Time perception and the filled-duration illusion

A reproduction design is used to show that temporal intervals containing brief tones appear longer than empty intervals of the same duration, the effect being independent of duration. These and previous data are discussed within a theoretical framework which allows for the interrelation of data from different time perception tasks; and a reversible encoding model is stated which accounts for much of the data obtained with empty intervals. A “chunking” model, in which tones occurring in an interval serve to segment the interval during encoding, can account for the filled-duration illusion if certain conditions are met. Finally, mechanisms that are consistent with these conditions are stated.     

Internal clock processes and the filled-duration illusion

In 3 experiments, the authors compared duration judgments of filled stimuli (tones) with unfilled ones (intervals defined by clicks or gaps in tones). Temporal generalization procedures (Experiment 1) and verbal estimation procedures (Experiments 2 and 3) all showed that subjective durations of the tones were considerably longer than those of unfilled intervals defined either by clicks or gaps, with the unfilled intervals being judged as approximately 55%-65% of the duration of the filled ones when real duration was the same. Analyses derived from the pacemaker-switch-accumulator clock model incorporated into scalar timing theory suggested that the filled/unfilled difference in mean estimates was due to higher pacemaker speed in the former case, although conclusively ruling out alternative interpretations in terms of attention remains difficult.     

Ordering and reordering in the auditory and visual modalities

This study investigates the hypothesis that the modality effect (i.e., the often-found recall advantage of the last few items presented in the auditory- rather than visual-input modality) is attributable to a directional auditory trace. Such a directional trace should help performance of forward item-to-item recall, but should hurt performance if mental reordering is required. However, it was found in our Experiment 1 that mental item-to-item reordering of the materials did not affect the modality effect. In Experiment 2, strict control was exercised over the order of recall of chunks of items, as well as over the order of recall within chunks. It was found that the item-to-item reordering of the materials had little effect on the modality effect. However, the larger scale order of recall of the chunks had a large effect on the modality effect. If recall was in a forward order (i.e., first chunk, second chunk, third chunk), there was a dramatic superiority of the auditory materials on the last chunk. If the recall order was backward (third chunk, second chunk, first chunk), the modality effect was inconsequential. These results suggest that the modality effect is related to access to large memorial units rather than to item-to-item associations.     

Spatial and temporal processing in the auditory and visual modalities

Three experiments tested the idea that auditory presentation facilitates temporal recall whereas spatial recall is better if the input modality is visual. Lists of words were presented in which the temporal and spatial orders were independent, and instructions to the subjects determined whether recall would be given in a spatial or temporal order. In all three experiments, a significant interaction between the input modality and the type of recall was found, such that visual presentation resulted in superior recall over auditory presentation in the spatial conditions and auditory presentation yielded superior recall to visual in the temporal conditions. The present results contradict an earlier study by Murdock that showed that auditory presentation resulted in better performance than visual presentation in a nominally spatial task. An explanation for the discrepancies between the results of that study and the present one is presented.     

Duration judgments of naturalistic events in the auditory and visual modalities

Two experiments were performed to examine whether the same underlying mechanisms apply to the duration estimates of both auditory and visual events. In Experiment 1, it was found that the durations of visual scenes are reproduced with the same level of accuracy in prospective and retrospective situations when these display a predictable array of information, a result consistent with past research on auditory durations. Experiment 2 further revealed that when participants are asked to prospectively or retrospectively judge the durations of various naturalistic events in their auditory, visual, or audiovisual modality, no differences in either accuracy or bias are observed. These findings diverge from previous research and are argued to stem from different processing mechanisms that arise from naturalistic events.     

