In a model on how the memory works there are three types of memory stores:

1. Sensory memory
   There is some information stored here for a couple of seconds even when you are not paying attention to it (e.g: you can remember things you hear for approximately 4 seconds after you heard it, even if you are not paying attention to it). There is a separate sensory-memory store for each memory system.
2. Short-term (working) memory
   Information in the working memory is lost within seconds when it is no longer actively attended to. Information can enter the working memory from long-term memory and sensory memory.
3. Long-term memory
   We are not conscious of information in the long-term memory unless the information has been activated and moved into short-term memory. The long-term memory is passive.

The model specifies a set of control processes, which govern the processing of information within stores and the movement of information from one store to another. The control processes are:

1. Attention
   This is the process that controls the flow of information from the sensory memory into the working memory. Attention restricts the flow of information because the capacity of the short-term memory is small.
2. Encoding
   This is the process that controls movement from the working memory to long-term memory.
3. Retrieval
   This is the process that controls the flow of information from the long-term memory to short-term memory.

Individual mental operations can be placed on a continuum with respect to how much of one’s limited capacity each requires for its execution.

1. Effortful processes (conscious)
   These processes are available to the consciousness, interfere with the execution of other effortful processes, improve with practice and are influenced by individual differences in intelligence, motivation and education.
2. Automatic processes (unconscious)
   These processes occur without intention, are not available to the consciousness, don’t interfere with other processes, don’t improve with practice and are not influenced by individual differences in intelligence, motivation and education.

All the sensory information is briefly analysed at an unconscious level and this is called preattentive processing. The preattentive processing helps determine whether something is significant and should be paid attention to. People are able to select what they pay attention to. This is shown in a couple of ways:

• Selective listening
  This includes the cocktail party phenomenon. We only hear the conversation we want to hear and are not disturbed by other conversations. We cannot fully select what we want to hear though, as we do hear our name the moment someone says it. In the preattentive processing part, this is determined as significant.
• Selective viewing
  When we look at something we tend to ignore other visuals than the thing we are paying attention to. It is possible to miss a significant event or change because we are paying attention to something else. This is called inattentional blindness.

Auditory sensory memory is called echoic memory and visual sensory memory is called iconic memory. Sensory input can alter behaviour and conscious thought, without itself becoming conscious. This is called priming. Priming is the activation, by sensory input, of information that is already stored in the long-term memory. It is sometimes impossible to not process a stimuli (e.g: it is sometimes not possible to not read a word).

There are three general conclusions that can be drawn from brain studies concerning preattentive processing and attention:

1. Stimuli that are not attended to nevertheless activate sensory and perceptual areas of the brain
2. Attention magnifies the activity that task-relevant stimuli produce in sensory and perceptual areas of the brain, and it diminishes the activity that task-irrelevant stimuli produce.
3. Neural mechanisms in anterior (forward) portions of the cortex are responsible for control of attention.

There are people with spatial neglect, meaning that they are unable to process information in the visual field opposite to the brain hemisphere in which they have a lesion.

The working memory consists of three separate, but interacting components:

1. Phonological loop
   This is responsible for holding verbal information
2. Visuospatial sketchpad
   This is responsible for holding visual and spatial information
3. Central executive
   This is responsible for coordinating the mind’s activities and for bringing new information into working memory from the sensory and long-term stores.

The number of pronounceable items that a person can keep in mind and report back accurately after a brief delay is called the short-term memory span or the phonological loop of working memory. The phonological loop is the part of working memory that holds on to verbal information by subvocally repeating it.  The memory of the working memory is generally two items shorter than the phonological loop.

The working memory is part of executive functions, relatively basic and general-purpose information-processing mechanisms that, together, are important in planning and regulating behaviour and performing complex cognitive tasks. The executive functions consist of three related components:

1. Working memory
   Updating, monitoring and rapidly adding/deleting the contents of the working memory.
2. Switching
   Shifting flexibly between different tasks or mindsets.
3. Inhibition
   Preventing a cognitive or behavioural response or keeping unwanted information out of mind.

There are four general conclusions about executive functions:

1. Executive functions show both unity and diversity
   The executive functions are separate functions but correlate strongly with each other.
2. There is a substantial genetic component to executive functions
   The heritability of executive functions is quite high.
3. Executive functions are related to and predictive of important clinical and societal outcomes
   People who perform better on tasks of executive functions have fewer behavioural problems.
4. There is substantial developmental stability of executive-function abilities
   Although the functions improve, children who perform well on tasks with executive functions tend to perform well on these tasks as adults.

