Homophone effects in visual word recognition depend on homophone type and task demands.

This experiment examined how the characteristics of homophones and their mates influence homophone effects, as a function of task demands. Two types of homophones were presented: 1) low-frequency homophones with higher-frequency mates that are not animal names (e.g., maid--made), and 2) low-frequency homophones with mates that are, on average, of equivalent frequency and are animal names (e.g., foul--fowl). We observed a double dissociation: In the lexical decision task (LDT), there was a homophone effect for the first type of homophones but not for the second, whereas in the semantic categorization task (SCT) the opposite was true. These results suggest that in these tasks the effects of homophony arise when the homophone's mate creates competition in terms of the type of processing emphasized in the task, namely, orthographic processing in the LDT and semantic processing in the SCT.     

The effects of aging and dual task demands on language production

A digital pursuit rotor task was used to measure dual task costs of language production by young and older adults. After training on the pursuit rotor, participants were asked to track the moving target while providing a language sample. When simultaneously engaged, young adults experienced greater dual task costs to tracking, fluency, and grammatical complexity than older adults. Older adults were able to preserve their tracking performance by speaking more slowly. Individual differences in working memory, processing speed, and Stroop interference affected vulnerability to dual task costs. These results demonstrate the utility of using a digital pursuit rotor to study the effects of aging and dual task demands on language production and confirm prior findings that young and older adults use different strategies to accommodate to dual task demands.     

The effect of auditory and visual models on acquisition of a timing task

While research on observational learning has typically employed visual models of correct performance, the characteristics of perceptual systems support the suggestion that an auditory model may be more effective in developing a cognitive representation of tasks for which timing is essential. Therefore, it was the purpose of this study to compare the relative effectiveness of auditory and visual models in the acquisition of a timing task. Subjects were provided with an auditory model, a visual model, a combined auditory and visual model, or no model of correct performance. There were significant main effects of groups and trials during acquisition. While performance of all groups improved during acquisition, the audio and audiovisual groups had generally better performance. The same effects were significant on immediate transfer, again reflecting the superior performance of the two auditory model groups. The results suggest an important role for audition in the development of a cognitive representation of movement timing.     

Transfer effects of incompatible location-relevant mappings on a subsequent visual or auditory Simon task

Two experiments investigated the influence of practice with an incompatible mapping of left and right stimuli to keypress responses on performance of a subsequent Simon task, for which stimulus location was irrelevant, after a delay of 5 min or 1 week. In Experiment 1, the visual Simon effect was eliminated when the practice modality was auditory and reversed to favor noncorresponding responses when it was visual, and there was no significant effect of delay interval. In Experiment 2, significant auditory Simon effects were obtained that did not vary as a function of practice modality, with delay having only a marginal effect on the magnitude of the Simon effect. The elimination of the visual Simon effect in the transfer session is most likely due to the short-term stimulus-response associations defined for the incompatible spatial mapping remaining active during the transfer session. Because the auditory Simon effect is stronger than the visual one, more practice with the incompatible mapping may be necessary to produce reliable transfer effects for it.     

The effects of auditory and visual distractors on children's performance in a short-term memory task

Five- and 8-year-old children's performance in a short-term memory task was assessed under two auditory and two visual distraction conditions, as well as with no extraneous stimuli present. Performance under distraction was found to be inferior to that under nondistraction, but the degree of difference was roughly the same at ages 5 and 8, indicating little developmental change in the effects of distraction over this age range. Other findings included differences in the effectiveness of the distractors used and evidence that the children adapted somewhat to the influence of extraneous stimulation.     

