in the two tasks. Reaction time measures revealed that the physical task was easier to perform than the semantic task. However, RP effects elicited by the physical and semantic tasks did not differ in either latency, amplitude, or topographic distribution. Thus, the results from the present study suggest that early semantic processing is automatically triggered whenever a linguistic stimulus enters the language processor.     

Lateralization of object-shape information in semantic processing

An experiment was conducted to examine whether perceptual information, specifically the shape of objects, is activated during semantic processing. Subjects judged whether a target word was related to a prime word. Prime-target pairs that were not associated, but whose referents had similar shapes (e.g. LADDER-RAILROAD) yielded longer "no" responses than unassociated prime-target pairs, suggesting that shape information had been activated. A visual-field manipulation showed that, in right-handed subjects, this effect was localized in the left hemisphere. This finding is consistent with behavioral, brain imaging, and lesion data, which suggest that object shape at the category level is represented in the left hemisphere.