Along with target amplification, distractor inhibition is regarded as a major contributor to sele... more Along with target amplification, distractor inhibition is regarded as a major contributor to selective attention. Some existing models suggest that the strength of inhibitory processing is proportional to the salience of the distractor. Other models suggest that there is no obvious relationship between the intensity of distractor processing and distractor inhibition. The present study aimed to elucidate the relationship between the initial intensity of the processing of a distractor and its subsequent inhibition. A flanker task with a variable distractor-target stimulus-onset asynchrony (SOA) was used to measure both distractor interference and distractor inhibition. We manipulated the intensity of the distractor in two separate ways, by varying its distance from the target (Experiment 1) and by varying its brightness (Experiment 2). The results indicate that more intensely processed distractors were associated with both increased interference and stronger distractor inhibition. This outcome supports reactive inhibition models, which posit that inhibition reacts to the strength of distractor input, producing a positive relationship between the strength of the distractor and the strength of distractor inhibition.
Research suggests that although target amplification acts as the main determinant of the efficacy... more Research suggests that although target amplification acts as the main determinant of the efficacy of selective attention, distractor inhibition contributes under some circumstances. Here we aimed to gain insight into the operating principles that regulate the use of distractor inhibition during selective attention. The results suggest that, in contrast to target amplification, distractor inhibition does not onset earlier or strengthen in response to advance location information. Instead, when the location of the impending distractor was predictable, evidence of inhibitory processing weakened. Furthermore, the results suggest that distractor inhibition does not operate as a compensatory mechanism for target amplification, as evidenced by the lack of an increase in inhibitory effects when reliance on target amplification was disrupted. Unexpected emergence of inhibitory effects for improbable targets provided evidence that distractor inhibition was at work even when no inhibitory effects manifested. Overall, the pattern of inhibitory effects is interpreted as indicating that, although distractor inhibition mounts primarily reactively rather than preemptively, advance information can help prevent overreaction to the distractor. Of course, less overreaction reduces the chances of behavioral inhibitory effects manifesting even when distractor inhibition has contributed to selective attention; thus, interpreting an absence of inhibitory effects should be done cautiously.
Humans have a remarkable capability to respond efficiently to a stimulus of interest despite othe... more Humans have a remarkable capability to respond efficiently to a stimulus of interest despite other stimuli competing for neural resources. The current study investigated how the human system copes with distracting stimuli. During each trial, participants viewed 2 sequential stimuli that were each associated with a specific action based on an arbitrary mapping. The 1st stimulus served as a distractor, and the 2nd stimulus required a response (target). When the distractor preceded the target by more than a few hundred milliseconds, response latencies were slower when the 2 stimuli were associated with the same response. The authors propose that this negative compatibility effect stemmed from an inhibitory mechanism that the human system utilizes to prevent the distractor from eliciting an unwanted response.
Focused attention can becompromised by the neurodegenerative processes associated with both healt... more Focused attention can becompromised by the neurodegenerative processes associated with both healthy aging and Parkinson’s disease (PD). Deficits in ignoring distractors with reflexive or overlearned response links have been attributed to impaired inhibition. The current research assessed whether similar deficits occur for distractors with recently learned arbitrary response associations, for which sensorimotor transformations are far less automatic and therefore considerably easier to resist.We used a selective attention task that evaluated distractibility and the use of distractor inhibition within the same context. The task involved stimuli that were arbitrarily assigned to responses based on a rule learned during the test-ing session. Performance showed that distraction increased with both healthy aging and PD. Moreover, these increases in distraction were accompanied by decreases in overt evidence of distractor inhibition, which appear to reflect at least in part a failure of reactive inhibition. Comparison of the deficits in the two groups indicates that the key difference reflects severity, rather than distinct symptoms, suggesting that they stem from neural changes associated with both aging and PD. These results demonstrate that aging- and PD-related hyper-distractibility and impaired inhibition during focused attention affect stimuli without prepotent response links, which implicates dopaminergic networks in the strategic control
of arbitrary visuomotor transformations.
