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.     

The role of anticipation and intention in the learning of effects of self-performed actions

The anticipative learning model for acquiring action-effect relations states that the acquisition of action-effect relations depends on processes that are part of action planning, in particular the anticipation of possible effects. Experiment 1 shows that response planning is indeed crucial for the learning of response effects. In this experiment distractors (tones) were presented either during response preparation or in the time interval between response execution and the presentation of a response effect. Response-effect learning was impaired when the distractors were presented during response preparation. The finding is consistent with the assumption that the distractors impaired the anticipation of potential effects and therefore reduced effect learning. In Experiment 2 all responses had two effects. Participants were instructed to produce one of the effects. Under this condition, response-effect learning was only found for the instructed effect, not for the non-instructed effect. The two experiments thus support the view that response-effect learning is selective and depends on the anticipation of potential effects during response planning. The results are discussed in terms of a model that explains both the learning of response-effect relations and the use of these effects for action control within the same theoretical framework.     

Miss it and miss out: Counterproductive nonspatial attentional capture by task-irrelevant,value-related stimuli

Recent studies of visual search suggest that learning about valued outcomes (rewards and punishments) influences the likelihood that distractors will capture spatial attention and slow search for a target, even when those value-related distractors have never themselves been the targets of search. In the present study, we demonstrated a related effect in the context of temporal, rather than spatial, selection. Participants were presented with a temporal stream of pictures in a fixed central location and had to identify the orientation of a rotated target picture. Response accuracy was reduced if the rotated target was preceded by a “valued” distractor picture that signaled that a correct response to the target would be rewarded (and an incorrect response punished), relative to a distractor picture that did not signal reward or punishment. This effect of signal value on response accuracy was short-lived, being most prominent with a short lag between distractor and target. Impairment caused by a valued distractor was observed if participants were explicitly instructed regarding its relation to reward/punishment (Exps. 1, 3, and 4), or if they could learn this relationship only via trial-by-trial experience (Exp. 2). These findings show that the influence of signal value on attentional capture extends to temporal selection, and also demonstrate that value-related distractors can interfere with the conscious perception of subsequent target information.     

Balancing cognitive control: How observed movements influence motor performance in a task with balance constraints

We investigated the influence of observed movements on executed movements in a task requiring lifting one foot from the floor while maintaining whole-body balance. Sixteen young participants (20–30 years) performed foot lift movements, which were either cued symbolically by a letter (L/R, indicating to lift the left/right foot) or by a short movie showing a foot lift movement. In the symbol cue condition, stimuli from the movie cue condition were used as distractors, and vice versa. Anticipatory postural adjustments (APAs) and actual foot lifts were recorded using force plates and optical motion capture. Foot lift responses were generally faster in response to the movie compared to the symbol cue condition. Moreover, incongruent movement distractors interfered with performance in the symbol cue condition, as shown by longer response times and increased number of APAs. Latencies of the first (potentially wrong) APA in a trial were shorter for movie compared to symbol cues but were not affected by cue-distractor congruency. Amplitude of the first APA was smaller when it was followed by additional APAs compared to trials with a single APA. Our results show that automatic imitation tendencies are integrated with postural control in a task with balance constraints. Analysis of the number, timing and amplitude of APAs indicates that conflicts between intended and observed movements are not resolved at a purely cognitive level but directly influence overt motor performance, emphasizing the intimate link between perception, cognition and action.     

The meaning of the mask matters: evidence of conceptual interference in the attentional blink

The rapid serial visual presentation (RSVP) experiment reported here investigated the role of conceptual interference in the attentional blink (AB). Subjects were presented with RSVP streams that contained five stimuli: Target 1, a distractor, Target 2, a second distractor, and a symbol mask. Target 1 was a green letter, Target 2 was a red letter, and the distractors were either white letters or white digits. The stimuli were presented in a font typically seen on the face of a digital watch. Thus, "S" and "O" were identical to "5" and "0," respectively. This allowed us to present streams that were conceptually different even though featurally identical: The two letter targets were followed by distractors that were recognized either as "5" and "0" or as "S" and "O." The AB was substantially attenuated when subjects were told the distractors were digits rather than letters. This result indicates that conceptual interference plays a role in the AB.     

Automatization and training in visual search.

