Parallel and serial search in haptics

Haptic processing of the location of a known property: does knowing what you've touched tell you where it is? Visual search for targets defined by combinations of color, shape, and size: an examination of the task constraints on feature and conjunction searches. Visual search for simple volumetric shapes. Response times and eye movements in feature and conjunction search as a function of target eccentricity.

Attentional requirements in a 'preattentive' feature search task. Show 10 more references 10 of Smart citations by scite. The number of the statements may be higher than the number of citations provided by EuropePMC if one paper cites another multiple times or lower if scite has not yet processed some of the citing articles.

Explore citation contexts and check if this article has been supported or disputed. Search efficiency for tactile features rendered by surface haptic displays. The effect of perceptual grouping on haptic numerosity perception. Roughness perception across the hands.

Similar Articles To arrive at the top five similar articles we use a word-weighted algorithm to compare words from the Title and Abstract of each citation. Haptic search with finger movements: using more fingers does not necessarily reduce search times. Perceptual grouping in haptic search: the influence of proximity, similarity, and good continuation.

Orientation asymmetry in the flanker task. Serial vs. Joining Europe PMC. Tools Tools overview. ORCID article claiming. Journal list. Grant finder. External links service. The same subjects as in Experiment 1 and 2 participated. The methodwas again as described in Experiment 1 , except that items consisted of high 4 cm and low 2 cm wooden blocks.

Subjects were instructed to respond with the number of high blocks. Setup and results of Experiment 3. The meaning of the symbols is the same as in Figs. Linear regression was performed on the response times for one to three items and those for three to five items Fig. The fact that the slope for small numerosities was not smaller than the slope for medium numerosities indicates that there was no subitizing in this case. Therefore, we conclude that differences in proprioceptive information across fingers does not enable subitizing.

This means that the absence of tactile stimulation on the fingers that were not being counted in Experiment 2 is crucial for subitizing to be enabled. Our results show that subitizing was possible only in Experiment 2 , in which the number of fingers touching a wooden block had to be determined.

In Experiment 1 , where subjects had to determine the number of fingers touching a raised line,and in Experiment 3 , in which subjects had to report the number of fingers touching a high wooden block, subitizing was not possible.

Riggs et al. In that study, the number of fingers receiving tactile information had to be determined. This iscomparable to the situation in Experiment 2 of the present study, in which some fingers did not receive any tactile stimulation.

These findings suggest that the number of objects can be subitized, but not a certain type of object among other objects, such as the raised lines among flat pieces of swell paper in Experiment 1 of the present study.

Note that in Experiment 1 , response times were remarkably large. In Experiment 1 , there was essentially only tactile information, while in Experiment 2 and 3 , there was also proprioceptive information. This does not mean that tactile information processing is generally slow. Braille reading, for instance, can be quite efficient. Note, however, that Braille reading involves pattern recognition of raised dots. Pattern recognition is much faster than numerosity judgment.

It is, however, possible that lateral scanning of tactile information,as in Braille reading, facilitates processing of the input. Note that there is serial input of information in this case. Since subitizing is believed to be a parallel process, all items should be available at the same time. The subitizing, as well as the counting, slopes found in Experiment 2 of the present study are somewhat smaller than those reported in previous studies for numerosity judgment.

In the study of Riggs et al. It is possible that this active touch improved performance in the present study. The counting slopes were, in the latter case, however, considerably larger. This difference is probably due to the fact that counting of loose objects grasped in the hand is more demanding due to the difficulty of keeping track of which items have been counted already.

The reason for this difference in response time slopes between the modalities is not yet clear. It is, however, congruent with the fact that haptic search slopes are generally found to be larger than visual search slopes Plaisier et al. This indicates that this difference in response time slope values between the modalities is notspecific to numerosity judgment and originates from a more general difference in processing of information.

A possible explanation for the absence of subitizing in Experiment 1 and 3 is that cutaneous input from a flat surface can be regarded as a distractor. As was mentioned already in the introduction, adding distractors impairs or even prohibits subitizing in both vision and touch Plaisier et al. The results of the present study can be interpreted in a similar way. A horizontal raised line among flat pieces of swell paper yields parallel search but cannot be subitized.

Apparently, fingers touching a flat surface can be regarded as distractors Experiments 1 and 3 , while fingers that do not receive tactile input do not function as distractors Experiment 2. In vision, a set of concentric circles is an example of a stimulus that cannot be subitized but can be counted accurately.

The same set of circles can, however, be subitized when spatially distributed. Trick and Pylyshyn suggested that items have to bespatially distributed to allow subitizing in vision. Trick and Pylyshyn suggested that items are individuated before the numerosity can be judged.

Spatial distribution of the items probably allows for fast item individuation, which could be necessary to enable subitizing.

In touch, we often judge the number of objects in our hand. In that case, there is no fixed spatial arrangement of the items, and they also do not need to be segmented from a background. An object is present or it is not; it is not a dot on a uniform surface,as is often the case in vision. Therefore, it would make sense that in touch,subitizing is used for judging the total number of objects being touched.

Objects that are not present simply do not give tactile input. In this light, it makes sense that the number of fingers touching an object can be subitized but the mechanism breaks down when all fingers are touching a surface and receive some type of tactile input.

