Kevin Dent | University of Essex (original) (raw)

Papers by Kevin Dent

Quarterly Journal of Experimental Psychology, 2022

We report two experiments investigating the effect of working memory (WM) load on selective atten... more We report two experiments investigating the effect of working memory (WM) load on selective attention. Experiment 1 was a modified version of Lavie et al. and confirmed that increasing memory load disrupted performance in the classic flanker task. Experiment 2 used the same manipulation of WM load to probe attention during the viewing of complex scenes while also investigating individual differences in attention deficit hyperactivity disorder (ADHD) traits. In the image-viewing task, we measured the degree to which fixations targeted each of two crucial objects: (1) a social object (a person in the scene) and (2) a non-social object of higher or lower physical salience. We compared the extent to which increasing WM load would change the pattern of viewing of the physically salient and socially salient objects. If attending to the social item requires greater default voluntary top-down resources, then the viewing of social objects should show stronger modulation by WM load compared w...

Quarterly Journal of Experimental Psychology, 2018

The “visual cocktail party effect” refers to superior report of a participant’s own name, under c... more The “visual cocktail party effect” refers to superior report of a participant’s own name, under conditions of inattention. An early selection account suggests this advantage stems from enhanced visual processing. A late selection account suggests the advantage occurs when semantic information allowing identification as one’s own name is retrieved. In the context of inattentional blindness (IB), Mack and Rock showed that the advantage does not generalise to a minor modification of a participant’s own name, despite extensive visual similarity, supporting the late selection account. This study applied the name modification manipulation in the context of the attentional blink (AB). Participants were presented with rapid streams of names and identified a white target name, while also reporting the presence of one of two possible probes. The probe names appeared either close (the third item following the target: Lag 3) or far in time from the target (the eighth item following the target: ...

Journal of Experimental Psychology: Learning, Memory, and Cognition, 2017

Three experiments examined the immediate free recall (IFR) of auditory-verbal and visuospatial ma... more Three experiments examined the immediate free recall (IFR) of auditory-verbal and visuospatial materials from single-modality and dual-modality lists. In Experiment 1, we presented participants with between 1 and 16 spoken words, with between 1 and 16 visuo-spatial dot locations, or with between 1 and 16 words and dots with synchronized onsets. We found that for dual-modality lists (1) overall performance, initial recalls, and serial position curves were largely determined by the within-modality list lengths, (2) there was only a small degree of dual-task trade-off (which was limited to the visuo-spatial items), and (3) there were strongly constrained output orders: participants tended to alternate between words and dots from equivalent or neighboring serial positions. In Experiments 2 and 3, we compared lists of 6 single-modality items with dual-modality lists of 6 words and 6 dots with synchronous or alternating onsets (Experiment 2), or random but asynchronous onsets (Experiment 3). In all three dual-modality conditions, we again found only a small trade-off in visuo-spatial (but not verbal) IFR performance. There were similarly highly constrained output orders with the synchronous and alternating onsets, and these patterns were present but attenuated with the randomized onsets. We propose that both auditory-verbal and visuospatial list items are associated with a common temporal episodic context that is used to guide crossmodal retrieval, and we speculate that the limited, asymmetric interference could arise because the less variable representations of the dots share only a relatively small subset of features with the more variable representations of the words.

NeuroImage, 2015

Visual perception is facilitated by the ability to selectively attend to relevant parts of the wo... more Visual perception is facilitated by the ability to selectively attend to relevant parts of the world and to ignore irrelevant regions or features. In visual search tasks, viewers are able to segment displays into relevant and irrelevant items, based on a number of factors including the colour, motion, and temporal onset of the target and distractors. Understanding the process by which viewers prioritise relevant parts of a display can provide insights into the effect of top-down control on visual perception. Here we investigate the behavioural and neural correlates of segmenting a display, according to the expected three dimensional (3D) location of a target. We ask whether this segmentation is based on low-level visual features (e.g., common depth or common surface) or on higher-order representations of 3D regions. Similar response-time benefits and neural activity were obtained when items fell on common surfaces or within depth-defined volumes, and when displays were vertical (such that items shared a common depth / disparity) or were tilted in depth. These similarities indicate that segmenting items according to their 3D location is based on attending to a 3D region, rather than a specific depth or surface. Segmenting the items in depth was mainly associated with increased activation in depth-sensitive parietal regions, rather than depth-sensitive visual regions. We conclude that segmenting items in depth is primarily achieved via higher-order, cue invariant representations rather than through filtering in lower-level perceptual regions.

