This brings us to the crux of our argument: serial processing and parallel processing systems can be thought of as organizational analogs to the types of decisionmaking defined earlier--that is, the constructivist and the ecological approaches. The information processing models assume serial processing of stimulus inputs. Serial processing effectively means one process has to be completed before the next starts. Parallel processing assumes some or all processes involved in a cognitive task(s) occur at the same time.
Various single-core processors can be used together for handling serial processing by means of parallel computer clusters that are networked, or by operating multiple processors on a single motherboard. Programs intended for serial processing can make use of just a single core at a time, where the tasks are processed in a sequential order.
Functions of a serial processor can be compared with a grocery store cashier who single-handedly handles different lanes, looking over every customer simultaneously. The cashier (like the CPU) switches from lane to lane to check out a number of items at a time prior to addressing the next one, with the objective of completing every order concurrently. Serial processing is purely sequential.
![Serial Serial](https://www.researchgate.net/profile/Jeannette_Stark/publication/312084432/figure/fig1/AS:455425679204352@1485593351468/Continuum-between-parallel-and-serial-processing-on-the-basis-of-11.png)
A system using standard serial processing techniques lets every object take exactly the same average time frame for processing. Moreover, the subsequent object starts processing only after the completion of the previous one. On the contrary, parallel processing implies simultaneous processing on various objects or subsystems. The processing, however, may complete at different times. Individual as well as overall processing periods can be random in either type of processing.
![Processing Processing](https://image.slidesharecdn.com/chapter02-new-110621165851-phpapp01/95/chapter02-new-14-728.jpg?cb=1308676214)
That is, the time periods essential for processing an item or executing an operation may differ from trial to trial.