Let me give you something to think about: Does needing to remember something new make it easier to forget something old?

In an item-method directed forgetting task, memory instructions presumably operate by promoting further rehearsal of to-be-remembered (TBR) items and limiting encoding of to-be-forgotten (TBF) items. We asked whether diverting attentional resources away from TBF items and towards a new item that needed to be committed to memory would improve forgetting. To this end, study words in our experiments were presented singly followed by a remember instruction (single-TBR), by a forget instruction (single-TBF), or else were replaced by a new word to be remembered (replace-TBR) in place of the original study word which could be forgotten (replace-TBF). A typical directed forgetting effect was observed across single and replace trials. However, there was no compelling evidence that forgetting was better for replace-TBF compared to single-TBF words, suggesting that, by itself, the explicit redirection of attentional and other processing resources away from forget items may not be sufficient to improve item-method directed forgetting.

The Active Suppression of a Distractor's Location Can Be Elusive.

Our visual system is inundated with distracting objects that vie for our attention. While visual attention selects relevant information, inhibitory mechanisms might be useful to suppress the locations occupied by irrelevant distractors. Yet, there is a dearth of behavioral evidence for the active suppression of a distractor's location (ASDL) using central cues that provide preliminary information about a distractor's location. In the first two experiments, we attempt to conceptually replicate, using an online platform, experiments that provide evidence of the ASDL. We replicate the distractor cueing effect in a localization task (Experiment 1) wherein responses to targets were faster when a central arrow cued the location of an impending distractor than an empty location. This effect was larger in the first block of trials than it was in the second. In a discrimination task (Experiment 2), unlike previous studies, we found no evidence for an effect of distractor cueing. In Experiment 3, we replaced the central arrow cues with central number cues because arrow cues may elicit a symbolic shift of attention that might offset the ASDL. Once again, the best model was one in which the distractor cueing effect was absent. We replicate these failures to find evidence of the ASDL in two more experiments. The results suggest that the ASDL can be elusive and may be tied to the response system, not attention.

Using Speed and Accuracy and the Simon Effect to Explore the Output Form of Inhibition of Return.

Inhibition of return (IOR) refers to slower responses to targets presented at previously cued locations. Contrasting target discrimination performance over various eye movement conditions has shown the level of activation of the reflexive oculomotor system determines the nature of the effect. Notably, an inhibitory effect of a cue nearer to the input end of the processing continuum is observed when the reflexive oculomotor system is actively suppressed, and an inhibitory effect nearer the output end of the processing continuum is observed when the reflexive oculomotor system is actively engaged. Furthermore, these two forms of IOR interact differently with the Simon effect. Drift diffusion modeling has suggested that two parameters can theoretically account for the speed-accuracy tradeoff rendered by the output-based form of IOR: increased threshold and decreased trial noise. In Experiment 1, we demonstrate that the threshold parameter best accounts for the output-based form of IOR by measuring it with intermixed discrimination and localization targets. Experiment 2 employed the response-signal methodology and showed that the output-based form has no effect on the accrual of information about the target's identity. These results converge with the response bias account for the output form of IOR.

Forgetting under difficult conditions: Item-method directed forgetting under perceptual processing constraints.

Intentional forgetting of unwanted items is effortful, yet directed forgetting seems to improve when a secondary task is performed. According to the cognitive load hypothesis of directed forgetting, allocating attentional resources to another task improves forgetting by restricting unwanted encoding of to-be-forgotten (TBF) items. Alternatively, it might be that anything that makes studying more difficult will encourage greater effort to perform the task well and therefore lead to improved intentional forgetting. To assess these proposals we imposed data-processing limitations on study words in an item-method directed forgetting paradigm. Across six experiments, the perceptual quality of study words was manipulated by varying: (1) the duration of study word presentation (Experiments 1-4); (2) the contrast of the displayed word against its visual background (Experiment 5); or (3) the amount of visual background noise on which the word was presented (Experiment 6). In Experiments 4-6, a lexical decision task corroborated the difficulty of study word processing. Despite evidence that relatively low visual contrast and relatively high visual background noise, in particular, create challenging conditions, we found no evidence that perceptual quality impacts the magnitude of the directed forgetting effect. This work suggests that data limitations have no discernible effect on forgetting and corroborate that only attentional resource limitations improve directed forgetting.