Vision research, 2014

In preview search when an observer ignores an early appearing set of distractors, there can subse... more In preview search when an observer ignores an early appearing set of distractors, there can subsequently be impeded detection of new targets that share the colour of this preview. This "negative carry-over effect" has been attributed to an active inhibitory process targeted against the old items and inadvertently their features. Here we extend negative carry-over effects to the case of stereoscopically defined surfaces of coplanar elements without common features. In Experiment 1 observers previewed distractors in one surface (1000ms), before being presented with the target and new distractors divided over the old and a new surface either above or below the old one. Participants were slower and less efficient to detect targets in the old surface. In Experiment 2 in both the first and second display the items were divided over two planes in the proportion 66/33% such that no new planes appeared following the preview, and there was no majority of items in any one plane in th...

Vision research, Jan 15, 2012

We examined visual search for letters that were distributed across both 3 dimensional space, and ... more We examined visual search for letters that were distributed across both 3 dimensional space, and time. In Experiment 1, when participants had foreknowledge of the depth plane and time interval where targets could appear, search was more efficient if the items could be segmented either by depth or by time (with a 1000 ms preview), and there were increased benefits when the two cues (depth and time) were combined. In Experiments 2 and 3 the target depth plane was always unknown to the participant. In this case, depth cues alone did not facilitate search, though they continued to increase the preview benefit. In Experiment 4 new items in preview search could fall at the same depth as preview items or a new depth. There was a substantial cost to search if the target appeared at a previewed depth. Experiment 5 showed that this cost remained even when participants knew the target would appear at the old depth on 75% of trials. The results indicate that spatial (depth) and temporal cues co...

Journal of experimental psychology. Learning, memory, and cognition, Jan 22, 2014

When participants are presented with a short list of unrelated words and they are instructed that... more When participants are presented with a short list of unrelated words and they are instructed that they may recall in any order, they nevertheless show a very strong tendency to recall in forward serial order. Thus, if asked to recall in any order: "hat, mouse, tea, stairs," participants often respond "hat, mouse, tea, stairs" even though there was no forward order requirement of the task. In 4 experiments, we examined whether this tendency is language-specific, reflecting mechanisms involved with speech perception, speech production, and/or verbal short-term memory. Specifically, we examined whether we would observe similar findings when participants were asked to recall, in any order, lists of between 1 and 15 nonverbal stimuli, such as visuospatial locations (Experiment 1, Experiment 3, Experiment 4), or touched facial locations (Experiment 2). Contrary to a language-specific explanation, we found corresponding tendencies (albeit somewhat reduced) in the immedi...

Quarterly Journal of Experimental Psychology, 2013

The present study compared the effects of age of acquisition (AoA) on object naming across groups... more The present study compared the effects of age of acquisition (AoA) on object naming across groups of older individuals with cognitive impairments, healthy older controls, and young healthy controls. All participants named a set of 80 pictures, within which both AoA and frequency were manipulated orthogonally. Early-acquired objects were named faster than late-acquired objects across all groups. Response time also declined with age and with cognitive impairment between the groups. The effect of AoA differed across groups, with AoA effects being largest for the older group with cognitive impairments and smallest for the young control group. The present study adds strength to the suggestion that AoA of picture names is one of the factors that influence survival or loss of memories in dementia and cognitive decline, and this could therefore be used as a potential screening test for cognitive impairment disorders in the future.

