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perceptual categorization

Germán Mendoza, Juan Carlos Méndez, Oswaldo Pérez, Luis Prado, Hugo Merchant
Perceptual categorization depends on the assignment of different stimuli to specific groups based, in principle, on the notion of flexible categorical boundaries. To determine the neural basis of categorical boundaries, we record the activity of pre-SMA neurons of monkeys executing an interval categorization task in which the limit between short and long categories changes between blocks of trials within a session. A large population of cells encodes this boundary by reaching a constant peak of activity close to the corresponding subjective limit...
March 15, 2018: Nature Communications
Onur Güntürkün, Charlotte Koenen, Fabrizio Iovine, Alexis Garland, Roland Pusch
We are surrounded by an endless variation of objects. The ability to categorize these objects represents a core cognitive competence of humans and possibly all vertebrates. Research on category learning in nonhuman animals started with the seminal studies of Richard Herrnstein on the category "human" in pigeons. Since then, we have learned that pigeons are able to categorize a large number of stimulus sets, ranging from Cubist paintings to English orthography. Strangely, this prolific field has largely neglected to also study the avian neurobiology of categorization...
March 12, 2018: Learning & Behavior
Mikko Lähteenmäki, Jaakko Kauramäki, Disa A Sauter, Lauri Nummenmaa
Recent work has challenged the previously widely accepted belief that affective processing does not require awareness and can be carried out with more limited resources than semantic processing. This debate has focused exclusively on visual perception, even though evidence from both human and animal studies suggests that existence for nonconscious affective processing would be physiologically more feasible in the auditory system. Here we contrast affective and semantic processing of nonverbal emotional vocalizations under different levels of awareness in three experiments, using explicit (two-alternative forced choice masked affective and semantic categorization tasks, Experiments 1 and 2) and implicit (masked affective and semantic priming, Experiment 3) measures...
March 5, 2018: Emotion
Xiaoqing Gao, Francesco Gentile, Bruno Rossion
Defining the neural basis of perceptual categorization in a rapidly changing natural environment with low-temporal resolution methods such as functional magnetic resonance imaging (fMRI) is challenging. Here, we present a novel fast periodic stimulation (FPS)-fMRI approach to define face-selective brain regions with natural images. Human observers are presented with a dynamic stream of widely variable natural object images alternating at a fast rate (6 images/s). Every 9 s, a short burst of variable face images contrasting with object images in pairs induces an objective face-selective neural response at 0...
March 3, 2018: Brain Structure & Function
Andrey Anikin, Rasmus Bååth, Tomas Persson
Recent research on human nonverbal vocalizations has led to considerable progress in our understanding of vocal communication of emotion. However, in contrast to studies of animal vocalizations, this research has focused mainly on the emotional interpretation of such signals. The repertoire of human nonverbal vocalizations as acoustic types, and the mapping between acoustic and emotional categories, thus remain underexplored. In a cross-linguistic naming task (Experiment 1), verbal categorization of 132 authentic (non-acted) human vocalizations by English-, Swedish- and Russian-speaking participants revealed the same major acoustic types: laugh, cry, scream, moan, and possibly roar and sigh...
2018: Journal of Nonverbal Behavior
Kun Guo, Yoshi Soornack, Rebecca Settle
Our capability of recognizing facial expressions of emotion under different viewing conditions implies the existence of an invariant expression representation. As natural visual signals are often distorted and our perceptual strategy changes with external noise level, it is essential to understand how expression perception is susceptible to face distortion and whether the same facial cues are used to process high- and low-quality face images. We systematically manipulated face image resolution (experiment 1) and blur (experiment 2), and measured participants' expression categorization accuracy, perceived expression intensity and associated gaze patterns...
February 26, 2018: Vision Research
Christian E Stilp, Ashley A Assgari
Speech perception is heavily influenced by surrounding sounds. When spectral properties differ between earlier (context) and later (target) sounds, this can produce spectral contrast effects (SCEs) that bias perception of later sounds. For example, when context sounds have more energy in low-F1 frequency regions, listeners report more high-F1 responses to a target vowel, and vice versa. SCEs have been reported using various approaches for a wide range of stimuli, but most often, large spectral peaks were added to the context to bias speech categorization...