Retraction Note: Losing control: Mostly incongruent lists postpone, but do not eliminate, the Stroop effect.

This article has been retracted at the request of all authors. In Experiments 3 and 4 an honest error in the experimental script pointed to the wrong stimulus file on 6.25% of trials, resulting in inaccurate output for each participant.

Losing control: Mostly incongruent lists postpone, but do not eliminate, the Stroop effect.

Identifying the color (e.g., red) of a color word that is incongruent (e.g., "BLUE") can be remarkably difficult. The Stroop effect is a measure of the interference between activity from word and color pathways. The efficacy of these pathways is thought to be highly contingent on the frequency of incongruent trials within a block. A block of trials with mostly incongruent (MI) trials typically results in a smaller Stroop effect than a block with mostly congruent (MC) trials. This reduction of the Stroop effect has been largely attributed to the strategic list-wide control of the word pathway. Here, the time course of the Stroop effect was explored using speed-accuracy tradeoff functions (SATfs) in tasks with 50 % congruent, MC, and MI trials. In the MC and 50 % congruent condition, color-word congruency affected the rate parameter of the SATf. In the MI condition, however, congruency affected the asymptote. This evidence is consistent with the idea that the strategic control of the word pathway is an effortful, temporary phenomenon, prone to buckle if responding is held in check.

Expect the unexpected: a paradoxical effect of cue validity on the orienting of attention.

Predictive central cues generate location-based expectancies, voluntary shifts of attention, and facilitate target processing. Often, location-based expectancies and voluntary attention are confounded in cueing tasks. Here we vary the predictability of central cues to determine whether they can evoke the inhibition of target processing in three go/no-go experiments. In the first experiment, the central cue was uninformative and did not predict the target's location. Importantly, these cues did not seem to affect target processing. In the second experiment, the central cue indicated the most or the least likely location of the target. Surprisingly, both types of cues facilitated target processing at the cued location. In the third experiment, the central cue predicted the most likely location of a no-go target, but it did not provide relevant information pertaining to the location of the go target. Again, the central cue facilitated processing of the go target. These results suggest that efforts to strategically allocate inhibition may be thwarted by the paradoxical monitoring of the cued location. The current findings highlight the need to further explore the relationship between location-based expectancies and spatial attention in cueing tasks.

On the temporal dynamics of spatial stimulus-response transfer between spatial incompatibility and Simon tasks.

The Simon effect refers to the performance (response time and accuracy) advantage for responses that spatially correspond to the task-irrelevant location of a stimulus. It has been attributed to a natural tendency to respond toward the source of stimulation. When location is task-relevant, however, and responses are intentionally directed away (incompatible) or toward (compatible) the source of the stimulation, there is also an advantage for spatially compatible responses over spatially incompatible responses. Interestingly, a number of studies have demonstrated a reversed, or reduced, Simon effect following practice with a spatial incompatibility task. One interpretation of this finding is that practicing a spatial incompatibility task disables the natural tendency to respond toward stimuli. Here, the temporal dynamics of this stimulus-response (S-R) transfer were explored with speed-accuracy trade-offs (SATs). All experiments used the mixed-task paradigm in which Simon and spatial compatibility/incompatibility tasks were interleaved across blocks of trials. In general, bidirectional S-R transfer was observed: while the spatial incompatibility task had an influence on the Simon effect, the task-relevant S-R mapping of the Simon task also had a small impact on congruency effects within the spatial compatibility and incompatibility tasks. These effects were generally greater when the task contexts were similar. Moreover, the SAT analysis of performance in the Simon task demonstrated that the tendency to respond to the location of the stimulus was not eliminated because of the spatial incompatibility task. Rather, S-R transfer from the spatial incompatibility task appeared to partially mask the natural tendency to respond to the source of stimulation with a conflicting inclination to respond away from it. These findings support the use of SAT methodology to quantitatively describe rapid response tendencies.