Quarterly Journal of Experimental Psychology, 2013

Age-of-acquisition (AoA) effects are such that early-acquired items are more quickly recognized a... more Age-of-acquisition (AoA) effects are such that early-acquired items are more quickly recognized and produced than later acquired items. In this laboratory analogue, participants were trained to name a group of Greeble pictures with a novel nonsense name. We manipulated order of acquisition of the stimuli: Half of the stimuli were presented from the onset of training (early acquired) whilst the other half were introduced later in the training schedule (late acquired). At test, when early and late stimuli had equal cumulative frequency, early stimuli were named significantly faster than late items. In a second test, it was also found that visual duration thresholds were significantly smaller for the early items when participants were asked to name the critical items. These findings support the notion that order-of-acquisition effects can be manifest over a short time span in the laboratory, and that the effect of order of acquisition is distinct from mere frequency of exposure. The fi...

Acta Psychologica, 2008

Four experiments examined how age of acquisition (AoA) and word frequency (WF) interact with mani... more Four experiments examined how age of acquisition (AoA) and word frequency (WF) interact with manipulations of image quality in a picture-naming task. Experiments 1 and 2 examined the effect of overlaying the to-be-named picture with irrelevant contours. The magnitude of the AoA effect increased when the contours were added (Experiment 1), but the effect of WF remained constant (Experiment 2). Experiments 3 and 4 examined the effects of reducing the contrast of the contours defining the to-be-named picture. Both the effects of AoA (Experiment 3) and WF (Experiment 4) remained constant in the face of contrast reduction. These results provide an empirical dissociation of the effects of AoA and WF. The results are consistent with the idea that both AoA and the addition of irrelevant contours affect the efficiency of object recognition, but WF affects later processes involved in retrieval of object names. The theoretical implications of these findings in relation to accounts of AoA and frequency and their functional localisation in the lexical system are discussed.

Frontiers in Psychology, 2012

The relatively common experimental visual search task of finding a red X amongst red O's and gree... more The relatively common experimental visual search task of finding a red X amongst red O's and green X's (conjunction search) presents the visual system with a binding problem. Illusory conjunctions (ICs) of features across objects must be avoided and only features present in the same object bound together. Correct binding into unique objects by the visual system may be promoted, and ICs minimized, by inhibiting the locations of distractors possessing non-target features (e.g., Treisman and Sato, 1990). Such parallel rejection of interfering distractors leaves the target as the only item competing for selection; thus solving the binding problem. In the present article we explore the theoretical and empirical basis of this process of active distractor inhibition in search. Specific experiments that provide strong evidence for a process of active distractor inhibition in search are highlighted. In the final part of the article we consider how distractor inhibition, as defined here, may be realized at a neurophysiological level (Treisman and Sato, 1990).

Four experiments examined the effect of pairing colours with either homogeneous or heterogeneous ... more Four experiments examined the effect of pairing colours with either homogeneous or heterogeneous shapes on a short-term memory task. Experiment 1 found no differences in colour memory for displays in which colours were each associated with different shapes, paired with individual homogeneous shapes, or paired with heterogeneous shapes. In contrast, Experiment 2 found that when participants were asked to remember the specific pairings of colours, memory was improved for heterogeneous shape displays. The benefit for heterogeneous shapes appears to be memorial, rather than a benefit at the time of encoding (Experiment 3) or retrieval (Experiment 4). The present study suggests that distinctive shapes can be used to help bind colour associations in visual short term memory.

Neurocase, Jan 1, 2011

Two experiments examined extinction to stimuli presented either with contracting or expanding mot... more Two experiments examined extinction to stimuli presented either with contracting or expanding motion. Experiment 1 used solid shapes which either increased or decreased in size rapidly, consistent with looming motion. Experiment 2 employed random dots so that stimulus size was not confounded with type of motion. In both experiments extinction was modulated by the type of motion presented, with extinction most evident when a contracting object was in the weaker visual field. In addition, in Experiment 2 there was evidence for grouping modulating extinction, when there were looming stimuli in both fields. The results suggest that looming motion is a powerful determinant of stimulus salience in selective attention.

