Previous studies have shown that spatial attention can shift in three-dimensional (3-D) space determined by binocular disparity. Using Posner's precueing paradigm, the current work examined whether attentional selection occurs in perceived 3-D space defined by occlusion. Experiment 1 showed that shifts of spatial attention induced by central cues between two surfaces in the left and right visual fields did not differ between the conditions when the two surfaces were located at the same or different perceptual depth. In contrast, Experiment 2 found that peripheral cues generated a stronger cue validity effect when the two surfaces were perceived at a different rather than at the same perceptual depth. The results suggest that exogenous but not endogenous attention operates in perceived 3-D space.
In the cyclic semantic blocking paradigm participants repeatedly name sets of objects with semantically related names (homogeneous sets) or unrelated names (heterogeneous sets). The naming latencies are typically longer in related than in unrelated sets. In Experiment 1 we replicated this semantic blocking effect and demonstrated that the effect only arose after all objects of a set had been shown and named once. In Experiment 2, the objects of a set were presented simultaneously (instead of on successive trials). Evidence for semantic blocking was found in the naming latencies and in the gaze durations for the objects, which were longer in homogeneous than in heterogeneous sets. For the gaze-to-speech lag between the offset of gaze on an object and the onset of the articulation of its name, a repetition priming effect was obtained but no blocking effect. Experiment 3 showed that the blocking effect for speech onset latencies generalized to new, previously unnamed lexical items. We propose that the blocking effect is due to refractory behaviour in the semantic system.
We studied context dependency of the representations underlying perceptual "goodness". Three experiments used a same-different task with classical Garner 5-dot patterns presented with an interstimulus interval (ISI) of 500 ms. Same patterns were allowed to be rotated or reflected versions of each other. Pattern goodness was varied according to rotation and reflection equivalence, using Garner's equivalence set size (ESS) measure. The ESS of both first and second patterns affected reaction time and accuracy. A model based on assumptions that Garner's equivalence sets constitute the generic representation of these patterns and that items within these sets are accessed serially was fitted to the data. Excellent fits were obtained, which were robust against frequency-induced bias at the level of the individual pattern, but sensitive to such bias at the level of the equivalence set. It was concluded that individual pattern representations are context independent, whereas their collective representations are context dependent. Simplicity and likelihood principles, therefore, seem to apply to different levels of a representation hierarchy.
The present study investigated the role of phonological and orthographic neighbourhood density in visual word recognition. Three mechanisms were identified that predict distinct facilitatory or inhibitory effects of each variable. The lexical competition account predicts overall inhibitory effects of neighbourhood density. The global activation (familiarity) account predicts overall facilitatory effects of neighbourhood density. Finally, the cross-code consistency account predicts an interaction, with inhibition of phonological neighbours in sparse orthographic regions and facilitation of phonological neighbours in dense orthographic regions. In Experiment 1 (lexical decision), a cross- over interaction was indeed found, supporting the prediction of the cross- code consistency account. In Experiment 2, this cross- over interaction was exaggerated by adding pseudohomo-phone stimuli (e. g., brane) among the nonword targets. Finally, in Experiment 3 (progressive demasking), we tried to shift the balance between inhibitory and facilitatory mechanisms by using a perceptual identification task. As predicted, the inhibitory effects of phonological neighbourhood were amplified, whereas the facilitatory effects disappeared. We conclude that the level of compatibility across co-activated orthographic and phonological representations is a major causal factor underlying this pattern of effects.
Age-related deficits have been consistently observed in free recall. Recent accounts of episodic memory suggest that these deficits could result from differential patterns of rehearsal. In the present study, 20 young and 20 older adults (mean ages 21 and 72 years, respectively) were presented with lists of 20 words for immediate free recall using the overt rehearsal methodology. The young outperformed the older adults at all serial positions. There were significant age-related differences in the patterns of overt rehearsals: Young adults rehearsed a greater number of different words than did older adults, they rehearsed words to more recent serial positions, and their rehearsals were more widely distributed throughout the list. Consistent with a recency-based account of episodic memory, age deficits in free recall are largely attributable to age differences in the recency, frequency, and distribution of rehearsals.