On the role of eye movement monitoring and discouragement on inhibition of return in a go/no-go task.

Inhibition of return (IOR) most often describes the finding of increased response times to cued as compared to uncued targets in the standard covert orienting paradigm. A perennial question in the IOR literature centers on whether the effect of IOR is on motoric/decision-making processes (output-based IOR), attentional/perceptual processes (input-based IOR), or both. Recent data converge on the idea that IOR is an output-based effect when eye movements are required or permitted whereas IOR is an input-based effect when eye movements are monitored and actively discouraged. The notion that the effects of IOR may be fundamentally different depending on the activation state of the oculomotor system has been challenged by several studies demonstrating that IOR exists as an output-, or output- plus input-based effect in simple keypress tasks not requiring oculomotor responses. Problematically, experiments in which keypress responses are required to visual events rarely use eye movement monitoring let alone the active discouragement of eye movement errors. Here, we return to an experimental method implemented by Ivanoff and Klein (2001) whose results demonstrated that IOR affected output-based processes when, ostensibly, only keypress responses occurred. Unlike Ivanoff and Klein, however, we assiduously monitor and discourage eye movements. We demonstrate that actively discouraging eye movements in keypress tasks changes the form of IOR from output- to input-based and, as such, we strongly encourage superior experimental control over or consideration of the contribution of eye movement activity in simple keypress tasks exploring IOR.

Functional neuroanatomy of response inhibition in bipolar disorders--combined voxel based and cognitive performance meta-analysis.

OBJECTIVES: Impaired response inhibition underlies symptoms and altered functioning in patients with bipolar disorders (BD). The interpretation of fMRI studies requires an accurate estimation of neurocognitive performance, for which individual studies are typically underpowered. Thus, we performed the first combined meta-analysis of fMRI activations and neurocognitive performance in studies investigating response inhibition in BD. METHODS: We used signed differential mapping to combine anatomical coordinates of activation and standardized differences between means to evaluate neurocognitive performance in 30 fMRI studies of response inhibition comparing controls (n = 667) and patients with BD (n = 635). RESULTS: Relative to controls, BD patients underactivated the right inferior frontal gyrus (rIFG) regardless of current mood state and behavioral performance. Unique to euthymia were cortical hyperactivations (left superior temporal, right middle frontal gyri) combined with subcortical hypoactivations (basal ganglia), whereas unique to mania were subcortical hyperactivations (bilateral basal ganglia), combined with cortical hypoactivations (right inferior and medial frontal gyri). The fMRI changes in euthymia were associated with normal cognitive performance, whereas manic patients committed more errors during response inhibition. CONCLUSIONS: The rIFG hypoactivations were congruent with a BD trait, which may underlie the impaired response inhibition in mania. Euthymic BD subjects may compensate for the rIFG hypoactivations by hyperactivations of adjacent cortical areas, yielding comparable performance in inhibitory functions and suggesting possibilities for neuromodulation treatment of these cognitive impairments. The reversal of the activation pattern between mania and euthymia has implications for monitoring of treatment response and identification of imminent relapse.

A derived transfer of eliciting emotional functions using differences among electroencephalograms as a dependent measure.

Emotional responses have specific electroencephalographic (EEG) signatures that arise within a few hundred milliseconds post-stimulus onset. In this experiment, EEG measures were employed to assess for transfer of emotional functions across three 3-member equivalence classes in an extension of Dougher, Auguston, Markham, Greenway, & Wulfert's (1994) seminal work on the transfer of arousal functions. Specifically, 12 human participants were trained in the following match-to-sample performances A1 = B1, A2 = B2, A3 = B3 and B1 = C1, B2 = C2, B3 = C3. After successfully testing for the emergence of symmetry relations (B1 = A1, B2 = A2, B3 = A3 and C1 = B1, C2 = B2, C3 = B3), visual images depicting emotionally positive and emotionally negative content were presented with A1 and A3, respectively, using a mixed stimulus pairing-compounding procedure. A2 was paired with emotionally neutral images. Next, EEG data were recorded as participants were exposed to a forced-choice recognition task with stimuli A1, B1, C1, A2, B2, C2, A3, B3, C3 and three novel stimuli A4, B4 and C4. Results yielded differential EEG effects for stimuli paired directly with emotional versus neutral images. Critically, differential EEG effects were also recorded across the C stimuli that were equivalently related to the A stimulus set. The EEG data coincide with previous reports of emotion-specific EEG effects, indicating that the initial emotional impact of a stimulus may emerge based on direct stimulus pairing and derived stimulus relations.

