Transfer of orthogonal stimulus–response mappings to an orthogonal Simon task

When up–down stimulus locations are mapped to left–right keypresses, an overall advantage for the up–right/down–left mapping is often obtained that varies as a function of response eccentricity. This orthogonal stimulus–response compatibility (SRC) effect also occurs when stimulus location is irrelevant, a phenomenon called the orthogonal Simon effect, and has been attributed to correspondence of stimulus and response code polarities. The Simon effect for horizontal stimulus–response (S–R) arrangements has been shown to be affected by short-term S–R associations established through the mapping used for a prior SRC task in which stimulus location was relevant. We examined whether such associations also transfer between orthogonal SRC and Simon tasks and whether correspondence of code polarities continues to contribute to performance in the Simon task. In Experiment 1, the orthogonal Simon effect was larger after practising with an up–right/down–left mapping of visual stimuli to responses than with the alternative mapping, for which the orthogonal Simon effect tended to reverse. Experiment 2 showed similar results when practice was with high (up) and low (down) pitch tones, though the influence of practice mapping was not as large as that in Experiment 1, implying that the short-term S–R associations acquired in practice are at least in part not modality specific. In Experiment 3, response eccentricity and practice mapping were shown to have separate influences on the orthogonal Simon effect, as expected if both code polarity and acquired S–R associations contribute to performance.     

Negations in syllogistic reasoning: Evidence for a heuristic–analytic conflict

Research indicates that cognitive age differences can be influenced by metacognitive factors. This research has generally focused on simple memory tasks. Age differences in working memory (WM) performance are pronounced, but are typically attributed to basic cognitive deficits rather than metacognitive factors. However, WM performance can be influenced by strategic behaviour that might be driven by metacognitive monitoring. In the current project, we attempted to connect these lines of research by examining age differences in metacognitive WM monitoring and strategies. In Experiment 1, younger and older adult participants completed a computerized operation span task in conditions that either required or did not require monitoring reports. Participants in the monitoring condition predicted and postdicted global performance for each block and rated their responses following each trial within a block. In Experiment 2, participants also reported their trial-level strategic approach. In contrast to the age equivalence typically found for simple memory monitoring, results demonstrated age differences in WM monitoring accuracy. Overall age differences in strategy use were not found, but using effective strategies benefited older adults' performance more than younger adults'. Furthermore, age-related differences in the WM task appear to be mediated by the accuracy of performance monitoring.     

Evidence for a role of the responding agent in the joint compatibility effect

The present study explored the role of the responding agent in a social context. To do so, we developed a compatibility task with socially relevant but task-irrelevant stimuli (own face, neutral face, and a friend's face). Participants were required to perform naming responses to coloured diamonds, while the faces were presented as irrelevant stimuli. We observed faster responses in face–name compatible than in incompatible conditions. When the task was distributed among two friends, we observed a compatibility effect in a joint go/no-go condition, in which both participants performed their go/no-go tasks together. In contrast, no compatibility effect was obtained in an individual go/no-go condition. Further, the experiment showed that this joint compatibility effect was based on the compatibility between the irrelevant face and the responding agent. This result demonstrates that features of the responding agent play a crucial role in the joint compatibility effect.     

Across-task long-term priming: Interaction of task readiness and automatic retrieval

When humans carry out actions in response to external stimulation, they acquire associations between the stimulus and the action it triggered. When the same stimulus is used in two different tasks, the retrieval of associations compiled in the competing task hampers current performance. Previous research suggests that this across-task priming depends on the task set for the preceding task remaining active across the switch of tasks and, thus, competing with the activations needed for the new task. We present two experiments investigating this notion. Participants switched between two semantic classification tasks. In Experiment 1, participants switched between short runs of the two tasks. Across-task priming was observed on switch and repeat trials. In Experiment 2, participants switched between longer runs of the two tasks. Across-task priming was markedly reduced on repeat trials. The data suggest that whether or not across-task priming affects behaviour after the switch trial depends, amongst others, on whether the task set necessary for the previous task spills into the repeat trials. The implications of these findings for mechanisms of cognitive and mnemonic control are discussed.     

Perceptual strength is different from sensorimotor strength: Evidence from the centre–periphery asymmetry in masked priming

Near-threshold prime stimuli can facilitate or hinder responses to target stimuli, creating either a positive compatibility effect (PCE) or a negative compatibility effect (NCE). An asymmetry has been reported between primes presented in near periphery, which produced a PCE, and foveal primes, which produced an NCE under comparable conditions. This asymmetry has been attributed to the difference in retinal sensitivity, but it remains unclear whether this means that equating discrimination performance for primes in fovea and periphery, in order to account for differences in perceptual sensitivity, would make the priming effects the same. Wider work indicates that perceptual ability can dissociate from visuomotor effects, predicting that equating perceptual ability for fovea and periphery would not equate priming. We tested these opposite possibilities by matching discrimination performance for masked Gabor patches in fovea and near periphery (6°) and using these as primes in a masked priming paradigm expected to elicit NCEs. We found the asymmetry remained: NCE for fovea and PCE for periphery. We replicated this with both blocked and randomized procedures to check for attentional effects. We conclude that equating perceptual strength (discriminability) of stimuli does not equate their sensorimotor impact due to differences in the relative importance of different visual pathways and differing temporal dynamics in perceptual and sensorimotor processes.     