The effects of periodic visual occlusion on ball catching

Four experiments were conducted to examine the effects of periodic visual occlusion on one-handed ball catching. Tennis balls were projected one at a time over distances of 8-12 m, and liquid-crystal visual occlusion spectacles provided intermittent vision by opening and closing the lens shutters at different frequencies. As well as frequency, we manipulated duty cycle, or the proportion of time that the lenses were open. Generally, catching performance deteriorated as frequency was reduced. Although longer visual samples (i.e., increased duty cycle) mediated this effect to some extent, the most potent variable was the time between visual samples; performance deteriorated rapidly when this interval was greater than 80 ms (i.e., 10 Hz with 20-ms lens open times). Presumably this occurred because subjects had difficulty integrating visual information separated by longer temporal intervals.     

The effects of music and task difficulty on performance at a visual vigilance task

Forty subjects performed a visual vigilance task in music or noise and when the task was difficult or easy. Response measures taken were: correct detections, commission errors, detection latencies and d' values. For the difficult version of the task a significant increase in detection latencies was found which music prevented. Broadly similar findings were obtained for correct detections. The results are compared with other studies of detection latency and task difficulty and are discussed in terms of arousal.     

The involvement of central attention in visual search is determined by task demands

Attention, the mechanism by which a subset of sensory inputs is prioritized over others, operates at multiple processing stages. Specifically, attention enhances weak sensory signal at the perceptual stage, while it serves to select appropriate responses or consolidate sensory representations into short-term memory at the central stage. This study investigated the independence and interaction between perceptual and central attention. To do so, I used a dual-task paradigm, pairing a four-alternative choice task with a visual search task. The results showed that central attention for response selection was engaged in perceptual processing for visual search when the number of search items increased, thereby increasing the demand for serial allocation of focal attention. By contrast, central attention and perceptual attention remained independent as far as the demand for serial shifting of focal attention remained constant; decreasing stimulus contrast or increasing the set size of a parallel search did not evoke the involvement of central attention in visual search. These results suggest that the nature of concurrent visual search process plays a crucial role in the functional interaction between two different types of attention.     

The lateral effects of Dohsa-method relaxation on visual and auditory responses

The effects of relaxation training, using the Dohsa method, on visual and auditory responses were examined. Twelve college students underwent relaxation training either to the left shoulder, left side of the waist, and the left foot, or to the right side. The measures used in this study were weight-bearing, body perception and external perception, visual field, and visual and hearing acuity. Weight-bearing significantly increased for the foot undergoing relaxation training, compared with the untreated foot, indicating that the subjects stood more firmly on the ground on the relaxed foot. Subjects could also perceive positive changes in their "sense of standing firmly on the ground,""sense of activity in the body,""sense of muscular relaxation," and "sense of fullness in the abdomen" on the side of the body receiving relaxation training. There were positive changes in external perception such as "vividness of the external world,""breadth of the visual field," and "active impression of the external world" for subjects' vision on the side receiving relaxation training. Furthermore, visual and hearing acuity on the side on which relaxation training was administered improved significantly.     

The effects of auditory and visual interference on the immediate recall of melody

College-age subjects recalled melodies or spoken sentences immediately after hearing them, by either pointing on a chart designed to interfere with a visual memory code orsaying the equivalent responses, which should interfere with an auditory code. Pointing took significantly longer than saying for melodies, but not for sentences. A second experiment showed that this task x materials interaction could be due to interference with contour per se rather than with visual coding of melody, because a similar effect was found for spoken contours consisting simply of the words “up” or “down.” In a third experiment, pointing and saying tasks were modified both to control and to manipulate the amount of contour interference. Visual control stimuli for melodies were introduced, employing a marker that moved up or down. This time the task x materials interaction could be explained in terms of an auditory memory code for melody, but there were some problems with this interpretation. Interference related to contour, rather than to a specific modality, appeared to account best for the results of all three experiments.     

Effect of subliminal visual material on an auditory signal detection task

An experiment assessed the effect of subliminally embedded, visual material on an auditory detection task. 22 women and 19 men were presented tachistoscopically with words designated as "emotional" or "neutral" on the basis of prior GSRs and a Word Rating List under four conditions: (a) Unembedded Neutral, (b) Embedded Neutral, (c) Unembedded Emotional, and (d) Embedded Emotional. On each trial subjects made forced choices concerning the presence or absence of an auditory tone (1000 Hz) at threshold level; hits and false alarm rates were used to compute non-parametric indices for sensitivity (A') and response bias (B"). While over-all analyses of variance yielded no significant differences, further examination of the data suggests the presence of subliminally "receptive" and "non-receptive" subpopulations.     

