Simultaneous attentional guidance by working-memory and selection history reveals two distinct sources of attention

Recent theories of attention have proposed that selection history is a separate, dissociable source of information that influences attention. The current study sought to investigate the simultaneous involvement of selection history and working-memory on attention during visual search. Experiments 1 and 2 used target feature probability to manipulate selection history and found significant effects of both working-memory and selection history, although working-memory dominated selection history when they cued different locations. Experiment 3 eliminated the contribution of voluntary refreshing of working-memory and replicated the main effects, although selection history became dominant. Using the same methodology, but with reduced probability cue validity, both effects were present in Experiment 4 and did not significantly differ in their contribution to attention. Effects of selection history and working-memory never interacted. These results suggest that selection history and working-memory are separate influences on attention and have little impact on each other. Theoretical implications for models of attention are discussed.     

Parallel averaging of size is possible but range-limited: A reply to Marchant,Simons, and De Fockert

In their recent paper, Marchant, Simons, and De Fockert (2013) claimed that the ability to average between multiple items of different sizes is limited by small samples of arbitrarily attended members of a set. This claim is based on a finding that observers are good at representing the average when an ensemble includes only two sizes distributed among all items (regular sets), but their performance gets worse when the number of sizes increases with the number of items (irregular sets). We argue that an important factor not considered by Marchant et al. (2013) is the range of size variation that was much bigger in their irregular sets. We manipulated this factor across our experiments and found almost the same efficiency of averaging for both regular and irregular sets when the range was stabilized. Moreover, highly regular sets consisting only of small and large items (two-peaks distributions) were averaged with greater error than sets with small, large, and intermediate items, suggesting a segmentation threshold determining whether all variable items are perceived as a single ensemble or distinct subsets. Our results demonstrate that averaging can actually be parallel but the visual system has some difficulties with it when some items differ too much from others.     

Sex differences in unfamiliar face identification: evidence from matching tasks

Research on sex differences in face recognition has reported mixed results, on balance suggesting an advantage for female observers. However, it is not clear whether this advantage is specific to face processing or reflects a more general superiority effect in episodic memory. The current study therefore examined sex differences with a face-matching task that eliminates memory demands. Across two experiments, female but not male observers showed an own-sex advantage on match trials, in which two pictures have to be identified as the same person. This advantage was present for whole faces and when only the internal or external facial features were shown. Female observers were also more accurate in these three conditions on mismatch encounters, in which two photographs have to be identified as different people, but this reflects a more general effect that is present for male and female faces. These findings converge with claims of a female advantage in face recognition and demonstrate that this effect persists when memory demands are eliminated.     

Object-based attention: sensory enhancement or scanning prioritization

The three experiments reported here test whether object-modulated attentional spreading can be obtained when the target location is 100% certain. Experiment 1 uses the reaction time (RT)-based flanker task similar to Shomstein and Yantis (2002), and replicates the null result of the object-modulated attentional spreading. RT and accuracy (ACC) have been shown to reflect different processes: postperceptual decision vs. perceptual process (Santee & Egeth, 1982). Experiment 2 adopts the data-limited ACC-based measure and reports that attention could spread within the attended object. To avoid ceiling effects, Experiment 3 adjusts the presentation time based on the trials where the target and flankers were compatible and on the same objects, and provides the convergent evidence supporting the object-modulated attentional spreading. These results suggest that because the RT-based measure is less sensitive in reflecting the quality of perceptual representations, it is not sufficiently a strong evidence to distinguish between sensory enhancement and scanning prioritization accounts.     

Visualizing the temporal dynamics of spatial information processing responsible for the Simon effect and its amplification by inhibition of return

Research has shown that the Simon effect is larger for targets suffering from inhibition of return (IOR). We used speed–accuracy trade-off (SAT) methodology to explore the temporal dynamics underlying this interaction. In Experiment 1, a new method for sorting the data was used to reveal a monotonic decay in the impact of task-irrelevant location information that is responsible for the Simon effect. In Experiment 2, we show that IOR delays both task-relevant identity and task-irrelevant location codes; a relatively longer delay for location than identity codes accounts for the effect of IOR on the Simon effect. When location information was made task-relevant in Experiment 3, IOR delayed the accumulation of this information by about the same amount as when location was irrelevant. The results suggest that IOR, therefore, has a greater effect on location than identity information.     

