The cerebellum and language: Evidence from patients with cerebellar degeneration

Clinical and imaging studies suggest that the cerebellum is involved in language tasks, but the extent to which slowed language production in cerebellar patients contributes to their poor performance on these tasks is not clear. We explored this relationship in 18 patients with cerebellar degeneration and 16 healthy controls who completed measures of verbal fluency (phonemic and semantic), word stem completion, and oral naming speed. Cerebellar patients showed significantly slower response times when naming common nouns, which correlated with their degree of motor impairment. Patients were significantly impaired on both phonemic and semantic fluency measures compared to controls (p < 0.001), even when naming speed was entered as a covariate (p = 0.03). On the word stem completion task, patients were significantly less accurate (p < 0.001), had more errors due to non-responses (p = 0.008), and were slower to respond (p = 0.036) than controls; group effects were significant for overall accuracy, but not response time, when the effects of naming speed were covaried (p = 0.014). These findings suggest that cerebellar patients’ poorer performance on language tasks cannot be explained solely by slower language production, and that the integrity of cerebellar-prefrontal loops might underlie poorer performance on measures of executive function in cerebellar patients.     

Infants' categorization of novel objects with more or less obvious features

In five experiments, 14- to 15-month-old infants' categorization of objects on the basis of more or less obvious features was investigated. Using an object examining paradigm, a total of 200 infants were familiarized with novel objects that shared either more obvious features (i.e., easily visible) or less obvious features (i.e., accessible by lifting a flap), followed by an in-category object and an out-of-category object. When only perceptual information was available, infants formed a category on the basis of the more obvious features but not on the basis of the less obvious features (Experiments 1 and 3). When infants were provided with animacy cues and/or object names, they formed categories on the basis of either more or less obvious features (Experiments 2, 4, and 5). The results of these studies delineate the role of animacy cues and object names in establishing categories on the basis of less obvious features.     

Consistent (but not variable) names as invitations to form object categories: new evidence from 12-month-old infants

Recent research documents that for infants just beginning to produce words on their own, novel words highlight commonalities among named objects and, in this way, serve as invitations to form categories. The current experiment identifies more precisely the source of this invitation. We asked whether applying a consistent name to a set of distinct objects is crucial to categorization, or whether variable names might serve the same conceptual function. The evidence suggests that for 12-month-old infants, consistency in naming is critical. Infants hearing a single consistent novel noun for a set of distinct objects successfully formed object categories. Infants hearing different novel nouns for the same set of objects did not. These results lend strength and greater precision to the argument that naming has powerful and rather nuanced conceptual consequences for infants as well as for mature speakers.     

图画与中、英文字词识别加工的比较

通过对不同材料进行加工的比较来探讨人脑的信息加工机制是认知心理学采用的主要研究方法之一。本研究采用了两个实验。实验一比较了图画、中文和英文字词在命名和分类任务中的差异。结果发现:中文是介于图画和英文之间的一种符号系统,在命名任务中,英文反应最快,图画反应最慢,中文居中;而在分类任务中,反应的快慢趋势却截然相反。实验二进一步探讨了言语及非言语信息的表征结构及加工特性,使用了图-图、图-字、字-图、字-字此四种组合材料进行命名一致性和语义分类两种任务,结果发现:字特征组(字-字,字-图)在命名一致性判断任务中的反应优于图特征组(图-图、图-字),而在语义一致性判断任务中则相反,这一结果很难用双编码理论和共同编码理论来解释。语词信息对语音码的接通是直接的,而对语义码的接通却是间接的,图画信息反之,而且由于某种策略产生了图特征组与字特征组的区别。     

Searching for the Right Word: Performance on Four Word-Retrieval Tasks Across Childhood

Word retrieval was assessed in 207 normally developing Hebrew-speaking children aged 8–17 through four tasks: picture naming, phonemic fluency, semantic fluency, and homophone meaning generation (HMGT). Scores on all tests correlated positively and significantly with participant age. Yet, age effects and the correlation between age and test scores were weakest for the naming test and strongest for the HMGT. We discuss the nature of the word search involved in each task and suggest that the more executive demands required by a test the steeper the slope of performance increase on this test.     

Task choice and semantic interference in picture naming

Evidence from dual-task performance indicates that speakers prefer not to select simultaneous responses in picture naming and another unrelated task, suggesting a response selection bottleneck in naming. In particular, when participants respond to tones with a manual response and name pictures with superimposed semantically related or unrelated distractor words, semantic interference in naming tends to be constant across stimulus onset asynchronies (SOAs) between the tone stimulus and the picture–word stimulus. In the present study, we examine whether semantic interference in picture naming depends on SOA in case of a task choice (naming the picture vs reading the word of a picture–word stimulus) based on tones. This situation requires concurrent processing of the tone stimulus and the picture–word stimulus, but not a manual response to the tones. On each trial, participants either named a picture or read aloud a word depending on the pitch of a tone, which was presented simultaneously with picture–word onset or 350 ms or 1000 ms before picture–word onset. Semantic interference was present with tone pre-exposure, but absent when tone and picture-word stimulus were presented simultaneously. Against the background of the available studies, these results support an account according to which speakers tend to avoid concurrent response selection, but can engage in other types of concurrent processing, such as task choices.     

