Does familiarity or conflict account for performance in the word-stem completion task? Evidence from behavioural and event-related-potential data

The conflict monitoring theory (CMT) assumes that word-stems associated with several completions should lead to crosstalk and conflict due to underdetermined responding situation (Botvinick et al. in Psychol Rev 108(3):624–652, 2001). In contrast, the Multiple-Read-Out-Model (MROM) of Jacobs and Grainger (J Exp Psychol 20(6): 1311–1334, 1994) predicts a high level of general lexical activity (GLA) for word-stems with many completions, indicating a higher stimulus familiarity because these stems are more probable to be read. We compared word-stems with several completions against word-stems with one possible completion while measuring response times and electrophysiological recordings. Slowest response times and a distinct FN400 component, which has previously been related to the concept of familiarity (Curran in Memory Cogn 28(6):923–938, 2000), were apparent for word-stems that could only be associated with a single response. These findings support the claims of the MROM. Furthermore, the lack of the N2-component for word-stems with several completions continues to challenge the EEG-extension of the CMT (Yeung et al. in Psychol Rev 111(4):2004).     

Memory development in the second year: for events or locations?

We employed an object-placement/object-removal design, inspired by recent work on 'episodic-like' memory in scrub jays (Clayton, N. S., & Dickinson, A. (1998). Episodic-like memory during cache recovery by scrub jays. Nature, 395, 272-274), to examine the possibility that children in the second year of life have event-based memories. In one task, a successful search could have been due to the recall of an object-removal event. In the second task, a successful search could only have been caused by recall of where objects were located. Success was general in the oldest group of children (21-25 months), while performance was broadly similar on the two tasks. The parsimonious interpretation of this outcome is that the first task was performed by location memory, not by event memory. We place these data in the context of object permanence development.     

Procedural memory effects in categorization: Evidence for multiple systems or task complexity?

According to an influential multiple-systems model of category learning, an implicit procedural system governs the learning of information-integration category structures, whereas a rule-based system governs the learning of explicit rule-based categories. Support for this idea has come in part from demonstrations that motor interference, in the form of inconsistent mapping between response location and category labels, results in observed deficits, but only for learning information-integration category structures. In this article, we argue that this response location manipulation results in a potentially more cognitively complex task in which the feedback is difficult to interpret. In one experiment, we attempted to attenuate the cognitive complexity by providing more information in the feedback, and demonstrated that this eliminates the observed performance deficit for information-integration category structures. In a second experiment, we demonstrated similar interference of the inconsistent mapping manipulation in a rule-based category structure. We claim that task complexity, and not separate systems, might be the source of the original dissociation between performance on rule-based and information-integration tasks.     

Regional accent variation in the shadowing task: Evidence for a loose perception–action coupling in speech

We investigated the relation between action and perception in speech processing, using the shadowing task, in which participants repeat words they hear. In support of a tight perception–action link, previous work has shown that phonetic details in the stimulus influence the shadowing response. On the other hand, latencies do not seem to suffer if stimulus and response differ in their articulatory properties. The present investigation tested how perception influences production when participants are confronted with regional variation. Results showed that participants often imitate a regional variation if it occurs in the stimulus set but tend to stick to their variant if the stimuli are consistent. Participants were forced or induced to correct by the experimental instructions. Articulatory stimulus–response differences do not lead to latency costs. These data indicate that speech perception does not necessarily recruit the production system.     

How modality specific is the iambic-trochaic law? Evidence from vision

The iambic-trochaic law has been proposed to account for the grouping of auditory stimuli: Sequences of sounds that differ only in duration are grouped as iambs (i.e., the most prominent element marks the end of a sequence of sounds), and sequences that differ only in pitch or intensity are grouped as trochees (i.e., the most prominent element marks the beginning of a sequence). In 3 experiments, comprising a familiarization and a test phase, we investigated whether a similar grouping principle is also present in the visual modality. During familiarization, sequences of visual stimuli were repeatedly presented to participants, who were asked to memorize their order of presentation. In the test phase, participants were better at remembering fragments of the familiarization sequences that were consistent with the iambic-trochaic law. Thus, they were better at remembering fragments that had the element with longer duration in final position (iambs) and fragments that had the element with either higher temporal frequency or higher intensity in initial position (trochees), as compared with fragments that were inconsistent with the iambic-trochaic law or that never occurred during familiarization.     