The whole is indeed more than the sum of its parts: perceptual averaging in the absence of individual item representation

We tested Ariely's (2001) proposal that the visual system represents the overall statistical properties of sets of objects against alternative accounts of rapid averaging involving sub-sampling strategies. In four experiments, observers could rapidly extract the mean size of a set of circles presented in an RSVP sequence, but could not reliably identify individual members. Experiment 1 contrasted performance on a member identification task with performance on a mean judgment task, and showed that the tasks could be dissociated based on whether the test probe was presented before or after the sequence, suggesting that member identification and mean judgment are subserved by different mechanisms. In Experiment 2, we confirmed that when given a choice between a probe corresponding to the mean size of the set and a foil corresponding to the mean of the smallest and largest items only, the former is preferred to the latter, even when observers are explicitly instructed to average only the smallest and largest items. Experiment 3 showed that a test item corresponding to the mean size of the set could be reliably discriminated from a foil but the largest item in the set, differing by an equivalent amount, could not. In Experiment 4, observers rejected test items dissimilar to the mean size of the set in a member identification task, favoring test items that corresponded to the mean of the set over items that were actually shown. These findings suggest that mean representation is accomplished without explicitly encoding individual items.     

How verbs can activate things: cross-language activation across word classes

The present study explored whether language-nonselective access in bilinguals occurs across word classes in a sentence context. Dutch–English bilinguals were auditorily presented with English (L2) sentences while looking at a visual world. The sentences contained interlingual homophones from distinct lexical categories (e.g., the English verb spoke, which overlaps phonologically with the Dutch noun for ghost, spook). Eye movement recordings showed that depictions of referents of the Dutch (L1) nouns attracted more visual attention than unrelated distractor pictures in sentences containing homophones. This finding shows that native language objects are activated during second language verb processing despite the structural information provided by the sentence context.     

Differential dynamics of spatial and non-spatial stimulus-response compatibility effects: a dual task LRP study

Choice reaction times are shorter when stimulus and response features are compatible rather than incompatible. Recent studies revealed that spatial compatibility effects in Simon tasks are strongly attenuated when there is temporal overlap with a different high-priority task. In contrast, non-spatial variants of the Simon task appear to be unaffected by task overlap. The present study used the lateralized readiness potential (LRP) within a dual task design to elucidate the dynamics underlying these differential effects for a color and a spatial variant of the Simon task. In the color version there was no sign of early response priming by irrelevant stimulus features in the LRP. The color compatibility effect was independent of task overlap and reflected in the LRP onset latency. In contrast, in the spatial version, priming by irrelevant stimulus location showed up and was mirrored by early LRP activation. Response priming and the corresponding Simon effect, however, were present only in case of little temporal overlap with the primary task. The absence of spatial compatibility effects at strong temporal overlap suggests that response conflicts due to stimulus-related priming depend on the availability of processing resources.     

Mind-wandering: phenomenology and function as assessed with a novel experience sampling method

Mind-wandering refers to the occurrence of thoughts whose content is both decoupled from stimuli present in the current environment and unrelated to the task being carried out at the moment of their occurrence. The core of this phenomenon is therefore stimulus-independent and task-unrelated thoughts (SITUTs). In the present study, we designed a novel experience sampling method which permitted to isolate SITUTs from other kinds of distractions (i.e., irrelevant interoceptive/exteroceptive sensory perceptions and interfering thoughts related to the appraisal of the current task). In Experiment 1, we examined the impact of SITUTs on the performance of the Sustained Attention to Response Task (SART; a Go/No-Go task). Analyses demonstrated that SITUTs impair SART performance to the same extent as irrelevant sensory perceptions. In Experiment 2, we further examined SITUTs in order to assess the possible functions of mind-wandering. We observed that the content of most of reported SITUTs refers to the anticipation and planning of future events. Furthermore, this “prospective bias” was increased when participants' attention had been oriented toward their personal goals before performing the SART. These data support the view that an important function of mind-wandering relates to the anticipation and planning of the future.     

Modulating Fitts's Law: perceiving targets at the last placeholder

Fitts's Law predicts increasing movement times (MTs) with increasing movement amplitudes; however, when targets are placed in a structured perceptual array containing placeholders, MTs to targets in the last position are shorter than predicted. We conducted three experiments to determine if this modulation has a perceptual cause. Experiment 1, which used extremely diminished (three pixel) placeholders, showed that the modulation is not due to perceptual interference from neighboring placeholders. Experiment 2, which measured reaction times using a target detection task, showed that the modulation does not result from speeded perceptual processing at the last position of the array. Experiment 3, which measured accuracy using a masked letter-discrimination task, showed that the modulation does not result from the increased quality of perceptual representation at the last position of the array. Overall, these findings suggest that the changes in effectiveness of visual processing (less interference, speeded processing, and increased quality) at the last position in the perceptual array do not drive the modulation. Thus, while the locus of the Fitts's Law modulation appears to be in the movement planning stage, it is likely not due to perceptual mechanisms.     

