Multiple attentional control settings at distinct locations without the confounding of repetition priming

An attentional control setting (ACS), which is based on the task goal, induces involuntary attentional capture by a stimulus possessing a target-defining feature. It is unclear whether ACSs are maintained for multiple targets defined as conjunctions of a color and location. In the present study we examined the possibility of local ACSs for dual targets defined as combinations of color and location, using different paradigms: visual search in Experiment 1, and spatial cueing in Experiment 2. In Experiment 1, a distractor captured attention only when its features matched the ACSs. Likewise, in Experiment 2, a significant attentional capture effect was found only with a matching cue, whose color and location were in line with the conjunction of the target definition. Importantly, the identical pattern of attentional capture was also obtained for a neutral-color target, which was unlikely to be primed by any color of the cue. Thus, these findings imply that the attentional bias depending on the match between the cue and target did not result from cue–target repetition priming. The present study highlights that top-down attentional control can be set flexibly to accomplish a complex task goal efficiently.     

Prioritization to visual objects: Roles of sensory uncertainty

Two hypotheses, attentional prioritization and attentional spreading, have been proposed to account for object-based attention. The attentional-prioritization hypothesis posits that the positional uncertainty of targets is sufficient to resolve the controversy raised by the competing attentional-spreading hypothesis. Here we challenge the sufficiency of this explanation by showing that object-based attention is a function of sensory uncertainty in a task with consistent high positional uncertainty of the targets. In Experiment 1, object-based attention was modulated by sensory uncertainty induced by the noise from backward masking, showing an object-based effect under high as compared to low sensory uncertainty. This finding was replicated in Experiment 2 with increased task difficulty, to exclude that as a confounding factor, and in Experiment 3 with a psychophysical method, to obtain converging evidence using perceptual threshold measurement. Additionally, such a finding was not observed when sensory uncertainty was eliminated by replacing the backward-masking stimuli with perceptually dissimilar ones in Experiment 4. These results reveal that object-based attention is influenced by sensory uncertainty, even under high positional uncertainty of the targets. Our findings contradict the proposition of attentional spreading, proposing instead an automatic form of object-based attention due to enhancement of the perceptual representation. More importantly, the attentional-prioritization hypothesis based solely on positional uncertainty cannot sufficiently account for object-based attention, but needs to be developed by expanding the concept of uncertainty to include at least sensory uncertainty.     

The influence of attention on value integration

People often have to make decisions based on many pieces of information. Previous work has found that people are able to integrate values presented in a rapid serial visual presentation (RSVP) stream to make informed judgements on the overall stream value (Tsetsos et al. Proceedings of the National Academy of Sciences of the United States of America, 109(24), 9659–9664, 2012). It is also well known that attentional mechanisms influence how people process information. However, it is unknown how attentional factors impact value judgements of integrated material. The current study is the first of its kind to investigate whether value judgements are influenced by attentional processes when assimilating information. Experiments 1–3 examined whether the attentional salience of an item within an RSVP stream affected judgements of overall stream value. The results showed that the presence of an irrelevant high or low value salient item biased people to judge the stream as having a higher or lower overall mean value, respectively. Experiments 4–7 directly tested Tsetsos et al.’s (Proceedings of the National Academy of Sciences of the United States of America, 109(24), 9659–9664, 2012) theory examining whether extreme values in an RSVP stream become over-weighted, thereby capturing attention more than other values in the stream. The results showed that the presence of both a high (Experiments 4, 6 and 7) and a low (Experiment 5) value outlier captures attention leading to less accurate report of subsequent items in the stream. Taken together, the results showed that valuations can be influenced by attentional processes, and can lead to less accurate subjective judgements.     