The present body of research explores some of the key conditions that influence the contribution ... more The present body of research explores some of the key conditions that influence the contribution of distractor inhibition to selective attention. In particular, the present experiments addressed three questions: (1) whether distractor inhibition is facilitated by foreknowledge of the location of a distractor; (2) whether distractor inhibition strengthens to compensate for disruption in target amplification that is caused by the target having an unpredictable location; and (3) whether distractor inhibition is strengthened by stronger processing of the distractors that is caused by the distractor being presented closer to or brighter than the target. Each of the present experiments employed a variation of Machado, Wyatt, Devine and Knight’s (2007) variable flanker task. By presenting the distractor in advance of the target, distractor interference could be measured at short intervals (via the positive compatibility effect), and distractor inhibition could be measured at longer intervals (via the negative compatibility effect). The results showed that distractor inhibition does not strengthen when the location of the distractor is known in advance; instead, advance knowledge of location can be used to apply inhibition at the appropriate level. Furthermore, distractor inhibition does not strengthen to compensate when a variable target location disrupts target processing, but weak inhibitory processing can be revealed in the presence of weaker target processing. Additionally, the strength of distractor inhibition was found to be controlled reactively, such that it strengthened when the distractor stimuli were intensely processed. These results indicate that the strength of distractor inhibition is determined not only by the physical characteristics of distractor stimuli, but also by top-down factors. As such, the present data suggest that the control of distractor inhibition is more complex than currently envisioned, and more research is required in order to fully understand the effect of advance knowledge of distractor stimuli on inhibition.
Our visual system is constantly bombarded with stimuli, much of which are irrelevant. Despite thi... more Our visual system is constantly bombarded with stimuli, much of which are irrelevant. Despite this, we are generally able to respond only to relevant information. Using a flanker task, B. A. Eriksen and Eriksen (1974) found that reaction times were faster when both the target and the distractor corresponded to the same response, than when they corresponded to different responses. Machado, Wyatt, Devine, and Knight (in press) found that this effect reverses if the target is presented more than a few hundred milliseconds after the distractor. This finding suggests that when a stimulus does not require a response, the neural representation associated with that stimulus becomes inhibited, rendering it less available for future responses. The present study investigated under which circumstances we utilise inhibition in order to respond effectively in the presence of distracting information. The difficulty of inhibiting the distractor was manipulated by adjusting the distance between the target and the distractor, the umber of possible distractor positions, and the number of possible target positions. The results showed that distractor inhibition was reduced when the distractor either did appear or could appear in close spatial proximity to the target. In addition, distractor inhibition was reduced when the distractor location was either certain or very uncertain. Furthermore, distractor inhibition was not enhanced when the target location was unknown, even when the distractor location was known. Taken together, these results indicate that the role of
distractor inhibition in selective attention is more complicated than current models
suggest.
Along with target amplification, distractor inhibition is regarded as a major contributor to sele... more Along with target amplification, distractor inhibition is regarded as a major contributor to selective attention. Some existing models suggest that the strength of inhibitory processing is proportional to the salience of the distractor. Other models suggest that there is no obvious relationship between the intensity of distractor processing and distractor inhibition. The present study aimed to elucidate the relationship between the initial intensity of the processing of a distractor and its subsequent inhibition. A flanker task with a variable distractor-target stimulus-onset asynchrony (SOA) was used to measure both distractor interference and distractor inhibition. We manipulated the intensity of the distractor in two separate ways, by varying its distance from the target (Experiment 1) and by varying its brightness (Experiment 2). The results indicate that more intensely processed distractors were associated with both increased interference and stronger distractor inhibition. This outcome supports reactive inhibition models, which posit that inhibition reacts to the strength of distractor input, producing a positive relationship between the strength of the distractor and the strength of distractor inhibition.
Research suggests that although target amplification acts as the main determinant of the efficacy... more Research suggests that although target amplification acts as the main determinant of the efficacy of selective attention, distractor inhibition contributes under some circumstances. Here we aimed to gain insight into the operating principles that regulate the use of distractor inhibition during selective attention. The results suggest that, in contrast to target amplification, distractor inhibition does not onset earlier or strengthen in response to advance location information. Instead, when the location of the impending distractor was predictable, evidence of inhibitory processing weakened. Furthermore, the results suggest that distractor inhibition does not operate as a compensatory mechanism for target amplification, as evidenced by the lack of an increase in inhibitory effects when reliance on target amplification was disrupted. Unexpected emergence of inhibitory effects for improbable targets provided evidence that distractor inhibition was at work even when no inhibitory effects manifested. Overall, the pattern of inhibitory effects is interpreted as indicating that, although distractor inhibition mounts primarily reactively rather than preemptively, advance information can help prevent overreaction to the distractor. Of course, less overreaction reduces the chances of behavioral inhibitory effects manifesting even when distractor inhibition has contributed to selective attention; thus, interpreting an absence of inhibitory effects should be done cautiously.
