Concurrent learning of temporal and spatial sequences.

In a serial reaction time task, stimulus events simultaneously defined spatial and temporal sequences. Responses were based on the spatial dimension. The temporal sequence was incidental to the task, defined by the response-to-stimulus intervals in Experiment 1 and stimulus onset asynchronies in Experiment 2. The two sequences were either of equal length and correlated or of unequal length. In both experiments, spatial learning occurred regardless of sequence length condition. In contrast, temporal learning occurred only in the correlated condition. These results suggest that timing is an integrated part of action representations and that incidental learning for a temporal pattern does not occur independently from the action. Interestingly, sequence learning was enhanced in the correlated condition, reflecting the integration of spatial-temporal information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Flexible visual statistical learning: Transfer across space and time.

The environment contains considerable information that is distributed across space and time, and the visual system is remarkably sensitive to such information via the operation of visual statistical learning (VSL). Previous VSL studies have focused on establishing what kinds of statistical relationships can be learned but have not fully explored how this knowledge is then represented in the mind. These representations could faithfully reflect the details of the learning context, but they could also be generalized in various ways. This was studied by testing how VSL transfers across changes between learning and test, and the results revealed a substantial degree of generalization. Learning of statistically defined temporal sequences was expressed in static spatial configurations, and learning of statistically defined spatial configurations facilitated detection performance in temporal streams. Learning of temporal sequences even transferred to reversed temporal orders during test when accurate performance did not depend on order, per se. These types of transfer imply that VSL can result in flexible representations, which may in turn allow VSL to function in ever-changing natural environments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and perception of visual form from temporal structure.

In this study, the authors examined age-related changes in participants' ability to perceive global spatial structure defined by temporal fine structure among elements undergoing rapid, irregular change. Participants were also tested on a task involving form recognition from luminance contrast and on a task dependent on perception of 3-dimensional shape from motion. Compared with young adults, older individuals were less sensitive to spatial form defined by temporal structure. In contrast, older observers performed as well as young adults on the other two tasks that were not dependent on temporal sensitivity, ruling out nonsensory factors as the cause of the deficits on the temporal structure task. This selective deficit may reveal reduced sensitivity within the temporal impulse response of the aging visual system, a deficit that could be related to reduced effectiveness of neural inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory dominance in temporal processing: New evidence from synchronization with simultaneous visual and auditory sequences.

Evidence that audition dominates vision in temporal processing has come from perceptual judgment tasks. This study shows that this auditory dominance extends to the largely subconscious processes involved in sensorimotor coordination. Participants tapped their finger in synchrony with auditory and visual sequences containing an event onset shift (EOS), expected to elicit an involuntary phase correction response (PCR), and also tried to detect the EOS. Sequences were presented in unimodal and bimodal conditions, including one in which auditory and visual EOSs of opposite sign coincided. Unimodal results showed greater variability of taps, smaller PCRs, and poorer EOS detection in vision than in audition. In bimodal conditions, variability of taps was similar to that for unimodal auditory sequences, and PCRs depended more on auditory than on visual information, even though attention was always focused on the visual sequences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of the temporal structure of spoken words on paired-associate learning.

In a series of experiments, participants learned to associate black-and-white shapes with nonsense spoken labels (e.g., “joop”). When tested on their recognition memory, participants falsely recognized as correct a shape paired with a label that began with the same sounds as the shape’s original label (onset-overlapping lure; e.g., joob) more often than a shape paired with a label that overlapped with the original label at offset (offset-overlapping lure; e.g., choop). Furthermore, the false-alarm rate was modulated by the phonetic distance between the sounds that distinguished the original label and the lures. Greater false-alarm rates to onset-overlapping labels were not predicted by explicit similarity ratings or by consonant identification and were not dependent upon label familiarity. The asymmetry at erroneously recognizing onset- versus offset-overlapping lures remained unchanged as the presentation of the shape at test was delayed in time, suggesting that response anticipation based on the first sounds of the spoken label did not contribute much to the false recognition of onset-overlapping lures. Thus, learning 2 words whose names differ in their last sounds appears to pose greater difficulty than learning 2 words whose names differ in their first sounds because, we argue, people are biased to give more importance to the early sounds of a name than to its last sounds when learning a novel label–referent association. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Subdivisions of inferior temporal cortex in squirrel monkeys make dissociable contributions to visual learning and memory.

Inferior temporal cortex of squirrel monkeys consists of caudal (ITC), intermediate (ITI), and rostral (ITR) subdivisions, possibly homologous to TEO, posterior TE, and anterior TE of macaque monkeys. The present study compared visual learning in squirrel monkeys with ablations of ITC; ITI and ITR (group ITRd); or ITI, ITR, and more ventral cortex, including perirhinal cortex (group ITR+), with visual learning in unoperated controls. The ITC monkeys had significant impairments on pattern discriminations and milder deficits on delayed nonmatching to sample (DNMS) of objects. The ITRd monkeys had deficits on some pattern discriminations but not on DNMS. The ITRd monkeys were significantly impaired on DNMS and some pattern discriminations. These results are similar to those found in macaques and support the proposed homologies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)