Biomedical subjects

Jutta Kray

Publications and source records attributed to Jutta Kray.

7 recordsLinked to original sources

PubMed2006

Effects of associative learning on age differences in task-set switching.

Costs of switching between tasks may disappear when subjects are able to learn associations between tasks, stimuli, and responses (cf. Rogers, R. D., & Monsell, S. (1995). Costs of a predictable switch between simple cognitive tasks. Journal of Experimental Psychology: General, 124, 207-231). The first aim of this study was to examine this possibility by manipulating stimulus-set size. We expected that costs of switching between tasks would be strongly reduced under conditions of small stimulus-set sizes (n=4) as compared to large stimulus-set sizes (n=96) with increasing time on task. The second aim was to determine whether younger as well as older adults were able to create associations between task components. As age differences in task switching are often found to be larger when response mappings are incompatible we also investigated interactions with response compatibility. Results of our study indicated that practice effects on switch costs were much more pronounced for small than large stimulus-set sizes, consistent with the view that the strength of associations between task components facilitates task switching. Furthermore, we found that practice benefits on task switching for small stimulus-set sizes were sensitive to age and response compatibility. In contrast to younger adults, who showed a reduction of switch costs for both response mapping conditions, older adults showed a reduction of switch costs only when response mappings were compatible. That is, older adults showed less associative learning when the currently irrelevant task feature had to be suppressed, supporting the view that older adults have primarily problems in separating overlapping task-set representations.

Adult↗

PubMed2006

Task-set switching under cue-based versus memory-based switching conditions in younger and older adults.

Adult age differences in task switching and advance preparation were examined by comparing cue-based and memory-based switching conditions. Task switching was assessed by determining two types of costs that occur at the general (mixing costs) and specific (switching costs) level of switching. Advance preparation was investigated by varying the time interval until the next task (short, middle, very long). Results indicated that the implementation of task sets was different for cue-based switching with random task sequences and memory-based switching with predictable task sequences. Switching costs were strongly reduced under cue-based switching conditions, indicating that task-set cues facilitate the retrieval of the next task. Age differences were found for mixing costs and for switching costs only under cue-based conditions in which older adults showed smaller switching costs than younger adults. It is suggested that older adults adopt a less extreme bias between two tasks than younger adults in situations associated with uncertainty. For cue-based switching with random task sequences, older adults are less engaged in a complete reconfiguration of task sets because of the probability of a further task change. Furthermore, the reduction of switching costs was more pronounced for cue- than memory-based switching for short preparation intervals, whereas the reduction of switch costs was more pronounced for memory- than cue-based switching for longer preparation intervals at least for older adults. Together these findings suggest that the implementation of task sets is functionally different for the two types of task-switching conditions.

Adult↗

PubMed2006

Language and action control: the acquisition of action goals in early childhood.

This study examined the role of verbal labeling in 4-year-old children's acquisition of action-effect learning. The acquisition of action-effect associations was tested by having children first perform a two-choice key-pressing task in which each key press was followed by an effect (i.e., a particular sound) and then respond to the previously perceived effects under either consistent or inconsistent key-sound mappings. During acquisition, the children overtly described the actions, the effects, both the actions and the effects, or, in a control condition, something irrelevant to the actions and effects. Action-effect learning was reliable only if the description related actions to effects, even though some evidence of learning was also obtained in the control condition. In contrast, learning was prevented if only the actions or only the effects were described. The results suggest that verbal labeling plays an important role in integrating and isolating event representations.

Child, Preschool↗

PubMed2005

The control of memory retrieval: insights from event-related potentials.

