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Stimulus Features (stimulus + feature)
Selected AbstractsProlonged maturation of auditory perception and learning in gerbilsDEVELOPMENTAL NEUROBIOLOGY, Issue 9 2010Emma C. Sarro Abstract In humans, auditory perception reaches maturity over a broad age range, extending through adolescence. Despite this slow maturation, children are considered to be outstanding learners, suggesting that immature perceptual skills might actually be advantageous to improvement on an acoustic task as a result of training (perceptual learning). Previous non-human studies have not employed an identical task when comparing perceptual performance of young and mature subjects, making it difficult to assess learning. Here, we used an identical procedure on juvenile and adult gerbils to examine the perception of amplitude modulation (AM), a stimulus feature that is an important component of most natural sounds. On average, Adult animals could detect smaller fluctuations in amplitude (i.e., smaller modulation depths) than Juveniles, indicating immature perceptual skills in Juveniles. However, the population variance was much greater for Juveniles, a few animals displaying adult-like AM detection. To determine whether immature perceptual skills facilitated learning, we compared naïve performance on the AM detection task with the amount of improvement following additional training. The amount of improvement in Adults correlated with naïve performance: those with the poorest naïve performance improved the most. In contrast, the naïve performance of Juveniles did not predict the amount of learning. Those Juveniles with immature AM detection thresholds did not display greater learning than Adults. Furthermore, for several of the Juveniles with adult-like thresholds, AM detection deteriorated with repeated testing. Thus, immature perceptual skills in young animals were not associated with greater learning. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70: 636,648, 2010 [source] Behavioral discrimination of sexually dimorphic calls by male zebra finches requires an intact vocal motor pathwayDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2001David S. Vicario Abstract Vocal communication between zebra finches includes the exchange of long calls (LCs) as well as song. By using this natural call behavior and quantifying the LCs emitted in response to playbacks of LCs of other birds, we have previously shown that adult male zebra finches have a categorical preference for the LCs of females over those of males. Female LCs are acoustically simpler than male LCs, which include complex acoustic features that are learned during development. Production of these male-typical features requires an intact nucleus RA, the sexually dimorphic source of the main telencephalic projection to brainstem vocal effectors. We have now made bilateral lesions of RA in 17 adult males and tested their discrimination behavior in the call response situation. Lesioned birds continue to call, but lose the male-typical preference for female LCs. The degree of loss is correlated with the extent of RA damage. Further, the simplified LCs of males with RA lesions have a variable duration that is correlated with stimulus features. In effect, the call response behavior of lesioned males becomes like that of females. Apparently, in the absence of RA, the remaining intact structures receive different call information than RA normally does, and/or process it differently. This suggests that the vocal motor nucleus RA could play a role in the transformation of a signal encoding the salience of stimulus parameters into a control signal that modulates the probability and strength of responding. © 2001 John Wiley & Sons, Inc. J Neurobiol 47: 109,120, 2001 [source] The influence of perceived suffering and vulnerability on the experience of pityEUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 6 2001Anton J. Dijker Pity is viewed as a function of two classes of perceived stimulus features and their interaction: the extent to which a person (when still healthy and nonsuffering) is perceived as vulnerable to physical harm, and the perceived intensity of his or her current suffering. Consistent with this view, Experiment 1 (N,=,141) showed that participants' pity reactions to photographs of persons expressing pain were influenced by age-related, sex-related, and postural vulnerability cues. Experiment 2 (N,=,258) manipulated both target's vulnerability by varying the muscularity of the same adult male stimulus and the intensity of suffering. As predicted, an interaction of vulnerability and suffering was found. Implications for the study of helping behavior are discussed. Copyright © 2001 John Wiley & Sons, Ltd. [source] A Certain Je Ne Sais QuoiHUMAN COMMUNICATION RESEARCH, Issue 2 2005Verbalization Bias in Evaluation People's evaluations of stimuli may change when they verbally attempt to communicate the reasons underlying their judgments. The reported experiments demonstrate the interactive influence of expertise, verbalizability (i.e., the ease with which stimulus features can be linguistically encoded), and appraisal mode in the verbalization bias phenomenon. In Experiment 1, art novices and experts rated their liking of artworks with compositional features that were easy (e.g., figurative,naturalistic) or difficult (e.g., abstract) to verbalize. When asked to verbalize the reasons underlying their judgments, novices assigned lower ratings to abstract but not figurative works. Experts, in contrast, were not influenced by the verbalization manipulation. Experiment 2 explored the possibility that verbalization bias is attributable to a componential appraisal mode that verbalization induces, rather than the specific reasons that people articulate. We found that verbalizing reasons for liking or disliking one abstract work influenced art novices' judgments of a second work for which they did not attempt to verbalize reasons. Moreover, those who merely attempted to verbalize their perceptual experiences also exhibited this contamination effect. The results of both studies suggest that verbalizing the attributes of complex stimuli can significantly alter the way we evaluate these stimuli. [source] Modeling Age Differences in Infant Category LearningINFANCY, Issue 2 2004Thomas R. Shultz We used an encoder version of cascade correlation to simulate Younger and Cohen's (1983, 1986) finding that 10-month-olds recover attention on the basis of correlations among stimulus features, but 4- and 7-month-olds recover attention on the basis of stimulus features. We captured these effects by varying the score threshold parameter in cascade correlation, which controls how deeply training patterns are learned. When networks learned deeply, they showed more error to uncorrelated than to correlated test patterns, indicating that they abstracted correlations during familiarization. When prevented from learning deeply, networks decreased error during familiarization and showed as much error to correlated as to uncorrelated tests but less than to test items with novel features, indicating that they learned features but not correlations among features. Our explanation is that older infants learn more from the same exposure than do younger infants. Unlike previous explanations that postulate unspecified qualitative shifts in processing with age, our explanation focuses on quantitatively deeper learning with increasing age. Finally, we provide some new empirical evidence to support this explanation. [source] Effects of prior stimulus and prior perception on neural correlates of auditory stream segregationPSYCHOPHYSIOLOGY, Issue 6 2009Joel S. Snyder Abstract We examined whether effects of prior experience are mediated by distinct brain processes from those processing current stimulus features. We recorded event-related potentials (ERPs) during an auditory stream segregation task that presented an adaptation sequence with a small, intermediate, or large frequency separation between low and high tones (,f), followed by a test sequence with intermediate ,f. Perception of two streams during the test was facilitated by small prior ,f and by prior perception of two streams and was accompanied by more positive ERPs. The scalp topography of these perception-related changes in ERPs was different from that observed for ERP modulations due to increasing the current ,f. These results reveal complex interactions between stimulus-driven activity and temporal-context-based processes and suggest a complex set of brain areas involved in modulating perception based on current and previous experience. [source] | ||||||||||