Humans have a remarkable capability to respond efficiently to a stimulus of interest despite othe... more Humans have a remarkable capability to respond efficiently to a stimulus of interest despite other stimuli competing for neural resources. The current study investigated how the human system copes with distracting stimuli. During each trial, participants viewed 2 sequential stimuli that were each associated with a specific action based on an arbitrary mapping. The 1st stimulus served as a distractor, and the 2nd stimulus required a response (target). When the distractor preceded the target by more than a few hundred milliseconds, response latencies were slower when the 2 stimuli were associated with the same response. The authors propose that this negative compatibility effect stemmed from an inhibitory mechanism that the human system utilizes to prevent the distractor from eliciting an unwanted response.
Focused attention can becompromised by the neurodegenerative processes associated with both healt... more Focused attention can becompromised by the neurodegenerative processes associated with both healthy aging and Parkinson’s disease (PD). Deficits in ignoring distractors with reflexive or overlearned response links have been attributed to impaired inhibition. The current research assessed whether similar deficits occur for distractors with recently learned arbitrary response associations, for which sensorimotor transformations are far less automatic and therefore considerably easier to resist.We used a selective attention task that evaluated distractibility and the use of distractor inhibition within the same context. The task involved stimuli that were arbitrarily assigned to responses based on a rule learned during the test-ing session. Performance showed that distraction increased with both healthy aging and PD. Moreover, these increases in distraction were accompanied by decreases in overt evidence of distractor inhibition, which appear to reflect at least in part a failure of reactive inhibition. Comparison of the deficits in the two groups indicates that the key difference reflects severity, rather than distinct symptoms, suggesting that they stem from neural changes associated with both aging and PD. These results demonstrate that aging- and PD-related hyper-distractibility and impaired inhibition during focused attention affect stimuli without prepotent response links, which implicates dopaminergic networks in the strategic control
of arbitrary visuomotor transformations.
The present body of research explores some of the key conditions that influence the contribution ... more The present body of research explores some of the key conditions that influence the contribution of distractor inhibition to selective attention. In particular, the present experiments addressed three questions: (1) whether distractor inhibition is facilitated by foreknowledge of the location of a distractor; (2) whether distractor inhibition strengthens to compensate for disruption in target amplification that is caused by the target having an unpredictable location; and (3) whether distractor inhibition is strengthened by stronger processing of the distractors that is caused by the distractor being presented closer to or brighter than the target. Each of the present experiments employed a variation of Machado, Wyatt, Devine and Knight’s (2007) variable flanker task. By presenting the distractor in advance of the target, distractor interference could be measured at short intervals (via the positive compatibility effect), and distractor inhibition could be measured at longer intervals (via the negative compatibility effect). The results showed that distractor inhibition does not strengthen when the location of the distractor is known in advance; instead, advance knowledge of location can be used to apply inhibition at the appropriate level. Furthermore, distractor inhibition does not strengthen to compensate when a variable target location disrupts target processing, but weak inhibitory processing can be revealed in the presence of weaker target processing. Additionally, the strength of distractor inhibition was found to be controlled reactively, such that it strengthened when the distractor stimuli were intensely processed. These results indicate that the strength of distractor inhibition is determined not only by the physical characteristics of distractor stimuli, but also by top-down factors. As such, the present data suggest that the control of distractor inhibition is more complex than currently envisioned, and more research is required in order to fully understand the effect of advance knowledge of distractor stimuli on inhibition.
Our visual system is constantly bombarded with stimuli, much of which are irrelevant. Despite thi... more Our visual system is constantly bombarded with stimuli, much of which are irrelevant. Despite this, we are generally able to respond only to relevant information. Using a flanker task, B. A. Eriksen and Eriksen (1974) found that reaction times were faster when both the target and the distractor corresponded to the same response, than when they corresponded to different responses. Machado, Wyatt, Devine, and Knight (in press) found that this effect reverses if the target is presented more than a few hundred milliseconds after the distractor. This finding suggests that when a stimulus does not require a response, the neural representation associated with that stimulus becomes inhibited, rendering it less available for future responses. The present study investigated under which circumstances we utilise inhibition in order to respond effectively in the presence of distracting information. The difficulty of inhibiting the distractor was manipulated by adjusting the distance between the target and the distractor, the umber of possible distractor positions, and the number of possible target positions. The results showed that distractor inhibition was reduced when the distractor either did appear or could appear in close spatial proximity to the target. In addition, distractor inhibition was reduced when the distractor location was either certain or very uncertain. Furthermore, distractor inhibition was not enhanced when the target location was unknown, even when the distractor location was known. Taken together, these results indicate that the role of
distractor inhibition in selective attention is more complicated than current models
suggest.
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of arbitrary visuomotor transformations.
distractor inhibition in selective attention is more complicated than current models
suggest.
of arbitrary visuomotor transformations.
distractor inhibition in selective attention is more complicated than current models
suggest.