Memory is our ability to encode, store, retain and subsequently recall information and past experiences in the human brain. It can be thought of in general terms as the use of past experience to affect or influence current behaviour.
|Did You Know?|
|For a time during the 1960s, it was hypothesized that all the cells of the human body were capable of storing memories, not only those in the brain, an idea known as cell memory or cellular memory.|
This was based on memory transfer research using cannibal flatworms, and on anecdotal evidence of organ transplants where the recipient was reported to have developed new habits or memories, but such theories are now considered pseudoscientific and have not made it into peer-reviewed science journals.
Memory is the sum total of what we remember and gives us the capability to learn and adapt from previous experiences as well as to build relationships. It is the ability to remember past experiences, and the power or process of recalling to mind previously learned facts, experiences, impressions, skills and habits. It is the store of things learned and retained from our activity or experience, as evidenced by modification of structure or behaviour, or by recall and recognition.
Etymologically, the modern English word “memory” comes to us from the Middle English memorie, which in turn comes from the Anglo-French memoire or memorie, and ultimately from the Latin memoria and memor, meaning “mindful” or “remembering”.
In more physiological or neurological terms, memory is, at its simplest, a set of encoded neural connections in the brain. It is the re-creation or reconstruction of past experiences by the synchronous firing of neurons that were involved in the original experience. As we will see, though, because of the way in which memory is encoded, it is perhaps better thought of as a kind of collage or jigsaw puzzle, rather than in the traditional manner as a collection of recordings or pictures or video clips, stored as discrete wholes. Our memories are not stored in our brains like books on library shelves but are actually on-the-fly reconstructions from elements scattered throughout various areas of our brains.
|Did You Know?|
|Recent studies suggest that repeated bouts of jet lag may cause harm to the temporal lobe, an area of the brain important to memory, causing it to shrink in size, and compromising performance on spatial memory tests.|
It is thought that stress hormones, such as cortisol, released by the body during times of stress (such as the sleep disturbance, general stress and fatigue caused by long flights) are responsible for this impairment of memory and other mental skills.
Memory is related to but distinct from learning, which is the process by which we acquire knowledge of the world and modify our subsequent behaviour. During learning, neurons that fire together to produce a particular experience are altered so that they have a tendency to fire together again. For example, we learn a new language by studying it, but we then speak it by using our memory to retrieve the words that we have learned. Thus, memory depends on learning because it lets us store and retrieve learned information. But learning also depends to some extent on memory, in that the knowledge stored in our memory provides the framework to which new knowledge is linked by association and inference. This ability of humans to call on past memories in order to imagine the future and to plan future courses of action is a hugely advantageous attribute in our survival and development as a species.
Since the development of the computer in the 1940s, memory is also used to describe the capacity of a computer to store information subject to recall, as well as the physical components of the computer in which such information is stored. Although there are indeed some parallels between the memory of a computer and the memory of a human being, there are also some fundamental and crucial differences, principally that the human brain is organized as a distributed network in which each brain cell makes thousands of connections, rather than as an addressable collection of discrete files.
The sociological concept of collective memory plays an essential role in the establishment of human societies. Every social group perpetuates itself through the knowledge that it transmits down the generations, either through oral tradition or through writing. The invention of writing made it possible for the first time for human beings to preserve precise records of their knowledge outside of their brains. Writing, audiovisual media and computer records can be considered a kind of external memory for humans.