There are at least two possibilities – one is that it helps to hear the information in your own voice, the other is that there’s something memorable about the act of speaking the words. A clever study put these two explanations to the test recently. It compared participants reading words aloud to listening to earlier recordings of themselves saying words, using a memory test.
The findings suggested that both the act of speaking, and hearing oneself, assist memory – the former because it’s a more active, involved process than silent reading, and the latter because hearing oneself speak makes the information more personally salient.
How is a memory formed?
There is really no such thing as ‘a memory’. Memory is a process, or set of inter-related processes, in which the brain changes in response to events. These changes then result in us being able to repeat a name or phone number (short-term memory), recall a specific event (episodic memory), recite a poem we learned at school (long-term verbal memory) or exercise a learned skill such as riding a bike or skateboarding (procedural memory).
Among the important mechanisms that underlie memory are changes to the strength of synapses (the gaps between nerve cells that signals have to cross), the growth of the tiny dendritic spines that grow out of the cells’ branching dendrites, and many chemical changes that strengthen some of the networks of neurons at the expense of others. These changes occur all over the brain but some areas, such as the tiny hippocampus in the temporal lobe of the brain, are especially important. Damage here can mean a permanent loss of any ability to lay down new memories.
What happens in your brain when you make a memory?
Memories are formed by the changing strength of connections between networks of brain cells, particularly in the hippocampus, which is found in each temporal lobe (the part of your brain near your ears). A key memory-related process is ‘long-term potentiation’, which refers to a lasting change in how strongly one neuron influences another. It’s tempting to think of memory like a recording, etched permanently into patterns of brain cells, but it’s more accurate to see it as a creative process. During recollection, earlier patterns of brain activity are re-enacted – a fragile process that leaves plenty of room for error and editing.