Programming of time-to-peak force for brief isometric force pulses: Effects on reaction time

According to the parallel force unit model (PFUM) the programming of an isometric force pulse requires the specification of the number of force units and force unit duration. The programming of a force pulse with minimal time-to-peak force is an exception, however, as force unit duration is limited by the minimal possible value, which should be easier to adjust than larger force unit durations. Therefore, the duration of the programming process should be shorter for these force pulses and hence should result in shorter reaction time (RT). Four experiments assessed this prediction using a response precueing procedure. In each experiment the participants produced isometric flexions with their left or right index finger, and time-to-peak force was manipulated within a block. The results are consistent with the predictions of PFUM. The results, however, are at variance with alternative accounts which assume that RT depends primarily on response duration or rate of force production.     

Location- and object-based inhibition of return are affected by different kinds of working memory

Castel, Pratt, and Craik (2003) have shown that inhibition of return (IOR, the delayed response to a recently cued item) is disrupted by a secondary task that involves spatial working memory (WM), and they suggest that IOR is mediated by spatial WM. However, they did not specify what kind of IOR was involved. We used a dual-task paradigm to examine whether the two kinds of IOR (location- and object-based IOR) are affected by two kinds of secondary task that involve spatial and nonspatial WM, respectively. The results show that location-based IOR was disrupted by a spatial secondary task while the object-based IOR was disrupted by a nonspatial secondary task. The present study further elaborates the conclusion of Castel et al. (2003) by differentiating the effect of the two kinds of WM (spatial vs. nonspatial) on the two kinds of IOR (location based vs. object based).     

Attentional orientation induced by temporarily established self-referential cues

Self-referential stimuli such as self-face surpass other-referential stimuli in capture of attention, which has been attributed to attractive perceptual features of self-referential stimuli. We investigated whether temporarily established self-referential stimuli are different from other-referential cues in guiding voluntary visual attention. Temporarily established self-referential or friend-referential shapes served as central cues in Posner's endogenous cueing task. We found that, relative to friend-referential cues, self-referential cues induced smaller cueing effect (i.e., the difference in reaction times to targets at cued and uncued locations) when the interstimulus interval was short but larger cueing effect when the interstimulus interval was long. Our findings suggest that temporarily established self-referential cues are more efficient to capture reflexive attention at the early stage of perceptual processing and to shift voluntary attention at the later stage of perceptual processing.     

The limits of visual mass perception

The theory of direct perception suggests that observers can accurately judge the mass of a box picked up by a lifter shown in a point-light display. However, accurate perceptual performance may be limited to specific circumstances. The purpose of the present study was to systematically examine the factors that determine perception of mass, including display type, lifting speed, response type, and lifter's strength. In contrast to previous research, a wider range of viewing manipulations of point-light display conditions was investigated. In Experiment 1, we first created a circumstance where observers could accurately judge lifts of five box masses performed by a lifter of average strength. In Experiments 2–5, we manipulated the spatial and temporal aspects of the lift, the judgement type, and lifter's strength, respectively. Results showed that mass judgement gets worse whenever the context deviates from ideal conditions, such as when only the lifted object was shown, when video play speed was changed, or when lifters of different strength performed the same task. In conclusion, observers' perception of kinetic properties is compromised whenever viewing conditions are not ideal.     

The role of meaning in contextual cueing: Evidence from chess expertise

In contextual cueing, the position of a search target is learned over repeated exposures to a visual display. The strength of this effect varies across stimulus types. For example, real-world scene contexts give rise to larger search benefits than contexts composed of letters or shapes. We investigated whether such differences in learning can be at least partially explained by the degree of semantic meaning associated with a context independently of the nature of the visual information available (which also varies across stimulus types). Chess boards served as the learning context as their meaningfulness depends on the observer's knowledge of the game. In Experiment 1, boards depicted actual game play, and search benefits for repeated boards were 4 times greater for experts than for novices. In Experiment 2, search benefits among experts were halved when less meaningful randomly generated boards were used. Thus, stimulus meaningfulness independently contributes to learning context–target associations.     