Pavlovian reward learning underlies value driven attentional capture

Recent evidence shows that distractors that signal high compared to low reward availability elicit stronger attentional capture, even when this is detrimental for task-performance. This suggests that simply correlating stimuli with reward administration, rather than their instrumental relationship with obtaining reward, produces value-driven attentional capture. However, in previous studies, reward delivery was never response independent, as only correct responses were rewarded, nor was it completely task-irrelevant, as the distractor signaled the magnitude of reward that could be earned on that trial. In two experiments, we ensured that associative reward learning was completely response independent by letting participants perform a task at fixation, while high and low rewards were automatically administered following the presentation of task-irrelevant colored stimuli in the periphery (Experiment 1) or at fixation (Experiment 2). In a following non-reward test phase, using the additional singleton paradigm, the previously reward signaling stimuli were presented as distractors to assess truly task-irrelevant value driven attentional capture. The results showed that high compared to low reward-value associated distractors impaired performance, and thus captured attention more strongly. This suggests that genuine Pavlovian conditioning of stimulus-reward contingencies is sufficient to obtain value-driven attentional capture. Furthermore, value-driven attentional capture can occur following associative reward learning of temporally and spatially task-irrelevant distractors that signal the magnitude of available reward (Experiment 1), and is independent of training spatial shifts of attention towards the reward signaling stimuli (Experiment 2). This confirms and strengthens the idea that Pavlovian reward learning underlies value driven attentional capture.     

Spontaneous prospective-memory processing: Unexpected fluency experiences trigger erroneous intention executions

Event-based prospective memory is the ability to remember to execute an intention when an environmental cue occurs. It has been argued that, due to their special meaning, these cues are discrepant from their environment and therefore are sometimes spontaneously noticed. In line with this assumption, the likelihood that an intention will be executed increases with increased cue-discrepancy. It is not yet clear, however, whether these improvements are due to facilitated spontaneous noticing rather than to an increase in the efficiency of controlled cue-processing. To further investigate the spontaneous nature of cue-discrepancy benefits, we presented participants with stimuli that were unrelated to the intention but discrepant from other stimuli. Therefore, we experimentally increased the processing fluency of some stimuli for participants currently holding an intention by using different priming procedures. We found that stimuli whose fluency was increased via spaced repeated stimulus presentation (Experiment 1) or via short pre-exposure (Experiment 2a to 3) elicited a tendency to fulfill the intention despite its actual inappropriateness. Findings were inconsistent as to whether cue-memory uncertainty fosters the reliance on cue discrepancy for intention retrieval (Experiments 2a and 3). Taken together, the present findings provide converging evidence for a spontaneous discrepancy-based prospective-memory process which works independent of controlled processes.     

Forgetting from lapses of sustained attention

When performing any task for an extended period of time, attention fluctuates between good and bad states. These fluctuations affect performance in the moment, but may also have lasting consequences for what gets encoded into memory. Experiment 1 establishes this relationship between attentional states and memory, by showing that subsequent memory for an item was predicted by a response time index of sustained attention (average response time during the three trials prior to stimulus onset). Experiment 2 strengthens the causal interpretation of this predictive relationship by treating the sustained attention index as an independent variable to trigger the appearance of an encoding trial. Subsequent memory was better when items were triggered from good versus bad attentional states. Together, these findings suggest that sustained attention can have downstream consequences for what we remember, and they highlight the inferential utility of adaptive experimental designs. By continuously monitoring attention, we can influence what will later be remembered.     

Motion and position shifts induced by the double-drift stimulus are unaffected by attentional load

The double-drift stimulus produces a strong shift in apparent motion direction that generates large errors of perceived position. In this study, we tested the effect of attentional load on the perceptual estimates of motion direction and position for double-drift stimuli. In each trial, four objects appeared, one in each quadrant of a large screen, and they moved upward or downward on an angled trajectory. The target object whose direction or position was to be judged was either cued with a small arrow prior to object motion (low attentional load condition) or cued after the objects stopped moving and disappeared (high attentional load condition). In Experiment 1, these objects appeared 10° from the central fixation, and participants reported the perceived direction of the target’s trajectory after the stimulus disappeared by adjusting the direction of an arrow at the center of the response screen. In Experiment 2, the four double-drift objects could appear between 6 ° and 14° from the central fixation, and participants reported the location of the target object after its disappearance by moving the position of a small circle on the response screen. The errors in direction and position judgments showed little effect of the attentional manipulation—similar errors were seen in both experiments whether or not the participant knew which double-drift object would be tested. This suggests that orienting endogenous attention (i.e., by only attending to one object in the precued trials) does not interact with the strength of the motion or position shifts for the double-drift stimulus.     

