A functional near-infrared spectroscopy study of sustained attention to local and global target features

Despite a long history of vigilance research, the role of global and local feature discrimination in vigilance tasks has been relatively neglected. In this experiment participants performed a sustained attention task requiring either global or local shape stimuli discrimination. Reaction time to local feature discriminations was characterized by a quadratic trend over time-on-task with performance levels returning to initial levels late in the task. This trend did not occur in the global shape discrimination task. Functional near-infrared spectroscopy (fNIRS) was utilized in this study as an index of cerebral activation. In both tasks there was increased right hemisphere relative to left hemisphere oxygenation and right hemisphere oxygenation increased with time-on-task. Left hemisphere oxygenation, however, decreased slightly in the global task, but increased significantly in the local task as task duration increased. Indeed, total oxygenation, averaging both right and left, increased more with time-on-task in the local discrimination task. Both the performance and physiological results of this study indicate increased utilization of bilateral cerebral resources with time-on-task in the local, but not the global discrimination vigil.     

Attractiveness as a Function of Skin Tone and Facial Features: Evidence from Categorization Studies

Participants rated the attractiveness and racial typicality of male faces varying in their facial features from Afrocentric to Eurocentric and in skin tone from dark to light in two experiments. Experiment 1 provided evidence that facial features and skin tone have an interactive effect on perceptions of attractiveness and mixed-race faces are perceived as more attractive than single-race faces. Experiment 2 further confirmed that faces with medium levels of skin tone and facial features are perceived as more attractive than faces with extreme levels of these factors. Black phenotypes (combinations of dark skin tone and Afrocentric facial features) were rated as more attractive than White phenotypes (combinations of light skin tone and Eurocentric facial features); ambiguous faces (combinations of Afrocentric and Eurocentric physiognomy) with medium levels of skin tone were rated as the most attractive in Experiment 2. Perceptions of attractiveness were relatively independent of racial categorization in both experiments.     

Improving Identity Matching of Newly Encountered Faces: Effects of Multi-image Training

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Immediate and long-term priming effects are independent of prime awareness

Subliminal primes are assumed to produce weaker and short-lived effects on subsequent behavior compared to clearly visible primes. However, this difference in priming effect may be due to differences in signal strength, rather than level of awareness. In the present study we manipulated prime discriminability by using metacontrast masks and pseudomasks, while keeping the prime strength equal. This manipulation resulted in large differences in discriminability of the primes. However, both immediate response priming and long-term response priming (measured with conflict adaptation) was equal for the poorly discriminable and well discriminable primes, and equal for groups that differed markedly in terms of how well they could discriminate the primes. Our findings imply that discriminability of information is independent of both the immediate and long-term effects that information can have on behavior.     

阿尔兹海默病患者中的范畴特异性语义记忆损伤

脑损伤可导致范畴特异性语义损伤, 即某一范畴的语义记忆选择性损伤或损伤更严重。阿尔兹海默病患者中的范畴特异性语义损伤可能来自不同范畴之间在熟悉度、词频、获得年龄、视觉复杂度、语义距离、加工要求以及所涉及的主要语义特征等方面的差别。然而, 有无生命范畴本身是否也是一个来源, 尚不清楚。进一步的研究不仅需要整合范畴途径和特征途径, 并区分语义记忆的存储和通达, 而且需要考查疾病严重程度如何影响语义记忆损伤模式。     

Verb aspect and perceptual simulations

Two experiments investigate the influence of verb aspect on situation representations. The results demonstrate that comprehenders use verb aspect as a cue to regulate the activation of ongoing simulations of situations over time. Experiment 1 measured word-by-word reading as well as sensibility judgements on sentences in which a target object word had been replaced by a picture. For the past imperfective sentences, participants were faster to process the picture, the two words following the picture, and the sensibility judgements when objects were pictured in use rather than not in use. However, this in-use facilitation was limited to processing of the picture for the past perfect sentences. Experiment 2 served as a control to ensure that the use effect and its interaction with verb aspect were a result of contextual manipulations rather than surface features of the pictures themselves. The results are interpreted within the framework of perceptual simulations during language comprehension.     

Integration of perceptual information in word access

According to experiential theories of language comprehension, perceptual information plays an essential role when word meanings are accessed. We conducted four experiments to investigate how different types of perceptual information such as colour and shape are combined during word access. One possibility is that the colour and shape of a word's referent are activated independently from one another and are combined in an additive manner. Alternatively, words might activate perceptual representations via a multiplicative integration of colour and shape. Experiment 1 established that participants follow a multiplicative similarity rule when they judge the similarity of schematic pictures to actual fruits and vegetables. In Experiments 2 to 4, participants performed a classification task, a lexical decision task, or a word-naming task on names of fruits and vegetables that were superimposed on a background picture. Responses were facilitated only when both colour and shape of the picture matched the word's referents. Response times were associated negatively with mean similarity ratings and the consistency of these ratings obtained in the first experiment. These results suggest a multiplicative integration of different types of perceptual information during word access.     

Inhibition of evaluative and perceptual odour–taste learning by attention to the stimulus elements

Pairing of odours and tastes in solution results in the odour taking on the taste's hedonic and perceptual properties. Theoretical accounts of such conditioning propose that the stimulus elements form a configuration with hedonic and/or perceptual properties. One implication of this account is that configural binding may be inhibited by allocation of attention to the individual elements during conditioning (analytical attention). This was tested here by training participants to attend analytically or synthetically during pairing of odours with either sucrose or water. Differential conditioning effects for sucrose- and water-paired odours were seen only in the synthetic group, with sucrose-paired odours increasing in both smelled sweetness and liking. These data support configural models as explanations for these forms of associative learning and emphasize the role of top-down processes in mediating transfer of perceptual and hedonic properties from tastes to odours.     

Temporal preparation decreases perceptual latency: Evidence from a clock paradigm

A clock paradigm was employed to assess whether temporal preparation decreases the time to detect the onset of a stimulus—that is, perceptual latency. In four experiments participants watched a revolving clock hand while listening to soft or loud target tones under high or low temporal preparation. At the end of each trial, participants reported the clock hand position at the onset of the target tone. The deviation of the reported clock hand position from the actual position indexed perceptual latency. As expected, perceptual latency decreased with target tone intensity. Most importantly, however, greater temporal preparation decreased perceptual latency in all four experiments, especially for soft tones, which supports rather directly the idea that temporal preparation diminishes the duration of perceptual processing.     

The role of perceptual salience during the segmentation of connected speech

Statistical learning allows listeners to track transitional probabilities among syllable sequences and use these probabilities for subsequent speech segmentation. Recent studies have shown that other sources of information, such as rhythmic cues, can modulate the dependencies extracted via statistical computation. In this study, we explored how syllables made salient by a pitch rise affect the segmentation of trisyllabic words from an artificial speech stream by native speakers of three different languages (Spanish, English, and French). Results showed that, whereas performance of French participants did not significantly vary across stress positions (likely due to language-specific rhythmic characteristics), the segmentation performance of Spanish and English listeners was unaltered when syllables in word-initial and word-final positions were salient, but it dropped to chance level when salience was on the medial syllable. We argue that pitch rise in word-medial syllables draws attentional resources away from word boundaries, thus decreasing segmentation effectiveness.