Transfer Of Perceptual Learning Research Articles

A Multi-Location Augmented Hebbian Reweighting Model (m-AHRM) of Transfer in Perceptual Learning

A Multi-Location Augmented Hebbian Reweighting Model (m-AHRM) of Transfer in Perceptual Learning

Asymmetric transfer of perceptual learning between coarse and fine depth discriminations

Asymmetric transfer of perceptual learning between coarse and fine depth discriminations

Disruption and Transfer of Perceptual Learning for Visual Hyperacuity

Disruption and Transfer of Perceptual Learning for Visual Hyperacuity

Multi-location Augmented Hebbian Re-Weighting Accounts for Transfer of Perceptual Learning following Double Training

Multi-location Augmented Hebbian Re-Weighting Accounts for Transfer of Perceptual Learning following Double Training

Perceptual learning transfers to untrained retinal locations after double training: A piggyback effect

Perceptual learning transfers to untrained retinal locations after double training: A piggyback effect

Task relevancy and demand modulate double-training enabled transfer of perceptual learning

Location-specific perceptual learning can be rendered transferrable to a new location with double training, in which feature training (e.g., contrast) is accompanied by additional location training at the new location even with an irrelevant task (e.g. orientation). Here we investigated the impact of relevancy (to feature training) and demand of location training tasks on double training enabled learning transfer. We found that location training with an irrelevant task (Gabor vs. letter judgment, or contrast discrimination) limited transfer of Vernier learning to the trained orientation only. However, performing a relevant suprathreshold orthogonal Vernier task prompted additional transfer to an untrained orthogonal orientation. In addition, the amount of learning transfer may depend on the demand of location training as well as the double training procedure. These results characterize how double training potentiates the functional connections between a learned high-level decision unit and visual inputs from an untrained location to enable transfer of learning across retinal locations.

Perceptual learning transfer between hemispheres and tasks for easy and hard feature search conditions

Perceptual learning involves modification of cortical processes so that transfer to new task variants depends on neuronal representation overlap. Neuron selectivity varies with cortical level, so that the degree of transfer should depend on training-induced modification level. We ask how different can stimuli be, how far apart can their representations be, and still induce training transfer. We measure transfer across both long distances within the visual field, namely across cerebral hemispheres, as well as across perceptual dimensions, i.e., between detection of odd color and orientation. In Experiment 1, subjects learned feature search using eccentric arrays randomly presented in the right or left hemifield. Odd elements differed in color or orientation, depending on the presentation hemifield. Following training and performance improvement, the dimensions were switched between hemifields. There was little cross-hemifield or cross-task transfer for difficult cases, and the greater transfer found for easier cases could be across hemispheres and/or perceptual dimensions. Testing these two elements separately, Experiment 2 confirmed considerable transfer across task dimensions, training one dimension and testing another, and Experiment 3 confirmed such transfer across hemifields, training search on one side and testing on the other. Results support Reverse Hierarchy Theory (M. Ahissar & S. Hochstein, 1997, 2004) in that, for easier perceptual tasks involving and modifying higher cortical levels, considerable transfer occurs both across perceptual dimensions and across visual field location even across hemifields.

Generalization of perceptual learning of vocoded speech.

Recent work demonstrates that learning to understand noise-vocoded (NV) speech alters sublexical perceptual processes but is enhanced by the simultaneous provision of higher-level, phonological, but not lexical content (Hervais-Adelman, Davis, Johnsrude, & Carlyon, 2008), consistent with top-down learning (Davis, Johnsrude, Hervais-Adelman, Taylor, & McGettigan, 2005; Hervais-Adelman et al., 2008). Here, we investigate whether training listeners with specific types of NV speech improves intelligibility of vocoded speech with different acoustic characteristics. Transfer of perceptual learning would provide evidence for abstraction from variable properties of the speech input. In Experiment 1, we demonstrate that learning of NV speech in one frequency region generalizes to an untrained frequency region. In Experiment 2, we assessed generalization among three carrier signals used to create NV speech: noise bands, pulse trains, and sine waves. Stimuli created using these three carriers possess the same slow, time-varying amplitude information and are equated for naïve intelligibility but differ in their temporal fine structure. Perceptual learning generalized partially, but not completely, among different carrier signals. These results delimit the functional and neural locus of perceptual learning of vocoded speech. Generalization across frequency regions suggests that learning occurs at a stage of processing at which some abstraction from the physical signal has occurred, while incomplete transfer across carriers indicates that learning occurs at a stage of processing that is sensitive to acoustic features critical for speech perception (e.g., noise, periodicity).