Motion direction discrimination training reduces perceived motion repulsion

Participants often exaggerate the perceived angular separation between two simultaneously presented motion stimuli, which is referred to as motion repulsion. The overestimation helps participants differentiate between the two superimposed motion directions, yet it causes the impairment of direction perception. Since direction perception can be refined through perceptual training, we here attempted to investigate whether the training of a direction discrimination task changes the amount of motion repulsion. Our results showed a direction-specific learning effect, which was accompanied by a reduced amount of motion repulsion both for the trained and the untrained directions. The reduction of the motion repulsion disappeared when the participants were trained on a luminance discrimination task (control experiment 1) or a speed discrimination task (control experiment 2), ruling out any possible interpretation in terms of adaptation or training-induced attentional bias. Furthermore, training with a direction discrimination task along a direction 150° away from both directions in the transparent stimulus (control experiment 3) also had little effect on the amount of motion repulsion, ruling out the contribution of task learning. The changed motion repulsion observed in the main experiment was consistent with the prediction of the recurrent model of perceptual learning. Therefore, our findings demonstrate that training in direction discrimination can benefit the precise direction perception of the transparent stimulus and provide new evidence for the recurrent model of perceptual learning.     

Numerosity estimates for attended and unattended items in visual search

The goal of this research was to examine memories created for the number of items during a visual search task. Participants performed a visual search task for a target defined by a single feature (Experiment 1A), by a conjunction of features (Experiment 1B), or by a specific spatial configuration of features (Experiment 1C). On some trials following the search task, subjects were asked to recall the total number of items in the previous display. In all search types, participants underestimated the total number of items, but the severity of the underestimation varied depending on the efficiency of the search. In three follow-up studies (Experiments 2A, 2B, and 2C) using the same visual stimuli, the participants’ only task was to estimate the number of items on each screen. Participants still underestimated the numerosity of the items, although the degree of underestimation was smaller than in the search tasks and did not depend on the type of visual stimuli. In Experiment 3, participants were asked to recall the number of items in a display only once. Subjects still displayed a tendency to underestimate, indicating that the underestimation effects seen in Experiments 1A-1C were not attributable to knowledge of the estimation task. The degree of underestimation depends on the efficiency of the search task, with more severe underestimation in efficient search tasks. This suggests that the lower attentional demands of very efficient searches leads to less encoding of numerosity of the distractor set.     

Immunity to attentional capture at ignored locations

Certain stimuli have the power to rapidly and involuntarily capture spatial attention against our will. The present study investigated whether such stimuli capture spatial attention even when they appear in ignored regions of visual space. In other words, which force is more powerful: attentional capture or spatial filtering? Participants performed a spatial cuing task, searching for a letter target defined by color (e.g., green) and then reporting that letter’s identity. Two of the four search locations were always irrelevant. Unlike many previous experiments, participants were forced to ignore these locations because they always contained a target-colored distractor letter. Experiment 1 assessed capture by a salient-but-irrelevant abrupt onset cue appearing 150 ms before the search display. One might expect onset cues to capture attention even at ignored locations given that the main function of capture, presumably, is to rapidly alert observers to unexpected yet potentially important stimuli. However, they did not. Experiment 2 replicated this result with a different neutral baseline condition. Experiment 3 replicated the absence of capture effects at ignored locations with an even more potent stimulus: a relevant cue possessing the target color. We propose that people are effectively immune to attentional capture by objects in ignored locations – spatial filtering dominates attentional capture.     

