Cognitive processes Flashcards
information processing, Crick & Mitchison reorganisational theory, Czeisler et al's study into shift work
Information processing
- may enhance insight
- brain imaging shows that the area associated with recent neural learning remains active while we sleep
Information processing
Sleep deprivation
Sleep deprivation has been shown to lead to reduced attention and short-term memory, which then influences what gets saved as long-term memories. It also impacts the performance of higher-level cognitive functions such as decision-making and reasoning.
Information processing
It was suggested that the different stages of sleep benefit different types of learning and memory
REM sleep - procedural memory
Stage 2 - memory of facts and events
Early non-REM - motor memory
REM sleep - emotional memory, creativity and insight
Information processing
Evidence - Mendrick et al (2003)
Mendrick et al (2003) found that participants’ performance in perception tasks were improved after sleeping
Information processing
Evidence - Seehagen (2015)
Seehagen (2015) found that when babies learn a new action, those who take a nap right after show better recall than those who don’t
Information processing
Information consolidation theory
- based on cognitive research and suggests that people sleep in order to process information that has been acquired during the day
- argues that sleep allows the brain to prepare for the day to come
Information processing
Cognitive process
- sleep is about increasing your consolidation of memory, processing new information and remaining alert enough to learn efficiently
- quantity and quality of sleep have a profound impact on learning and memory
research suggest that sleep helps in two distinct ways
- a sleep-deprived person cannot focus attention optimally and therefore cannot learn efficiently
- sleep itself has a role in the consolidaton of memory, which is essential for processing new information
Information processing
Acquisition
Consolidation
Recall
acquisition - the introduction of new information into the brain
consolidation - the processes by which a memory becomes stable and permanent
recall - the ability to access the information, whether consciously or unconsciously after it has been stored
acquisition and recall occur only when we are awake, but research suggests that memory consolidation takes place during sleep through the strengthening of the neural connections that form our memories
Information processing
Benefits
Wagner et al (2004) - challenging maths problems are easier understood after sleeping
Gais et al (2006) - retention of new foreign words is better after sleeping
Information processing
Karni et al (1994)
method - trained participants on a perceptual speed task
results
- response times did not improve with practise
- after a nights sleep, they performed the task faster
Information processing
Schemas
allows us to organise, store and retrieve information efficiently within our minds
However, information that does not fit with our own schema is often forgotten or distorted until it fits
Information processing
Smith (1999)
method
- trained in two drawing tasks
- one simple and one more complex
- half of the participants were denied SWS and the other half REM sleep, the night following the training
results
- SWS deprivation only affected the simple task
- REM deprivation only affected the complex task
Information processing
Concept of schemas
useful when explaining the cognitive processes taking place during sleep.
During memory consolidation, similar memories seem to reactivate in a pattern, suggesting they are linked in the brain
Crick & Mitchison’s (1986) reorganisational theory (dreams)
Reverse learning
the theory is based on the idea of reverse learning which means that memories can be unravelled and destroyed during REM sleep.
During the day, the cortex becomes overloaded with information. During REM sleep, unwanted memories are deleted in order to improve organisation and make safe
Reorganisation theory of dreams
Adaptive and parastic memory
adaptive - useful to retain, such as a new skill or relevant information
parastic - useless memories that waste resources
REM sleep prevents parastic memories from forming or destroying those which have already formed. During REM, the brain’s major connections to the ‘outside world’ are switched off. The brain stem (medulla) then sends random but poweful stimuli to the cortex, which gradually weaken neural connections in the brain.
Parastic memories
Crick & Mitichison suggest that as these parastic memories are being unravelled, a random selection of thoughts and memories form themselves into a dream.
Crick & Mitichison’s Reorganisational theory
Supporting evidence - dolphins and spiny anteaters
both of these mammals have an abnormally large cortex, presumably because they cannot ‘unlearn’ through REM and must store everything they have ever seen and heard
Reorganisational theory
Evaluation
Most mental illnesses could be defined in terms of ‘faulty learning’.
