Yoav Arieh

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.

Brighter noise: Sensory enhancement of perceived loudness by concurrent visual stimulation

Two experiments investigated the effect of concurrently presented light on the perceived loudness of a low-level burst of white noise. The results suggest two points. First, white noise presented with light tends to be rated as louder than noise presented alone. Second, the enhancement in loudness judgments is resistant to two experimental manipulations: varying the probability that light accompanies sound and shifting from a rating method to a forced choice comparison. Both manipulations were previously shown to eliminate a complementary noise-induced enhancement in ratings of brightness. Whereas noise-induced enhancement of brightness seems to reflect a late-stage decisional process, such as a response bias, the present results suggest that light-induced enhancement of loudness may reflect an early-stage sensory interaction.

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.

Time course of loudness recalibration: Implications for loudness enhancement

Loudness recalibration, the effect of a relatively loud 2500-Hz recalibrating tone on the loudness of a relatively soft 2500-Hz target tone, was measured as a function of the interstimulus interval (ISI) between them. The loudness of the target tone, assessed by a 500-Hz comparison tone, declined when the ISI equaled or exceeded about 200 ms and leveled off at an ISI of about 700 ms. Notably, the target tones loudness did not change significantly at very short ISIs (< 150 ms). The latter result is incompatible with the literature reporting loudness enhancement in this time window, but is compatible with the suggestion made by Scharf, Buus, and Nieder [J. Acoust. Soc. Am. 112, 807-810 (2002)] that early measurements of enhancement were contaminated by the influence of the recalibrating tone on the comparison tone when the two shared the same frequency. In a second experiment the frequency of the comparison tone was changed to 2500 Hz and the results of a loudness enhancement paradigm was successfully predicted from the time course of recalibration obtained in experiment 1.

Tracking the time to recovery after induced loudness reduction (L)

In induced loudness reduction (ILR), a strong tone causes the loudness of a subsequently presented weak tone to decrease. The aim of the experiment was to determine the time required for loudness to return to its initial level after ILR. Twenty-four subjects were exposed to 5, 10, 20, or 40 brief bursts of 2500-Hz pure tones at 80-dB SPL (inducers) and then tested in a series of paired comparison trials. Subjects compared the loudness of a weak target (2500 Hz at 60-dB SPL) to the loudness of a comparison tone at 500 Hz previously judged to match the target. The comparison task was repeated until the two tones were again judged equally loud. The results showed that (a) recovery after ILR is a relatively long process with a time scale of minutes, and (b) recovery time increased approximately 20 s with each doubling of the number of inducers.

Cross-modal interaction between vision and hearing : A speed-accuracy analysis

Cross-modal facilitation of response time (RT) is said to occur in a selective attention task when the introduction of an irrelevant sound increases the speed at which visual stimuli are detected and identified. To investigate the source of the facilitation in RT, we asked participants to rapidly identify the color of lights in the quiet and when accompanied by a pulse of noise. The resulting measures of accuracy and RT were used to derive speed-accuracy trade-off functions (SATFs) separately for the noise and the no-noise conditions. The two resulting SATFs have similar slopes and intercepts and, thus, can be treated as overlapping segments of a single function. That speeded identification of color with and without the presence of noise can be described by one SATF suggests, in turn, that cross-modal facilitation of RT represents a change in decision criterion induced by the auditory stimulus. Analogous changes in decision criteria might also underlie other measures of cross-modal interactions, such as auditory enhancement of brightness judgments.

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.

Measurement of Loudness, Part II: Context Effects

The acoustic environment is typically in a constant flux. Not only do sounds often change over time in their intensity and spectral composition, but they also commonly impinge on our ears in the company of other sounds. The dynamic ensemble of acoustic energies constitutes a Heraclitean context for the perception of auditory intensity, or loudness. Depending on how listeners direct their attention, they may focus on the loudness of an individual component discernible within the complex, on a set of components, or on the entire auditory experience – the Gesamtempfindung. Indeed, researchers have long recognized that the loudness of a sound heard at any moment reflects not only the acoustical energy of that particular sound, but also other sounds heard at the same time as well as the history of acoustical stimulation to which the listeners have been exposed. In other words, a sound of fixed physical properties may be judged as louder or softer depending on the context in which it is perceived. The purpose of this chapter is twofold: to review and summarize current understanding of the ways that context affects loudness and loudness judgments and to put forth a general, sequential, information-processing framework in which to describe and explain the possible sources of these effects.

Posttransient shifts in auditory lateralization

Presenting an intense (e.g., 80-dB [SPL]) “transient” (e.g., 50-msec) inducer to the ear reduces the loudness of subsequent signals at or near the frequency of the inducer. In this study, we ask whether similar inducers also affect lateralization. In two experiments, we asked how inducing tones presented to one ear (the exposed ear) affect judgments of the lateral position of subsequent target tones having various interaural intensity differences. In Experiment 1, inducers had the same frequency as the targets, and, as predicted, reduced the tendency to lateralize the targets to the exposed ear. In Experiment 2, the frequency of the inducers and the target differed (different critical bands), thereby eliminating the effect on lateralization. These results are consistent with the hypothesis that inducers temporarily reduce the magnitude of the representation of intensity signals in the frequency region around them and that this reduction occurs, at least partly, peripherally to the site at which binaural intensity differences are encoded. The results imply further that the reduction in loudness previously reported under similar stimulus conditions reflects a more general reduction of intensity-based information in hearing.

Loudness recalibration at short ISI: A closer look

The loudness of a moderate level tone is substantially reduced when preceded by a louder tone of the same frequency (loudness recalibration). The reduction in loudness depends on the interstimulus interval (ISI) between the tones. Arieh and Marks (2003) reported that loudness starts to decline only when ISI exceeds about 200 m. One possible explanation is that loudness reduction takes 200 ms to develop. Alternatively, the delay in loudness reduction could reflect the combination of two processes: short‐term facilitation and longer‐term suppression. To test this hypothesis, subjects compared the loudness of a roving‐level 500‐Hz tone to a 60‐dB 2500‐Hz target tone presented, first, 100 ms after an 80‐dB 2500‐Hz recalibration tone and, subsequently, with the recalibration tone omitted; by omitting the recent recalibration tone, we hoped to observe the long‐term effects on loudness of earlier recalibration tones. As expected, the loudness of the target was unaffected when it followed the recalibration tone b...