Asymmetric transfer of perceptual learning of luminance- and contrast-modulated motion

Perceptual learning was used as a tool for studying motion perception. The pattern of transfer of learning of luminance- (LM) and contrast-modulated (CM) motion is diagnostic of how their respective processing pathways are integrated. Twenty observers practiced fine direction discrimination with either additive (LM) or multiplicative (CM) mixtures of a dynamic noise carrier and a radially isotropic texture modulator. The temporal frequency was 10 Hz, speed was 10 deg/s, and duration was 400 ms, with feedback. Group 1 pre-tested CM for 2 blocks, trained LM for 16 blocks, and post-tested CM for 6 blocks during 6 sessions on separate days. In Group 2, the LM and CM roles were reversed. The d' improved almost twofold in both groups. There seemed to be full transfer from CM to LM but no significant transfer from LM to CM. The pattern of post-switch improvement was asymmetric as well-no further learning during the LM post-test versus rapid relearning during the CM post-test. These strong asymmetries suggest a dual-pathway architecture with Fourier channels sensitive only to LM signals and non-Fourier channels sensitive to both LM and CM. We hypothesize that the channels tuned for the same motion direction but different carriers are integrated using a MAX operation.

Perceptual learning transfers from luminance- to contrast-defined motion

Perceptual learning transfers from luminance- to contrast-defined motion

Enabling complete transfer of perceptual learning across orientations in foveal vision through double training

Enabling complete transfer of perceptual learning across orientations in foveal vision through double training

Transfer in perceptual learning as extrapolation

Transfer in perceptual learning as extrapolation

Transfer of perceptual learning to completely untrained locations after double training

Transfer of perceptual learning to completely untrained locations after double training

Transfer of perceptual learning of depth discrimination between local and global stereograms

Several previous studies reported differences when stereothresholds are assessed with local-contour stereograms vs. complex random-dot stereograms (RDSs). Dissimilar thresholds may be due to differences in the properties of the stereograms (e.g. spatial frequency content, contrast, inter-element separation, area) or to different underlying processing mechanisms. This study examined the transfer of perceptual learning of depth discrimination between local and global RDSs with similar properties, and vice versa. If global and local stereograms are processed by separate neural mechanisms, then the magnitude and rate of training for the two types of stimuli are likely to differ, and the transfer of training from one stimulus type to the other should be minimal. Based on previous results, we chose RDSs with element densities of 0.17% and 28.3% to serve as the local and global stereograms, respectively. Fourteen inexperienced subjects with normal binocular vision were randomly assigned to either a local- or global- RDS training group. Stereothresholds for both stimulus types were measured before and after 7700 training trials distributed over 10 sessions. Stereothresholds for the trained condition improve for approximately 3000 trials, by an average of 0.36 ± 0.08 for local and 0.29 ± 0.10 for global RDSs, and level off thereafter. Neither the rate nor the magnitude of improvement differ statistically between the local- and global-training groups. Further, no significant difference exists in the amount of improvement on the trained vs. the untrained targets for either training group. These results are consistent with the operation of a single mechanism to process both local and global stereograms.

Transfer of perceptual learning between local and global random-dot stereograms

Transfer of perceptual learning between local and global random-dot stereograms

A dissociation in the transfer of perceptual learning based on visual temporal structure

A dissociation in the transfer of perceptual learning based on visual temporal structure

Transfer of Auditory Perceptual Learning with Spectrally Reduced Speech to Speech and Nonspeech Tasks: Implications for Cochlear Implants