Memory refers to all the information in a person´s mind and to the mind´s capacity to store and retrieve that information. There are two types of memory:

1. Explicit memory
   This is the memory that can be brought into a person’s consciousness. It is also called declarative memory. This is memory we are aware of.
2. Implicit memory
   This refers to memory that we are not aware of. Implicit memories are much more closely tied to the context of the specific stimuli, tasks or problems to which they pertain.

There are two types of explicit memory:

1. Episodic memory
   This is memory from one’s own past experiences. Episodic memories have a personal quality.
2. Semantic memory
   This is general knowledge. There is no personal quality attached to these memories. These memories are more stable and less often forgotten.

The spreading activation model of explicit memory shows that words that are related to words seen earlier are thought of more often than words that are not related (e.g: after hearing the colour red and then asked for a flower they say rose more often than when they are not presented with the colour red first).

There are two types of implicit memory:

1. Classical conditioning effects
   These are memories that lead people to unconsciously react to certain conditioned stimuli.
2. Procedural memory
   These include motor skills, habit and unconsciously learned rules (e.g: riding a bicycle).

Any loss of long-term memory, usually resulting from some sort of physical disruption, is called amnesia. The inability to create new memories is called temporal-lobe amnesia, which is strongly correlated with damage to the hippocampus. With temporal-lobe amnesia, skill learning is not affected. People can recall nothing or barely anything from their infant years and this is called infantile amnesia.

There are two types of rehearsal:

1. Maintenance rehearsal
   This is the process by which a person holds information in working memory for a period of time
2. Encoding rehearsal
   This is the process by which a person encodes information into the long-term memory

There are several ways in which encoding is promoted:

1. Elaboration
   This is also called elaborative rehearsal and promotes encoding.
2. Organization
   This can be done through the procedure known as chunking, grouping several single items together to make them a single item. (e.g: remembering the letters b b c u v a n b c is more difficult if trying to remember it letter by letter, but easier if trying to remember it as bbc, uva and nbc).

Anterograde amnesia is the loss of capacity to form long term memories of events occurring after the injury. Retrograde amnesia Is loss of memories of events that occurred before the injury. Long-term memories are encoded in the brain in two forms: a labile, easily disrupted form and a stable, not easily disrupted form. Consolidation occurs the labile memory form is converted into the stable form. 

Sleep is important for the consolidation of memories, especially the slow-wave in the deep sleep stage.

Memories are linked to each other through associations. A stimulus or thought that becomes a particular memory is a retrieval cue for that memory. There are two principles of association:

1. Association by contiguity
   Some concepts are associated because they have occurred contiguously (e.g: plate is associated to napkin because they occur contiguously).
2. Association by similarity
   Some concepts are associated because they are similar to each other (e.g: apple is associated with pear because they are similar. They are both fruits).

Schema refers to one’s generalized mental representation, or concept, of any given class of objects, scenes or events (e.g: western people might share a schema for a living room). Schemas that involve the organization of events in time, rather than objects in space, are called scripts (e.g: a typical night out).

Leading questions can cause false memories to be created. Memories are often adapted to the schemas and scripts in the mind of a person. The word choice is also important in memories and the word choice can determine memories.

There are two possible causes of false memory construction:

1. Source confusion
   We hear many different stories of an event and may be confused about the hierarchy of the sources over time. This causes us to believe that a story about an event is closer to the truth than the first-hand experience you have yourself. Leading questions and implied meanings are important here (e.g: the roadworker said ‘crash’, so the speed must’ve been great, although you saw the cars just bump each other).
2. Social pressure
   This can lead to the construction of false memories as well.

Prospective memory is memory about things we still have to do in the future. There are two types of prospective memory:

1. Time-based prospective memory
   This involves remembering to perform a particular action when cued by a target time (e.g: answering e-mails in the evening).
2. Event-based prospective memory
   This involves remembering to perform a particular action when cued by a target event (e.g: sending someone a text message next time you see them).

There are three phases in prospective memory: an intention, the intention must be maintained and there must be a switch from the ongoing task to execute the intention.