Separating value from selection frequency in rapid reaching biases to visual targets

Stimuli associated with positive rewards in one task often receive preferential processing in a subsequent task, even when those associations are no longer relevant. Here we use a rapid reaching task to investigate these biases. In Experiment 1 we first replicated the learning procedure of Raymond and O'Brien (2009), for a set of arbitrary shapes that varied in value (positive, negative) and probability (20%, 80%). In a subsequent task, participants rapidly reached toward one of two shapes, except now the previously learned associations were irrelevant. As in the previous studies, we found significant reach biases toward shapes previously associated with a high probable, positive outcome. Unexpectedly, we also found a bias toward shapes previously associated with a low probable, negative outcome. Closer inspection of the learning task revealed a potential second factor that might account for these results; since a low probable negative shape was always paired with a high probable negative shape, it was selected with disproportionate frequency. To assess how selection frequency and reward value might both contribute to reaching biases we performed a second experiment. The results of this experiment at a group level replicated the reach-bias toward positively rewarding stimuli, but also revealed a separate bias toward stimuli that had been more frequently selected. At the level of individual participants, we observed a variety of preference profiles, with some participants biased primarily by reward value, others by frequency, and a few actually biased away from both highly rewarding and high frequency targets. These findings highlight that: (1) rapid reaching provides a sensitive readout of preferential processing; (2) target reward value and target selection frequency are separate sources of bias; and (3) group-level analyses in complex decision-making tasks can obscure important and varied individual differences in preference profiles.     

Consciousness wanted,attention found: Reasons for the advantage of the left visual field in identifying T2 among rapidly presented series

Everyday experience suggests that people are equally aware of events in both hemi-fields. However, when two streams of stimuli are rapidly presented left and right containing two targets, the second target is better identified in the left than in the right visual field.This might be considered evidence for a right-hemisphere advantage in generating conscious percepts. However, this putative asymmetry of conscious perception cannot be measured independently of participants’ access to their conscious percepts, and there is actually evidence from split-brain patients for the reverse, left-hemisphere advantage in having access to conscious percepts. Several other topics were studied in search of the responsible mechanism, among others: Mutual inhibition of hemispheres, cooperation of hemispheres in perceiving midline stimuli, and asymmetries in processing various perceptual inputs. Directing attention by salient cues turned out to be one of the few mechanisms capable of modifying the left visual-field advantage in this paradigm. Thus, this left visual-field advantage is best explained by the notion of a right-hemisphere advantage in directing attention to salient events. Dovetailing with the pathological asymmetries of attention after right-hemisphere lesions and with asymmetries of brain activation when healthy participants shift their attention, the present results extend that body of evidence by demonstrating unusually large and reliable behavioral asymmetries for attention-directing processes in healthy participants.     

Cognitive and emotional processes during dreaming: a neuroimaging view

Dream is a state of consciousness characterized by internally-generated sensory, cognitive and emotional experiences occurring during sleep. Dream reports tend to be particularly abundant, with complex, emotional, and perceptually vivid experiences after awakenings from rapid eye movement (REM) sleep. This is why our current knowledge of the cerebral correlates of dreaming, mainly derives from studies of REM sleep. Neuroimaging results show that REM sleep is characterized by a specific pattern of regional brain activity. We demonstrate that this heterogeneous distribution of brain activity during sleep explains many typical features in dreams. Reciprocally, specific dream characteristics suggest the activation of selective brain regions during sleep. Such an integration of neuroimaging data of human sleep, mental imagery, and the content of dreams is critical for current models of dreaming; it also provides neurobiological support for an implication of sleep and dreaming in some important functions such as emotional regulation.     

Rapid word learning in 13- and 17-month-olds in a naturalistic two-word procedure: looking versus reaching measures

This study investigated infants’ rapid learning of two novel words using a preferential looking measure compared with a preferential reaching measure. In Experiment 1, 21 13-month-olds and 20 17-month-olds were given 12 novel label exposures (6 per trial) for each of two novel objects. Next, in the label comprehension tests, infants were shown both objects and were asked, “Where’s the [label]?” (looking preference) and then told, “Put the [label] in the basket” (reaching preference). Only the 13-month-olds showed rapid word learning on the looking measure; neither age group showed rapid word learning on the reaching measure. In Experiment 2, the procedure was repeated 24 h later with 10 participants per age group from Experiment 1. After a further 12 labels per object, both age groups now showed robust evidence of rapid word learning, but again only on the looking measure. This is the earliest looking-based evidence of rapid word learning in infants in a well-controlled (i.e., two-word) procedure; our failure to replicate previous reports of rapid word learning in 13-month-olds with a preferential reaching measure may be due to our use of more rigorous controls for object preferences. The superior performance of the younger infants on the looking measure in Experiment 1 was not straightforwardly predicted by existing theoretical accounts of word learning.