Neural Evidence Suggests Both Interference and Facilitation from Embedding Regularity into Visual Search

2020 ◽  
pp. 1-13
Author(s):  
Anna Vaskevich ◽  
Alon Nishry ◽  
Yotam Smilansky ◽  
Roy Luria

In this work, we relied on electrophysiological methods to characterize the processing stages that are affected by the presence of regularity in a visual search task. EEG was recorded for 72 participants while they completed a visual search task. Depending on the group, the task contained a consistent-mapping condition, a random-mapping condition, or both consistent and random conditions intermixed (mixed group). Contrary to previous findings, the control groups allowed us to demonstrate that the contextual cueing effect that was observed in the mixed group resulted from interference, not facilitation, to the target selection, response selection, and response execution processes (N2-posterior-contralateral, stimulus-locked lateralized readiness potential [LRP], and response-locked LRP components). When the regularity was highly valid (consistent-only group), the presence of regularity drove performance beyond general practice effects, through facilitation in target selection and response selection (N2-posterior-contralateral and stimulus-locked LRP components). Overall, we identified two distinct effects created by the presence of regularity: a global effect of validity that dictates the degree to which all information is taken into account and a local effect of activating the information on every trial. We conclude that, when considering the influence of regularity on behavior, it is vital to assess how the overall reliability of the incoming information is affected.

Perception ◽  
1976 ◽  
Vol 5 (2) ◽  
pp. 225-231
Author(s):  
Robert T Solman

By increasing the number of display items and the physical similarity between the target and the irrelevant items it was possible to vary the difficulty of target selection in a visual-search task. The results showed that the accuracy with which the target was located declined as target selection became more difficult. On the other hand, estimates of the cumulative probability and the probability distributions of times necessary to form the icon indicated that these times were not influenced by changes in the difficulty of the task. The latter result supports Neisser's suggestion that the information processing carried out during the first stage of analysis can be attributed to the action of a distinct cognitive mechanism.


2009 ◽  
Vol 102 (5) ◽  
pp. 2681-2692 ◽  
Author(s):  
Joo-Hyun Song ◽  
Robert M. McPeek

We examined the coordination of saccades and reaches in a visual search task in which monkeys were rewarded for reaching to an odd-colored target among distractors. Eye movements were unconstrained, and monkeys typically made one or more saccades before initiating a reach. Target selection for reaching and saccades was highly correlated with the hand and eyes landing near the same final stimulus both for correct reaches to the target and for incorrect reaches to a distractor. Incorrect reaches showed a bias in target selection: they were directed to the distractor in the same hemifield as the target more often than to other distractors. A similar bias was seen in target selection for the initial saccade in correct reaching trials with multiple saccades. We also examined the temporal coupling of saccades and reaches. In trials with a single saccade, a reaching movement was made after a fairly stereotyped delay. In multiple-saccade trials, a reach to the target could be initiated near or even before the onset of the final target-directed saccade. In these trials, the initial trajectory of the reach was often directed toward the fixated distractor before veering toward the target around the time of the final saccade. In virtually all cases, the eyes arrived at the target before the hand, and remained fixated until reach completion. Overall, these results are consistent with flexible temporal coupling of saccade and reach initiation, but fairly tight coupling of target selection for the two types of action.


2002 ◽  
Vol 88 (4) ◽  
pp. 2019-2034 ◽  
Author(s):  
Robert M. McPeek ◽  
Edward L. Keller

Because real-world scenes typically contain many different potential objects of interest, selecting one goal from many is clearly a fundamental problem faced by the saccadic system. We recorded from visual, movement, and visuo-movement (VM) neurons in the superior colliculus (SC) of monkeys performing a reaction-time visual-search task requiring them to make saccades to an odd-colored target presented with distractors. First, we compared the responses of SC neurons in search with their responses when a single target was presented without distractors (single-stimulus task). Consistent with earlier reports, initial visual activity was smaller in search than in the single-stimulus task, while movement-related activity in the two tasks was comparable. Further experiments showed that much of the reduction in the initial visual response during search was due to lateral inhibition, although a top-down task-related component was also evident. Although the initial visual activity did not discriminate the target from the distractors, some neurons showed a biphasic pattern of visual activity. In VM burst neurons, the second phase of this activity was significantly larger when the target, rather than a distractor, was in the response field. We traced the time course of target/distractor discrimination using receiver operating characteristic (ROC) analysis and found that VM burst neurons, VM prelude neurons, and pure movement neurons discriminated the target from distractors before saccade onset but that phasic and tonic pure visual neurons did not. We also examined the relationship between target/distractor discrimination time and saccade latency. Discrimination in VM burst neurons having a biphasic pattern of visual activity and in many VM prelude neurons occurred after a consistent delay that did not depend on saccade latency, suggesting that these neurons are involved in target selection as well as movement initiation. In contrast, VM burst neurons lacking a biphasic pattern of visual activity, pure movement neurons, and a subset of VM prelude neurons discriminated the target at a time that was well correlated with saccade latency, suggesting that this latter group of neurons is involved in triggering movement execution but not in target selection. Thus a mix of signals likely related to target selection and movement initiation co-exists in different groups of SC neurons. This suggests that certain types of SC neurons participate in the target selection process and that the SC as a whole represents a gateway for target selection signals to be converted into a saccadic command.


1976 ◽  
Vol 42 (2) ◽  
pp. 399-402 ◽  
Author(s):  
Paul N. Russell ◽  
Anthony E. Page

The response times of 16 paranoids, 16 nonparanoids and 16 normals were compared on a search task which required subjects to identify target letters embedded in displays of varying numbers of non-targets. The rate of increase in response times with increased numbers of letters displayed was not markedly different for the various groups, although a derived measure of decision and response-selection time indicated that normals selected responses more rapidly. When compared with normals, schizophrenics seemed to experience more difficulty in response selection and decision than in processing visual stimulus information.


2019 ◽  
Vol 19 (10) ◽  
pp. 308b
Author(s):  
M Pilar Aivar ◽  
Sandra Miguel ◽  
Elena Sanz

2019 ◽  
Author(s):  
Kaleb A. Lowe ◽  
Jeffrey D. Schall

ABSTRACTNeurons in macaque frontal eye field contribute to spatial but typically not feature selection during visual search. Using an innovative visual search task, we report a serendipitous discovery that some frontal eye field neurons can develop rapid selectivity for stimulus orientation that is used to guide gaze during a visual search task with pro-saccade and anti-saccade responses. This feature selectivity occurs simultaneously at multiple locations for all objects sharing that feature and coincides with when neurons select the singleton of a search array. This feature selectivity also reveals the distinct, subsequent operation of selecting the endpoint of the saccade in pro-saccade as well as anti-saccade trials. These results demonstrate that target selection preceding saccade preparation is composed of multiple operations. We conjecture that singleton selection indexes the allocation of attention, which can be divided, to conspicuous items. Consequently, endpoint selection indexes the focused allocation of attention to the endpoint of the saccade. These results demonstrate that saccade target selection is not a unitary process.SIGNIFICANCE STATEMENTFrontal eye field is well known to contribute to spatial selection for attention and eye movements. We discovered that some frontal eye field neurons can acquire selectivity for stimulus orientation when it guides visual search. The chronometry of neurons with and without feature selectivity reveal distinct operations accomplishing visual search.


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