In several search tasks, the amount of practice on particular combinations of targets and distractors was equated in varied-mapping (VM) and consistent-mapping (CM) conditions. The results indicate the importance of distinguishing between memory and visual search tasks, and implicate a number of factors that play important roles in visual search and its learning. Visual search was studied in Experiment 1. VM and CM performance were almost equal, and slope reductions occurred during practice for both, suggesting the learning of efficient attentive search based on features, and no important role for automatic attention attraction. However, positive transfer effects occurred when previous CM targets were re-paired with previous CM distractors, even though these targets and distractors had not been trained together. Also, the introduction of a demanding simultaneous task produced advantages of CM over VM. These latter two results demonstrated the operation of automatic attention attraction. Visual search was further studied in Experiment 2, using novel characters for which feature overlap and similarity were controlled. The design and many of the findings paralleled Experiment 1. In addition, enormous search improvement was seen over 35 sessions of training, suggesting the operation of perceptual unitization for the novel characters. Experiment 3 showed a large, persistent advantage for CM over VM performance in memory search, even when practice on particular combinations of targets and distractors was equated in the two training conditions. A multifactor theory of automatization and attention is put forth to account for these findings and others in the literature.     

The shielding function of task rules in the context of task switching

There is increasing evidence that task rules help shield the response against distractor interference. Here, the authors investigate the cognitive mechanisms underlying this assumed shielding function of task rules and how it is adjusted to changing task demands. In two experiments, participants switched between a noun categorization and an adjective categorization task. Target words were superimposed on distractor pictures. These pictures were always irrelevant and depicted either objects also used as target words in the noun task (noun distractors) or objects that were not part of the noun target-set but could be categorized according to the noun task (noun-related distractors). Results show that (a) on task repetitions shielding prevents interference from any distractors associated with a competing task; this is indicated by the lack of interference on adjective task repetitions; and (b) shielding is reduced on task switches. In the noun task, this reduction resulted in attenuated interference by noun-related distractors. In the adjective task, spatial distractors did not interfere despite the reduction. This result suggests that shielding is supported by a processing advantage for task-related information and not by distractor suppression.     

Control by association: Transfer of implicitly primed attentional states across linked stimuli

Although cognitive control has traditionally been viewed in opposition to associative learning, recent studies show that people can learn to link particular stimuli with specific cognitive control states (e.g., high attentional selectivity). Here, we tested whether such learned stimulus-control associations can transfer across paired-associates. In the Stimulus-Stimulus (S-S) Association phase, specific face or house images repeatedly preceded the presentation of particular scene stimuli, creating paired face/house-scene associates in memory. The Stimulus-Control (S-C) Association phase then associated these scenes with different attentional control states by probabilistically biasing specific scenes to mostly precede either congruent or incongruent trials in a Stroop task. Finally, in the Stimulus-Control Transfer (S-CT) phase, the faces and houses from the S-S phase preceded Stroop trials but were not predictive of congruency, testing whether stimulus-control associations would transfer from scenes to their associated face/house stimuli. In Experiments 1 and 3, we found that learned implicit stimulus-control associations could transfer across closely linked cues, and in Experiment 2, we showed that this transfer depended on the memory associations formed in the S-S phase. While this form of transfer learning has previously been demonstrated for stimulus-reward associations, the present study provides the first evidence for the associative transfer of stimulus-control associations across arbitrarily linked stimuli. This work demonstrates how people can learn to implicitly adapt their processing strategies in a flexible context-dependent manner and establishes a novel learning mechanism supporting the generalization of cognitive control.     

Transfer of avoidance responding to a sensory preconditioned cue: Evidence for the role of S-S and R-S knowledge in avoidance learning

In avoidance learning studies, a warning signal (Sd) is directly paired with an aversive unconditioned stimulus (US) unless a particular response is performed. Research by Augustson and Dougher (1997) demonstrated that not only warning signals but also stimuli that are indirectly paired with the aversive event are capable of affecting the avoidance response. In the present study, we extended these results by incorporating a sensory preconditioning paradigm in an avoidance learning procedure. Sensory preconditioning training influenced the selection of avoidance responses in the presence of warning signals that were never paired directly with the aversive events. Moreover, results suggest that the selection of the avoidance responses was based on an integration of knowledge about the relation between the Sd and the US (S-S knowledge) and knowledge about the relation between the avoidance response and the US (R-S knowledge). As the expectancy-based theory of Lovibond (2006) is the only theory of avoidance that incorporates both knowledge structures, the results provide unique support for this theory.     

Dilution of compatibility effects in Simon-type tasks depends on categorical similarity between distractors and diluters

The presence of a distracting stimulus during performance of the Stroop color-naming task leads to dilution of the Stroop effect. Because the automatic activation of word meaning may interfere with the task-relevant stimulus feature (text color; stimulus-stimulus [S-S] interference) and the response (saying the text color; stimulus-response [S-R] interference), it is unclear which of these types of interference is diluted. We introduce a new dilution paradigm using word- and arrow-based Simon tasks, in which only S-R interference is present. Participants made a left or right response to a central color target. A task-irrelevant location-word (Experiment 1) or arrow (Experiment 2) distractor adjacent to the target produced S-R compatibility effects. An additional neutral word or symbol series (diluter) was sometimes presented on the opposite side of the target from the distractor. The compatibility effect was smaller when the distractor and diluter category domains matched than when they mismatched. This result provides evidence that S-R compatibility effects are susceptible to the presence of diluters that are categorically similar to the distractors.     