Age of avatar modulates the altercentric bias in a visual perspective-taking task: ERP and behavioral evidence

Despite being able to rapidly and accurately infer their own and other peoples’ visual perspectives, healthy adults experience difficulty ignoring the irrelevant perspective when the two perspectives are in conflict; they experience egocentric and altercentric interference. We examine for the first time how the age of an observed person (adult vs. child avatar) influences adults’ visual perspective-taking, particularly the degree to which they experience interference from their own or the other person’s perspective. Participants completed the avatar visual perspective-taking task, in which they verified the number of discs in a visual scene according to either their own or an on-screen avatar’s perspective (Experiments 1 and 2) or only from their own perspective (Experiment 3), where the two perspectives could be consistent or in conflict. Age of avatar was manipulated between (Experiment 1) or within (Experiments 2 and 3) participants, and interference was assessed using behavioral (Experiments 1–3) and ERP (Experiment 1) measures. Results revealed that altercentric interference is reduced or eliminated when a child avatar was present, suggesting that adults do not automatically compute a child avatar’s perspective. We attribute this pattern to either enhanced visual processing for own-age others or an inference on reduced mental awareness in younger children. The findings argue against a purely attentional basis for the altercentric effect, and instead support an account where both mentalising and directional processes modulate automatic visual perspective-taking, and perspective-taking effects are strongly influenced by experimental context.     

Whose hand is this? Differential responses of right and left extrastriate body areas to visual images of self and others’ hands

The extrastriate body area (EBA) is involved in perception of human bodies and nonfacial body parts, but its role in representing body identity is not clear. Here, we used on-line high-frequency repetitive transcranial magnetic stimulation (rTMS) to test the role of EBA in self–other distinction. In Experiments 1 and 2 we compared rTMS of right EBA with stimulation of left ventral premotor cortex (vPM), whereas in Experiment 3 we compared stimulation of right and left EBA. RTMS was applied during a hand laterality task in which self or others’ hand images were presented in first- versus third-person view (Experiments 1 and 3), or while participants had to explicitly recognize their own hands (Experiment 2) presented in first- versus third-person view. Experiment 1 showed that right EBA stimulation selectively speeded judgments on others’ hands, whereas no effect of left vPM stimulation was found. Experiment 2 did not reveal any effect of rTMS. Experiment 3 confirmed faster responses on others’ hands while stimulating right EBA and also showed an advantage when judging self with respect to others’ hands during stimulation of left EBA. These results would demonstrate that EBA responds to morphological features of human body contributing to identity processing.     

The concreteness effect on judgments of learning: Evaluating the contributions of fluency and beliefs

Researchers have often determined how cues influence judgments of learning (JOLs; e.g., concrete words are assigned higher JOLs than are abstract words), and recently there has been an emphasis in understanding why cues influence JOLs (i.e., the mechanisms that underlie cue effects on JOLs). The analytic-processing (AP) theory posits that JOLs are constructed in accordance with participants’ beliefs of how a cue will influence memory. Even so, some evidence suggests that fluency is also important to cue effects on JOLs. In the present experiments, we investigated the contributions of participants’ beliefs and processing fluency to the concreteness effect on JOLs. To evaluate beliefs, participants estimated memory performance in a hypothetical experiment (Experiment 1), and studied concrete and abstract words and made a pre-study JOL for each (Experiments 2 and 3). Participants’ predictions demonstrated the belief that concrete words are more likely to be remembered than are abstract words, consistent with the AP theory. To evaluate fluency, response latencies were measured during lexical decision (Experiment 4), self-paced study (Experiment 5), and mental imagery (Experiment 7). Number of trials to acquisition was also evaluated (Experiment 6). Fluency did not differ between concrete and abstract words in Experiments 5 and 6, and it did not mediate the concreteness effect on JOLs in Experiments 4 and 7. Taken together, these results demonstrate that beliefs are a primary mechanism driving the concreteness effect on JOLs.     