The filled-duration illusion: The function of temporal and nontemporal set

Studies of the perception of time have demonstrated that large visual stimuli presented for the same duration as small stimuli will appear to have been presented longer. Two theoretical approaches have been offered to explain this effect. Both have emphasized the absolute amount of information in the stimulus. Thus, both would predict the effect when size is varied between sessions. The present study found no effect of size when size was held constant within sessions, but a substantial effect resulted when size was varied within sessions. Also examined was the range of stimulus durations used within a session. In one condition, patterns of various sizes were presented at 15, 30, or 45 msec, while in a second condition, the same patterns were presented to a different group of subjects at 15, 85, or 155 msec. The size effect was significantly reduced when longer time intervals were presented. A third group of subjects was shown patterns at even longer times but with a reduced range (155, 170, and 185 msec). Here the size effect was of equal magnitude to that of the 15-msec interval condition. The implications of these results are that current theoretical explanations of the filled-duration illusion rely on incorrect assumptions.     

The role of the native language in auditory and visual context effect modalities

Facilitation of memory for target stimuli due to similar context in the learning and testing phases is known as “context effect” (CE). The present study aimed to investigate the interaction between CE as elicited by the consistency of the language of presentation (Hebrew vs. English) with the native language (Hebrew vs. English) in both auditory and visual modalities. Overall, 120 individuals participated in the experiment. As predicted, CE was evident when the language of presentation remained consistent between study and test. Contrary to our prediction, Hebrew speakers remembered more English words, and vice versa. A possible explanation is that this difference is due to the cognitive effort invested when processing a less dominant language, thus resulting in better recognition. This study has several practical implications, including a recommendation that academic institutions test students in the language in which the material was presented in order to measure the students' knowledge more accurately.     

The effect of a flashing visual stimulus on the auditory continuity illusion

The effect of a visual stimulus on the auditory continuity illusion was examined. Observers judged whether a tone that was repeatedly alternated with a band-pass noise was continuous or discontinuous. In most observers, a transient visual stimulus that was synchronized with the onset of the noise increased the limit of illusory continuity in terms of maximum noise duration and maximum tone level. The smaller the asynchrony between the noise onset and the visual stimulus onset, the larger the visual effect on this illusion. On the other hand, detection of a tone added to the noise was not enhanced by the visual stimulus. These results cannot be fully explained by the conventional theory that illusory continuity is created by the decomposition of peripheral excitation produced by the occluding sound.     

A further investigation of the filled-duration illusion with a comparison between children and adults

This study investigated the filled duration illusion in children in comparison to adults, using a temporal bisection task with two ranges of anchor durations (1 vs. 4s and 2 vs. 8s). The results revealed a marked filled duration effect when filled and empty durations were presented in the same session (within-subjects condition), with the filled durations being judged to be longer than the empty durations in all age groups. However, the magnitude of this effect appeared to be larger in the children than in the adults. Furthermore, the filled duration effect decreased with the longest duration stimuli, and apparent reversals of this effect were observed with the empty durations being judged longer. In the between-subjects experiment, the filled duration effect disappeared in all age groups. However, in the children, the variability in the temporal judgment appeared to be greater for the empty than for the filled durations, thus indicating a lower sensitivity to empty durations.     

Classifying by dimensions and reading: a comparison of the auditory and visual modalities

Children have difficulty learning to read alphabetic writing systems, in part, because they have difficulty segmenting spoken language into phonemes. Young children also have difficulty attending to the individual dimensions of visual objects. Thus, children's early difficulty in reading may be one sign of a general inability to selectively attend to the parts of any perceptual wholes. To explore this notion, children in kindergarten through fourth grade (Experiments 1, 3, and 4) and adults (Experiment 2) classified triads of spoken syllables and triads of visual objects. Classifying speech by common parts was positively related to reading and spelling ability (Experiments 1 and 4), but usually not to classifying visual stimuli by common parts under free classification instructions (Experiments 1 through 3). However, classification was more consistent across the visual and auditory modalities when the children were told to classify based on a shared constituent (Experiment 4). Regardless of instructions, performance on the visual tasks did not usually relate to reading and spelling skill. The ability to attend selectively to phonemes seems to be a "special" skill--one which may require specific experiences with language, such as those involved in learning to read an alphabetic writing system.     