February 28, 2018: Attention, Perception & Psychophysics
Lisbeth Van Ruijssevelt, Yining Chen, Kaya von Eugen, Julie Hamaide, Geert De Groof, Marleen Verhoye, Onur Güntürkün, Sarah C Woolley, Annemie Van der Linden
Selection of sexual partners is among the most critical decisions that individuals make and is therefore strongly shaped by evolution. In social species, where communication signals can convey substantial information about the identity, state, or quality of the signaler, accurate interpretation of communication signals for mate choice is crucial. Despite the importance of social information processing, to date, relatively little is known about the neurobiological mechanisms that contribute to sexual decision making and preferences...
February 21, 2018: Current Biology: CB
Katherine Kimura, Samuel B Hunley, Laura L Namy
Although young children often rely on salient perceptual cues, such as shape, when categorizing novel objects, children eventually shift towards deeper relational reasoning about category membership. This study investigates what information young children use to classify novel instances of familiar categories. Specifically, we investigated two sources of information that have the potential to facilitate the classification of novel exemplars: (1) comparison of familiar category instances, and (2) attention to function information that might direct children's attention to functionally relevant perceptual features...
February 21, 2018: Journal of Experimental Child Psychology
Mark Vergeer, Naoki Kogo, Andrey R Nikolaev, Nihan Alp, Veerle Loozen, Brenda Schraepen, Johan Wagemans
Shape perception is intrinsically holistic: combinations of features give rise to configurations with emergent properties that are different from the sum of the parts. The current study investigated neural markers of holistic shape representations learned by means of categorization training. We used the EEG frequency tagging technique, where two parts of a shape stimulus were 'tagged' by modifying their contrast at different temporal frequencies. Signals from both parts are integrated and, as a result, emergent frequency components (so-called, intermodulation responses, IMs), caused by nonlinear interaction of two frequency signals, are observed in the EEG spectrum...
February 20, 2018: Vision Research
Bianca Thorup, Kate Crookes, Paul P W Chang, Nichola Burton, Stephen Pond, Tze Kwan Li, Janet Hsiao, Gillian Rhodes
People are better at recognizing own-race than other-race faces. This other-race effect has been argued to be the result of perceptual expertise, whereby face-specific perceptual mechanisms are tuned through experience. We designed new tasks to determine whether other-race effects extend to categorizing faces by national origin. We began by selecting sets of face stimuli for these tasks that are typical in appearance for each of six nations (three Caucasian, three Asian) according to people from those nations (Study 1)...
February 23, 2018: British Journal of Psychology
Valentina Proietti, Sarah Laurence, Claire M Matthew, Xiaomei Zhou, Catherine J Mondloch
Adults' ability to recognize individual faces is shaped by experience. Young adults recognize own-age and own-race faces more accurately than other-age and other-race faces. The own-age and own-race biases have been attributed to differential perceptual experience and to differences in how in-group vs. out-group faces are processed, with in-group faces being processed at the individual level and out-group faces being processed at the categorical level. To examine this social categorization hypothesis, young adults studied young and older faces in Experiment 1 and own- and other-race faces in Experiment 2...
February 15, 2018: Vision Research
Steven Samuel, Emanuel Bylund, Rachel Cooper, Panos Athanasopoulos
Walsh's A Theory Of Magnitude (ATOM) contends that we represent magnitudes such as number, space, time and luminance on a shared metric, such that "more" of one leads to the perception of "more" of the other (e.g. Walsh, 2003). In support of ATOM, participants have been shown to judge intervals between stimuli that are more discrepant in luminance as having a longer duration than intervals between stimuli whose luminance differs by a smaller degree (Xuan, Zhang, He, & Chen, 2007). We tested the potential limits to the ability of luminance to influence duration perception by investigating the possibility that the luminance-duration relationship might be interrupted by a concurrent change in the colour of that luminance...