This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author s and source are credited. Read article at publisher's site DOI : Front Hum Neurosci , , 21 Jun Psychol Res , 82 3 , 26 Dec Cited by: 2 articles PMID: Perception , 45 , 01 Jan Cited by: 0 articles PMID: Perception , 45 , 03 Nov Cited by: 1 article PMID: To arrive at the top five similar articles we use a word-weighted algorithm to compare words from the Title and Abstract of each citation.

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Europe PMC requires Javascript to function effectively. Recent Activity. Because of noise in the parallel that case equals the total number of items. As a result of maps, a serial stage has to examine incorrect items if the these facts, the slope of the search function in the target- differences are not very large. The presence of a unique fea- present condition will be half the magnitude of that in the ture generates a strong signal that quickly exceeds the back- target-absent condition.

The serial search number of distractors. Both of these modifications become model is a single linear regression if the search time is relevant when it is difficult to distinguish the target from the expressed as a function of the effective number of items, distractors, so that performance is intermediate between the including both the target-present and target-absent con- purely serial and purely parallel predictions. To conform to the tradition in the search litera- The value of all such theories is that they can be used ture, we will report the slope for the target-present trials to develop quantitative models of human performance.

In in terms of the total number of display elements for our this article, we propose a model for haptic search with a fit of the serial search model. This slope is by definition clear distinction between serial and parallel search pat- half of the slope in the target-absent condition i.

In this model, we assume that we are certain about the slope in terms of the effective number of items. This the relevant units and, therefore, the number of items. In results in the following search functions with slope s i. Haptic search models for serial and parallel search. The slope of the target-absent function is 2s. At the intercept i.

In the target-present condition, average time required to process one item in the display, this does not influence the overall search time; the overall which depends only on the difficulty of identifying the average search time equals the average search time of an items presented.

We will next examine whether found. If we as- many items they were going to be shown. No Edge Edge Horiz. No Edge Horizontal vs. The lines represent the best fits of our serial top three graphs and parallel bottom three graphs models.

Par- location of the items was not known in advance. Thus, ticipants had to indicate target presence or absence by lifting participants had to detect the target when it was present, the finger under which they thought the target was present. Before we conducted the search experiments, we wanted ones , reveals that this difference in their methodology to check whether all fingers index, middle, and ring have may be an issue.

The lines in the figure show the best fits about the same mechanical lifting time. Our initial thoughts of the two sets of equations that we propose. It is evident were that the ring finger would have the slowest lifting time, that neither fits the data very well. In particular, there is because subjectively it seems to be harder to lift this finger. The participant therefore first had to determine ment. Two of them stated that they were left-handed.

Stimuli and Apparatus. If searching for Cheshire, England. They were positioned so that par- our model to these data. An obvious solution would be ticipants could easily put the fingertips of their index, middle, and to repeat such experiments, keeping the number of items ring fingers on the centers of the display elements.

A sensor under each element measured whether there was a finger on top of it. In constant within each block. A In our experiments, we presented different numbers of curtain was placed between the participant and the apparatus to pre- items in separate blocks to both index fingers; both index vent the participant from seeing the display.

The stimulus in this experiment was a Hz tone. The experimental setup. The positions of the stimulus elements could be adjusted to the posi- tions of the fingers of the participant. Under each element was a sensor that measured whether a finger was on top of it. Participants put their fingers on the display ele- presented trials with the same number of items in blocks ments.

Their task was to lift one or all of their fingers as soon as and used a simple stimulus—response compatibility. We possible after hearing the tone. To indicate which finger or fingers chose a very common target—distractor pair for eliciting the participant had to lift, the experimenter either touched the finger a parallel pattern in visual search, a cross as a target and in question or stated that the participant had to lift all fingers.

There was a single block This target differs from the distractors in many ways line of trials. Within this block, 20 replications of each of the seven crossings, line endings, closed shape, curvature ; we ex- conditions lifting the index, middle, and ring finger of each hand, or pected the distinction itself to be quite easy to make, so lifting all six fingers were presented in a random order.

RT was defined as the time that elapsed from the mo- the introduction above. In the all- fingers condition, the RT was the time that elapsed until the first finger was lifted. Eight participants, 4 male and 4 female, with a bad positioning of the finger on the sensor. We calculated the median mean age of To see whether there were any ment.

The target was a Results cross, and the distractors were circles. There was no main effect of finger and no resulting in widths of the stimuli of 8. The task was to find the target among the distractors.

If anything, the ring finger seemed to be faster onto the display elements in response to a tone. As soon as they than the others. Thus, we did not need to take account of found the target, they had to lift the finger under which they felt the mechanical lifting time when designing the following the target. A feature-integration theory of attention. Cognitive Psychology , 12 , 97— Feature analysis in early vision: Evidence from search asymmetries.

Psychological Review , 95 , 15— Conjunction search revisited. Wolfe, J. Guided Search 2. Guided search: An alternative to the feature integration model for visual search. What attributes guide the deployment of visual attention and how do they do it? Nature Reviews Neuroscience , 5 , — Download references. Overvliet, J. You can also search for this author in PubMed Google Scholar. Correspondence to K.

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