On the nature of the delayed "inhibitory" cueing effects generated by uninformative arrows at fixation.

When the interval between a spatially uninformative arrow and a visual target is short (<500 ms), response times (RTs) are fastest when the arrow points to the target. When this interval exceeds 500 ms, there is a near-universal absence of an effect of the arrow on RTs. Contrary to this expected pattern of results, Taylor and Klein (J Exp Psychol Hum Percept Perform 26:1639-1656, 2000) observed that RTs were slowest when a to-be-localized visual target occurred in the direction of a fixated arrow presented 1 s earlier (i.e., an "inhibitory" Cueing effect; ICE). Here we examined which factor(s) may have allowed the arrow to generate an ICE. Our experiments indicated that the ICE was a side effect of subthreshold response activation attributable to a task-induced association between the arrow and a keypress response. Because the cause of this ICE was more closely related to subthreshold keypress activation than to oculomotor activation, we considered that the effect might be more similar to the negative compatibility effect (NCE) than to inhibition of return (IOR). This similarity raises the possibility that classical IOR, when caused by a spatially uninformative peripheral onset event and measured by a keypress response to a subsequent onset, might represent, in part, another instance of an NCE. Serendipitously, we discovered that context (i.e., whether an uninformative peripheral onset could occur at the time of an uninformative central arrow) ultimately determined whether the "inhibitory" aftermath of automatic response activation would affect output or input pathways.

Perceptual and motor inhibition of return: components or flavors?

The most common evidence for inhibition of return (IOR) is the robust finding of increased response times to targets that appear at previously cued locations following a cue-target interval exceeding ~300 ms. In a variation on this paradigm, Abrams and Dobkin (Journal of Experimental Psychology: Human Perception and Performance 20:467-477, 1994b) observed that IOR was greater when measured with a saccadic response to a peripheral target than with that to a central arrow, leading to the conclusion that saccadic responses to peripheral targets comprise motoric and perceptual components (the two-components theory for saccadic IOR), whereas saccadic responses to a central target comprise a single motoric component. In contrast, Taylor and Klein (Journal of Experimental Psychology: Human Perception and Performance 26:1639-1656, 2000) discovered that IOR for saccadic responses was equivalent for central and peripheral targets, suggesting a single motoric effect under these conditions. Rooted in methodological differences between the studies, three possible explanations for this discrepancy can be found in the literature. Here, we demonstrate that the empirical discrepancy is rooted in the following methodological difference: Whereas Abrams and Dobkin (Journal of Experimental Psychology: Human Perception and Performance 20:467-477, 1994b) administered central arrow and peripheral onset targets in separate blocks, Taylor and Klein (Journal of Experimental Psychology: Human Perception and Performance 26:1639-1656, 2000) randomly intermixed these stimuli in a single block. Our results demonstrate that (1) blocking central arrow targets fosters a spatial attentional control setting that allows for the long-lasting IOR normally generated by irrelevant peripheral cues to be filtered and (2) repeated sensory stimulation has no direct effect on the magnitude of IOR measured by saccadic responses to targets presented about 1 s after a peripheral cue.

Two components in IOR: evidence for response bias and perceptual processing delays using the SAT methodology.

Inhibition of return (IOR) occurs when reaction times (RTs) are slowed to respond to a target that appears at a previously attended location. We used the speed-accuracy trade-off (SAT) procedure to obtain conjoint measures of IOR on sensitivity and processing speed by presenting targets at cued and uncued locations. The results showed that IOR is associated with both delays in processing speed and shifts in response criterion. When the target was briefly presented, the results supported a criterion shift account of IOR. However, when the target was presented until response, the evidence indicated that, in addition to a response bias effect, there was an increase in the minimal time required for information about the target to accumulate above chance level. A hybrid account of IOR is suggested that describes effects on both response bias and perceptual processing.