February 13, 2018: Acta Psychologica
Ja Young Choi, Elly R Hu, Tyler K Perrachione
The nondeterministic relationship between speech acoustics and abstract phonemic representations imposes a challenge for listeners to maintain perceptual constancy despite the highly variable acoustic realization of speech. Talker normalization facilitates speech processing by reducing the degrees of freedom for mapping between encountered speech and phonemic representations. While this process has been proposed to facilitate the perception of ambiguous speech sounds, it is currently unknown whether talker normalization is affected by the degree of potential ambiguity in acoustic-phonemic mapping...
February 7, 2018: Attention, Perception & Psychophysics
Sharon Cameron, Nicky Chong-White, Kiri Mealings, Tim Beechey, Harvey Dillon, Taegan Young
BACKGROUND: Previous research suggests that a proportion of children experiencing reading and listening difficulties may have an underlying primary deficit in the way that the central auditory nervous system analyses the perceptually important, rapidly varying, formant frequency components of speech. PURPOSE: The Phoneme Identification Test (PIT) was developed to investigate the ability of children to use spectro-temporal cues to perceptually categorize speech sounds based on their rapidly changing formant frequencies...
February 2018: Journal of the American Academy of Audiology
Kristina Küper, Hubert D Zimmer
It is still unclear which role the right hemisphere (RH) preference for perceptually specific and the left hemisphere (LH) bias towards abstract memory representations play at the level of episodic memory retrieval. When stimulus characteristics hampered the retrieval of abstract memory representations, these hemispheric asymmetries have previously only modulated event-related potential (ERP) correlates of recollection (late positive complex, LPC), but not of familiarity (FN400). In the present experiment, we used stimuli which facilitated the retrieval of abstract memory representations...
January 19, 2018: Brain and Cognition
Rachel G Stephens, Michael L Kalish
Delayed feedback during categorization training has been hypothesized to differentially affect 2 systems that underlie learning for rule-based (RB) or information-integration (II) structures. We tested an alternative possibility: that II learning requires more precise item representations than RB learning, and so is harmed more by a delay interval filled with a confusable mask. Experiments 1 and 2 examined the effect of feedback delay on memory for RB and II exemplars, both without and with concurrent categorization training...
February 1, 2018: Journal of Experimental Psychology. Learning, Memory, and Cognition
Angela Mahr, Dirk Wentura
Findings from three experiments support the conclusion that semantic auditory primes facilitate processing of complex warning icons in the automotive context. In Experiment 1, we used a cross-modal icon identification task with auditory primes and visual icons as targets, presented in a high perceptual load context. Responses were faster for congruent priming in comparison to neutral or incongruent priming. This effect also emerged for different levels of time-compression of auditory primes. In Experiment 2, participants took part in a driving simulation with target icons on a gantry road sign...
February 1, 2018: Journal of Experimental Psychology. Applied
Anke Braun, Anne E Urai, Tobias H Donner
Perceptual decision-making is biased by previous events, including the history of preceding choices: Observers tend to repeat (or alternate) their judgments of the sensory environment more often than expected by chance. Computational models postulate that these so-called choice history biases result from the accumulation of internal decision signals across trials. Here, we provide psychophysical evidence for such a mechanism and its adaptive utility. Male and female human observers performed different variants of a challenging visual motion discrimination task near psychophysical threshold...
January 25, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Duncan A Wilson, Masaki Tomonaga
Many primate studies have investigated discrimination of individual faces within the same species. However, few studies have looked at discrimination between primate species faces at the categorical level. This study systematically examined the factors important for visual discrimination between primate species faces in chimpanzees, including: colour, orientation, familiarity, and perceptual similarity. Five adult female chimpanzees were tested on their ability to discriminate identical and categorical (non-identical) images of different primate species faces in a series of touchscreen matching-to-sample experiments...
January 23, 2018: Primates; Journal of Primatology
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