Age differences in memory control: evidence from updating and retrieval-practice tasks

Some contemporary approaches suggest that inhibitory mechanisms play an important role in cognitive development. In addition, several authors distinguish between intentional and unintentional inhibitory processes in cognition. We report two experiments aimed at exploring possible developmental changes in these two types of inhibitory mechanisms. In Experiment 1, an updating task was used. This task requires that participants intentionally suppress irrelevant information from working memory. In Experiment 2, the retrieval-practice task was used. Retrieval practice of a subset of studied items is thought to involve unintentional inhibitory processes to overcome interference from competing memories. As a result, suppressed items become forgotten in a later memory test. Results of the experiments indicated that younger children (8) were less efficient than older children (12) and adults at intentionally suppressing information (updating task). However, when the task required unintentional inhibition of competing items (retrieval-practice task), this developmental trend was not found and children and adults showed similar levels of retrieval-induced forgetting. The results are discussed in terms of the development of efficient inhibition and the distinction between intentional and unintentional inhibitions.     

Introduction to the special issue on formal modeling of semantic concepts

We introduce the special issue on formal models of semantic concepts. After outlining the research questions that motivated the issue, we summarize the rich set of data provided by the Leuven Natural Concepts Database, and provide an overview of the seven research articles in the special issue. Each of these articles applies a formal modeling approach to one or more parts of the database, attempting to further our understanding of how people represent and use semantic concepts.     

Contextual repetition facilitates word learning via fast mapping

The current study explores whether contextual repetition during fast mapping facilitates word learning. Three-year-old children completed fast mapping and test trials using a touchscreen computer. For half of the children, the non-targets (competitors) repeated across learning trials and for other children there was no repetition. All children received the same test trials. Children who experienced contextual repetition, that is, children for whom the competitors repeated during the initial fast mapping task, demonstrated word learning. These data demonstrate that children's word learning is facilitated by the presence of extraneous yet predictable information in the initial fast mapping task.     

A dynamical approach to speech categorization: Two routes to learning

Learning to perceive a non-native speech sound reliably is a specific instance of the more general issue of category learning. Here we take a dynamical approach that provides a theoretically motivated way to understand individual differences in the process of learning to perceive new speech sounds. Fundamental to this approach is the focus on the initial categorization and discrimination abilities of individual perceivers and how these structure the form of learning over time. Two distinct patterns of learning were observed that were predictable based on initial perceptual abilities. In one pattern, subjects became more attuned to small acoustic distinctions between stimuli and could use that sensitivity to label tokens reliably. In the second pattern, subjects became less attuned to within-category acoustic distinctions, suggesting cognitive restructuring. Finally, we present a dynamical model that incorporates both modes of category learning, and also allows for failure to learn.     

Developmental changes in oculomotor control and working-memory efficiency

In the present study, we examined the developmental changes in the efficiency of saccadic inhibitory control. More specifically, the contribution of age-related changes in working-memory engagement was investigated. We manipulated the efficiency of inhibitory oculomotor control in antisaccade tasks by using fixation-offset conditions, which are supposed to affect inhibitory demands, and by adding increasing working-memory loads to the antisaccade task. In general, in comparison to antisaccade performance of adults, the antisaccade performance of 8-year-old and 12-year-old children was characterized by an increase in direction errors, and/or longer saccadic onset latencies on correct antisaccades. However, this pattern was not altered by the fixation-offset manipulations. In contrast, increased working-memory demands deteriorated 8-year-olds' antisaccade performance unequally as compared to older children and young adults. These findings suggest that - at least in young children - the available functional working-memory capacity is engaged in oculomotor inhibition.     

Learning and performance effects of accurate and erroneous knowledge of results on time perception

Performance feedback (also known as knowledge of results or KR) has both performance and learning effects on many tasks. Earlier studies have demonstrated performance but not learning effects on time perception tasks. In this experiment, we dissociate and identify these two phenomena on two different time perception tasks. Participants were presented with either accurate (100%) or erroneous (80% or 120% of actual performance) KR on either a reproduction or a numerical estimation time perception task. Accurate (100%) KR reduced the group variability and increased the accuracy of response magnitude but left individual variability unchanged. Erroneous (80% or 120%) KR also reduced the group variability while leaving individual variation unchanged, but decreased the true accuracy of the response, with response magnitudes increasing for the 80% KR group and decreasing for the 120% group. Thus external KR that is in conflict with internal time cues overrides these internal cues and dictates response magnitude on these two tasks. Thus KR provides guidance for these behaviors. KR did not reduce the variability (dispersion) of participants' responses, but centered each participant's responses closer to the targeted performance. This decreased group response variability reflected a performance enhancing effect of KR because group response variability increased after KR was withdrawn. In contrast, response magnitudes remained changed for the duration of the post-KR period, indicating that KR also induced a learned response. Thus individual response variability, group response variability and response magnitude represent dissociable features of performance on these time perception tasks.     