Attention, Perception, & …, Jan 1, 2011

We used a probe-dot procedure to examine the roles of excitatory attentional guidance and distrac... more We used a probe-dot procedure to examine the roles of excitatory attentional guidance and distractor suppression in search for movement-form conjunctions. Participants in Experiment 1 completed a conjunction (moving X amongst moving Os and static Xs) and two single-feature (moving X amongst moving Os, and static X amongst static Os) conditions. "Active" participants searched for the target, whereas "passive" participants viewed the displays without responding. Subsequently, both groups located (left or right) a probe dot appearing in either an occupied or an unoccupied location. In the conjunction condition, the active group located probes presented on static distractors more slowly than probes presented on moving distractors, reversing the direction of the difference found within the passive group. This disadvantage for probes on static items was much stronger in conjunction than in single-feature search. The same pattern of results was replicated in Experiment 2, which used a go/no-go procedure. Experiment 3 extended the go/no-go procedure to the case of search for a static target and revealed increased probe localisation times as a consequence of active search, primarily for probes on moving distractor items. The results demonstrated attentional guidance by inhibition of distractors in conjunction search.

Psychonomic Bulletin & Review, Jan 1, 2011

A growing number of studies have shown that significant impairments to search and selection can o... more A growing number of studies have shown that significant impairments to search and selection can occur if the target item carries a feature of the irrelevant distractors currently being ignored Braithwaite, Humphreys, and Hodsoll (Journal of Experimental Psychology: Human Perception and Performance, 29, 758-778, 2003). However, these effects have been documented only when search has been extended over time (i.e., in preview search), and not in standard search displays with simultaneously presented items. Here, we present the first evidence that similar costs to selection can occur in simultaneous displays under appropriate circumstances. In the present experiment, participants searched a display for a moving target letter among static and moving distractors. Search efficiency was significantly enhanced for a moving target when half of the letters moved (and half remained static), allowing the static items to be excluded from search. However, if the moving target then shared its color with the irrelevant static items, significant costs emerged, relative to baselines. These results are consistent with the involvement of a general feature-based suppression mechanism in selection, operating over space as well as time.

Cognitive neuropsychology, Jan 1, 2010

It has been argued that area hMT+/V5 in humans acts as a motion filter, enabling targets defined ... more It has been argued that area hMT+/V5 in humans acts as a motion filter, enabling targets defined by a conjunction of motion and form to be efficiently selected. We present data indicating that (a) damage to parietal cortex leads to a selective problem in processing motion-form conjunctions, and (b) that the presence of a structurally and functional intact hMT+/V5 is not sufficient for efficient search for motion-form conjunctions. We suggest that, in addition to motion-processing areas (e.g., hMT+/V5), the posterior parietal cortex is necessary for efficient search with motion-form conjunctions, so that damage to either brain region may bring about deficits in search. We discuss the results in terms of the involvement of the posterior parietal cortex in the top-down guidance of search or in the binding of motion and form information.

Behavior research …, Jan 1, 2010

In the present study, we presented picture-naming latencies along with ratings for a set of impor... more In the present study, we presented picture-naming latencies along with ratings for a set of important characteristics of pictures and picture names: age of acquisition, frequency, picture-name agreement, name agreement, visual complexity, familiarity, and word length. The validity of these data was established by calculating correlations with previous studies. Regression analyses show that our ratings account for a larger amount of variance in RTs than do previous data. RTs were predicted by all variables except complexity and length. A complete database presenting details about all of these variables is available in the supplemental materials, downloadable from http://brm.psychonomic-journals.org/content/supplemental.

