Timing the “magical number seven”: Presentation rate and regularity affect verbal working memory performance

The informative value of time and temporal structure often remains neglected in cognitive assessments. However, next to information about stimulus identity we can exploit temporal ordering principles, such as regularity, periodicity, or grouping to generate predictions about the timing of future events. Such predictions may improve cognitive performance by optimising adaptation to dynamic stimuli. Here, we investigated the influence of temporal structure on verbal working memory by assessing immediate recall performance for aurally presented digit sequences (forward digit span) as a function of standard (1000 ms stimulus-onset-asynchronies, SOAs), short (700 ms), long (1300 ms) and mixed (700–1300 ms) stimulus timing during the presentation phase. Participant's digit spans were lower for short and mixed SOA presentation relative to standard SOAs. This confirms an impact of temporal structure on the classic “magical number seven,” suggesting that working memory performance can in part be regulated through the systematic application of temporal ordering principles.     

The utility of ground rule instructions with younger and older adult witnesses

This study examined the effectiveness of ground rules—simple instructions outlining the communication expectations of an investigative interview—with 73 younger (age 18–40) and 57 older (age 60+) adults. Participants watched a film depicting an implied sexual assault and were interviewed after a brief delay. One third received no ground rules, one third received ground rules as statements, and one third received the statements along with practice examples. The interview contained questions that required participants to apply one of the rules. Those who received ground rules were asked their perceptions of the rules. Results demonstrated that practicing ground rules improved response quality to problematic recognition questions, younger adults showed more variability in responses to different ground rules than older adults, and most participants found ground rule instructions useful in investigative interviews. Results provide support for the use of ground rules in interviews with adult witnesses.     

Feeling time in nature: The influence of directed and undirected attention on time awareness

In the present study, we examined the impact of the interaction of environmental and task-induced attentional focus on time perception, specifically awareness of the time flow. We tested 48 participants in either a natural or urban setting over three 25- to 35-min sessions. We manipulated the within-subjects factor task by means of two tasks—one requiring directed attention on the task itself, the other undirected attention on the environment—alongside a control condition with no specific task. We measured time awareness, passage of time judgments, felt time judgments, and estimated time as dependent variables. For time awareness, we found an interaction between environment and task: in the natural environment, only a task requiring directed attention reduced time awareness; whereas, in the urban environment, both tasks reduced time awareness compared to the control condition. The results suggest that natural environments increase time awareness unless we focus our attention on a task.     

Remembering changes: repetition effects in face recollection.

Two experiments examined effects of repetition and change on states of awareness in face recognition. Participants studied repeatedly presented photographs of faces, with the second presentation following either immediately after the first presentation (massed repetition) or following six intervening items (spaced repetition). To manipulate perceptual change, each repeated face was either identical or a mirror image of the first presentation. Subsequently, when recognising a face, participants indicated whether they consciously recollected its prior occurrence ("remembering") or recognised it on the basis of familiarity ("knowing"). Changes in appearance between repeated faces enhanced remember, but not know, responses, and these effects were accentuated for spaced, rather than massed, repetition. These findings suggest that distinctiveness of encoding supports the phenomenological experience of conscious remembering.