Biomedical subjects

Hubert D Zimmer

Publications and source records attributed to Hubert D Zimmer.

4 recordsLinked to original sources

PubMed2003

Spatio-temporal working-memory and short-term object-location tasks use different memory mechanisms.

Spatial short-term memory for objects' locations was investigated in a spatial relocation task. During maintenance, dynamic visual noise or spatial tapping were administered as visual or spatial secondary tasks, respectively. Because memory for location should tap the visual component of working memory, a visual but not a spatial secondary task should impair location memory. In fact, neither of the tasks impaired memory (Experiment 1), although the expected dissociation between visual and spatial components was clearly confirmed for a spatio-temporal main task (Corsi test) (Experiment 2). We then contrasted location memory for pictures of objects and of nonsense figures under visual interference. Real objects were relocated much better than nonsense figures, and visual noise was again ineffective (Experiment 3). When spatial tapping was combined with the same material (Experiment 3a), again no influence on memory for locations of objects was observed and only a small influence on remembering nonsense figures. We suggest that the Corsi and the relocation VSWM-tasks use different memory mechanisms. The configuration of objects is reconstructed from perceptual records in an episodic buffer, provided by the same structures that enable visual memory after longer intervals. Rehearsal is not necessary for the persistence of these traces. In contrast, in the Corsi task remembering, a temporal sequence across homogeneous locations needs spatio-temporal marking and therefore active rehearsal of the locations by shifting spatial attention. A spatially demanding secondary task during retention interrupts this rehearsal.

Adult↗

PubMed2003

Signing enhances memory like performing actions.

In three experiments, we investigated the influence of the overt performance of signs on memory. Deaf and hearing participants studied lists of action phrases (Experiment 1) or nouns (Experiment 2) under standard verbal instruction, under the instructions to sign the verbal phrase, to symbolically perform the denoted action, or to carry out a prototypical action corresponding to each noun. Higher recall and recognition performances were observed when actions were performed than in the verbal encoding condition, and signing was as effective for memory as was enactment. Thus, overt signing can induce an enactment effect. In contrast, Experiment 3 demonstrated that performing an unrelated action did not. A unique but unrelated action was not memory efficient.

Deafness↗

PubMed2002

Free recall and organization as a function of varying relational encoding in action memory.

A new approach was taken to study the question whether the free recall advantage of enacting actions (SPT), over only listening to their verbal descriptions (VT), is due to better relational encoding of SPTs than of VTs. The approach consisted of studying related lists and manipulating the degree of relational encoding by repeated list presentation in Experiment 1 and by presenting the list items at random or blocked in Experiment 2. In both experiments, free recall and adjusted ratio of clustering (ARC) scores increased as to be expected with repeated list presentation and blocking. However, these effects proved to be independent of the type of encoding. There was a clear SPT effect in free recall, but in contrast a slight though nonsignificant advantage of VTs over SPTs in ARC scores. Altogether, the experiments show that the SPT effect in free recall is not due to better relational encoding in SPTs than in VTs, in line with the assumption that this effect is due to good item-specific encoding.

Adult↗

PubMed2002

How "implicit" are implicit color effects in memory?

Processing colored pictures of objects results in a preference to choose the former color for a specific object in a subsequent color choice test (Wippich & Mecklenbräuker, 1998). We tested whether this implicit memory effect is independent of performances in episodic color recollection (recognition). In the study phase of Experiment 1, the color of line drawings was either named or its appropriateness was judged. We found only weak implicit memory effects for categorical color information. In Experiment 2, silhouettes were colored by subjects during the study phase. Performances in both the implicit and the explicit test were good. Selections of "old" colors in the implicit test, though, were almost completely confined to items for which the color was also remembered explicitly. In Experiment 3, we applied the opposition technique in order to check whether we could find any implicit effects regarding items for which no explicit color recollection was possible. This was not the case. We therefore draw the conclusion that implicit color preference effects are not independent of explicit recollection, and that they are probably based on the same episodic memory traces that are used in explicit tests.

Color Perception↗