Cortex; a journal devoted to the study of …, Jan 1, 2010

J.J. Braithwaite). a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l ... more J.J. Braithwaite). a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c o r t e x c o r t e x 4 7 ( 2 0 1 1 ) 6 2 8 e6 3 2 0010-9452/$ e see front matter ª

Quarterly Journal of Experimental Psychology, 2022

We report two experiments investigating the effect of working memory (WM) load on selective atten... more We report two experiments investigating the effect of working memory (WM) load on selective attention. Experiment 1 was a modified version of Lavie et al. and confirmed that increasing memory load disrupted performance in the classic flanker task. Experiment 2 used the same manipulation of WM load to probe attention during the viewing of complex scenes while also investigating individual differences in attention deficit hyperactivity disorder (ADHD) traits. In the image-viewing task, we measured the degree to which fixations targeted each of two crucial objects: (1) a social object (a person in the scene) and (2) a non-social object of higher or lower physical salience. We compared the extent to which increasing WM load would change the pattern of viewing of the physically salient and socially salient objects. If attending to the social item requires greater default voluntary top-down resources, then the viewing of social objects should show stronger modulation by WM load compared w...

Quarterly Journal of Experimental Psychology, 2018

The “visual cocktail party effect” refers to superior report of a participant’s own name, under c... more The “visual cocktail party effect” refers to superior report of a participant’s own name, under conditions of inattention. An early selection account suggests this advantage stems from enhanced visual processing. A late selection account suggests the advantage occurs when semantic information allowing identification as one’s own name is retrieved. In the context of inattentional blindness (IB), Mack and Rock showed that the advantage does not generalise to a minor modification of a participant’s own name, despite extensive visual similarity, supporting the late selection account. This study applied the name modification manipulation in the context of the attentional blink (AB). Participants were presented with rapid streams of names and identified a white target name, while also reporting the presence of one of two possible probes. The probe names appeared either close (the third item following the target: Lag 3) or far in time from the target (the eighth item following the target: ...

Journal of Experimental Psychology: Learning, Memory, and Cognition, 2017

Three experiments examined the immediate free recall (IFR) of auditory-verbal and visuospatial ma... more Three experiments examined the immediate free recall (IFR) of auditory-verbal and visuospatial materials from single-modality and dual-modality lists. In Experiment 1, we presented participants with between 1 and 16 spoken words, with between 1 and 16 visuo-spatial dot locations, or with between 1 and 16 words and dots with synchronized onsets. We found that for dual-modality lists (1) overall performance, initial recalls, and serial position curves were largely determined by the within-modality list lengths, (2) there was only a small degree of dual-task trade-off (which was limited to the visuo-spatial items), and (3) there were strongly constrained output orders: participants tended to alternate between words and dots from equivalent or neighboring serial positions. In Experiments 2 and 3, we compared lists of 6 single-modality items with dual-modality lists of 6 words and 6 dots with synchronous or alternating onsets (Experiment 2), or random but asynchronous onsets (Experiment 3). In all three dual-modality conditions, we again found only a small trade-off in visuo-spatial (but not verbal) IFR performance. There were similarly highly constrained output orders with the synchronous and alternating onsets, and these patterns were present but attenuated with the randomized onsets. We propose that both auditory-verbal and visuospatial list items are associated with a common temporal episodic context that is used to guide crossmodal retrieval, and we speculate that the limited, asymmetric interference could arise because the less variable representations of the dots share only a relatively small subset of features with the more variable representations of the words.