Conflict in object affordance revealed by grip force

Viewing objects can result in automatic, partial activation of motor plans associated with them—“object affordance”. Here, we recorded grip force simultaneously from both hands in an object affordance task to investigate the effects of conflict between coactivated responses. Participants classified pictures of objects by squeezing force transducers with their left or right hand. Responses were faster on trials where the object afforded an action with the same hand that was required to make the response (congruent trials) compared to the opposite hand (incongruent trials). In addition, conflict between coactivated responses was reduced if it was experienced on the preceding trial, just like Gratton adaptation effects reported in “conflict” tasks (e.g., Eriksen flanker). This finding suggests that object affordance demonstrates conflict effects similar to those shown in other stimulus–response mapping tasks and thus could be integrated into the wider conceptual framework on overlearnt stimulus–response associations. Corrected erroneous responses occurred more frequently when there was conflict between the afforded response and the response required by the task, providing direct evidence that viewing an object activates motor plans appropriate for interacting with that object. Recording continuous grip force, as here, provides a sensitive way to measure coactivated responses in affordance tasks.     

Orienting numbers in mental space: Horizontal organization trumps vertical

While research on the spatial representation of number has provided substantial evidence for a horizontally oriented mental number line, recent studies suggest vertical organization as well. Directly comparing the relative strength of horizontal and vertical organization, however, we found no evidence of spontaneous vertical orientation (upward or downward), and horizontal trumped vertical when pitted against each other (Experiment 1). Only when numbers were conceptualized as magnitudes (as opposed to nonmagnitude ordinal sequences) did reliable vertical organization emerge, with upward orientation preferred (Experiment 2). Altogether, these findings suggest that horizontal representations predominate, and that vertical representations, when elicited, may be relatively inflexible. Implications for spatial organization beyond number, and its ontogenetic basis, are discussed.     

Modulation of the affordance effect through transfer of learning

Consistent evidence shows that practising with spatially incompatible stimulus–response trials modulates performance on following tasks requiring the solution of cognitive conflict such as the Simon and Stroop tasks. In the present study we assessed whether a spatially incompatible practice can modulate another effect that is thought to be due to a conflict between two response alternatives, the affordance effect. To this end, we requested participants to categorize pictures of common objects on the basis of their upright or inverted orientation. A group of participants performed the categorization task alone, while the other two groups performed the categorization task after practising with a spatial compatibility task with either a compatible or an incompatible mapping. Results showed that the spatially incompatible practice eliminated the affordance effect. These results indicate that the conflict at the basis of the affordance effect is not unavoidable but it rather permeable to modulations affecting the response selection stage. Indeed the “emit the alternative spatial response” rule acquired during the spatially incompatible task can transfer to and modulate how the subsequent affordance task is performed.     

Spelling–stress regularity effects are intact in developmental dyslexia

The current experiment investigated conflicting predictions regarding the effects of spelling–stress regularity on the lexical decision performance of skilled adult readers and adults with developmental dyslexia. In both reading groups, lexical decision responses were significantly faster and significantly more accurate when the orthographic structure of a word ending was a reliable as opposed to an unreliable predictor of lexical stress assignment. Furthermore, the magnitude of this spelling–stress regularity effect was found to be equivalent across reading groups. These findings are consistent with intact phoneme-level regularity effects also observed in dyslexia. The paper discusses how findings of intact spelling–sound regularity effects at both prosodic and phonemic levels, as well as other similar results, can be reconciled with the obvious difficulties that people with dyslexia experience in other domains of phonological processing.     

Semantic interference in picture naming during dual-task performance does not vary with reading ability

Previous dual-task studies examining the locus of semantic interference of distractor words in picture naming have obtained diverging results. In these studies, participants manually responded to tones and named pictures while ignoring distractor words (picture–word interference, PWI) with varying stimulus onset asynchrony (SOA) between tone and PWI stimulus. Whereas some studies observed no semantic interference at short SOAs, other studies observed effects of similar magnitude at short and long SOAs. The absence of semantic interference in some studies may perhaps be due to better reading skill of participants in these than in the other studies. According to such a reading-ability account, participants’ reading skill should be predictive of the magnitude of their interference effect at short SOAs. To test this account, we conducted a dual-task study with tone discrimination and PWI tasks and measured participants’ reading ability. The semantic interference effect was of similar magnitude at both short and long SOAs. Participants’ reading ability was predictive of their naming speed but not of their semantic interference effect, contrary to the reading ability account. We conclude that the magnitude of semantic interference in picture naming during dual-task performance does not depend on reading skill.