Learning To Read Words

The ease with which we process the written word belies its complexities and makes it easy to forget that it is a highly skilled behaviour and one that takes time to master. In this paper, I argue that our ability to read words has its roots in our capacity for language. Good progress has been made towards understanding how children discover the systematic relationship between speech sounds and the letters used to represents those sounds, very early in reading development. However, we understand much less about how beginning readers become skilled readers. To understand this, I argue that it is important to view the visual word recognition system within the context of a broader language system, one that incorporates a rich network of semantic and episodic knowledge.     

Does conspicuity enhance distraction? Saliency and eye landing position when searching for objects

While visual saliency may sometimes capture attention, the guidance of eye movements in search is often dominated by knowledge of the target. How is the search for an object influenced by the saliency of an adjacent distractor? Participants searched for a target amongst an array of objects, with distractor saliency having an effect on response time and on the speed at which targets were found. Saliency did not predict the order in which objects in target-absent trials were fixated. The within-target landing position was distributed around a modal position close to the centre of the object. Saliency did not affect this position, the latency of the initial saccade, or the likelihood of the distractor being fixated, suggesting that saliency affects the allocation of covert attention and not just eye movements.     

Processing fluency as a predictor of salience asymmetries in the Implicit Association Test

The Implicit Association Test (IAT) is the most popular indirect measure of attitudes in social psychology. Rothermund and Wentura (2001, 2004) suggested that artifacts such as salience asymmetries are a source of compatibility effects in the IAT, and, therefore, the IAT does not necessarily measure attitude. They claim that salience asymmetries correspond with visual search asymmetries, such that the stimulus categories that are more quickly detected in a visual search task are also compatible in the IAT. We propose that processing fluency is a more reliable indicator of salience asymmetries in the IAT than are visual search asymmetries. To test this hypothesis, we set processing fluency in opposition to visual search asymmetry to see which variable better predicted IAT effects. In one pair of categories, the category that was more quickly detected in visual search was also more fluently processed in a binary classification task. In a second pair of categories, the category that was more quickly detected in visual search was the less fluently processed category. Across four experiments, we demonstrated that compatibility effects in the IAT corresponded with differences in processing fluency between categories, rather than with visual search asymmetries.     

Masked priming effect reflects evidence accumulated by the prime

In the same–different match task, masked priming is observed with the same responses but not different responses. Norris and Kinoshita's (2008) Bayesian reader account of masked priming explains this pattern based on the same principle as that explaining the absence of priming for nonwords in the lexical decision task. The pattern of priming follows from the way the model makes optimal decisions in the two tasks; priming does not depend on first activating the prime and then the target. An alternative explanation is in terms of a bias towards responding “same” that exactly counters the facilitatory effect of lexical access. The present study tested these two views by varying both the degree to which the prime predicts the response and the visibility of the prime. Unmasked primes produced effects expected from the view that priming is influenced by the degree to which the prime predicts the response. In contrast, with masked primes, the size of priming for the same response was completely unaffected by predictability. These results rule out response bias as an explanation of the absence of masked priming for different responses and, in turn, indicate that masked priming is not a consequence of automatic lexical access of the prime.     

The role of attention in binding visual features in working memory: Evidence from cognitive ageing

Two experiments were conducted to assess the costs of attentional load during a feature (colour–shape) binding task in younger and older adults. Experiment 1 showed that a demanding backwards counting task, which draws upon central executive/general attentional resources, reduced binding to a greater extent than individual feature memory, but the effect was no greater in older than in younger adults. Experiment 2 showed that presenting memory items sequentially rather than simultaneously, such that items are required to be maintained while new representations are created, selectively affects binding performance in both age groups. Although this experiment exhibited an age-related binding deficit overall, both age groups were affected by the attention manipulation to an equal extent. While a role for attentional processes in colour–shape binding was apparent across both experiments, manipulations of attention exerted equal effects in both age groups. We therefore conclude that age-related binding deficits neither emerge nor are exacerbated under conditions of high attentional load. Implications for theories of visual working memory and cognitive ageing are discussed.