Categorical flexibility in children: Distinguishing response flexibility from conceptual flexibility; the protracted development of taxonomic representations

This research explored the development of children's use of multiple conceptual organizations (thematic, taxonomic) in sorting sets of pictures. Experiment 1 revealed that between 5 and 9 years, two forms of categorical flexibility can be distinguished: response and conceptual flexibility. It appeared that children's multiple sorts do not necessarily reflect the use of different conceptual organizations. Such a lag was mainly due to a difficulty in accessing taxonomic representations, specifically in the younger age groups. Therefore, Experiment 2 investigated the development of taxonomic representations using an original approach requiring participants to decide whether new items could be included into an existing taxonomic sort. This approach showed that taxonomic representations were only gradually differentiated from thematic and perceptual ones over the 5 to 10 years period. The discussion raises new hypotheses about the interaction between developing executive control (specifically, increasing resistance to interference of irrelevant information) and increasing conceptual knowledge in accounting for the development of conceptual flexibility.     

Predictors of semantic categorical flexibility in older adults

This study investigated the processes involved in the aging of semantic categorical flexibility. A previous study revealed the effects of aging on the flexible use of taxonomic relations. We aimed to explain our previous results regarding the performance of older adults; we carried out investigations into the respective roles of executive and conceptual factors in semantic categorical flexibility. Fifty older adults carried out a semantic categorical flexibility task alongside conceptual and executive measures. The results replicate our previous findings and indicate that the predictors of the maintenance of the use of taxonomic relations are conceptual and the predictors of the switching from thematic to taxonomic relations are executive.     

Conceptual preference for thematic or taxonomic relations: A nonmonotonic age trend from preschool to old age

Two experiments examined the development of conceptual preference for either thematic (functional) or taxonomic relationships in a match-to sample task. In Experiment 1 twenty subjects from each of five age groups—preschool to old age—completed a method of triads preference test where they were forced to choose a thematic or taxonomic match. Young and old individuals preferred the thematic parings while school age and college adults preferred the taxonomic matches. Although the Age × Preference relation was pronounced, the majority of subjects at all ages could provide adequate justification of both the preferred and nonpreferred relationship. In addition, kindergarten subjects in Experiment 2 could readily be trained to respond on the basis of the nonpreferred mode. These data suggest that the pervasive shift in conceptual responding from syntagmatic to paradigmatic, thematic to taxonomic, etc., represents a change in preference rather than a shift to a fundamentally new way of organizing knowledge.     

The role of associative strength and conceptual relations in matching tasks in 4‐ and 6‐year‐old children

T he associative strength between target and associates, a factor assumed to be critical but generally not controlled, and the type of conceptual relation (thematic and taxonomic) were manipulated independently in a matching to sample task to determine their respective effects on the matching behaviour of 4‐ and 6‐year‐old children. Perceptual similarity between target and associates was controlled and maintained at a low level. A preliminary task was designed to assess the associative strength between targets and several associated pictures. These judgments served to construct for each child the sets of stimuli used in the matching task. Exp. 1 opposed a strong and a weak associate with the target in different configurations: the sets included a target and two thematic associates, two taxonomic associates, or one associate of each type. Children were asked to choose the picture that “went well” with the target. Data revealed the role of associative strength on matching choices. This factor interacted sometimes with the greater availability of thematic relations in 4‐ and 6‐year‐old children. In Exp. 2, two other configurations were tested. Thematic and taxonomic associates were both either strongly or weakly related with the target. Results replicated those of Exp. 1 and extended them. They showed that younger children were biased towards thematic relations only when these relations corresponded to strong associations. Thus, increasing experience with objects appears to reinforce both associative strength and thematic orientation. Finally, in Exp. 3, instructions orienting toward taxonomic choices modified responses in 6‐year‐olds only. Altogether, these results show the influence of specific instances and suggest that preschoolers' matching decisions are partly stimulus driven.     

