Role of the preprobe delay in memory-scanning tasks.

Area of Science:

• Cognitive Psychology
• Human Memory Research

Background:

• Sternberg's memory-scanning task is a standard paradigm for studying short-term memory retrieval.
• Prior research indicated a preprobe delay is necessary for the set-size effect in modified tasks.

Purpose of the Study:

• To investigate the role of preprobe delay in the memory-scanning task's set-size effect.
• To explore the influence of expectancy on response latency and set-size effects.

Main Methods:

• Experiment 1: Examined preprobe delay in a typical two-response memory-scanning task.
• Experiment 2: Manipulated expectancy by informing participants of the memory set size beforehand.
• Experiment 3: Assessed expectancy effects in a non-memory search task.

Main Results:

• Without a preprobe delay, response latency showed minimal set-size effect for negative responses but a significant effect for positive responses.
• Informing participants of set size prior to presentation restored the set-size effect without a preprobe delay.
• A non-memory search task showed a decrease in response latency with increasing set size, suggesting expectancy influences performance.

Conclusions:

• The preprobe delay's primary function appears to be controlling expectancy effects, which otherwise reduce the set-size effect.
• Expectancy, independent of memory search load, can influence response latencies in tasks resembling memory scanning.