Memory Guides the Comprehension of Event Changes for Older and Younger Adults

Two experiments examined adult age differences in the use of memory to comprehend changes in everyday activities. Participants viewed movies depicting an actor performing activities on two fictive days in her life. Some activities were repeated across days, other activities were repeated with a changed feature (e.g., waking up to an alarm clock or a phone alarm), and a final set of activities was performed on Day 2 only. After a one-week delay, participants completed a cued recall test for the activities of Day 2. Unsurprisingly, exact repetition boosted final recall. More surprising, features that changed from Day 1 to Day 2 were remembered approximately as well as features that were only presented on Day 2—showing an absence of proactive interference and in some cases proactive facilitation. Proactive facilitation was strongly related to participants’ ability to detect and recollect the changes. Younger adults detected and recollected more changes than older adults, which in part explained older adults’ differential deficit in memory for changed activity features. We propose that this pattern may reflect observers’ use of episodic memory to make predictions during the experience of a new activity, and that when predictions fail, this triggers processing that benefits subsequent episodic memory. Disruption of this chain of processing could play a role in age-related episodic memory deficits.

Salience of working-memory maintenance and manipulation deficits in schizophrenia

BackgroundEncoding and maintenance of information in working memory, followed by internal manipulation of that information for planning adaptive behavior, are two key components of working-memory systems. Both processes have been reported to be impaired in schizophrenia, but few studies have directly compared the relative severity of these abnormalities, or the degree to which manipulation deficits might be secondary to alterations in maintenance processes.MethodClinically stable schizophrenia patients (n=25) and a demographically similar healthy comparison group (n=24) were administered a verbal span task with three levels of working-memory load. Maintenance was assessed using sequential position questions. Manipulation processes were assessed by requiring comparison of the relative sequential position of test items, which entailed simultaneous serial search strategies regarding item order.ResultsBoth groups showed reduced accuracy and increased reaction time for manipulation compared with maintenance processing. There were significant patient impairments across working-memory loads. There was no differential deficit in manipulation processing, and effect sizes of relative deficit in the patient group were higher for maintenance than manipulation processing.ConclusionsThe strong correlation for maintenance and manipulation deficits suggest that impairments in the ability to internally manipulate information stored in working-memory systems are not greater than alterations in the encoding and maintaining of information in working memory and that disturbances in maintenance processing may contribute to deficits in higher-order working-memory operations.