Serial position effects in 2-alternative forced choice recognition: Functional equivalence across visual and auditory modalities

Two experiments examined Ward, Avons, and Melling's (2005) proposition that the serial position function is task, rather than modality, dependent. Specifically, they proposed that for backward testing the 2-alternative forced-choice (2AFC) recognition paradigm is characterised by single-item recency irrespective of the modality of the stimulus presentation. In Experiment 1 the same nonword sequences, presented both visually or auditorily, produced qualitatively equivalent serial position functions with 2AFC testing. Forward testing produced a flat serial position function, while backward testing produced two-item recency in the absence of primacy. In order to rule out the possibility that the serial position functions for visual stimuli were the product of sub-vocal rehearsal, Experiment 2 employed articulatory suppression during the presentation phase. Serial position function equivalence was again observed together with a modest impairment in overall recognition rates. Taken together, these data are consistent with the Ward et al. proposition and further support the existence of a visual memory that can facilitate storage of visual-verbal material (e.g. Logie, Della Sella, Wynn, & Baddeley, 2000). However, the observation of two-item recency contradicts the original duplex account of single-item recency traditionally observed for backwards recognition testing of visual stimuli (Phillips & Christie, 1977).     

Dimension- and space-based intertrial effects in visual pop-out search: modulation by task demands for focal-attentional processing

Two experiments compared reaction times (RTs) in visual search for singleton feature targets defined, variably across trials, in either the color or the orientation dimension. Experiment 1 required observers to simply discern target presence versus absence (simple-detection task); Experiment 2 required them to respond to a detection-irrelevant form attribute of the target (compound-search task). Experiment 1 revealed a marked dimensional intertrial effect of 34 ms for an target defined in a changed versus a repeated dimension, and an intertrial target distance effect, with an 4-ms increase in RTs (per unit of distance) as the separation of the current relative to the preceding target increased. Conversely, in Experiment 2, the dimension change effect was markedly reduced (11 ms), while the intertrial target distance effect was markedly increased (11 ms per unit of distance). The results suggest that dimension change/repetition effects are modulated by the amount of attentional focusing required by the task, with space-based attention altering the integration of dimension-specific feature contrast signals at the level of the overall-saliency map.

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Abstract versus modality-specific memory representations in processing auditory and visual speech

Serial recall of lip-read, auditory, and audiovisual memory lists with and without a verbal suffix was examined. Recency effects were the same in the three presentation modalities. The disrupting effect of a suffix was largest when it was presented in the same modality as the list items. The results suggest that abstract linguistic as well as modality-specific codes play a role in memory for auditory and visual speech.     

The role of attention in visual and auditory suffix effects

Memory & Cognition - The auditory suffix effect (SE), in which recall of the terminal items of a sequence is impaired by presenting a redundant item at the end of the sequence, has been...     

Different effects of dual task demands on the speech of young and older adults

Young and older adults provided language samples in response to elicitation questions while concurrently performing 3 different tasks. The language samples were scored on three dimensions: fluency, grammatical complexity, and content. Previous research had suggested the hypothesis that the restricted speech register of older adults is buffered from the costs of dual task demands. This hypothesis was tested by comparing language samples collected during a baseline condition with those produced while the participants were performing the concurrent tasks. The results indicate that young and older adults adopt different strategies when confronted with dual task demands. Young adults shift to a restricted speech register when confronted with dual task demands. Older adults, who were already using a restricted speech register, became less fluent although the grammatical complexity and informational content of their speech was preserved. Hence, some but not all aspects of older adults' speech are buffered from dual task demands.