NeuroImage, 2015

Visual perception is facilitated by the ability to selectively attend to relevant parts of the wo... more Visual perception is facilitated by the ability to selectively attend to relevant parts of the world and to ignore irrelevant regions or features. In visual search tasks, viewers are able to segment displays into relevant and irrelevant items, based on a number of factors including the colour, motion, and temporal onset of the target and distractors. Understanding the process by which viewers prioritise relevant parts of a display can provide insights into the effect of top-down control on visual perception. Here we investigate the behavioural and neural correlates of segmenting a display, according to the expected three dimensional (3D) location of a target. We ask whether this segmentation is based on low-level visual features (e.g., common depth or common surface) or on higher-order representations of 3D regions. Similar response-time benefits and neural activity were obtained when items fell on common surfaces or within depth-defined volumes, and when displays were vertical (such that items shared a common depth / disparity) or were tilted in depth. These similarities indicate that segmenting items according to their 3D location is based on attending to a 3D region, rather than a specific depth or surface. Segmenting the items in depth was mainly associated with increased activation in depth-sensitive parietal regions, rather than depth-sensitive visual regions. We conclude that segmenting items in depth is primarily achieved via higher-order, cue invariant representations rather than through filtering in lower-level perceptual regions.

Vision research, 2014

In preview search when an observer ignores an early appearing set of distractors, there can subse... more In preview search when an observer ignores an early appearing set of distractors, there can subsequently be impeded detection of new targets that share the colour of this preview. This "negative carry-over effect" has been attributed to an active inhibitory process targeted against the old items and inadvertently their features. Here we extend negative carry-over effects to the case of stereoscopically defined surfaces of coplanar elements without common features. In Experiment 1 observers previewed distractors in one surface (1000ms), before being presented with the target and new distractors divided over the old and a new surface either above or below the old one. Participants were slower and less efficient to detect targets in the old surface. In Experiment 2 in both the first and second display the items were divided over two planes in the proportion 66/33% such that no new planes appeared following the preview, and there was no majority of items in any one plane in th...

Vision research, Jan 15, 2012

We examined visual search for letters that were distributed across both 3 dimensional space, and ... more We examined visual search for letters that were distributed across both 3 dimensional space, and time. In Experiment 1, when participants had foreknowledge of the depth plane and time interval where targets could appear, search was more efficient if the items could be segmented either by depth or by time (with a 1000 ms preview), and there were increased benefits when the two cues (depth and time) were combined. In Experiments 2 and 3 the target depth plane was always unknown to the participant. In this case, depth cues alone did not facilitate search, though they continued to increase the preview benefit. In Experiment 4 new items in preview search could fall at the same depth as preview items or a new depth. There was a substantial cost to search if the target appeared at a previewed depth. Experiment 5 showed that this cost remained even when participants knew the target would appear at the old depth on 75% of trials. The results indicate that spatial (depth) and temporal cues co...

Journal of experimental psychology. Learning, memory, and cognition, Jan 22, 2014

When participants are presented with a short list of unrelated words and they are instructed that... more When participants are presented with a short list of unrelated words and they are instructed that they may recall in any order, they nevertheless show a very strong tendency to recall in forward serial order. Thus, if asked to recall in any order: "hat, mouse, tea, stairs," participants often respond "hat, mouse, tea, stairs" even though there was no forward order requirement of the task. In 4 experiments, we examined whether this tendency is language-specific, reflecting mechanisms involved with speech perception, speech production, and/or verbal short-term memory. Specifically, we examined whether we would observe similar findings when participants were asked to recall, in any order, lists of between 1 and 15 nonverbal stimuli, such as visuospatial locations (Experiment 1, Experiment 3, Experiment 4), or touched facial locations (Experiment 2). Contrary to a language-specific explanation, we found corresponding tendencies (albeit somewhat reduced) in the immedi...

Quarterly Journal of Experimental Psychology, 2013

The present study compared the effects of age of acquisition (AoA) on object naming across groups... more The present study compared the effects of age of acquisition (AoA) on object naming across groups of older individuals with cognitive impairments, healthy older controls, and young healthy controls. All participants named a set of 80 pictures, within which both AoA and frequency were manipulated orthogonally. Early-acquired objects were named faster than late-acquired objects across all groups. Response time also declined with age and with cognitive impairment between the groups. The effect of AoA differed across groups, with AoA effects being largest for the older group with cognitive impairments and smallest for the young control group. The present study adds strength to the suggestion that AoA of picture names is one of the factors that influence survival or loss of memories in dementia and cognitive decline, and this could therefore be used as a potential screening test for cognitive impairment disorders in the future.

