When presidential candidate Rick Perry was not able to name one of the governmental agencies he wants to abolish during an infamous presidential debate this fall, the public’s reaction covered a wide range from sympathetic to outright gleeful at the flub. While his supporters would have liked to cite neurological problems as responsible for the lapse , critics just saw it as proof that the Republican does not know his own politics. So why did he forget when he needed to remember?

In an article posted online, The Washington Post‘s Joel Achenbach analyzes Perry’s “brain-freeze”, deeming it a common case of “retrieval failure”. What may seem like fancy words for what happened – he forgot – in fact describes an interesting phenomenon that everyone has experienced at some point. An incapability to retrieve a word we know, a word we may have used hundreds of times before, is widely known as that ‘tip of the tongue’ feeling, when what you want to express is just barely out of reach. Citing a neuroscientist, the Post article goes on to point out how in a situation of increased stress, we are even more unlikely to find the word we seek. Instead of actually concentrating on solving the problem, the mind analyzes the consquences of our shortcoming, making it highly unlikely that we will recover the situation.

There are different theories about forgetting in psychology, generally divided into forgetting from short-term or long-term memory. Naturally it is much ‘easier’ to forget things that were not stored in our long-term memory (LTM), as we never made a conscious effort to remember what we saw, read or learned.  Nevertheless there are different theories that try to explain why things are ‘deleted’ from our short-term memory (STM).

The first concept is that of trace decay, which assumes that memories leave an actual physical and chemical trace on our nervous system. However, if a fact is not rehearsed to be remembered, our STM can hold this information for no more than 15-30 seconds, after which the trace decays and the memory is forgotten. One of the assumptions of this theory is that the events that happen between the act of learning and the retrieval of the information have no influence whatsoever on recall, time is the only relevant factor. There is little evidence to support this theory, as it is impossible to recreate a situation where there is no intervening event without promoting automatic rehearsal of the fact.

Another and more commonly accepted belief about STM forgetting is that of displacement. Based on a model created by Atkinson & Shiffrin in 1968, our STM-store has only a limited capacity that allows for no more than 7 +/- 2 items to be remembered at the same time. If any additional facts are added, the oldest is displaced – or in other words forgotten – to make room for something new. This theory is supported by the free recall test. Participants are asked to remember words off a list that was read to them before in no particular order. Most likely to be recalled were the first (primacy effect, due to rehearsal) and the last (recency effect) items on the list.

There are also different theories about why we forget things that were stored in our long-term memory. In some cases, especially when two individual memories are quite similar to each other, interference can cause us to either forget an old memory (retroactive interference) or prohibit us from learning something new (proactive interference). Interference gives no information about the cognitive process that takes place and as tests have only been conducted in lab environments so far, it is unclear how much forgetting can actually be attributed to it.

A biological explanation for forgetting can be a lack of consolidation in our brain. When a permanent memory is formed, the neurons in our nervous system have to modify, a process which takes time. Factors like old age or damage to an area of our brain called hipocampus can impair consolidation, therefore memories cannot be formed or are forgotten more quickly.

The final theory offers an explanation for the most common act of forgetting from LTM: retrieval failure. As happened to Rick Perry, the fact or word we are trying to access is still stored in our brain and therefore should be available, but it seems to be just barely out of reach. A failure to access a memory can be linked to the existence of retrieval cues. These cues can be external and internal and describe either the events surrounding the forming of a memory or our internal state in that moment. What it comes down to is this: If you receive good news while a certain song is playing, you will likely always have fond memories when you hear it again. If you misplace your key when you’re drunk, you have better chances at finding it again when you’re intoxicated once more because your internal state mirrors the one you were in when it got lost. Therefore in moments of great stress or concentration, forgetting something you know is a result of our tumultous internal state or changed surroundings that differ so greatly from that memory’s moment of creation. If it is possible, try to relax and not think about what you’re missing too much. The more you dig, the deeper the hole you’re in.

References:

Achenbach, Joel (2011). Perry’s ‘brain freeze’, by another name, is common ‘retrieval failure’. Retrieved 16 November 2011, URL: http://www.washingtonpost.com/national/health-science/perrys-brain-freeze-by-another-name-is-common-retrieval-failure/2011/11/10/gIQAkIoq9M_story.html

Mcleod, S. A. (2008). Simply Psychology; Forgetting Theories in Psychology. Retrieved 18 November 2011, URL: http://www.simplypsychology.org/forgetting.html