Relationship between vection and motion perception in depth

This study examined the effects of cues to motion in depth – namely, stereoscopic (i.e., changing-disparity cues and interocular velocity differences) and changing-size cues on forward and backward vection. We conducted four experiments in which participants viewed expanding or contracting optical flows with the addition of either or both cues. In Experiment 1, participants reported vection by pressing a button whenever they felt it. After each trial, they also rated the magnitude of the vection (from 0 to 100). In Experiments 2 and 3, the participants rated the perceived velocity and motion-in-depth impression of the flows relative to standard stimuli, respectively. In Experiment 4, the participants rated the perceived depth and distance of the display. We observed enhancements in vection, motion-in-depth impression, and perceived depth and distance when either or both types of cues indicated motion-in-depth, as compared to those when the cues did not (Experiments 1, 3, and 4). The perceived velocity changed with cue conditions only for the high velocity condition (Experiment 2). Correlational analyses showed that the vection can be best explained by the motion-in-depth impression. This was partially supported by the multiple regression analyses. These results indicate that the enhancement of vection caused by cues is related to the impression of motion-in-depth rather than the perceived velocity and perceived three-dimensionality.     

Revisiting von Restorff’s early isolation effect

An item that is conceptually or physically different from other items in a series is often remembered well. This isolation effect has been found independent of the position of the isolated item in the list, suggesting that special attention to or processing of the isolated item is not a necessary precondition of the effect. Three experiments are reported that challenge this conclusion. In Experiment 1a, we compared memory for conceptually isolated items to memory for the same items in unrelated and homogeneous lists. Under moderately distracting conditions, isolation effects were observed with midlist but not with early isolates. In fact, early isolation impaired memory for the conceptually distinct items relative to the same items in homogeneous lists. Experiment 1b replicated this memory impairment for early conceptual isolates and extended it to nondistracting conditions. In Experiment 2, we focused on early isolation, manipulating the type of isolation and whether or not participants performed judgments of learning (JOLs). An early isolation effect was observed for numbers isolated in lists of words (and vice versa), but not for conceptual isolates. Performing the JOL task reduced the size of the early isolation effect. These results suggest that number/word stimulus contrasts are coded automatically and support an isolation effect independent of list position. However, conceptual contrasts require relational processing and will only support an early isolation effect when such processing occurs. The results of Experiments 1a, 1b, and 2 suggest that attentional resources during list presentation and a favorable retrieval environment combine to support good memory for distinctive events.     

Out of sight,out of mind: Occlusion and eye closure destabilize moving bistable structure-from-motion displays

Our brain constantly tries to anticipate the future by using a variety of memory mechanisms. Interestingly, studies using the intermittent presentation of multistable displays have shown little perceptual persistence for interruptions longer than a few hundred milliseconds. Here we examined whether we can facilitate the perceptual stability of bistable displays following a period of invisibility by employing a physically plausible and ecologically valid occlusion event sequence, as opposed to the typical intermittent presentation, with sudden onsets and offsets. To this end, we presented a bistable rotating structure-from-motion display that was moving along a linear horizontal trajectory on the screen and either was temporarily occluded by another object (a cardboard strip in Exp. 1, a computer-generated image in Exp. 2) or became invisible due to eye closure (Exp. 3). We report that a bistable rotation direction reliably persisted following occlusion or interruption only (1) if the pre- and postinterruption locations overlapped spatially (an occluder with apertures in Exp. 2 or brief, spontaneous blinks in Exp. 3) or (2) if an object’s size allowed for the efficient grouping of dots on both sides of the occluding object (large objects in Exp. 1). In contrast, we observed no persistence whenever the pre- and postinterruption locations were nonoverlapping (large solid occluding objects in Exps. 1 and 2 and long, prompted blinks in Exp. 3). We report that the bistable rotation direction of a moving object persisted only for spatially overlapping neural representations, and that persistence was not facilitated by a physically plausible and ecologically valid occlusion event.     

Mixed signals: The effect of conflicting reward- and goal-driven biases on selective attention