Quarterly Journal of Experimental Psychology, 2013

Age-of-acquisition (AoA) effects are such that early-acquired items are more quickly recognized a... more Age-of-acquisition (AoA) effects are such that early-acquired items are more quickly recognized and produced than later acquired items. In this laboratory analogue, participants were trained to name a group of Greeble pictures with a novel nonsense name. We manipulated order of acquisition of the stimuli: Half of the stimuli were presented from the onset of training (early acquired) whilst the other half were introduced later in the training schedule (late acquired). At test, when early and late stimuli had equal cumulative frequency, early stimuli were named significantly faster than late items. In a second test, it was also found that visual duration thresholds were significantly smaller for the early items when participants were asked to name the critical items. These findings support the notion that order-of-acquisition effects can be manifest over a short time span in the laboratory, and that the effect of order of acquisition is distinct from mere frequency of exposure. The fi...

Acta Psychologica, 2008

Four experiments examined how age of acquisition (AoA) and word frequency (WF) interact with mani... more Four experiments examined how age of acquisition (AoA) and word frequency (WF) interact with manipulations of image quality in a picture-naming task. Experiments 1 and 2 examined the effect of overlaying the to-be-named picture with irrelevant contours. The magnitude of the AoA effect increased when the contours were added (Experiment 1), but the effect of WF remained constant (Experiment 2). Experiments 3 and 4 examined the effects of reducing the contrast of the contours defining the to-be-named picture. Both the effects of AoA (Experiment 3) and WF (Experiment 4) remained constant in the face of contrast reduction. These results provide an empirical dissociation of the effects of AoA and WF. The results are consistent with the idea that both AoA and the addition of irrelevant contours affect the efficiency of object recognition, but WF affects later processes involved in retrieval of object names. The theoretical implications of these findings in relation to accounts of AoA and frequency and their functional localisation in the lexical system are discussed.

Frontiers in Psychology, 2012

The relatively common experimental visual search task of finding a red X amongst red O's and gree... more The relatively common experimental visual search task of finding a red X amongst red O's and green X's (conjunction search) presents the visual system with a binding problem. Illusory conjunctions (ICs) of features across objects must be avoided and only features present in the same object bound together. Correct binding into unique objects by the visual system may be promoted, and ICs minimized, by inhibiting the locations of distractors possessing non-target features (e.g., Treisman and Sato, 1990). Such parallel rejection of interfering distractors leaves the target as the only item competing for selection; thus solving the binding problem. In the present article we explore the theoretical and empirical basis of this process of active distractor inhibition in search. Specific experiments that provide strong evidence for a process of active distractor inhibition in search are highlighted. In the final part of the article we consider how distractor inhibition, as defined here, may be realized at a neurophysiological level (Treisman and Sato, 1990).

Four experiments examined the effect of pairing colours with either homogeneous or heterogeneous ... more Four experiments examined the effect of pairing colours with either homogeneous or heterogeneous shapes on a short-term memory task. Experiment 1 found no differences in colour memory for displays in which colours were each associated with different shapes, paired with individual homogeneous shapes, or paired with heterogeneous shapes. In contrast, Experiment 2 found that when participants were asked to remember the specific pairings of colours, memory was improved for heterogeneous shape displays. The benefit for heterogeneous shapes appears to be memorial, rather than a benefit at the time of encoding (Experiment 3) or retrieval (Experiment 4). The present study suggests that distinctive shapes can be used to help bind colour associations in visual short term memory.

Neurocase, Jan 1, 2011

Two experiments examined extinction to stimuli presented either with contracting or expanding mot... more Two experiments examined extinction to stimuli presented either with contracting or expanding motion. Experiment 1 used solid shapes which either increased or decreased in size rapidly, consistent with looming motion. Experiment 2 employed random dots so that stimulus size was not confounded with type of motion. In both experiments extinction was modulated by the type of motion presented, with extinction most evident when a contracting object was in the weaker visual field. In addition, in Experiment 2 there was evidence for grouping modulating extinction, when there were looming stimuli in both fields. The results suggest that looming motion is a powerful determinant of stimulus salience in selective attention.