Towards the naturalization of agency based on an interactivist account of autonomy

This paper attempts to provide the basis for a broader naturalized account of agency. Naturalization is considered as the need for an ongoing and open-ended process of scientific inquiry driven by the continuous formulation of questions regarding a phenomenon. The naturalization of agency is focused around the interrelation of the fundamental notions of autonomy, functionality, intentionality and meaning. Certain naturalized frameworks of agency are critically considered in an attempt to bring together all the characteristic properties that constitute an autonomous agent, as well as to indicate the shaping of these notions/properties during the development and the evolution of its agential capacity. Autonomy and interaction are proved to be key concepts in this endeavor.     

Native language effects in learning second-language grammatical gender: A training study

We investigated cross-language influences in the representation and acquisition of Dutch word gender by native speakers of German. Participants named pictures in Dutch, using gender-marked noun phrases, and were trained on this task using feedback. Nouns differed in gender compatibility and cognate status with respect to German. The results show clear effects of cross-language gender compatibility and cognate status on response accuracy, certainty, and consistency. Feedback during training reduced gender errors approximately by half, and affected the different item conditions similarly. Furthermore, relative to the initial error rates, incorrect gender responses given with great certainty were not harder to modify than those with lower certainty. The results provide insights into the nature and stability of correct and incorrect gender representations in L2, and demonstrate the pervasiveness of transfer from the first to the second language even after intensive training.     

Aging and intuitive physics

The present study was aimed at comparing the judgment capacities manifested by young adults, middle-aged adults, and elderly people in an everyday life setting implying the consideration of direct as well as inverse relationships between the cues and the criterion. The chosen situation was borrowed from elementary physics and concerned the relationships between mass, volume and density. In forming their estimations of mass, all elderly people were able to use volume and density information. In addition, most of them were able to combine these pieces of information in a correct, multiplicative way. In forming their estimations of volume, all elderly people were able to use mass and density information but a majority of them used the density information in a direct way. By contrast, most young and middle-aged adults correctly used the density information in an inverse way. The findings strengthen and extend the case made by Chasseigne et al. [Acta Psychologica 97 (1997) 235] as regards the trouble elderly people face in using inverse relationships in a judgment situation. The difficulty elderly people face is not confined to learning settings. It may also be observed in ecological, non-learning environments, where the relationships considered do not entirely depend on the experimenter's choice.     

Differential involvement of internal clock and working memory in the production and reproduction of duration: a study on older adults

The present study uses the inter-individual variability in time perception of a group of elderly participants to differentiate the processes underlying time production and time reproduction. Participants performed duration production and reproduction tasks. They were also administered working memory tests and a spontaneous motor tempo task. The findings suggest that duration production and duration reproduction involve different mechanisms. Correlational analyses revealed a double dissociation: production was only correlated with spontaneous motor tempo and reproduction only with working memory measures. These findings suggest that the internal clock rate modulates the production of duration and that reproduced duration varies according to working memory capacities.     

Duration processing in children as determined by time reproduction: implications for a few seconds temporal window

From research carried out over recent years using different experimental paradigms, it has become apparent that central information processing is temporally segmented into sequential units of a few seconds. This segmentation presumably reflects a neuronal process of temporal integration (TI) which automatically binds successive events into temporal units. Support for such TI comes, for example, from studies on temporal reproduction where standards up to approximately 2-3 s are reproduced veridically. Using this paradigm of temporal reproduction, we investigated the effect of normal cognitive development of sensory modality and of the range of presented standards on TI. Sixty children aged 6-7, 9-10 and 13-14 years reproduced visual or auditory standard durations ranged from 1 to 5.5 s or from 1 to 3 s. The results showed that durations of approximately 2 s were reproduced correctly, whereas those longer than 2.5 s were under-reproduced in the three age groups. For standards shorter than 2 s substantial age-related differences were revealed: the youngest group displayed significant over-reproduction comparing to older subjects. These observations indicate that the upper limit for TI is a stable feature across the different age groups. Furthermore an age-related modulation within the temporal window of the operating TI seems to be linked to cognitive development.     

Norms of age of acquisition and concreteness for 30,000 Dutch words

Word processing studies increasingly make use of regression analyses based on large numbers of stimuli (the so-called megastudy approach) rather than experimental designs based on small factorial designs. This requires the availability of word features for many words. Following similar studies in English, we present and validate ratings of age of acquisition and concreteness for 30,000 Dutch words. These include nearly all lemmas language researchers are likely to be interested in. The ratings are freely available for research purposes.     