Attentional selection depends on the interaction between exogenous (stimulus-driven), endogenous (goal-driven), and selection history (experience-driven) factors. While endogenous and exogenous biases have been widely investigated, less is known about their interplay with value-driven attention. The present study investigated the interaction between reward-history and goal-driven biases on perceptual sensitivity (d’) and response time (RT) in a modified cueing paradigm presenting two coloured cues, followed by sinusoidal gratings. Participants responded to the orientation of one of these gratings. In Experiment 1, one cue signalled reward availability but was otherwise task irrelevant. In Experiment 2, the same cue signalled reward, and indicated the target’s most likely location at the opposite side of the display. This design introduced a conflict between reward-driven biases attracting attention and goal-driven biases directing it away. Attentional effects were examined comparing trials in which cue and target appeared at the same versus opposite locations. Two interstimulus interval (ISI) levels were used to probe the time course of attentional effects. Experiment 1 showed performance benefits at the location of the reward-signalling cue and costs at the opposite for both ISIs, indicating value-driven capture. Experiment 2 showed performance benefits only for the long ISI when the target was at the opposite to the reward-associated cue. At the short ISI, only performance costs were observed. These results reveal the time course of these biases, indicating that reward-driven effects influence attention early but can be overcome later by goal-driven control. This suggests that reward-driven biases are integrated as attentional priorities, just as exogenous and endogenous factors.     

Cue quality and criterion setting in recognition memory

Previous studies on how people set and modify decision criteria in old-new recognition tasks (in which they have to decide whether or not a stimulus was seen in a study phase) have almost exclusively focused on properties of the study items, such as presentation frequency or study list length. In contrast, in the three studies reported here, we manipulated the quality of the test cues in a scene-recognition task, either by degrading through Gaussian blurring (Experiment 1) or by limiting presentation duration (Experiment 2 and 3). In Experiments 1 and 2, degradation of the test cue led to worse old-new discrimination. Most importantly, however, participants were more liberal in their responses to degraded cues (i.e., more likely to call the cue “old”), demonstrating strong within-list, item-by-item, criterion shifts. This liberal response bias toward degraded stimuli came at the cost of increasing the false alarm rate while maintaining a constant hit rate. Experiment 3 replicated Experiment 2 with additional stimulus types (words and faces) but did not provide accuracy feedback to participants. The criterion shifts in Experiment 3 were smaller in magnitude than Experiments 1 and 2 and varied in consistency across stimulus type, suggesting, in line with previous studies, that feedback is important for participants to shift their criteria.     

Bindings in working memory: The role of object-based attention

Over the past decade, it has been debated whether retaining bindings in working memory (WM) requires more attention than retaining constituent features, focusing on domain-general attention and space-based attention. Recently, we proposed that retaining bindings in WM needs more object-based attention than retaining constituent features (Shen, Huang, & Gao, 2015, Journal of Experimental Psychology: Human Perception and Performance, doi: 10.1037/xhp0000018). However, only unitized visual bindings were examined; to establish the role of object-based attention in retaining bindings in WM, more emperical evidence is required. We tested 4 new bindings that had been suggested requiring no more attention than the constituent features in the WM maintenance phase: The two constituent features of binding were stored in different WM modules (cross-module binding, Experiment 1), from auditory and visual modalities (cross-modal binding, Experiment 2), or temporally (cross-time binding, Experiments 3) or spatially (cross-space binding, Experiments 4–6) separated. In the critical condition, we added a secondary object feature-report task during the delay interval of the change-detection task, such that the secondary task competed for object-based attention with the to-be-memorized stimuli. If more object-based attention is required for retaining bindings than for retaining constituent features, the secondary task should impair the binding performance to a larger degree relative to the performance of constituent features. Indeed, Experiments 1–6 consistently revealed a significantly larger impairment for bindings than for the constituent features, suggesting that object-based attention plays a pivotal role in retaining bindings in WM.     

The texture of causal construals: Domain-specific biases shape causal inferences from discourse

We conducted five sets of experiments asking whether psychological and physical events are construed in broadly different manners concerning the underlying textures of their causes. In Experiments 1a–1d, we found a robust tendency to estimate fewer causes (but not effects) for psychological than for physical events; Experiment 2 showed a similar pattern of results when participants were asked to generate hypothetical causes and effects; Experiment 3 revealed a greater tendency to ascribe linear chains of causes (but not effects) to physical events; Experiment 4 showed that the expectation of linear chains was related to intuitions about deterministic processes; and Experiment 5 showed that simply framing a given ambiguous event in psychological versus physical terms is sufficient to induce changes in the patterns of causal inferences. Adults therefore consistently show a tendency to think about psychological and physical events as being embedded in different kinds of causal structures.