Evaluating the precision of auditory sensory memory as an index of intrusion in tinnitus

Objectives: The purpose of this study was to investigate the potential of measures of auditory short-term memory (ASTM) to provide a clinical measure of intrusion in tinnitus. Design: Response functions for six normal listeners on a delayed pitch discrimination task were contrasted in three conditions designed to manipulate attention in the presence and absence of simulated tinnitus: (1) no-tinnitus, (2) ignore-tinnitus, and (3) attend-tinnitus. Results: Delayed pitch discrimination functions were more variable in the presence of simulated tinnitus when listeners were asked to divide attention between the primary task and the amplitude of the tinnitus tone. Conclusions: Changes in the variability of auditory short-term memory may provide a novel means of quantifying the level of intrusion associated with the tinnitus percept during listening

Change perception and change interference within and across feature dimensions

The ability to perceive a change in a visual object is reduced when that change is presented in competition with other changes which are task-irrelevant. We performed two experiments which investigate the basis of this change interference effect. We tested whether change interference occurs as a consequence of some form of attentional capture, or whether the interference occurs at a stage prior to attentional selection of the task-relevant change. A modified probe-detection task was used to explore this issue. Observers were required to report the presence/absence of a specified change-type (colour, shape) in the probe, in a context in which - on certain trials - irrelevant changes occur in non-probe items. There were two key variables in these experiments: the attentional state of the observer, and the dimensional congruence of changes in the probe and non-probe items. Change interference was strongest when the irrelevant changes were the same as those on the report dimension. However the interference pattern persisted even when observers did not know the report dimension at the time the changes occurred. These results seem to rule out attention as a factor. Our results fit best with an interpretation in which change interference produces feature-specific sensory noise which degrades the signal quality of the target change

Attentional control via parallel target-templates in dual-target search

Simultaneous search for two targets has been shown to be slower and less accurate than independent searches for the same two targets. Recent research suggests this ‘dual-target cost’ may be attributable to a limit in the number of target-templates than can guide search at any one time. The current study investigated this possibility by comparing behavioural responses during single- and dual-target searches for targets defined by their orientation. The results revealed an increase in reaction times for dual- compared to single-target searches that was largely independent of the number of items in the display. Response accuracy also decreased on dual- compared to single-target searches: dual-target accuracy was higher than predicted by a model restricting search guidance to a single target-template and lower than predicted by a model simulating two independent single-target searches. These results are consistent with a parallel model of dual-target search in which attentional control is exerted by more than one target-template at a time. The requirement to maintain two target-templates simultaneously, however, appears to impose a reduction in the specificity of the memory representation that guides search for each target

Concurrent evaluation of independently cued features during perceptual decisions and saccadic targeting in visual search

Simultaneoussearchforone-of-twotargetsisslowerandlessaccuratethansearchfora single-target. Within the Signal Detection Theoretic (SDT) framework, this can be attributed to the division of resources during the comparison of visual input against independentlycuedtargets.Thecurrentstudyusedoneortwocuestoelicitsingle- and dual-target searchesfororientationtargetsamongsimilaranddissimilardistractors.In Experiment1,theaccuracyoftargetdiscriminationinbriefdisplayswascomparedatset sizesof1,2and4 Resultsrevealedareductioninaccuracythatscaledwiththeproduct ofsetsizeandthenumberofcuedtargets.InExperiment2,theaccuracyandlatencyof observers’saccadictargetingwerecompared.Fixationsonsingle-target searcheswere highlyselectivetowardsthetarget.Ondual-targetsearches,therequirementtodetect one-of-two targets produceda significant reductionin target fixationsandequivalent ratesoffixationstodistractorswithoppositeorientations.Formostobservers,thedual targetcostwaspredictedbyanSDTmodelthatsimulatedincreasesindecision-noiseand thedistributionofcapacity-limitedresourcesduring thecomparisonofselectedinput againstindependentlycued targets.Forothers,searchaccuracywasconsistentwitha single-item limit on perceptual decisions and saccadic targeting during search. These findingssupportaflexibleaccountofthedual-targetcostbasedondifferentstrategiesto resolvecompetitionbetweenindependentlycuedtargets

Dimension-based attention in visual short-term memory

We investigated how dimension-based attention influences visual short-term memory (VSTM). This was done through examining the effects of cueing a feature dimension in two perceptual comparison tasks (change detection and sameness detection). In both tasks, a memory array and a test array consisting of a number of colored shapes were presented successively, interleaved by a blank interstimulus interval (ISI). In Experiment 1 (change detection), the critical event was a feature change in one item across the memory and test arrays. In Experiment 2 (sameness detection), the critical event was the absence of a feature change in one item across the two arrays. Auditory cues indicated the feature dimension (color or shape) of the critical event with 80 % validity; the cues were presented either prior to the memory array, during the ISI, or simultaneously with the test array. In Experiment 1, the cue validity influenced sensitivity only when the cue was given at the earliest position; in Experiment 2, the cue validity influenced sensitivity at all three cue positions. We attributed the greater effectiveness of top-down guidance by cues in the sameness detection task to the more active nature of the comparison process required to detect sameness events (Hyun, Woodman, Vogel, Hollingworth, & Luck, Journal of Experimental Psychology: Human Perception and Performance, 35; 1140–1160, 2009)

Action video game training reduces the Simon Effect.

A number of studies have shown that training on action video games improves various aspects of visual cognition including selective attention and inhibitory control. Here, we demonstrate that action video game play can also reduce the Simon Effect, and, hence, may have the potential to improve response selection during the planning and execution of goal-directed action. Non-game-players were randomly assigned to one of four groups; two trained on a first-person-shooter game (Call of Duty) on either Microsoft Xbox or Nintendo DS, one trained on a visual training game for Nintendo DS, and a control group who received no training. Response times were used to contrast performance before and after training on a behavioral assay designed to manipulate stimulus-response compatibility (the Simon Task). The results revealed significantly faster response times and a reduced cost of stimulus-response incompatibility in the groups trained on the first-person-shooter game. No benefit of training was observed in the control group or the group trained on the visual training game. These findings are consistent with previous evidence that action game play elicits plastic changes in the neural circuits that serve attentional control, and suggest training may facilitate goal-directed action by improving players' ability to resolve conflict during response selection and execution