- might paranoid schizophrenia be the result of hallucinatory/bizarre thought connections
- might obsessive disorders be a result of obsessive thoughts persisting in the mind
- could depression result from the brain becoming ‘jammed up’ with negative or disorded memories
Reorganisational theory
Strengths
- gives a good explanation for why we sometimes can’t remember our dreams
- gives a clear theory about why REM sleep might be important
- proposed that a reverse learning mechanism in REM sleep removes certain undesirable models of interaction in neural networks within the cerebral cortex
Reorganisational theory
Weaknesses
- based largely on computer models rather than human participants and lacks research support, therefore lacks validity
- there is more evidence to support REM sleep strengthening memories than weakening the memory for anything
- does not explain why most of our dreams make sense and follow a narrative as it doesn’t fit well with the idea that random memories are being activated and destroyed
- how does the brain decide which memories to keep and which to unlearn?
Czeisler et al’s (1990) study into shift work
Aim
to show the link between dark/light cycles and circadian rhythms.
aimed to show that properly timed exposure to bright light can re-set the pacemaker by up-to 12 hours in 2-3 days
Czeisler et al’s (1990) study into shift work
Method - during the 1st week
For the first week of each participant’s 2 week study period, baseline temperature, physical activity and heart rate were obtained and then the participant completed a week of night shift work. The men lived at home during the study and reported to the laboratory at night.
Czeisler et al’s (1990) study into shift work
Method - Dor 4 nights …
For 4 nights, the men in the experimental group (Group 1) were exposed to bright lights from 00.15am - 07.45am. Whereas those in the control group (Group 2) experienced light which was normal room light. All participants completed cognitve tasks each hour in which they had to correctly add up as many pairs of 2 digit numbers as possible in 4 minutes.
Czeisler et al’s (1990) study into shift work
Method - during the night …
Those in the experimental group (Group 1) were instructed to remain in the dark in their bedrooms from 09.00am to 17.00pm each day. Those in the control group (Group 2) were told not to remain in the dark at any specific time. Most closed their existing curtains while they slept at a time of their own choosing. The circadian rhythms were monitored and the lowest body temperature time was noted. Blood samples were taken to measure blood plasma cortisol concentrations. The volume of urine was measured at 3 hour intervals.
Czeisler et al’s (1990) tudy into shift work
Results - temperature
Temperature had been on average lowest at 04:59am in the baseline week. In the experiemental group (Group 1) their lowest body temperature was occuring 9.6 hours after the baseline of the previous week.
Czeislar et al’s (1990) study into shift work
Results - circadian rhythms
There was a failure of the control group (Group 2) to change their circadian rhythm to suit night work. The men in the experimental group (Group 1) exposed to bright light and darkness from 09.00am - 17.00pm changed their circadian rhtyhm for all measures.
Czeislar et al’s (1990) study into shift work
Conclusion
Cziesler et al concluded that ‘maladaption of the human circadian rhythm to shift work can easily be treated with scheduled exposure to bright light during the night’.
Czeislar et al’s (1990) study into shift work
Strengths
- good control of conditions in a lab experiment when most prior research has been a field experiment
- multiple physiological and behavioural assessments were used to provide robust findings that were in agreement
- the time difference between the mean low point of body temperature in the control group versus the experimental group was statisfically significant and unlikely to have occurred by chance
Czeislar et al’s (1990) study into shift work
Weaknesses
- the study used a very small sample that contained only men so it was difficult to generalise to the whole working population
- lacks ecological validity as it is taking people out of their normal environment
Czeislar et al’s (1990) study into shift work
Applications
- possible implications for industrial productivity and safety of people on night shift
- highlighted possible health consequences of sleep deprivation and disruption of the circadian rhythm such as cardiovascular, digestive or sleep disorders
- caused many companies to brightly light their workplaces at all times to ensure shift work is not harmful.