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Auditory working memory for objects vs. features.

Joseph S, Kumar S, Husain M, Griffiths TD - Front Neurosci (2015)

Bottom Line: Memory recall was more accurate when the objects had to be maintained as a whole compared to the individual features alone.Additionally a feature extraction cost was associated with maintenance and recall of individual features, when extracted from bound object representations.The results have implications for feature-integration theory in the context of WM in the auditory system.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cognitive Neuroscience, University College London London, UK ; Institute of Neurology, University College London London, UK.

ABSTRACT
This work considers bases for working memory for non-verbal sounds. Specifically we address whether sounds are represented as integrated objects or individual features in auditory working memory and whether the representational format influences WM capacity. The experiments used sounds in which two different stimulus features, spectral passband and temporal amplitude modulation rate, could be combined to produce different auditory objects. Participants had to memorize sequences of auditory objects of variable length (1-4 items). They either maintained sequences of whole objects or sequences of individual features until recall for one of the items was tested. Memory recall was more accurate when the objects had to be maintained as a whole compared to the individual features alone. This is due to interference between features of the same object. Additionally a feature extraction cost was associated with maintenance and recall of individual features, when extracted from bound object representations. An interpretation of our findings is that, at some stage of processing, sounds might be stored as objects in WM with features bound into coherent wholes. The results have implications for feature-integration theory in the context of WM in the auditory system.

No MeSH data available.


Related in: MedlinePlus

Task and control conditions. Shown are sample trials for each control condition (each row illustrates one of 3 conditions). In the spectral control condition (1st row) subjects focus only on the spectral feature (in purple). In the temporal control condition (2nd row) subjects only focus on the temporal feature (in yellow). In the object control condition (3rd row), they encode the object as a whole (both features in combination). Both single feature control conditions differ from the single feature experimental conditions in the following way: the irrelevant feature (*) is held constant at the middle value of the corresponding stimulus range. The object control condition differs from the experimental object condition in the way that on change trials, the item presented at recall (probe) differs from the target (here: 2nd item in the sequence presented at encoding) by 1 feature, instead of 2 features.
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Figure 2: Task and control conditions. Shown are sample trials for each control condition (each row illustrates one of 3 conditions). In the spectral control condition (1st row) subjects focus only on the spectral feature (in purple). In the temporal control condition (2nd row) subjects only focus on the temporal feature (in yellow). In the object control condition (3rd row), they encode the object as a whole (both features in combination). Both single feature control conditions differ from the single feature experimental conditions in the following way: the irrelevant feature (*) is held constant at the middle value of the corresponding stimulus range. The object control condition differs from the experimental object condition in the way that on change trials, the item presented at recall (probe) differs from the target (here: 2nd item in the sequence presented at encoding) by 1 feature, instead of 2 features.

Mentions: There was a control condition (see Figure 2) for each of the three experimental conditions. When a single feature (e.g., spectral) had to be maintained in WM, the other irrelevant dimension (e.g., temporal) may have caused interference with the relevant dimension of sound. In the experimental condition the dimension of the irrelevant sound feature was varied at random. However, the irrelevant dimension was held constant in the control condition in order to capture the amount of interference when comparing across conditions (experimental vs. control).


Auditory working memory for objects vs. features.

Joseph S, Kumar S, Husain M, Griffiths TD - Front Neurosci (2015)

Task and control conditions. Shown are sample trials for each control condition (each row illustrates one of 3 conditions). In the spectral control condition (1st row) subjects focus only on the spectral feature (in purple). In the temporal control condition (2nd row) subjects only focus on the temporal feature (in yellow). In the object control condition (3rd row), they encode the object as a whole (both features in combination). Both single feature control conditions differ from the single feature experimental conditions in the following way: the irrelevant feature (*) is held constant at the middle value of the corresponding stimulus range. The object control condition differs from the experimental object condition in the way that on change trials, the item presented at recall (probe) differs from the target (here: 2nd item in the sequence presented at encoding) by 1 feature, instead of 2 features.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4321563&req=5

Figure 2: Task and control conditions. Shown are sample trials for each control condition (each row illustrates one of 3 conditions). In the spectral control condition (1st row) subjects focus only on the spectral feature (in purple). In the temporal control condition (2nd row) subjects only focus on the temporal feature (in yellow). In the object control condition (3rd row), they encode the object as a whole (both features in combination). Both single feature control conditions differ from the single feature experimental conditions in the following way: the irrelevant feature (*) is held constant at the middle value of the corresponding stimulus range. The object control condition differs from the experimental object condition in the way that on change trials, the item presented at recall (probe) differs from the target (here: 2nd item in the sequence presented at encoding) by 1 feature, instead of 2 features.
Mentions: There was a control condition (see Figure 2) for each of the three experimental conditions. When a single feature (e.g., spectral) had to be maintained in WM, the other irrelevant dimension (e.g., temporal) may have caused interference with the relevant dimension of sound. In the experimental condition the dimension of the irrelevant sound feature was varied at random. However, the irrelevant dimension was held constant in the control condition in order to capture the amount of interference when comparing across conditions (experimental vs. control).

Bottom Line: Memory recall was more accurate when the objects had to be maintained as a whole compared to the individual features alone.Additionally a feature extraction cost was associated with maintenance and recall of individual features, when extracted from bound object representations.The results have implications for feature-integration theory in the context of WM in the auditory system.

View Article: PubMed Central - PubMed

Affiliation: Institute of Cognitive Neuroscience, University College London London, UK ; Institute of Neurology, University College London London, UK.

ABSTRACT
This work considers bases for working memory for non-verbal sounds. Specifically we address whether sounds are represented as integrated objects or individual features in auditory working memory and whether the representational format influences WM capacity. The experiments used sounds in which two different stimulus features, spectral passband and temporal amplitude modulation rate, could be combined to produce different auditory objects. Participants had to memorize sequences of auditory objects of variable length (1-4 items). They either maintained sequences of whole objects or sequences of individual features until recall for one of the items was tested. Memory recall was more accurate when the objects had to be maintained as a whole compared to the individual features alone. This is due to interference between features of the same object. Additionally a feature extraction cost was associated with maintenance and recall of individual features, when extracted from bound object representations. An interpretation of our findings is that, at some stage of processing, sounds might be stored as objects in WM with features bound into coherent wholes. The results have implications for feature-integration theory in the context of WM in the auditory system.

No MeSH data available.


Related in: MedlinePlus