Is optimal vision required for the successful execution of an interceptive task?

The importance of optimal visual function in demanding interceptive tasks is far from established. The aim of the study was to determine whether induced myopic blur and hence sub-optimal visual function would give rise to a detrimental effect on performance in the execution of an interceptive task. The batting performance of grade level cricket players was assessed facing a bowling machine whilst wearing contact lenses of four different refractive conditions (plano (nil), +1.00, +2.00 and +3.00D over-refraction), inducing increasing amounts of myopic blur. Performance for each condition was assessed based both on the shot quality against each delivery judged by a qualified cricket coach blind to each condition, along with an evaluation of the quality of ball-bat contact for each delivery. No significant change was found in batting performance with the introduction of +1.00 and +2.00D of induced myopic blur. A +3.00D over-correction was required before any significant decrease in batting performance was detected, demonstrating that batters needed to be essentially legally blind (as simulated through the use of the +3.00D over-refraction) before there was any significant measurable decrement in batting performance. We concluded that optimal visual correction is not necessarily required for optimal performance in a demanding interceptive task, and that the human perceptual-motor system is capable of compensating for marked alterations in input.     

Real Evidence for the Failure of the Jamesian Perspective or More Evidence in Support of It?

Hardy and Moriarty (2006) presented evidence in support of James's (1890) individual importance hypothesis using a new methodology. Marsh (in press) criticized the Hardy and Moriarty approach, claiming that it did not constitute a valid test of the hypothesis and that in his article he had produced more evidence against it. In this article, we refute both these claims and argue instead that Marsh's individually weighted-averages method does not constitute a valid test of the hypothesis. We also assert that his new analyses actually offer further evidence in support of the Jamesian perspective. Finally, we direct attention toward questionable assumptions that appear to underpin Marsh's approach, and we try to point a way forward for future research in this area.     

Interactive context integration in children? Evidence from an action memory study

Action–object phrases (e.g., “lift the bottle”) are remembered better if they have been enacted rather than learned verbally. This enactment effect is largest in free recall for phrases with objects (e.g., “bottle”) present because these phrases can be interactively encoded with those context objects (interactive context integration) that serve as retrieval cues. The current study investigated whether 6- and 8-year-olds are already capable of interactive context integration. Experiment 1 demonstrated interactive context integration with 8-year-olds. This was hindered in a condition where attention was directed away from context objects. Experiment 2 demonstrated interactive context integration with 6-year-old kindergartners. Taken together, our findings show that even 6-year-olds are capable of incidental context integration through enactment and that this process is attention based.     

Holistic or compositional representation of two-digit numbers? Evidence from the distance, magnitude, and SNARC effects in a number-matching task

Whether two-digit numbers are represented holistically (each digit pair processed as one number) or compositionally (each digit pair processed separately as a decade digit and a unit digit) remains unresolved. Two experiments were conducted to examine the distance, magnitude, and SNARC effects in a number-matching task involving two-digit numbers. Forty undergraduates were asked to judge whether two two-digit numbers (presented serially in Experiment 1 and simultaneously in Experiment 2) were the same or not. Results showed that, when numbers were presented serially, unit digits did not make unique contributions to the magnitude and distance effects, supporting the holistic model. When numbers were presented simultaneously, unit digits made unique contributions, supporting the compositional model. The SNARC (Spatial-Numerical Association of Response Codes) effect was evident for the whole numbers and the decade digits, but not for the unit digits in both experiments, which indicates that two-digit numbers are represented on one mental number line. Taken together, these results suggested that the representation of two-digit numbers is on a single mental number line, but it depends on the stage of processing whether they are processed holistically or compositionally.     

Do innocent victims threaten the belief in a just world? Evidence from a modified Stroop task

Two experiments tested whether innocent victims threaten observers' belief in a just world. In both experiments, participants viewed an innocent victim then performed a modified Stroop task in which they identified the color of several words presented for brief exposures (followed by a mask) on a computer screen. When the threat to justice beliefs was presumably highest, color-identification latencies were greater for justice-related words than for neutral words. In Experiment 2, under conditions of high threat, justice-related interference predicted participants' tendency to disassociate themselves from and derogate the victim. These findings suggest that innocent victims do threaten justice beliefs and responses to these victims may, at times, be attempts to reduce this threat. The methodology presented here may be applied to future investigations of defensive, counternormative processes reflecting people's concern with justice.     

