Changes across the psychometric function following perceptual learning of an RSVP reading task

Perceptual learning involves long-lasting improvements in the ability to perceive simple sensory stimuli. Some forms of perceptual learning are thought to involve an increasingly selective readout of sensory neurons that are most sensitive to the trained stimulus. Here we report novel changes in the relationship between the threshold and slope of the psychometric function during learning that are consistent with such changes in readout and can provide insights into the underlying neural mechanisms. In monkeys trained on a direction-discrimination task, perceptual improvements corresponded to lower psychometric thresholds and slightly shallower slopes. However, this relationship between threshold and slope was much weaker in comparable, ideal-observer “neurometric” functions of neurons in the middle temporal (MT) area, which represent sensory information used to perform the task and whose response properties did not change with training. We propose a linear/nonlinear pooling scheme to account for these results. According to this scheme, MT responses are pooled via linear weights that change with training to more selectively read out responses from the most sensitive neurons, thereby reducing predicted thresholds. An additional nonlinear (power-law) transformation does not change with training and causes the predicted psychometric function to become shallower as uninformative neurons are eliminated from the pooled signal. We show that this scheme is consistent with the measured changes in psychometric threshold and slope throughout training. The results suggest that some forms of perceptual learning involve improvements in a process akin to selective attention that pools the most informative neural signals to guide behavior.

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Perceptual Learning of Vocoded Speech With and Without Contralateral Hearing: Implications for Cochlear Implant Rehabilitation

Journal of Speech Language and Hearing Research ◽

10.1044/2020_jslhr-20-00385 ◽

2020 ◽

pp. 1-10

Author(s):

Martin Chavant ◽

Alexis Hervais-Adelman ◽

Olivier Macherey

Keyword(s):

Cochlear Implant ◽

Perceptual Learning ◽

Speech Signal ◽

Training Phase ◽

Monosyllabic Words ◽

Low Pass ◽

Contralateral Ear ◽

Number Of Individuals ◽

Insight Into ◽

Vocoded Speech

Purpose An increasing number of individuals with residual or even normal contralateral hearing are being considered for cochlear implantation. It remains unknown whether the presence of contralateral hearing is beneficial or detrimental to their perceptual learning of cochlear implant (CI)–processed speech. The aim of this experiment was to provide a first insight into this question using acoustic simulations of CI processing. Method Sixty normal-hearing listeners took part in an auditory perceptual learning experiment. Each subject was randomly assigned to one of three groups of 20 referred to as NORMAL, LOWPASS, and NOTHING. The experiment consisted of two test phases separated by a training phase. In the test phases, all subjects were tested on recognition of monosyllabic words passed through a six-channel “PSHC” vocoder presented to a single ear. In the training phase, which consisted of listening to a 25-min audio book, all subjects were also presented with the same vocoded speech in one ear but the signal they received in their other ear differed across groups. The NORMAL group was presented with the unprocessed speech signal, the LOWPASS group with a low-pass filtered version of the speech signal, and the NOTHING group with no sound at all. Results The improvement in speech scores following training was significantly smaller for the NORMAL than for the LOWPASS and NOTHING groups. Conclusions This study suggests that the presentation of normal speech in the contralateral ear reduces or slows down perceptual learning of vocoded speech but that an unintelligible low-pass filtered contralateral signal does not have this effect. Potential implications for the rehabilitation of CI patients with partial or full contralateral hearing are discussed.

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Categorization and Perceptual Learning: An Analogue of the Face Inversion Effect

The Quarterly Journal of Experimental Psychology Section A ◽

10.1080/027249897392080 ◽

1997 ◽

Vol 50 (2) ◽

pp. 257-273 ◽

Cited By ~ 8

Author(s):

I.P.L. Mclaren

Keyword(s):

Perceptual Learning ◽

Inversion Effect ◽

Face Inversion Effect ◽

Face Inversion ◽

The Face

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A Unique Asymmetrical Stroop Effect in Absolute Pitch Possessors

Experimental Psychology (formerly Zeitschrift für Experimentelle Psychologie) ◽

10.1027/1618-3169/a000153 ◽

2012 ◽

Vol 59 (5) ◽

pp. 272-278 ◽

Cited By ~ 19

Author(s):

Lilach Akiva-Kabiri ◽

Avishai Henik

Keyword(s):

Selective Attention ◽

Stroop Task ◽

Stroop Effect ◽

Congruency Effect ◽

Absolute Pitch ◽

Naming Task ◽

Color Naming ◽

Reading Task ◽

Pitch Processing ◽

Reverse Pattern

The Stroop task has been employed to study automaticity or failures of selective attention for many years. The effect is known to be asymmetrical, with words affecting color naming but not vice versa. In the current work two auditory-visual Stroop-like tasks were devised in order to study the automaticity of pitch processing in both absolute pitch (AP) possessors and musically trained controls without AP (nAP). In the tone naming task, participants were asked to name the auditory tone while ignoring a visual note name. In the note naming task, participants were asked to read a note name while ignoring the auditory tone. The nAP group showed a significant congruency effect only in the tone naming task, whereas AP possessors showed the reverse pattern, with a significant congruency effect only in the note reading task. Thus, AP possessors were unable to ignore the auditory tone when asked to read the note, but were unaffected by the verbal note name when asked to label the auditory tone. The results suggest that pitch identification in participants endowed with AP ability is automatic and impossible to suppress.

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