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 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.

Mapping the pathways of information processing from sensation to action in four distinct sensorimotor tasks.

Two sensorimotor tasks that share neither sensory nor motor modality can interfere with one another when they are performed simultaneously. A possible cause for this interference is the recruitment of common brain regions by these two tasks, thereby creating a bottleneck of information processing. This hypothesis predicts that such "bottleneck" regions would be activated by each task even when they are performed separately. To test this prediction, we sought to identify, with fMRI, brain regions commonly activated by sensorimotor tasks that share neither sensory input nor motor output. One group of subjects was scanned while they performed in separate runs an auditory-vocal (AVo) task and a visuo-manual (ViM) task, while a second group of subjects performed the reversed sensorimotor mapping tasks (AM and ViVo). The results revealed strong activation preferences in specific sensory and motor cortical areas for each sensory and motor modality. By contrast, the posterior portion of the lateral prefrontal cortex (pLPFC), anterior insula, and, less consistently, the anterior cingulate, presupplementary and supplementary motor areas, and subcortical areas were commonly activated across all four sensorimotor tasks. These results were observed in both blocked and event-related fMRI designs, in both 3D-group averaged and 2D-individual subject analyses, and were replicated within individuals across scanning sessions. These findings not only suggest that these brain regions serve a common amodal function in sensorimotor tasks, they also point to these regions--particularly, the pLPFC and anterior insula--as candidate neural substrates underlying a central hub of information processing in the human brain.

Nonattentional effects of nonpredictive central cues.

Recent evidence suggests that nonpredictive gaze, hand, arrow, and peripheral cues elicit shifts of reflexive attention. In the present article, we address whether these cues also influence the decision criterion in a go/no-go task. Nonpredictive central gaze and hand cues pointed toward or away from the location of an imminent target. Responses to the targets were faster, and false alarm errors were more frequent, when cues pointed toward the target than when they were directed away from it. Although a similar pattern was observed with nonpredictive arrow cues, it was not seen with nonpredictive peripheral cues. These results suggest that nonpredictive central cues not only affect attention, but also bias decision processes.

fMRI evidence for a dual process account of the speed-accuracy tradeoff in decision-making.

BACKGROUND: The speed and accuracy of decision-making have a well-known trading relationship: hasty decisions are more prone to errors while careful, accurate judgments take more time. Despite the pervasiveness of this speed-accuracy trade-off (SAT) in decision-making, its neural basis is still unknown. METHODOLOGY/PRINCIPAL FINDINGS: Using functional magnetic resonance imaging (fMRI) we show that emphasizing the speed of a perceptual decision at the expense of its accuracy lowers the amount of evidence-related activity in lateral prefrontal cortex. Moreover, this speed-accuracy difference in lateral prefrontal cortex activity correlates with the speed-accuracy difference in the decision criterion metric of signal detection theory. We also show that the same instructions increase baseline activity in a dorso-medial cortical area involved in the internal generation of actions. CONCLUSIONS/SIGNIFICANCE: These findings suggest that the SAT is neurally implemented by modulating not only the amount of externally-derived sensory evidence used to make a decision, but also the internal urge to make a response. We propose that these processes combine to control the temporal dynamics of the speed-accuracy trade-off in decision-making.

Isolation of a central bottleneck of information processing with time-resolved FMRI.

When humans attempt to perform two tasks at once, execution of the first task usually leads to postponement of the second one. This task delay is thought to result from a bottleneck occurring at a central, amodal stage of information processing that precludes two response selection or decision-making operations from being concurrently executed. Using time-resolved functional magnetic resonance imaging (fMRI), here we present a neural basis for such dual-task limitations, e.g. the inability of the posterior lateral prefrontal cortex, and possibly the superior medial frontal cortex, to process two decision-making operations at once. These results suggest that a neural network of frontal lobe areas acts as a central bottleneck of information processing that severely limits our ability to multitask.