Accounting for sequential trial effects in the flanker task: Conflict adaptation or associative priming?

The conflict-control loop theory proposes that the detection of conflict in information processing triggers an increase in cognitive control, resulting in improved performance on the subsequent trial. This theory seems consistent with the robust finding that conflict susceptibility is reduced following correct trials associated with high conflict: the conflict adaptation effect. However, despite providing favorable conditions for eliciting and detecting conflict-triggered performance adjustments, none of the five experiments reported here provide unequivocal evidence of such adjustments. Instead, the results corroborate and extend earlier findings by demonstrating that the conflict adaptation effect, at least in the flanker task, is only present for a specific subset of trial sequences that is characterized by a response repetition. This pattern of results provides strong evidence that the conflict adaptation effect reflects associative stimulus-response priming instead of conflict-driven adaptations in cognitive control.     

Is task switching nothing but cue priming? Evidence from ERPs

Recent findings suggesting that switch costs in the task-cuing paradigm are largely attributable to a change in the task-indicating cue have been interpreted in terms of a priming model of task-switch costs (Logan & Bundesen, 2003). According to this explanation, participants do not actually switch task sets, but merely use a cue-stimulus compound to disambiguate competing response tendencies associated with bivalent stimuli. Here, we report an event-related potential (ERP) experiment that provides evidence against this notion. In a paradigm with a 2:1 mapping between cues and tasks, we show that cue-switch and task-switch effects are dissociable on a neurophysiological level, indicating that task switching is more than a switch in the task-indicating cue. Moreover, a systematic analysis of the ERPs during the cue-stimulus interval suggests that updating processes can run in advance, before the stimulus is presented.     

Single-digit Arabic numbers do not automatically activate magnitude representations in adults or in children: Evidence from the symbolic same–different task

We investigated whether the mere presentation of single-digit Arabic numbers activates their magnitude representations using a visually-presented symbolic same–different task for 20 adults and 15 children. Participants saw two single-digit Arabic numbers on a screen and judged whether the numbers were the same or different. We examined whether reaction time in this task was primarily driven by (objective or subjective) perceptual similarity, or by the numerical difference between the two digits. We reasoned that, if Arabic numbers automatically activate magnitude representations, a numerical function would best predict reaction time; but if Arabic numbers do not automatically activate magnitude representations, a perceptual function would best predict reaction time. Linear regressions revealed that a perceptual function, specifically, subjective visual similarity, was the best and only significant predictor of reaction time in adults and in children. These data strongly suggest that, in this task, single-digit Arabic numbers do not necessarily automatically activate magnitude representations in adults or in children. As the first study to date to explicitly study the developmental importance of perceptual factors in the symbolic same–different task, we found no significant differences between adults and children in their reliance on perceptual information in this task. Based on our findings, we propose that visual properties may play a key role in symbolic number judgements.     

Distributional reaction time properties in the Eriksen task: marked differences or hidden similarities with the Simon task?

In conflict tasks, the irrelevant stimulus attribute needs to be suppressed for the correct response to be produced. In the Simon task, earlier researchers have proposed that this suppression is the reason that, after an initial increase, the interference effect decreases for longer RTs, as reflected by late, negative-going delta plots. This view has been challenged by observations of positive-going delta plots, even for long RTs, in other conflict tasks, despite a similar necessity for suppression. For late negative-going delta plots to be interpreted as reflecting suppression, a necessary, although maybe not sufficient, condition is that similar patterns should be observed for other conflict tasks. We reasoned that a similar suppression could be present, but hidden, in the Eriksen flanker task. By recording and analyzing electromyograms of the muscles involved in response execution, we could compute delta plots separately for trials that elicited a subthreshold incorrect response activation (partial error). Late negative-going delta plots were observable on partial-error trials, although they were weaker than for the Simon task, reducing the impact of this inversion on the overall distribution. We further showed that this pattern is modulated by time pressure. Those results indicate that mechanisms leading to negative-going delta plots, similar to those observed in the Simon task, are also at play in the Eriksen task. The link between negative-going delta plots and executive online control is discussed.     