The cost of switching between taxonomic and thematic semantics

Current models and theories of semantic knowledge primarily capture taxonomic relationships (DOG and WOLF) and largely do not address the role of thematic relationships in semantic knowledge (DOG and LEASH). Recent evidence suggests that processing or representation of thematic relationships may be distinct from taxonomic relationships. If taxonomic and thematic relations are distinct, then there should be a cost associated with switching between them even when the task remains constant. This hypothesis was tested using two different semantic-relatedness judgment tasks: Experiment 1 used a triads task and Experiment 2 used an oddball task. In both experiments, participants were faster to respond when the same relationship appeared on consecutive trials than when the relationship types were different, even though the task remained the same and the specific relations were different on each trial. These results are consistent with the theory that taxonomic and thematic relations rely on distinct processes or representations.     

Differences in preschool children's conceptual strategies when thinking about animate entities and artifacts.

Two-, 3-, and 4-year-old children viewed 10 stimulus sets. Each set contained a sample picture (e.g., a dog), a basic-level taxonomic match (e.g., another dog), a thematic match (e.g., a bone), and an irrelevant match (e.g., a pen). The children were asked to choose a match that "goes with" each sample. Sample pictures were either animate entities or artifacts. The children's choice behavior indicated that a shift occurs between 3 and 4 years of age from a taxonomic bias to a thematic bias and that, at both ages, animate sample stimuli enhance the children's tendency to adopt thematic conceptual strategies. These data are consistent with recent suggestions that thematic thinking presupposes basic-level taxonomic thinking during early conceptual development and that this developmental progression occurs more rapidly in some domains of knowledge than in others.     

Contribution of the priming paradigm to the understanding of the conceptual developmental shift from 5 to 9 years of age

We conducted three experiments to study the role of instrumental (e.g. knife–bread) and categorical (e.g. cake–bread) relations in the development of conceptual organization with a priming paradigm, by varying the nature of the task (naming – Experiment 1 – or categorical decision – Experiments 2 and 3). The participants were 5‐, 7‐ and 9‐year‐old children and adults. The results showed that on both types of task, adults and 9‐year‐old children presented instrumental and categorical priming effects, whereas 5‐year‐old children presented mainly instrumental priming effects, with categorical effects remaining marginal. Moreover, the magnitude of the instrumental priming effects decreased with age. Finally, the priming effects observed for 7‐year‐old children depended on the task, especially for the categorical effects. The theoretical implications of these results for our understanding of conceptual reorganization from 5 to 9 years of age are discussed.     

Stimulus–response translation in manual and vocal modality: Is age‐related slowing influenced by changes in working memory functioning?

In some conditions, age‐related slowing rates are higher for manual than for vocal responses. The interaction between age and response modality was examined in four experiments in which the performance of younger (M = 22.6 years) and older (M = 70.8 years) adults was compared under various stimulus–response mapping rules. The interaction effect was not observed in a simple localisation task on which the manual modality had an advantage in both age groups (Experiment 1). When congruence between stimulus and response was reduced (Experiment 2), manual responses were disproportionately slowed in older participants. In conceptual and size comparison tasks (Experiment 3), the age‐by‐modality effect was not influenced by working memory load during the interval between the first and the second stimulus presentation. In an identification task, age‐related slowing effects were less when responses were spoken names than when nonwords were used as labels (Experiment 4). These results indicate that older participants experience a specific difficulty in activating arbitrary S–R mapping rules during executive control.     

The contribution of executive control to semantic cognition: Convergent evidence from semantic aphasia and executive dysfunction