Suppression of overt attentional capture by salient-but-irrelevant color singletons

For more than 2 decades, researchers have debated the nature of cognitive control in the guidance of visual attention. Stimulus-driven theories claim that salient stimuli automatically capture attention, whereas goal-driven theories propose that an individual’s attentional control settings determine whether salient stimuli capture attention. In the current study, we tested a hybrid account called the signal suppression hypothesis, which claims that all stimuli automatically generate a salience signal but that this signal can be actively suppressed by top-down attentional mechanisms. Previous behavioral and electrophysiological research has shown that participants can suppress covert shifts of attention to salient-but-irrelevant color singletons. In this study, we used eye-tracking methods to determine whether participants can also suppress overt shifts of attention to irrelevant singletons. We found that under conditions that promote active suppression of the irrelevant singletons, overt attention was less likely to be directed toward the salient distractors than toward nonsalient distractors. This result provides direct evidence that people can suppress salient-but-irrelevant singletons below baseline levels.     

Explaining efficient search for conjunctions of motion and form: Evidence from negative color effects

Dent, Humphreys, and Braithwaite (2011) showed substantial costs to search when a moving target shared its color with a group of ignored static distractors. The present study further explored the conditions under which such costs to performance occur. Experiment 1 tested whether the negative color-sharing effect was specific to cases in which search showed a highly serial pattern. The results showed that the negative color-sharing effect persisted in the case of a target defined as a conjunction of movement and form, even when search was highly efficient. In Experiment 2, the ease with which participants could find an odd-colored target amongst a moving group was examined. Participants searched for a moving target amongst moving and stationary distractors. In Experiment 2A, participants performed a highly serial search through a group of similarly shaped moving letters. Performance was much slower when the target shared its color with a set of ignored static distractors. The exact same displays were used in Experiment 2B; however, participants now responded “present” for targets that shared the color of the static distractors. The same targets that had previously been difficult to find were now found efficiently. The results are interpreted in a flexible framework for attentional control. Targets that are linked with irrelevant distractors by color tend to be ignored. However, this cost can be overridden by top-down control settings.     

Remembering the news: Modeling retention data from a study with 14,000 participants

A retention study is presented in which participants answered questions about news events, with a retention interval that varied within participants between 1 day and 2 years. The study involved more than 14,000 participants and around 500,000 data points. The data were analyzed separately for participants who answered questions in Dutch or in English, providing an opportunity for replication. We fitted models of varying complexity to the data in order to test several hypotheses concerning retention. Evidence for an asymptote in retention was found in only one data set, and participants with greater media exposure displayed a higher degree of learning but no difference in forgetting. Thus, forgetting was independent of initial learning. Older adults were found to have forgetting curves similar to those of younger adults.     

On the fate of distractor representations

Research on the topic of distractor inhibition has used different empirical approaches to study how the human mind selects relevant information from the environment, and the results are controversially discussed. One key question that typically arises is how selection deals with the irrelevant information. We used a new selection task, in which participants sometimes had to respond to the distractors instead of the target. Importantly, we varied the time interval between stimuli onset and the cue that signaled participants to respond to the distractors. We analyzed RTs and error rates from responses to distractors as a function of how long the target had been processed (and the distractor ignored) before the cue required a response to the distractor (i.e., stimulus-cue SOA). The data are compatible with selection models assuming that distractor stimuli are initially activated and then deactivated. Thus, we argue for selection models assuming top down deactivation of distractor representations that work in parallel with top down activation of target representations.     

Learning in combined-feature search: specificity to orientation

We investigated the dynamics and specificity of learning in the search for a target defined by combined features belonging to the same dimension (a rotated L) among homogeneous or heterogeneous distractors (differently rotated Ls). We found that learning makes searching faster although the search strategy does not change, remaining parallel with homogeneous distractors and serial with heterogeneous distractors. Learning was found to be specific for combined-feature orientation, although simple features did not change in the transfer stimulus: Transfer was partial when either the target or the distractors were rotated (so that their global orientation became the same) and totally absent when target and distractors were swapped. These results, which apply to searches among both homogeneous and heterogeneous distractors, rule out the possibility that learning is specific for orientation of just simple features. Instead, the results suggest that specificity of learning with combined features reflects the activation of junction detectors responding to a combined feature of a particular orientation.     