Attention, Perception, & …, Jan 1, 2011

We used a probe-dot procedure to examine the roles of excitatory attentional guidance and distrac... more We used a probe-dot procedure to examine the roles of excitatory attentional guidance and distractor suppression in search for movement-form conjunctions. Participants in Experiment 1 completed a conjunction (moving X amongst moving Os and static Xs) and two single-feature (moving X amongst moving Os, and static X amongst static Os) conditions. "Active" participants searched for the target, whereas "passive" participants viewed the displays without responding. Subsequently, both groups located (left or right) a probe dot appearing in either an occupied or an unoccupied location. In the conjunction condition, the active group located probes presented on static distractors more slowly than probes presented on moving distractors, reversing the direction of the difference found within the passive group. This disadvantage for probes on static items was much stronger in conjunction than in single-feature search. The same pattern of results was replicated in Experiment 2, which used a go/no-go procedure. Experiment 3 extended the go/no-go procedure to the case of search for a static target and revealed increased probe localisation times as a consequence of active search, primarily for probes on moving distractor items. The results demonstrated attentional guidance by inhibition of distractors in conjunction search.

Psychonomic Bulletin & Review, Jan 1, 2011

A growing number of studies have shown that significant impairments to search and selection can o... more A growing number of studies have shown that significant impairments to search and selection can occur if the target item carries a feature of the irrelevant distractors currently being ignored Braithwaite, Humphreys, and Hodsoll (Journal of Experimental Psychology: Human Perception and Performance, 29, 758-778, 2003). However, these effects have been documented only when search has been extended over time (i.e., in preview search), and not in standard search displays with simultaneously presented items. Here, we present the first evidence that similar costs to selection can occur in simultaneous displays under appropriate circumstances. In the present experiment, participants searched a display for a moving target letter among static and moving distractors. Search efficiency was significantly enhanced for a moving target when half of the letters moved (and half remained static), allowing the static items to be excluded from search. However, if the moving target then shared its color with the irrelevant static items, significant costs emerged, relative to baselines. These results are consistent with the involvement of a general feature-based suppression mechanism in selection, operating over space as well as time.

Cognitive neuropsychology, Jan 1, 2010

It has been argued that area hMT+/V5 in humans acts as a motion filter, enabling targets defined ... more It has been argued that area hMT+/V5 in humans acts as a motion filter, enabling targets defined by a conjunction of motion and form to be efficiently selected. We present data indicating that (a) damage to parietal cortex leads to a selective problem in processing motion-form conjunctions, and (b) that the presence of a structurally and functional intact hMT+/V5 is not sufficient for efficient search for motion-form conjunctions. We suggest that, in addition to motion-processing areas (e.g., hMT+/V5), the posterior parietal cortex is necessary for efficient search with motion-form conjunctions, so that damage to either brain region may bring about deficits in search. We discuss the results in terms of the involvement of the posterior parietal cortex in the top-down guidance of search or in the binding of motion and form information.

Behavior research …, Jan 1, 2010

In the present study, we presented picture-naming latencies along with ratings for a set of impor... more In the present study, we presented picture-naming latencies along with ratings for a set of important characteristics of pictures and picture names: age of acquisition, frequency, picture-name agreement, name agreement, visual complexity, familiarity, and word length. The validity of these data was established by calculating correlations with previous studies. Regression analyses show that our ratings account for a larger amount of variance in RTs than do previous data. RTs were predicted by all variables except complexity and length. A complete database presenting details about all of these variables is available in the supplemental materials, downloadable from http://brm.psychonomic-journals.org/content/supplemental.

Cortex; a journal devoted to the study of …, Jan 1, 2010

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