Age of acquisition, not word frequency affects object recognition: evidence from the effects of visual degradation

Four experiments examined how age of acquisition (AoA) and word frequency (WF) interact with manipulations of image quality in a picture-naming task. Experiments 1 and 2 examined the effect of overlaying the to-be-named picture with irrelevant contours. The magnitude of the AoA effect increased when the contours were added (Experiment 1), but the effect of WF remained constant (Experiment 2). Experiments 3 and 4 examined the effects of reducing the contrast of the contours defining the to-be-named picture. Both the effects of AoA (Experiment 3) and WF (Experiment 4) remained constant in the face of contrast reduction. These results provide an empirical dissociation of the effects of AoA and WF. The results are consistent with the idea that both AoA and the addition of irrelevant contours affect the efficiency of object recognition, but WF affects later processes involved in retrieval of object names. The theoretical implications of these findings in relation to accounts of AoA and frequency and their functional localisation in the lexical system are discussed.     

Strategic and automatic components in the processing of linguistic spatial relations

The objective of the present study was to determine the extent to which strategies influence the representational format of a linguistic spatial relation. The propositional model assumes that a sentence describing a spatial relation is always represented as a set of propositions, whereas the strategic model claims that a spatial sentence can be represented either as a set of propositions or as a mental image, depending on the strategy (verbal or visual-spatial) an individual follows. Participants read a sentence (spatial or non-spatial) followed by a picture or sentence, which did or did not exemplify the information of the first sentence. In order to examine the involvement of strategic and automatic components the probability (20% or 80%) of the nature (sentence or picture) of the second stimulus was varied. Participants had slower verification RTs for unexpected stimuli than for expected stimuli, but this cost was significantly larger for an unexpected picture than an unexpected sentence. Furthermore, this asymmetric cost for the unexpected visual-spatial stimulus only occurred with spatial sentences and not with non-spatial sentences. Surprisingly, these data do not support a strictly propositional or a strategic model. Instead, we propose a third option: a dual representational model, in which people automatically represent the spatial sentence propositionally. In addition, depending on the context, a pictorial strategy is employed, which results in a supplementary visual-spatial representation.     

Maximum vs. minimum values: Preferences of speakers and listeners for upper and lower limit estimates

Estimates about uncertain quantities can be expressed in terms of lower limits (more than X, minimum X), or upper limits (less than Y, maximum Y). It has been shown that lower limit statements generally occur much more often than upper limit statements (Halberg & Teigen, 2009). However, in a conversational context, preferences for upper and lower limit statements will be moderated by the concerns of the interlocutors. We report three studies asking speakers and listeners about their preferences for lower and upper limit statements, in the domains of distances, durations, and prices. It appears that travellers prefer information about maximum distances and maximum durations, and buyers (but not sellers) prefer to be told about maximum prices and maximum delivery times. Mistaken maxima are at the same time regarded as more “wrong” than mistaken minima. However, this preference for “worst case” information is not necessarily shared by providers of information (advisors), who are also concerned about being blamed if wrong.     

Language integration in bilingual sentence production

To what extent are processes used in sentence production integrated between the different languages of a bilingual and to what extent are they kept separate? We consider three models that differ in their assumptions about the degree of integration: De Bot's [De Bot, K. (1992). A bilingual production model: Levelt's Speaking model adapted. Applied Linguistics, 13, 1-24] bilingual blueprint of the speaker, Ullman's [Ullman, M. T. (2001). The neural basis of lexicon and grammar in first and second language: The declarative/procedural model. Bilingualism: Language and Cognition, 4, 105-122] declarative/procedural model of bilingualism, and Hartsuiker et al.'s [Hartsuiker, R. J., Pickering, M. J., & Veltkamp, E. (2004). Is syntax separate or shared between languages? Cross-linguistic syntactic priming in Spanish/English bilinguals. Psychological Science, 15, 409-414] integrated model. A review of the evidence from bilingual sentence production studies shows that Hartsuiker et al.'s predictions are supported, but argues against the other two models. We discuss some repercussions for bilingual language use.     

Age-related changes in motor imagery from early childhood to adulthood: Probing the internal representation of speed-accuracy trade-offs

The purpose of this study was to chart the development of motor imagery ability between 5 and 29 years of age and its relationship to fine-motor skill. 237 participants performed a computerized Virtual Radial Fitts Task (VRFT) as a measure of Motor Imagery (MI) ability. Participants aimed at five targets, positioned along radial axes from a central target circle. The targets differed in width over trials (2.5, 5, 10, 20 or 40 mm). Performance was indexed by the relationship between the movement time (MT) in executed and imagined movements. A subset of participants (11–19 years old, n = 22) also performed the task with their non-preferred hand. We also examined if manual skill (measured by peg board task and posting coins) was related to the executed and imagined MT on the VRFT. Our results showed that the accuracy of the imagined movement improved steadily over childhood, reaching an asymptote during adolescence and into early adulthood. The correlation between the real and virtual MT using the preferred hand did not differ appreciably from that using the non-preferred hand. If the children could perform the tasks with their non-preferred hand (11 years and older), they also scaled performance in relatively precise terms using the less dextrous non-preferred hand. The correlation between real MT on the VRFT and fine-motor performance ranged between .53 and .42, while that for virtual movement was between .37 and .34. MI ability predicts manual skill to a moderate degree.