Parallel Search

Memory is categorized into short term and long-term systems. In which, the system of short-term memory is known for holding information for a few seconds. If information stored in short term memory is not transferred to long-term memory; for a permanent storage, the memory of the items is decay. Researchers have looked into the existence of short-term memory. Within memory their properties and theory in how information is retrieved and encoded. The two types of retrieval theories is serial and parallel search. Serial search assumes that individuals scan items in short term memory one at a time, while parallel search assumes that individuals scan items all at once. Additionally, other properties that function in memory is self terminating; which

What seem to be important and what many researchers investigate and explore is how symbolic memory is retrieved from short-term memory.

Saul Sternberg (1966) developed an experimental approach to explore how symbolic memory is retrieved from STM. Specifically he looked into the effects of the number of elements in memory on response latency. Response latency is measured by which subjects note the test stimulus to the occurrence of the response. Sternberg examined the types of retrieval theories in which he hypothesis, if parallel processing occurred, the length of the display should not influence the reaction time, but if serial processing occurred, the reaction time should increase with an increase in the length of the display. Sternberg ran a series of experiments so that he could test parallel and serial STM search. Overall, the experiment consisted of subject being instructed first to memorize a short series of symbols, where on each trial a

M. Van Gerven, Fred Paas, Jeroen J. G. Van Merriënboer, Henk G. Schmidt, (2004) investigate the effect of memory load on the cognitive pupillary response while conducting a Sternberg’s memory search task. In which, the researchers wanted to see if they came across the same findings as Sternberg (1966) and if there’s a difference in age by examining their pupillary response. The study was consisted of 16 young adults and 16 older adults. The memory search task involves two phases. In the encoding phase, participants are required to remember a specific number of randomly selected digits (ranging from 0 to 9), none of which happens more than once. The number of digits in the memory set varies from one to six. In the search phase, the participant is given a succession of randomly selected single digit probes. In each trial, the participant has to decide as quickly as possible whether a probe belongs to the memory set (i.e., positive probe) or not (i.e., negative probe). Van Gerven et.al (2004) results suggest the reaction times of the elderly participants increased more as a function of memory load than the reaction times of the young participants. As well for pupillary response the young participants had greater pupil dilation than older participant when there was an increase in memory load (set size). Both of these finding demonstrated that older and young participants took longer to respond when memory load increased, but just older participant took even longer.