When increasing distraction helps learning: Distractor number and content interact in their effects on memory

Previous work has demonstrated that increasing the number of distractors in a search array can reduce interference from distractor content during target processing. However, it is unclear how this reduced interference influences learning of target information. Here, we investigated how varying the amount and content of distraction present in a learning environment affects visual search and subsequent memory for target items. In two experiments, we demonstrate that the number and content of competing distractors interact in their influence on target selection and memory. Specifically, while increasing the number of distractors present in a search array made target detection more effortful, it did not impair learning and memory for target content. Instead, when the distractors contained category information that conflicted with the target, increasing the number of distractors from one to three actually benefitted learning and memory. These data suggest that increasing numbers of distractors may reduce interference from conflicting conceptual information during encoding.

     

Visual search for simple volumetric shapes.

Five experiments measured reaction time (RT) to detect the presence or absence of a simple volumetric shape (target) dependent on the number of display items (distractors) and their depicted three-dimensional (3-D) orientation. Experiments 1-4 examined every pairwise combination of two different simple volumetric shapes in two 3-D orientations. Conditions exhibiting "pop-out" could be predicted by differences in their two-dimensional (2-D) features. Conditions in which search was slower support previously found search asymmetries for particular 2-D features. When the distractors were a mixture of the other shapes in the same 3-D orientation, search was serial, except when the target had a curved principal axis (Experiment 5). The results suggest that these simple volumetric shapes are not processed preattentively.     

Is the devil in the detail? Evidence for S-S learning after unconditional stimulus revaluation in human evaluative conditioning under a broader set of experimental conditions

Whether valence change during evaluative conditioning is mediated by a link between the conditional stimulus (CS) and the unconditional stimulus (US; S-S learning) or between the CS and the unconditional response (S-R learning) is a matter of continued debate. Changing the valence of the US after conditioning, known as US revaluation, can be used to dissociate these accounts. Changes in CS valence after US revaluation provide evidence for S-S learning but if CS valence does not change, evidence for S-R learning is found. Support for S-S learning has been provided by most past revaluation studies, but typically the CS and US have been from the same stimulus category, the task instructions have suggested that judgements of the CS should be based on the US, and USs have been mildly valenced stimuli. These factors may bias the results in favour of S-S learning. We examined whether S-R learning would be evident when CSs and USs were taken from different categories, the task instructions were removed, and more salient USs were used. US revaluation was found to influence explicit US evaluations and explicit and implicit CS evaluations, supporting an S-S learning account and suggesting that past results are stable across procedural changes.     

Learning in repeated visual search

Visual search (e.g., finding a specific object in an array of other objects) is performed most effectively when people are able to ignore distracting nontargets. In repeated search, however, incidental learning of object identities may facilitate performance. In three experiments, with over 1,100 participants, we examined the extent to which search could be facilitated by object memory and by memory for spatial layouts. Participants searched for new targets (real-world, nameable objects) embedded among repeated distractors. To make the task more challenging, some participants performed search for multiple targets, increasing demands on visual working memory (WM). Following search, memory for search distractors was assessed using a surprise two-alternative forced choice recognition memory test with semantically matched foils. Search performance was facilitated by distractor object learning and by spatial memory; it was most robust when object identity was consistently tied to spatial locations and weakest (or absent) when object identities were inconsistent across trials. Incidental memory for distractors was better among participants who searched under high WM load, relative to low WM load. These results were observed when visual search included exhaustive-search trials (Experiment 1) or when all trials were self-terminating (Experiment 2). In Experiment 3, stimulus exposure was equated across WM load groups by presenting objects in a single-object stream; recognition accuracy was similar to that in Experiments 1 and 2. Together, the results suggest that people incidentally generate memory for nontarget objects encountered during search and that such memory can facilitate search performance.     

Semisupervised category learning facilitates the development of automaticity

In the human category of learning, learning is studied in a supervised, an unsupervised, or a semisupervised way. The rare human semisupervised category of learning studies all focus on early learning. However, the impact of the semisupervised category learning late in learning, when automaticity develops, is unknown. Therefore, in Experiment 1, all participants were first trained on the information-integration category structure for 2 days until they reached an expert level. Afterwards, half of the participants learned in a supervised way and the other half in a semisupervised way over two successive days. Both groups received an equal number of feedback trials. Finally, all participants took part in a test day where they were asked to respond as quickly as possible. Participants were significantly faster on this test in the semisupervised group than in the supervised group. This difference was not found on day 2, implying that the no-feedback trials in the semisupervised condition facilitated automaticity. Experiment 2 was designed to test whether the higher number of trials in the semisupervised condition of Experiment 1 caused the faster response times. We therefore created an almost supervised condition where participants almost always received feedback (95%) and an almost unsupervised condition where participants almost never received feedback (5%). All conditions now contained an equal number of trials to the semisupervised condition of Experiment 1. The results show that receiving feedback almost always or almost never led to slower response times than the semisupervised condition of Experiment 1. This confirms the advantage of semisupervised learning late in learning.