Effect of sleep on memory for binding different types of visual information

Visual long-term memory has a large and detailed storage capacity for individual scenes, objects, and actions. Sleep can enhance declarative memory of information, with sleep strengthening associations between item and context. However, the fidelity of the representation is currently underexplored. Experiments 1a and 1b tested effects of sleep on binding objects and scenes, and Experiments 2-3 tested binding of actions and scenes. Participants viewed composites and were tested 12-hours later after a delay consisting of sleep (9pm-9am) or wake (9am-9pm), on an alternative forced choice recognition task. For object-scene composites sleep did improve recognition compared to an equivalent period of wake. For action-scene composites, there was no significant effect observed, with recognition at chance level, suggesting issues with initial encoding. Sleep can promote binding in memory, depending on the type of information to be combined

Effect of sleep on memory for binding different types of visual information

Visual long-term memory has a large and detailed storage capacity for individual scenes, objects, and actions. However, memory for combinations of actions and scenes is poorer, suggesting difficulty in binding this information together. Sleep can enhance declarative memory of information, but whether sleep can also boost memory for binding information and whether the effect is general across different types of information is not yet known. Experiments 1 to 3 tested effects of sleep on binding actions and scenes, and Experiments 4 and 5 tested binding of objects and scenes. Participants viewed composites and were tested 12-hours later after a delay consisting of sleep (9pm-9am) or wake (9am-9pm), on an alternative forced choice recognition task. For action-scene composites, memory was relatively poor with no significant effect of sleep. For object-scene composites sleep did improve memory. Sleep can promote binding in memory, depending on the type of information to be combined

Effect of culture on memory for binding different types of visual information

The degree of individualism or collectivism in a culture has observable effects on cognitive processing. Participants from collectivist cultures are less able to identify a previously displayed object when presented with a novel background than participants from individualist cultures. This can be interpreted as collectivist cultures more likely to process information field dependently. We tested explicitly whether collectivist or individualist cultures are more likely to bind foreground and background images and whether such binding is differentially affected for object-scene and action-scene combinations. Across three experiments participants viewed item-context composites, then completed a forced-choice recognition task. In Experiment 1, 61 UK and 57 Malaysian participants viewed object-scene composites, with UK participants significantly more accurate in correct composite recognition, with Experiment 2 demonstrating this difference was not due to cultural differences in object familiarity. In Experiment 3, 62 UK and 67 Malaysian participants viewed action-scene composites, with no significant difference between cultures in proportion of items recognised. The results of Experiment 1 suggest that the UK sample were able to store high-fidelity representations of visual features as an association between item and context, while the Malaysian sample were unable to. This result is discussed in relation to both cultural, and cognitive psychology

Eye movements support the link between conscious memory and medial temporal lobe function

When individuals select the recently studied (and familiar) item in a multiple-choice memory test, they direct a greater proportion of viewing time toward the to-be-selected item when their choice is correct than when their choice is incorrect. Thus, for both correct and incorrect choices, individuals indicate that the chosen item is old, but viewing time nevertheless distinguishes between old and new items. What kind of memory supports this preferential viewing effect? We recorded eye movements while participants made three-alternative, forced-choice recognition memory judgments for scenes. In experiment 1 (n = 30), the magnitude of the preferential viewing effect was strongly correlated with measures of conscious, declarative memory: recognition accuracy as well as the difference in confidence ratings and in response times for correct and incorrect choices. In four analyses that minimized the contribution of declarative memory in order to detect a possible contribution from other processes, the preferential viewing effect was absent. In experiment 2, five memory-impaired patients with medial temporal lobe lesions exhibited a diminished preferential viewing effect. These patients also exhibited poor recognition accuracy and reduced differences in confidence ratings and response times for correct and incorrect choices. We propose that the preferential viewing effect is a phenomenon of conscious, declarative memory and is dependent on the medial temporal lobe. The findings support the link between medial temporal lobe function and declarative memory. When the effects of experience depend on the medial temporal lobe, the effects reflect conscious memory