Keeping Simon simple: Examining the relationship between sequential modulations and feature repetitions with two stimuli, two locations and two responses

The present study examined performance across three two-choice tasks that used the same two stimuli, the same two stimulus locations, and the same two responses to determine how task demands can alter the Simon Effect, its distribution across reaction time, and its sequential modulation. In two of the tasks, repetitions of stimulus features were not confounded with sequences of congruent and incongruent trials. This attribute allowed us to investigate the sequential modulation of the Simon Effect in a two-choice task while equalizing the occurrence of feature repetitions. All tasks showed a similar sequential modulation, suggesting that it is not driven by feature repetitions. Moreover, distributional analyses revealed that the advantage for congruent trials decreased as reaction time increased similarly following congruent and incongruent trials. Finally, a large increase in RT was observed when repeated responses were made to novel stimuli and when novel responses were made to repeated stimuli. This effect also showed a sequential modulation regardless of whether the stimulus repeated. The findings suggest that, even in two-choice tasks, response selection is mediated by complex, dynamic representations that encode abstract properties of the task rather than just simple features.     

The components of visual attention and the ubiquitous Simon effect

Spatial responding is influenced by the degree of correspondence between the stimulus–response (S–R) code activated by the target's task-irrelevant location and the S–R code activated by the target's non-spatial, task-relevant feature. A generally accepted explanation of this “Simon effect,” named after its discoverer, is that there is a natural tendency to respond towards the source of stimulation. First we will review the ubiquity of the Simon effect. Then we will review the literature, including our own studies when appropriate, that has explored the relationship between the Simon effect and the components of attention: alertness, orienting and executive control, with an emphasis on visual orienting. The Simon effect is reduced when participants are not alert and when executive control is effective in filtering out the irrelevant location information. When attention is oriented endogenously, or is captured exogenously by uninformative peripheral stimulation, the Simon effect is additive with attentional facilitation (i.e., the Simon effect is the same magnitude for targets presented at attended and unattended locations). Yet, some forms of orienting, such as orienting directed by gaze and biased by inhibition of return, modulate the Simon effect. We will explore the implications of these patterns of additivity and interaction for our understanding of both the Simon effect and spatial attention.     

Does temporal preparation increase the rate of sensory information accumulation?

Recent studies showed that temporal preparation, i.e., the ability to prepare for an upcoming stimulus, improves perceptual processing. The mechanisms underlying this benefit are still controversial. Based upon the theoretical framework of accumulation models, it has been proposed that the accumulation of sensory stimulus information begins earlier when participants are temporally prepared than when they are unprepared. Alternatively, however, temporal preparation might also affect the accumulation rate of sensory information. In the present study, we examined these possibilities. Specifically, in three experiments, we manipulated participants' decision criterion. This manipulation should interact with any experimental manipulation affecting the rate of information processing, but produce additive effects with any manipulation affecting the onset of information accumulation rather than its rate. We obtained additive effects on RT, irrespective of whether the decision criterion was manipulated by increasing catch trial proportion or nogo trial proportion. These results suggest that temporal preparation improves perceptual processing by operating on the onset of sensory information accumulation rather than the rate of sensory information accumulation.     

Bayesian confusions surrounding simplicity and likelihood in perceptual organization

In the study of perceptual organization, the Occamian simplicity principle (which promotes efficiency) and the Helmholtzian likelihood principle (which promotes veridicality) have been claimed to be equivalent. Proposed models of these principles may well yield similar outcomes (especially in everyday situations), but as argued here, claims that the principles are equivalent confused subjective probabilities (which are used in Bayesian models of the Occamian simplicity principle) and objective probabilities (which are needed in Bayesian models of the Helmholtzian likelihood principle). Furthermore, Occamian counterparts of Bayesian priors and conditionals have led to another confusion, which seems to have been triggered by a dual role of regularity in perception. This confusion is discussed by contrasting complete and incomplete Occamian approaches to perceptual organization.     

Traditional response interference effects from anticipated action outcomes: a response-effect compatibility paradigm

An act as simple as pressing a button involves various stages of processing. Each stage of action production is susceptible to interference from competing representations/processes. For example, in the Simon Effect, interference arises from an incongruence between incidental spatial information and the spatial properties of intended action; in the flanker task, interference arises when visual targets and distracters are associated with different responses (response interference [RI]). Less interference arises in the flanker task when targets and distracters are different in appearance but associated with the same response (perceptual interference [PI]). Interference also stems from the automatic activation of representations associated with the anticipated effects of an action, response-effect (R–E) compatibility (e.g., the presence of a left-pointing arrow after one presses a button on the right will increase interference in future trials). This has been explained by ideomotor theory—that the mental representation of anticipated action-effects are activated automatically by voluntary action and that such representations can cause facilitation or interference by automatically priming their associated action plans. To illuminate the nature of action production and provide additional support for ideomotor theory, we examined for the first time the effects of PI and RI in a new R–E compatibility paradigm.     