Factors affecting the magnitude of the Ponzo perspective illusion among the Baganda

The magnitude of the Ponzo perspective illusion, utilizing stimuli with varying amounts of context, was determined for a population of Ugandan villagers. The subjects were classified as two-dimensional, three-dimensional, or mixed perceivers based upon their verbal responses to photographs portraying symbolic depth cues. The illusion magnitude among those subjects classified as three-dimensional was similar to that of college observers who demonstrate an increase in illusion magnitude with increasing background context. The two-dimensional observers’ responses were similar to those of villagers tested previously, showing no significant increase for the same conditions. The role of two-dimensional flatness cues was eliminated on the basis of a control experiment. The data are interpreted as reflecting the operation of a. cognitive factor determining responsiveness to symbolic depth cues in two-dimensional reproductions.     

The interaction between emotion and executive control: Comparison between visual,auditory, and tactile modalities

The reciprocal connections between emotion and attention are vital for adaptive behaviour. Previous results demonstrated that the behavioural effects of emotional stimuli on performance are attenuated when executive control is recruited. The current research studied whether this attenuation is modality dependent. In two experiments, negative and neutral pictures were presented shortly before a visual, tactile, or auditory target in a Simon task. All three modalities demonstrated a Simon effect, a conflict adaptation effect, and an emotional interference effect. However, the interaction between picture valence and Simon congruency was found only in the visual task. Specifically, when the Simon target was visual, emotional interference was reduced during incongruent compared to congruent trials. These findings suggest that although the control-related effects observed in the Simon tasks are not modality dependent, the link between emotion and executive control is modality dependent. Presumably, this link occurs only when the emotional stimulus and the target are presented in the same modality.     

Factors affecting processing mode in visual search

Visual search was studied under a variety of conditions to clarify some differences among the results of previous investigations and to provide a testing ground for models of visual information processing. Display configuration, target and field composition, exposure duration, and display size (up to 16 elements) were among the parameters investigated. In some conditions, mean reaction time was essentially invariant with display size, while in other conditions it increased substantially and linearly with display size. Current models of visual information processing were evaluated in the light of these and previous findings; all were found wanting. The data seem to demand a system subject to flexible cognitive control processes.     

The coordination of visual and tactual input in infants

Traditionally it has been taught that “touch teaches vision” in ontogeny. Recent experiments have shown that in judgment situations vision dominates touch, a finding that has been taken to weaken the traditional argument. The force of the finding is vitiated to some extent by the functional dominance of touch. Developmental experiments show that initially in ontogeny vision is functionally dominant, strengthening the case against the traditional argument.     

The tactual horizontal-vertical illusion depends on radial motion of the entire arm

Wesought to clarify the causes of the tactual horizontal-vertical illusion, where vertical lines are overestimated as compared with horizontals in Land inverted-T figures. Experiment 1 did not use L or inverted-T figures, but examined continuous or bisected horizontal and vertical lines. It was expected that bisected lines would be perceived as shorter than continuous lines, as in the inverted-T figure in the horizontal-vertical illusion. Experiment 1 showed that the illusion could not be explained solely by bisection, since illusory effects were similar for continuous and bisected vertical and horizontal lines. Experiments 2 and 3 showed that the illusory effects were dependent upon stimulus size and scanning strategy. Overestimation of the vertical was minimal or absent for the smallest patterns, where it was proposed that stimuli were explored by finger movement, with flexion at the wrist. Larger stimuli induce whole-arm motions, and illusory effects were found in conditions requiring radial arm motion. The illusion was weakened or eliminated in Experiment 4 when subjects were forced to examine stimuli with finger-and-hand motion alone, that is, their elbows were kept down on the table surface, and they were prevented from making radial arm motions. Whole-arm motion damaged performance and induced perceptual error. The experiments support the hypothesis that overestimation of the vertical in the tactual horizontal-vertical illusion derives from radial scanning by the entire arm.