A unity of the self or a multiplicity of locations? How the graphesthesia task sheds light on the role of spatial perspectives in bodily self-consciousness

Integrating multisensory stimuli from a self-centred perspective is crucial for the unity of the self. On the other hand, understanding external space and communicating spatial knowledge with others necessitate the adoption of decentred perspectives. How do we juggle these two requirements? In this article, we review those studies that have used the graphesthesia task in order to investigate the perspectives that people adopt when interpreting ambiguous tactile symbols (e.g., b, d, p, and q). With such ambiguous symbols, self-centred and decentred perspectives conflict with one another. The results reviewed here reveal that the perspectives adopted vary significantly with spatial, personal, and interpersonal factors. Such findings suggest that the self can adopt a multiplicity of spatial locations. However, the unity of the self can partly be explained by the predominance of a head-centred perspective. On the other hand, perspective-taking abilities contribute to the distinction between self and others, reinforcing self-consciousness.     

Automated vision occlusion-timing instrument for perception–action research

Vision occlusion spectacles are a highly valuable instrument for visual-perception–action research in a variety of disciplines. In sports, occlusion spectacles have enabled invaluable knowledge to be obtained about the superior capability of experts to use visual information to guide actions within in-situ settings. Triggering the spectacles to occlude a performer’s vision at a precise time in an opponent’s action or object flight has been problematic, due to experimenter error in using a manual buttonpress approach. This article describes a new laser curtain wireless trigger for vision occlusion spectacles that is portable and fast in terms of its transmission time. The laser curtain can be positioned in a variety of orientations to accept a motion trigger, such as a cricket bowler’s arm that distorts the lasers, which then activates a wireless signal for the occlusion spectacles to change from transparent to opaque, which occurs in only 8 ms. Results are reported from calculations done in an electronics laboratory, as well as from tests in a performance laboratory with a cricket bowler and a baseball pitcher, which verified this short time delay before vision occlusion. In addition, our results show that occlusion consistently occurred when it was intended—that is, near ball release and during mid-ball-flight. Only 8% of the collected data trials were unusable. The laser curtain improves upon the limitations of existing vision occlusion spectacle triggers, indicating that it is a valuable instrument for perception–action research in a variety of disciplines.     

Is recursion language-specific? Evidence of recursive mechanisms in the structure of intentional action

In their 2002 seminal paper Hauser, Chomsky and Fitch hypothesize that recursion is the only human-specific and language-specific mechanism of the faculty of language. While debate focused primarily on the meaning of recursion in the hypothesis and on the human-specific and syntax-specific character of recursion, the present work focuses on the claim that recursion is language-specific. We argue that there are recursive structures in the domain of motor intentionality by way of extending John R. Searle’s analysis of intentional action. We then discuss evidence from cognitive science and neuroscience supporting the claim that motor-intentional recursion is language-independent and suggest some explanatory hypotheses: (1) linguistic recursion is embodied in sensory-motor processing; (2) linguistic and motor-intentional recursions are distinct and mutually independent mechanisms. Finally, we propose some reflections about the epistemic status of HCF as presenting an empirically falsifiable hypothesis, and on the possibility of testing recursion in different cognitive domains.     

Is attention needed for word identification? Evidence from the Stroop paradigm

One of the most robust findings in attention research is that the time to name a color is lengthened markedly in the presence of an irrelevant word that spells a different color name: the Stroop effect. The Stroop effect is found even when the word is physically separated from the color, apparently indicating that words can be read outside the focus of spatial attention. The present study critically evaluated this claim. We employed several stringent measures within a Stroop paradigm to prevent participants from attending to the irrelevant words (e.g., limiting exposure duration to prevent attention capture). Nonetheless, residual Stroop effects were obtained for both color words and semantic associates (e.g., sky to blue). These data suggest that lexical processing can sometimes occur outside the focus of spatial attention.     

On the limits of advance preparation for a task switch: do people prepare all the task some of the time or some of the task all the time?

This study investigated the nature of advance preparation for a task switch, testing 2 key assumptions of R. De Jong's (2000) failure-to-engage theory: (a) Task-switch preparation is all-or-none, and (b) preparation failures stem from nonutilization of available control capabilities. In 3 experiments, switch costs varied dramatically across individual stimulus-response (S-R) pairs of the tasks-virtually absent for 1 pair but large for others. These findings indicate that, across trials, task preparation was not all-or-none but, rather, consistently partial (full preparation for some S-R pairs but not others). In other words, people do not prepare all of the task some of the time, they prepare some of the task all of the time. Experiments 2 and 3 produced substantial switch costs even though time deadlines provided strong incentives for optimal advance preparation. Thus, there was no evidence that people have a latent capability to fully prepare for a task switch.