The objective of this study was to assess whether training on speech processed with an eight-channel noise vocoder to simulate the output of a cochlear implant would produce transfer of auditory perceptual learning to the recognition of nonspeech environmental sounds, the identification of speaker gender, and the discrimination of talkers by voice. Twenty-four normal-hearing subjects were trained to transcribe meaningful English sentences processed with a noise vocoder simulation of a cochlear implant. An additional 24 subjects served as an untrained control group and transcribed the same sentences in their unprocessed form. All subjects completed pre- and post-test sessions in which they transcribed vocoded sentences to provide an assessment of training efficacy. Transfer of perceptual learning was assessed using a series of closed set, nonlinguistic tasks: subjects identified talker gender, discriminated the identity of pairs of talkers, and identified ecologically significant environmental sounds from a closed set of alternatives. Although both groups of subjects showed significant pre- to post-test improvements, subjects who transcribed vocoded sentences during training performed significantly better at post-test than those in the control group. Both groups performed equally well on gender identification and talker discrimination. Subjects who received explicit training on the vocoded sentences, however, performed significantly better on environmental sound identification than the untrained subjects. Moreover, across both groups, pre-test speech performance and, to a higher degree, post-test speech performance, were significantly correlated with environmental sound identification. For both groups, environmental sounds that were characterized as having more salient temporal information were identified more often than environmental sounds that were characterized as having more salient spectral information. Listeners trained to identify noise-vocoded sentences showed evidence of transfer of perceptual learning to the identification of environmental sounds. In addition, the correlation between environmental sound identification and sentence transcription indicates that subjects who were better able to use the degraded acoustic information to identify the environmental sounds were also better able to transcribe the linguistic content of novel sentences. Both trained and untrained groups performed equally well ( approximately 75% correct) on the gender-identification task, indicating that training did not have an effect on the ability to identify the gender of talkers. Although better than chance, performance on the talker discrimination task was poor overall ( approximately 55%), suggesting that either explicit training is required to discriminate talkers' voices reliably or that additional information (perhaps spectral in nature) not present in the vocoded speech is required to excel in such tasks. Taken together, the results suggest that although transfer of auditory perceptual learning with spectrally degraded speech does occur, explicit task-specific training may be necessary for tasks that cannot rely on temporal information alone.

Complete Transfer of Perceptual Learning across Retinal Locations Enabled by Double Training

Practice improves discrimination of many basic visual features, such as contrast, orientation, and positional offset. Perceptual learning of many of these tasks is found to be retinal location specific, in that learning transfers little to an untrained retinal location. In most perceptual learning models, this location specificity is interpreted as a pointer to a retinotopic early visual cortical locus of learning. Alternatively, an untested hypothesis is that learning could occur in a central site, but it consists of two separate aspects: learning to discriminate a specific stimulus feature ("feature learning"), and learning to deal with stimulus-nonspecific factors like local noise at the stimulus location ("location learning"). Therefore, learning is not transferable to a new location that has never been location trained. To test this hypothesis, we developed a novel double-training paradigm that employed conventional feature training (e.g., contrast) at one location, and additional training with an irrelevant feature/task (e.g., orientation) at a second location, either simultaneously or at a different time. Our results showed that this additional location training enabled a complete transfer of feature learning (e.g., contrast) to the second location. This finding challenges location specificity and its inferred cortical retinotopy as central concepts to many perceptual-learning models and suggests that perceptual learning involves higher nonretinotopic brain areas that enable location transfer.

Mirror symmetrical transfer of perceptual learning by prism adaptation

Recent study of [Sugita, Y. (1996) Global plasticity in adult visual cortex following reversal of visual input. Nature, 380, 523–526.] demonstrated that prism adaptation to reversed retinal input generates the transfer of neuronal activities in monkey V1 to the opposite visual cortex. This raises the question if perceptual learning on one side of the visual field can transfer to the other side. We tested this in using the Gabor lateral masking paradigm. Before adaptation, long-range interaction was induced vertically on one side (i.e., the right) of the visual field with training (perceptual learning). Prism adaptation was achieved by wearing right-left reversing goggles. During adaptation period, perceptual learning transferred to a mirror symmetrical region across the vertical meridian. Results in the post adaptation period revealed that both learning and transfer persisted for over three months. These results provide direct evidence of transferred perceptual plasticity across the visual field, the underlying mechanism of which is supported by the mirror symmetrical connection between the right and left cortices.

Identical transfer of perceptual learning following easy and difficult task training

Identical transfer of perceptual learning following easy and difficult task training