Semantic cognition, as described by the controlled semantic cognition (CSC) framework (Rogers et al., 2015 , Neuropsychologia, 76, 220), involves two key components: activation of coherent, generalizable concepts within a heteromodal ‘hub’ in combination with modality‐specific features (spokes), and a constraining mechanism that manipulates and gates this knowledge to generate time‐ and task‐appropriate behaviour. Executive–semantic goal representations, largely supported by executive regions such as frontal and parietal cortex, are thought to allow the generation of non‐dominant aspects of knowledge when these are appropriate for the task or context. Semantic aphasia (SA) patients have executive–semantic deficits, and these are correlated with general executive impairment. If the CSC proposal is correct, patients with executive impairment should not only exhibit impaired semantic cognition, but should also show characteristics that align with those observed in SA. This possibility remains largely untested, as patients selected on the basis that they show executive impairment (i.e., with ‘dysexecutive syndrome’) have not been extensively tested on tasks tapping semantic control and have not been previously compared with SA cases. We explored conceptual processing in 12 patients showing symptoms consistent with dysexecutive syndrome (DYS) and 24 SA patients, using a range of multimodal semantic assessments which manipulated control demands. Patients with executive impairments, despite not being selected to show semantic impairments, nevertheless showed parallel patterns to SA cases. They showed strong effects of distractor strength, cues and miscues, and probe–target distance, plus minimal effects of word frequency on comprehension (unlike semantic dementia patients with degradation of conceptual knowledge). This supports a component process account of semantic cognition in which retrieval is shaped by control processes, and confirms that deficits in SA patients reflect difficulty controlling semantic retrieval.     

Categorization Deficit in Old Age: Reality or Artefact?

When categorization behaviour is compared between young and elderly adults, results usually show a decrease in taxonomic choices along with an increase in thematic choices. This can be interpreted in two ways: a decline in the ability to perceive and use taxonomic relations, or a modification of conceptual preferences with aging related to a bias stemming from material which favours young adults. We evaluated the second hypothesis by studying whether the salience of categorical associations could explain the differences generally observed between young and elderly adults. This hypothesis was tested on 25 young subjects (M = 45.3 years, SD =5.6 years) and 30 elderly subjects (M = 71.5 years, SD = 7.1 years) using a matching task: individual judgments were used to build triads in which a target was presented along with a strong and a weak associate. In line with our hypothesis, both age groups were influenced by associative strength and type of relation in the same way. Results are interpreted with Baltes’s [1987, Developmental Psychology, 23, 611–626] model.     

Conceptual and non-conceptual repetition priming in category exemplar generation: Evidence from bilinguals

One measure of conceptual implicit memory is repetition priming in the generation of exemplars from a semantic category, but does such priming transfer across languages? That is, do the overlapping conceptual representations for translation equivalents provide a sufficient basis for such priming? In Experiment 1 (N=96) participants carried out a deep encoding task, and priming between languages was statistically reliable, but attenuated, relative to within-language priming. Experiment 2 (N=96) replicated the findings of Experiment 1 and assessed the contributions of conceptual and non-conceptual processes using a levels-of-processing manipulation. Words that underwent shallow encoding exhibited within-language, but not between-language, priming. Priming in shallow conditions cannot therefore be explained by incidental activation of the concept. Instead, part of the within-language priming effect, even under deep-encoding conditions, is due to increased availability of language-specific lemmas or phonological word forms.     

Real‐world word learning: Exploring children's developing semantic representations of a science term

Assessments of lexical acquisition are often limited to preschool children on forced‐choice comprehension measures. This study assessed the nature of the understandings 30 school‐age children (mean age = 6;7) acquired about the science term eclipse following a naturalistic exposure to a solar eclipse. The knowledge children acquired about eclipses and a control term comet was assessed at three points in time (baseline‐test, 2‐week post‐test and 5‐month post‐test) using a range of assessment tasks (multiple‐choice comprehension, picture‐naming, drawing and a model solar system manipulation task). Children's knowledge at the baseline‐test and 2‐week post‐test was compared with that of 15 adult controls. The analysis focused on the range of knowledge children acquired about eclipses and the relationships between aspects of knowledge they acquired. We found that children acquired extensive knowledge about eclipses, but not comets. At the 2‐week post‐test, the majority of children were able to produce the term eclipse and provided evidence of accurate comprehension and wider conceptual knowledge about solar eclipses, which was retained at the 5‐month post‐test. Further, children's ability to produce the term was related to their acquisition of ‘rich’ semantic and conceptual knowledge.     

