Biomedical subjects

Lawrence E Marks

Publications and source records attributed to Lawrence E Marks.

5 recordsLinked to original sources

PubMed2003

Recalibrating the auditory system: a speed-accuracy analysis of intensity perception.

Recalibration in loudness perception refers to an adaptation-like change in relative responsiveness to auditory signals of different sound frequencies. Listening to relatively weak tones at one frequency and stronger tones at another makes the latter appear softer. The authors showed recalibration not only in magnitude estimates of loudness but also in simple response times (RTs) and choice RTs. RTs depend on sound intensity and may serve as surrogates for loudness. Most important, the speeded classification paradigm also provided measures of errors. RTs and errors can serve jointly to distinguish changes in sensitivity from changes in response criterion. The changes in choice RT under different recalibrating conditions were not accompanied by changes in error rates predicted by the speed-accuracy tade-off. These results lend support to the hypothesis that loudness recalibration does not result from shifting decisional criteria but instead reflects a change in the underlying representation of auditory intensity.

Adolescent↗

PubMed2003

Cross-modal enhancement of perceived brightness: sensory interaction versus response bias.

Stein, London, Wilkinson, and Price (1996) reported the presence of cross-modal enhancement of perceived visual intensity: Participants tended to rate weak lights as brighter when accompanied by a concurrent pulse of white noise than when presented alone. In the present study, two methods were used to determine whether the enhancement reflects an early-stage sensory process or a later-stage decisional process, such as a response bias. First, enhancement was eliminated when the noise accompanied the light on only 25% versus 50% of the trials. Second, enhancement was absent when tested with a paired-comparison method. These findings are consistent with the hypothesis that the sound-induced enhancement in judgments of brightness reflects a response bias, rather than an early sensory process--that is, enhancement is the result of a relatively late decisional process.

Adult↗

PubMed2002

Visual marking: dissociating effects of new and old set size.

Visual marking makes it possible to ignore old items during search. In a typical study, old items are previewed 1 s before adding an equal number of new items, one of which is the target. Previewing half of the items reduces the search slope relating response time (RT) to overall set size by half. However, this manipulation sometimes only reduces overall RT but not search slope (Experiment 1). By orthogonally varying the numbers of old and new items, Experiment 2 shows that old and new set sizes interactively affect visual marking. Given a constant new set size, the size of the old set has negligible effect on RT. However, increasing the new set size reduces the preview benefit in overall RT. Experiment 3 shows that this reduction may be restricted to paradigms that use temporal segregation cues. Studies should vary old and new set size orthogonally to avoid missing a visual marking effect where one may be present.

Cognition↗

PubMed2002

Context effects in visual length perception: role of ocular, retinal, and spatial location.

In three experiments, we examined the transfer of orientation-contingent context effects between the eyes and across portions of the retina with or without variation in external spatial location. Previous research had shown that vertical lines are judged long, relative to horizontal lines, when the stimulus set comprises relatively long horizontals and short verticals (Contextual Condition B), as compared with the reverse when the stimulus set comprises relatively short horizontals and long verticals (Contextual Condition A). Consequently, the contextual set of stimuli influences the magnitude of the horizontal-vertical illusion (HVI), decreasing its size under Contextual Condition A and increasing its size under Contextual Condition B. Experiment 1 showed that exposing one eye to different stimulus contexts modulated the size of the HVI at the exposed eye but had little or no effect at the other eye. Experiments 2 and 3 showed that the effect of the contextual sets generalized poorly across adjacent portions of the retina but transferred almost perfectly across different locations in external space when retinal location was constant. Thus, orientation-contingent context effects in visual length perception appear to be specific to the eye and to the region of the retina stimulated, suggesting that these effects reflect relatively early and local changes in sensitivity, rather than relatively late and general shifts in response criteria.

Adolescent↗

PubMed2002

Visual marking: selective attention to asynchronous temporal groups.

In visual search, when a subset of distractors is previewed 1 s before the target and the remaining distractors, search speed is independent of the number of previewed items. This is visual marking. What allows old items to be marked? Four experiments show that marking is disrupted if the onset of the new items is accompanied by synchronous changes to the old items, but it is not disrupted by changes restricted to the background or by asynchronous changes to the old items. Further, behaviorally relevant old items can be prioritized over new items. Visual marking is based on temporal asynchrony between new and old items, which allows segregation of these items into 2 temporal groups. Attention is then selectively applied to 1 group.

Adolescent↗