Effects Of Explicit Knowledge Research Articles

Effects of explicit knowledge and predictability on auditory distraction and target performance

This study tested effects of task requirements and knowledge on auditory distraction effects. This was done by comparing the response to a pitch change (an irrelevant, distracting tone feature) that occurred predictably in a tone sequence (every 5th tone) under different task conditions. The same regular sound sequence was presented with task conditions varying in what information the participant was given about the predictability of the pitch change, and when this information was relevant for the task to be performed. In all conditions, participants performed a tone duration judgment task. Behavioral and event-related brain potential (ERP) measures were obtained to measure distraction effects and deviance detection. Predictable deviants produced behavioral distraction effects in all conditions. However, the P3a amplitude evoked by the predictable pitch change was largest when participants were uninformed about the regular structure of the sound sequence, showing an effect of knowledge on involuntary orienting of attention. In contrast, the mismatch negativity (MMN) component was only modulated when the regularity was relevant for the task and not by stimulus predictability itself. P3a and behavioral indices of distraction were not fully concordant. Overall, our results show differential effects of knowledge and predictability on auditory distraction effects indexed by neurophysiological (P3a) and behavioral measures.

Implicit probabilistic sequence learning is independent of explicit awareness

Studies into interactions between explicit and implicit motor sequence learning have yielded mixed results. Some of these discrepancies have been attributed to difficulties in isolating implicit learning. In the present study, the effect of explicit knowledge on implicit learning was investigated using a modified version of the Alternating Serial Response Time (ASRT) task, a probabilistic sequence learning paradigm that yields continuous and relatively pure measures of implicit learning. Results revealed that implicit learning occurred to the same extent, whether or not subjects had explicit knowledge. Some evidence, however, indicated that explicit knowledge could interfere with the expression of implicit learning early in training. In addition, there were dissociations between learning measures, in that reaction time and accuracy were differentially affected by explicit knowledge. These findings indicate that implicit sequence learning occurs independently of explicit knowledge, and help to explain previous discrepant findings.

The effect of familiarity with a voice on continuous shadowing: Effects of explicit knowledge, but not of implicit familiarity

Listeners were asked to shadow a target voice while a second voice spoke fluently in the background. Listeners differed in their familiarity with the target voice: members of the first group of listeners were familiar with the voice and were told explicitly whose voice they would be hearing; members of a second group were familiar with the target voice but were not warned whose voice it was, and members of a third group were entirely unfamiliar with the target voice. Familiarity was from real-world experience: the voice was that of one of the participant’s professors. Explicit knowledge of talker identity appeared to have the larger effect on listener performance: Participants in the first group made significantly fewer shadowing errors than those in the second group. In contrast, simple familiarity with a voice had no such influence. Familiarity did influence the types of errors listeners made, however: those participants who were familiar with the target voice prior to the test session made fewer incorrect responses than did those who had not heard the talker previously, although their total number of errors (including misses, as well as incorrect responses) did not differ.