Partial Knowledge of Word Meanings: Thematic and Taxonomic Representations

The type of information (taxonomic or thematic) available at different levels of knowledge was investigated. Following extensive norming to identify taxonomic and thematic associates of low-frequency nouns, participants determined if taxonomic or thematic associates were meaningfully related to target words at three levels of knowledge: target words they correctly defined (known), recognized as familiar (frontier), or mistakenly denied as part of the language (unknown). In another experiment, participants reported which type of relationship (taxonomic or thematic) was preferred. Results indicated that both types of information were available at all levels of knowledge. However, accuracy and preference were greater for taxonomic associates across word levels. A differential increase in available thematic information relative to taxonomic information was found. Implications for the acquisition and representation of word meanings are discussed.     

Relationship between language switching experience and executive functions in bilinguals: an Internet-based study*

We examined the relationship between self-reported everyday language switching experience and the performance of early bilinguals in tasks measuring different executive functions. Our participants were Finnish–Swedish early bilinguals, aged 16–41 years (N?=?66, Experiment 1) and 18–69 years (N?=?111, Experiment 2). An earlier study using a sample from a similar population discovered a negative relationship between self-reported language switching and a mixing cost in error rates in a number–letter task. This finding was not replicated. Instead, we found that a higher rate of reported contextual language switching predicted larger switching cost reaction times in the number–letter task, and that a higher rate of reported unintended language switches predicted larger error rates in a spatial n-back task. We conclude that these results likely reflect individual differences in executive skills, and do not provide evidence for the hypothesis that language switching trains executive functions.     

Divergent thinking: Strategies and executive involvement in generating novel uses for familiar objects

Although the Alternative Uses divergent thinking task has been widely used in psychometric and experimental studies of creativity, the cognitive processes underlying this task have not been examined in detail before the two studies are reported here. In Experiment 1, a verbal protocol analysis study of the Alternative Uses task was carried out with a Think aloud group (N = 40) and a Silent control group (N = 64). The groups did not differ in fluency or novelty of idea production indicating no verbal overshadowing. Analysis of protocols from the Think aloud group suggested that initial responses were based on a strategy of Retrieval from long‐term memory of pre‐known uses. Later responses tended to be based on a small number of other strategies: property‐use generation, imagined Disassembly of the target object into components and scanning of Broad Use categories for possible uses of the target item. Novelty of uses was particularly associated with the Disassembly strategy. Experiment 2 (N = 103) addressed the role of executive processes in generating new and previously known uses by examining individual differences in category fluency, letter fluency and divergent task performance. After completing the task, participants were asked to indicate which of their responses were new for them. It was predicted and found in regression analyses that letter fluency (an executively loading task) was related to production of ‘new’ uses and category fluency was related to production of ‘old’ uses but not vice versa.     

Too exhausted to remember: Ego depletion undermines subsequent event‐based prospective memory

Past research has consistently found that people are likely to do worse on high‐level cognitive tasks after exerting self‐control on previous actions. However, little has been unraveled about to what extent ego depletion affects subsequent prospective memory. Drawing upon the self‐control strength model and the relationship between self‐control resources and executive control, this study proposes that the initial actions of self‐control may undermine subsequent event‐based prospective memory (EBPM). Ego depletion was manipulated through watching a video requiring visual attention (Experiment 1) or completing an incongruent Stroop task (Experiment 2). Participants were then tested on EBPM embedded in an ongoing task. As predicted, the results showed that after ruling out possible intervening variables (e.g. mood, focal and nonfocal cues, and characteristics of ongoing task and ego depletion task), participants in the high‐depletion condition performed significantly worse on EBPM than those in the low‐depletion condition. The results suggested that the effect of ego depletion on EBPM was mainly due to an impaired prospective component rather than to a retrospective component.     

Modulation of taxonomic (versus thematic) similarity judgments and product choices by inducing local and global processing

Perceived similarity is influenced by both taxonomic and thematic relations. Assessing taxonomic relations requires comparing individual features of objects whereas assessing thematic relations requires exploring how objects functionally interact. These processes appear to relate to different thinking styles: abstract thinking and a global focus may be required to explore functional interactions whereas attention to detail and a local focus may be required to compare specific features. In four experiments we explored this idea by assessing whether a preference for taxonomic or thematic relations could be created by inducing a local or global perceptual processing style. Experiments 1–3 primed processing style via a perceptual task and used a choice task to examine preference for taxonomic (versus thematic) relations. Experiment 4 induced processing style and examined the effect on similarity ratings for pairs of taxonomic and thematically related items. In all cases processing style influenced preference for taxonomic/thematic relations.     