The influence of motor simulations on language comprehension

This study investigates the influence of activating specific motor codes on the comprehension of passages that describe the use of an object requiring similar motor manipulations. In three experiments, participants either imagined or pantomimed performing an action involving a common object. Participants then held the action in memory while reading a brief story, which described another object that required similar or different motor behaviors. Reading times were collected on the complementary actions. Finally, participants acted out the original action. In Exp. 1 and 2, reading slowed to the verbs. Exp. 2 revealed the slowing to be true interference, which disappeared in Exp. 3 when the action did not need to be recalled. The results suggest that readers activate motor codes when reading story actions, which supports an embodied view. The results also indicate that activated codes bound to an action will, at least briefly, impair reading about a complementary action requiring the same codes, consistent with Hommel's (2009) theory of event coding.     

The relationship between attentional capture and deviations in movement trajectories in a selective reaching task

According to action-centered models of attention, attention and action systems are tightly linked such that the capture of attention by an object automatically initiates response-producing processes. In support of this link, studies have shown that movements deviate towards or away from non-target stimuli. These deviations are thought to emerge because attentional capture by non-target stimuli generates responses that summate with target responses to develop a combined movement vector. The present study tested attention–action coupling by examining movement trajectories in the presence of non-target stimuli that do or do not capture attention. Previous research has revealed that non-target cue stimuli only capture attention when they share critical features with the target. Cues that do not share this feature do not capture attention. Following these studies and their findings, participants in the present study aimed to the location of a single white square (onset singleton target) or a single red square presented with two white squares (color singleton target). In separate blocks, targets were preceded by non-predictive cues that did or did not share the target feature (color or onset singleton cues). The critical finding of the present study was that trajectory effects mirrored the temporal interference effects in that deviations were only observed when cue and target properties matched. Deviations were not observed when the cue and target properties did not match. These data provide clear support for the link between attentional capture and the activation of response-producing processes.     

The time course of face matching for featural and relational image manipulations

It was found recently that horizontal and vertical relationships of facial features are differently vulnerable to inversion (Goffaux & Rossion, 2007). When faces are upside down manipulations of vertical relations are difficult to detect, while only moderate performance deficits are found for manipulations of horizontal relations, or when features differ. We replicate the findings of Goffaux and Rossion, and record the temporal courses of face matching performance and the effects of inversion. For vertical relations and featural changes inversion effects arise immediately, starting with the first 50 ms of processing. For horizontal relations inversion effects are absent at brief timings, but arise later, after about 200 ms. The final magnitudes of inversion effects are different in all three conditions, reaching 23.4% for vertical displacement, 10.7% for feature replacement, and 5.8% for horizontal displacement. Our results underline the special status of horizontal in contrast to vertical feature relations, and indicate that local and global configural information is handled in parallel by specific routines, as proposed recently (Senunkova & Barton, 2008).     

Playing the Simon game: Use of the Simon task for investigating human information processing

A little more than 40 years ago, J. R. Simon and colleagues introduced what is now called the Simon task, which yielded a correspondence effect known as the Simon effect. In this paper, I set Simon's contribution in the context of research on stimulus-response compatibility. The novel contribution of the Simon task is described, along with foundational findings using the task that Simon and colleagues reported. I acknowledge the significance of Simon's (1990) review chapter in generating my own interests in the Simon task and describe four selected lines of research from my lab that have been a result of those interests. The article concludes with a brief tribute to Simon and his contribution to experimental psychology.     

Integration of disparity and velocity information for haptic and perceptual judgments of object depth

Do reach-to-grasp (prehension) movements require a metric representation of three-dimensional (3D) layouts and objects? We propose a model relying only on direct sensory information to account for the planning and execution of prehension movements in the absence of haptic feedback and when the hand is not visible. In the present investigation, we isolate relative motion and binocular disparity information from other depth cues and we study their efficacy for reach-to-grasp movements and visual judgments. We show that (i) the amplitude of the grasp increases when relative motion is added to binocular disparity information, even if depth from disparity information is already veridical, and (ii) similar distortions of derived depth are found for haptic tasks and perceptual judgments. With a quantitative test, we demonstrate that our results are consistent with the Intrinsic Constraint model and do not require 3D metric inferences (Domini, Caudek, & Tassinari, 2006). By contrast, the linear cue integration model (Landy, Maloney, Johnston, & Young, 1995) cannot explain the present results, even if the flatness cues are taken into account.