According to a recent hypothesis, executive functions should be particularly vulnerable to the effects of total sleep deprivation. Random generation is a task that taps executive functions. In three experiments we examined the effects of total sleep deprivation on random generation of key-presses, numbers, and nouns, in particular on the suppression of prepotent responses and the selection of next responses by way of applying a local-representativeness heuristic. With random key-presses suppression of prepotent responses did not suffer from lack of sleep, but it became poorer at a sufficiently high pacing rate. In contrast, suppression of prepotent responses suffered when numbers and nouns were generated. According to these findings different types of random generation tasks involve different types of inhibitory process. With only four response alternatives, but not with larger response sets, application of the local-representativeness heuristic was impaired after a night without sleep. In terms of a simple formal model, serial-order representations of the preceding responses are used in selecting the next response only for the small response set, and not for larger response sets. Thus, serial-order representations are likely to suffer from loss of sleep. These findings strongly suggest that random generation involves multiple processes and that total sleep deprivation does not impair all sorts of executive functions, but only some.
Multiple-step arithmetic problems can be solved by diverse strategies depending on the mental representation constructed by individuals from the situation described in the text of the problem. This representation will indeed determine the organization of subgoals to be reached or in other words the order of completion of calculations. This study aims at determining the conditions under which specific strategies are set up by adults. Using a paradigm that allows us to assess when calculations are performed, we show that adults usually organize their subgoals as they are explicitly mentioned in the problem, even though a strategy that is less demanding on working memory could have been used. However, we show that increasing the difficulty of the problem leads individuals to set up more economic strategies. Moreover, these economic strategies are even more likely to be used when the cognitive cost of the construction of the representation they rely on is low.
A group of older adults with good hearing and a group with mild-to-moderate hearing loss were tested for recall of the final three words heard in a running memory task. Near perfect recall of the final words of the three-word sets by both good- and poor-hearing participants allowed the inference that all three words had been correctly identified. Nevertheless, the poor-hearing group recalled significantly fewer of the nonfinal words than did the better hearing group. This was true even though both groups were matched for age, education, and verbal ability. Results were taken as support for an effortfulness hypothesis: the notion that the extra effort that a hearing-impaired listener must expend to achieve perceptual success comes at the cost of processing resources that might otherwise be available for encoding the speech content in memory.
We present an integrated model for the understanding of and the reasoning from conditional statements. Central assumptions from several approaches are integrated into a causal path model. According to the model, the cognitive availability of exceptions to a conditional reduces the subjective conditional probability of the consequent, given the antecedent. This conditional probability determines people's degree of belief in the conditional, which in turn affects their willingness to accept logically valid inferences. In addition to this indirect pathway, the model contains a direct pathway: Availability of exceptional situations directly reduces the endorsement of valid inferences. We tested the integrated model with three experiments using conditional statements embedded in pseudonaturalistic cover stories. An explicitly mentioned causal link between antecedent and consequent was either present (causal conditionals) or absent (arbitrary conditionals). The model was supported for the causal but not for the arbitrary conditional statements.
When people monitor a visual stream of rapidly presented stimuli for two targets (T1 and T2), they often miss T2 if it falls into a time window of about half a second after T1 onset--the attentional blink. However, if T2 immediately follows T1, performance is often reported being as good as that at long lags--the so-called Lag-1 sparing effect. Two experiments investigated the mechanisms underlying this effect. Experiment 1 showed that, at Lag 1, requiring subjects to correctly report both identity and temporal order of targets produces relatively good performance on T2 but relatively bad performance on T1. Experiment 2 confirmed that subjects often confuse target order at short lags, especially if the two targets are equally easy to discriminate. Results suggest that, if two targets appear in close succession, they compete for attentional resources. If the two competitors are of unequal strength the stronger one is more likely to win and be reported at the expense of the other. If the two are equally strong, however, they will often be integrated into the same attentional episode and thus get both access to attentional resources. But this comes with a cost, as it eliminates information about the targets' temporal order.
