The Louder, the Longer: Object Length Perception Is Influenced by Loudness, but Not by Pitch

Sound by itself can be a reliable source of information about an object’s size. For instance, we are able to estimate the size of objects merely on the basis of the sound they make when falling on the floor. Moreover, loudness and pitch are crossmodally linked to size. We investigated if sound has an effect on size estimation even in the presence of visual information, that is if the manipulation of the sound produced by a falling object influences visual length estimation. Participants watched videos of wooden dowels hitting a hard floor and estimated their lengths. Sound was manipulated by (A) increasing (decreasing) overall sound pressure level, (B) swapping sounds among the different dowel lengths, and (C) increasing (decreasing) pitch. Results showed that dowels were perceived to be longer with increased sound pressure level (SPL), but there was no effect of swapped sounds or pitch manipulation. However, in a sound-only-condition, main effects of length and pitch manipulation were found. We conclude that we are able to perceive subtle differences in the acoustic properties of impact sounds and use them to deduce object size when visual cues are eliminated. In contrast, when visual cues are available, only loudness is potent enough to exercise a crossmodal influence on length perception.

The Effect of Cane Material on Length Perception with Long Canes by Visually Impaired, Sighted-Blindfolded, and Sighted Participants

Introduction Individuals with visual impairments may use long canes for estimating distances and detecting gaps, obstacles, and texture patterns. The study presented here investigated whether length perception with canes is influenced by cane material. Methods Visually impaired, sighted-blindfolded, and sighted individuals (n = 30 for each group) participated in this study. Each group was divided into three subgroups (with 5 females and 5 males each) according to cane material. The canes (length = 80 cm, diameter = 1.5 cm) were made of wood, polyethene plastic, or aluminum. The participants were required to judge whether comparison stimuli were shorter than, equal to, or longer than the standard stimulus. Two sessions (for horizontal or vertical lines) were carried out on consecutive days. Results Cane material was not a significant factor influencing accuracy, F(2, 79) = 2.47, p = .091, and difference threshold, F(2, 79) = 2.01, p = .14, in length perception for the three groups of participants, but cane material interacted with orientation of stimuli, F(2, 79) = 3.24, p = .044. There were significant group differences for accuracy, F(2, 79) = 9.6, p <.001, and difference threshold, F(2, 79) = 8.8, p < .001, revealing that participants with visual impairments were better at discriminating length than sighted-blindfolded participants. Discussion Our results provide evidence that length perception with canes is not significantly influenced by cane material. The significant group differences for accuracy and difference threshold indicate that assessing visually impaired participants may be more adequate in studies aimed at investigating aspects related to long canes. Implications for practitioners Orientation and mobility (O&M) instructors can report that there is experimental evidence that cane material is not a significant factor in conveying spatial (length) information, although some evidence suggests that it is a significant factor in conveying tactile information such as the roughness of surface textures.

Thai Rate-Varied Vowel Length Perception and the Impact of Musical Experience

Musical experience has been demonstrated to play a significant role in the perception of non-native speech contrasts. The present study examined whether or not musical experience facilitated the normalization of speaking rate in the perception of non-native phonemic vowel length contrasts. Native English musicians and non-musicians (as well as native Thai control listeners) completed identification and AX (same–different) discrimination tasks with Thai vowels contrasting in phonemic length at three speaking rates. Results revealed facilitative effects of musical experience in the perception of Thai vowel length categories. Specifically, the English musicians patterned similarly to the native Thai listeners, demonstrating higher accuracy at identifying and discriminating between-category vowel length distinctions than at discriminating within-category durational differences due to speaking rate variations. The English musicians also outperformed non-musicians at between-category vowel length discriminations across speaking rates, indicating musicians’ superiority in perceiving categorical phonemic length differences. These results suggest that musicians’ attunement to rhythmic and temporal information in music transferred to facilitating their ability to normalize contextual quantitative variations (due to speaking rate) and perceive non-native temporal phonemic contrasts.