Effective performance on episodic retrieval tasks requires the ability to flexibly adapt to changing retrieval demands ('retrieval orientations'; [M.D. Rugg, E.L. Wilding, Retrieval processing and episodic memory, Trends Cogn. Sci. 4 (2000) 108-115]). We used event-related potentials (ERP) to examine whether maintaining a specific retrieval orientation and changing flexibly between different retrieval demands are mediated by the same brain systems or whether dissociable aspects of cognitive control are involved. Sixteen participants performed two recognition memory tasks. One required mere old/new decisions for words (general task), whereas the other task required the additional retrieval of each word's study font typeface (specific task). Furthermore, the participants either were asked to perform the same task continuously or to switch between the two tasks after every second test word. ERPs elicited by correctly rejected new (unstudied) words were analyzed. This enabled us to examine the ERP correlates of having adapted and maintained a task instruction as required during continuous blocks and of flexibly changing between retrieval demands during alternating blocks. The ERP analysis revealed more positive-going ERP slow waves for alternating blocks than for continuous blocks over bilateral frontal recording sites. This effect started around 250 ms after the test word and extended for several hundred milliseconds. As it was present for trials requiring a switch to the other task or to stay on the same task between 500 and 750 ms and no differences between the latter two trial types were obtained, it can be assumed that it is more related to general coordination requirements in alternating blocks, rather than to the actual control required to switch the retrieval task set. In addition, contrasting ERPs for the two task types revealed more positive-going ERP slow waves in the specific task than in the general task in the continuous blocks at lateral frontal recording sites between 250 and 700 ms. Together, these findings suggest that there are electrophysiologically dissociable aspects of cognitive control, namely for adapting and maintaining a retrieval orientation and for flexibly changing between varying retrieval demands.

Adult↗

PubMed2005

Age differences in attentional control: an event-related potential approach.

We examined age differences in event-related potentials (ERPs) associated with attentional control of task-set selection and response interference by means of a cue-based switching paradigm in which participants performed the color or word Stroop task. The results of ERPs in the cue interval indicated that P3 latencies were slowed for older adults, suggesting age-related slowing in updating currently relevant task sets. Older adults also showed a larger CNV under switching than nonswitching conditions, indicating age differences in maintaining task sets over longer periods of time. The results of target-locked ERPs revealed a negativity to incompatible Stroop trials (Ni) that was prolonged for older adults, suggesting age differences in early conflict processing. Response-locked ERPs showed a negative deflection to incompatible Stroop trials (CRN) only for younger adults, suggesting age differences also in response-related conflict processing.

Adult↗

PubMed2002

Age-related changes in task-switching components: the role of task uncertainty.

The present study examined age differences in executive functioning, using an externally cued task-switching paradigm. Two components of task switching were assessed: the ability to maintain and select among task sets (general switch costs) and the ability to switch between task sets (specific switch costs). In contrast to previous findings, we found large age-related differences in specific switch costs, especially when the number of potentially relevant task sets is increased from two to four. Age-related differences in general switch costs were absent when external task cues subserved executive processing in task switching. Generally, the findings suggest that age-related impairments in task-switching components vary as a function of task uncertainty, such as the presence of environmental prompts to behavior.

Adult↗

PubMedDate not supplied

Age differences in executive functioning across the lifespan: the role of verbalization in task preparation.

Age-related changes in executive functioning across the lifespan were assessed in children (mean age=9.4 years), younger adults (mean age=21.5 years), and older adults (mean age=65.3 years). Executive functioning was investigated with a task-switching paradigm that permits the separation of two control components: to select and to switch between task sets. The specific aims of this study were (a) to determine developmental functions in both control components across the lifespan; and (b) to examine whether age-related changes in these components are influenced by verbal prompts during task preparation. The results revealed an inverted u-shaped developmental function for the ability to select between task sets but not for the ability to switch between task sets. In contrast to younger adults and children, older adults generally benefited from verbalizations during task preparation. Children, but not older adults, showed a facilitation of task execution when verbal prompts were task-compatible. Conversely, older adults, but not children, showed stronger interference when verbal prompts are task-incompatible. Our findings suggest that inner speech in an important modulator of developmental changes in executive functioning across the lifespan.

Adult↗