A group of young ( n = 52, M = 23.27 years) and old ( n = 52, M = 68.62 years) adults studied two lists of semantically unrelated nouns. For one list a time of 2 s was allowed for encoding, and for the other, 5 s. A recognition test followed where participants classified their responses according to Gardiner's (1988) remember-know procedure. Age differences for remembering and knowing were minimal in the faster 2-s encoding condition. However, in the longer 5-s encoding condition, younger persons produced significantly more remember responses, and older adults a greater number of know responses. This dissociation suggests that in the longer encoding condition, younger adults utilized a greater level of elaborative rehearsal governed by executive processes, whereas older persons employed maintenance rehearsal involving short-term memory. Statistical control procedures, however, found that independent measures of processing speed accounted for age differences in remembering and knowing and that independent measures of executive control had little influence. The findings are discussed in the light of contrasting theoretical accounts of recollective experience in old age.
Recent motivational affective priming studies (Moors & De Houwer, 2001; Moors, De Houwer, & Eelen, 2004) showed that primes that indicate success on a goal-inducing task facilitate positive target responses whereas primes that indicate failure on that task facilitate negative target responses. In the current studies, we examined whether these priming effects depend on consciously intentional processing of the motivational valence of the primes. In Experiment 1, the outcome of success or failure was presented not only immediately before the target (i.e., the prime) but also a second time after the target response. This should encourage participants to ignore the prime. In Experiment 2, participants were asked to respond to the targets within 600 ms after target onset. As a result, participants had little opportunity to process the motivational prime valence in a consciously intentional way. Nevertheless, strong affective priming effects were found in both studies. These results provide additional support for the claim that motivational valence can be processed without the conscious intention to do so.
Groups of 5-year-olds, 10-year-olds, and adults completed either an episodic temporal generalization task, in which no stimuli were repeated, or a repeated standard temporal generalization task, in which there was a fixed standard that was repeated on every trial. Significant developmental improvements were found on both tasks. In both tasks, gradients of performance over two different stimulus ranges superimposed well when plotted on the same relative scale. Performance was similar for the adults and 10-year-olds across tasks, but the 5-year-olds performed better on the repeated standard task. These findings suggest that perceptual processes are a source of scalar variability in timing, and that there are developmental changes in levels of such variability.
To perform a task that differs from a previously performed one, it is necessary to prepare for the new task as well as to disable the task set of the preceding task. In a series of three experiments we examined whether preparation for a task shift implies a direct update of the task set that is carried over from the preceding trial. To this end, in Experiments 1 and 2 we factorially varied the relation of the task in trial n, first, to the task in trial n − 1 (intertask relation) and, second, to the task that was precued for trial n (precue-to-task relation). Invalid precues resulted in substantial costs, which increased with longer precueing intervals. However, this increasing effect of the precue-to-task relation was not accompanied by a decreasing effect of the intertask relation. Furthermore, both effects had different qualitative properties. These findings suggest that two tasks can be represented concurrently but on two different levels of representation. In Experiment 3 we observed that the persistence of the effect of the intertask relation depends on the possibility that task repetitions can occur in trials in which a task shift is precued. This suggests that the persistence of the effect of the intertask relation is controlled in a context-sensitive way.
Previous research (Oberauer & Wilhelm, 2000) has shown an inherent directionality between the two terms linked in premises of typical deductive reasoning tasks. With three experiments we investigated the effect of inherent directionality on the time to integrate two premises and for the derivation of a conclusion. We varied figure (i.e., order of terms in the premises) and direction of inference (i.e., order of terms in the conclusion) in deduction tasks from various domains (propositional reasoning, syllogisms, spatial, temporal, and linear order reasoning). Effects of figure on premise reading times varied with the directionality of the relations. Effects of direction of inference reflected the same directionality for a subset of relations. We propose that two factors are jointly responsible for a large part of observed directionality effects in premise integration: the inherent directionality of relational statements and a general advantage for a given-new order of terms in the second premise. Difficulty of deriving a conclusion is affected by the directionality or relations if and only if the relation is semantically asymmetric, so that the directionality must be preserved in the integrated mental model.