Dynamic categorization and slot-filler representation in 4- and 6-year-old children

This experiment was aimed at studying both the role of narrow/contextualized categories in the acquisition/organization of conceptual knowledge and the dynamics of categorization decisions. A forced-choice categorization task contrasting thematic and taxonomic responding was used in 4- and 6-year-old children. Before response alternatives were presented, a conceptual organization was pre-activated by means of a matching between the target stimulus and a thematically related, taxonomically related or slot-filler related object. Although taxonomic sorting was prominent overall, it varied as a function of age and of the nature of the pre-activated relation. Responses in accordance with the thematic or taxonomic activations occurred similarly in 4- and 6-year-old children. Age-related effects were however at work in the case of a slot-filler activation: 4-year-old children considered the contextual/contiguity relations between the stimuli but did not weight the equivalence relations (i.e., same occurrence of responses based on the kind of object in the slot-filler and in the thematic activation conditions). More diversified processes appeared to be at work in 6-year-old children. Slot-filler categories were this time considered throughout both their contextual/contiguity structure and their equivalence relations. Results were discussed in terms of availability of conceptual organizations, flexibility abilities, dynamic categorization and preferences. The focus was on implication of slot-filler representations in the construction of conceptual knowledge and in the development of categorization. An important point was to determine whether the age-related changes observed in the slot-filler activation condition could be consistent with Nelson's ( 1983 ) idea that slot-fillers would help passing from a schema-based to a conventional superordinate organization.     

Alternating Incubation Effects in the Generation of Category Exemplars

Four experiments tested the forgetting fixation hypothesis of incubation effects, comparing continuous vs. alternating generation of exemplars from three different types of categories. In two experiments, participants who listed as many members as possible from two different categories produced more responses, and more novel responses, when they alternated back and forth between the two categories, as compared to continuous uninterrupted listing from each of the two categories. This incubation effect was not found in Experiment 1, when participants were given taxonomic categories (birds and clothing ) for the generation task, but was found in Experiment 2 with sense impression categories (cold things and heavy things ), and in Experiment 3 with ad hoc categories (equipment you take camping and fattening foods ). A similar incubation effect was observed in Experiment 4 when a non‐verbal task was given between category generation tasks, but only for flexibly defined categories. The results suggest that forgetting from one alternating listing period to the next in the form of altering category cue representations was consistent with the observed incubation effects. These alternating incubation effects have implications for understanding cognitive processes that underlie creative cognition.     

Effect of achievement motivation on cognitive control adaptations

Previous research addressing motivational effects on cognitive control adaptations primarily manipulated external rewards. In the present study, we examined whether achievement motivation, reflecting intrinsic motivation, modulates cognitive control adaptations. In each of two experiments, students were divided into a high achievement motivation group (HAM; Experiment 1: N?=?36; Experiment 2: N?=?39) and a low achievement motivation group (LAM; Experiment 1: N?=?30; Experiment 2: N?=?39) on the basis of the Achievement Motivation Scale. Cognitive control adaptations were assessed by sequential congruency effects (SCEs) in Flanker tasks. Using a standard Flanker task in Experiment 1 and examining response times, the HAM but not LAM participants showed evidence of cognitive control adaptations. Because SCEs in a standard Flanker task may reflect lower-level, bottom-up processes rather than cognitive control adaptations, we used an adapted version of the Flanker task in Experiment 2 that controlled for the potential influence of such processes. Experiment 2 again revealed evidence of SCEs in the HAM but not LAM participants. These results suggest that cognitive control adaptions may be modulated by achievement motivation. Such potential modulation could be taken into account when evaluating results of previous and future fundamental and applied studies on cognitive control adaptations.