As considering multiple instances of past data (i.e. experiences) from the database to compare their details, summaries, trends, etc. with the current interaction can only be done serially, i.e. one after the other, the interaction processing areas of right hemisphere are limited to serial processing, i.e. they can process only one task at a time, whereas left hemisphere is capable of parallel processing, and thus is capable of multitasking, making it faster in processing speed than the right hemisphere.
Even with the limitation of serial processing in (the interaction processing areas of) the right hemisphere, both hemispheres work jointly in a specific manner to make the brain capable of multitasking, though in a limited capacity, as explained below:
Interactions which are either first time occurrences or are not distinctly similar to past Interactions may require the database to judge how to execute them further, and thus are initialized in the right hemisphere.
When such interaction or a part of it becomes sufficiently repetitive, as repetitive interactions do not need past data, its processing transfers to the left hemisphere, which is then on a standby mode. Such temporary transfer frees up interaction processing areas of the right hemisphere to execute other tasks (i.e. to pay attention to other tasks), which is a valuable resource, as it has the limitation of processing only one task at a time. The standby mode is cancelled when interrupted (i.e. attention is drawn) by right hemisphere, which is when processing is transferred back to it (in detail).
The best way to understand the above is to see it in action. Try the following exercise:
An exercise to understand the reason why human multitasking has limitations
Start shaking your leg continuously. Now mull over something that happened yesterday. You will notice how you had to pay attention to initiate the movement of your leg, but once it became repetitive, you could simultaneously mull over the previous day’s happenings (i.e. multitask), the reason for which is that the interaction processing for the repetitive movement transferred to the left hemisphere, freeing up interaction processing areas of the right hemisphere to mull over previous day’s happenings using the database.
It would be obvious to you that instead if shaking your leg, if you were asked to make a list of your favourite food while mulling over previous day’s happenings, it would not be possible for you to do so, the reason for which is that both the processes require continuous retrieval of data from the database in the right hemisphere, which cannot process two tasks at the same time as it is a serial processor.