Some recent evidence has favoured purely response-based implicit representation of sequences in serial reaction time tasks. Three experiments were conducted using serial reaction time tasks featuring four spatial stimuli mapped in categories to two responses. Deviant items from the expected sequence that required the expected response resulted in increased response latencies. The findings demonstrated a stimulus-specific form of representation that operates in the serial reaction time task. No evidence was found to suggest that the stimulus-specific learning was contingent on explicit knowledge of the sequence. Such stimulus-based learning would be congruent with a shortcut within an information-processing framework and, combined with other research findings, suggests that there are multiple loci for learning effects.
We conducted two experiments using a modified version of the N-Back task. For younger adults, there was an abrupt increase in reaction time of about 250 ms in passing from N = 1 to N > 1, indicating a cost associated with switching of the focus of attention within working memory. Response time costs remained constant over the range N = 2 to N = 5. Accuracy declined steadily over the full range of N (Experiment 1). Focus switch costs did not interact with either working memory updating (Experiment 1), or global task switching (Experiment 2). There were no age differences in RT costs once general slowing was taken into account, but there was a larger focus-switch-related accuracy cost in older adults than in younger adults. No age sensitivity was found for either updating or global task switching. The results suggest (a) that focus switching is a cognitive primitive, distinct from task switching and updating, and (b) that focus switching shows a specific age-related deficit in the accuracy domain.
I argue here that functional neuroimaging data—which I restrict to the haemodynamic techniques of fMRI and PET—can inform psychological theorizing, provided one assumes a “systematic” function–structure mapping in the brain. In this case, imaging data simply comprise another dependent variable, along with behavioural data, that can be used to test competing theories. In particular, I distinguish two types of inference: function-to-structure deduction and structure-to-function induction. With the former inference, a qualitatively different pattern of activity over the brain under two experimental conditions implies at least one different function associated with changes in the independent variable. With the second type of inference, activity of the same brain region(s) under two conditions implies a common function, possibly not predicted a priori. I illustrate these inferences with imaging studies of recognition memory, short-term memory, and repetition priming. I then consider in greater detail what is meant by a “systematic” function–structure mapping and argue that, particularly for structure-to-function induction, this entails a one-to-one mapping between functional and structural units, although the structural unit may be a network of interacting regions and care must be taken over the appropriate level of functional/structural abstraction. Nonetheless, the assumption of a systematic function–structure mapping is a “working hypothesis” that, in common with other scientific fields, cannot be proved on independent grounds and is probably best evaluated by the success of the enterprise as a whole. I also consider statistical issues such as the definition of a qualitative difference and methodological issues such as the relationship between imaging and behavioural data. I finish by reviewing various objections to neuroimaging, including neophrenology, functionalism, and equipotentiality, and by observing some criticisms of current practice in the imaging literature.
Using short and long contexts, the present study investigated musical priming effects that are based on chord repetition and harmonic relatedness. A musical target (a chord) was preceded by either an identical prime or a different but harmonically related prime. In contrast to words, pictures, and environmental sounds, chord processing was not facilitated by repetition. Experiments 1 and 2 using single-chord primes showed either no significant difference between chord repetition and harmonic relatedness or facilitated processing for harmonically related targets. Experiment 3 using longer prime contexts showed that musical priming depended more on the musical function of the target in the preceding context than on target repetition. The effect of musical function was decreased, but not qualitatively changed, by chord repetition. The outcome of this study challenges predictions of sensory approaches and supports a cognitive approach of musical priming.
Five experiments performed in a desktop virtual-reality setting investigated the influence of environmental features—that is, noticeable landmarks along the route—on distance estimation. Landmarks were of two types: Either they simply “filled” the route or they “filled” and also segmented it, thereby inducing a hierarchical structuring of the route. Previous research had left the question open of whether a filling or a segmenting feature leads to an overestimation of a distance along the route. Our experiments showed different results dependent on the kind of space: If an environment was learned from a route perspective, filling and segmenting environmental features led to overestimations of distances, while the segmenting of a route induced by a grouping of similar features did not. If the environment was learned from a map that afforded a survey perspective, route structuring induced through a segmenting feature or by phenomenal grouping led to an overestimation of distances, whereas features that merely filled the route did not.
