Psychology Blog

As a rule, we will often not like foods if they are unfamiliar or look very dissimular to anything we would have eaten before. This is due to an evolutionary response to new foods called neophobia; the fear of new foods due to potentially being poisonous (as it was used millions of years ago.) 

Birch and Marlin found that an exposure to a new food over a six week period will increase that person’s preference for that food. A minimum of 8-10 exposures is needed for the person to become fond of the food. They have by this time learnt that the food is safe.

Parents often find this with childeren, but of course it won’t work with everything, so they also use operant conditioning to encourage the child to eat a certain type of food.
Operant conditioning is a certain type of learning method, in which certain behaviour is rewarded or punished, dependant on whether you want the child to repeat that action.
Lepper et al completed a study in which children were told about two imaginary foods hupe and huel. Within one group, Lepper said to them ‘If you eat your hupe, you can have your hule,’ and in the other group Lepper told them ‘If you eat your hule, you can have your hupe.’ The children were then asked which food they believed would taste better, and, confirming the hypothesis, the children had a preference for the food that was served as a reward.

As well as conditioning, a child is more likely to eat the new and unfamiliar food if someone they share a close personal bond with or someone they trust eats it.
Ogden found that there was a positive correlation between mother’s and children’s diets. 

Children are also exposed to peer’s eating habit’s and widespread advertising.
Duncker completed a study observing what kind of role model would change a child’s eating behaviour.
The findings were that a child is more likely to make a food preference if eaten by an older child, their mother, a friend and a fictional hero. But only their mother eating an unfamiliar food would make them eat it, confirming Ogden’s findings.

The restoration theory of sleep was brought about by Oswald in the 1970’s. It states that we need sleep in oder to be able to function properly, that sleep is a time for rest and recovery. This theory suggests that we need sleep in order for our body and mind to restore itself; hence the name.

He came about this theory after he noticed that drug recoveres spent more time in REM, and that new skin cells in adults grew more quickly during sleep. It was this that allowed him to make the conclusion that REM is for restoration of the brain, whilst NREM is for restoration of the body.
Supporting this, babies spend 50% of their first couple of years’ sleep time in REM. This is most likely due to the fact they need extra brain development within the critical period for creating new synapses and neurotransmitters, and the fact that this brain activity is almost as active as a waking state, would explain the work the brain is completing in order to recover.
In addition to this, we know that growth hormone is released in NREM, hence why this must be resoration within the body.

Shapiro studied ‘ultra marathon’ runners and found that their sleep time increased by 1.5 hours for 2 nights after the race, a greater proportion of their sleep being in stage 4 NREM. This shows physical excercise effects the amount of sleep and the amount of NREM had, positively correlating the both, and confirming restoration theory [of the body.]
In contrast to this, Ryback and Lewis conducted a study in which they made participants remian on bed rest for 6 weeks, and found absolutely no change to their sleep patterns. 

In relation to sleep deprivation, a factor the evolutionary theory could not explain, we have surporting evidence to the restoration theory in terms of Peter Tripp, a radio DJ who volunteered to go 8 days without sleep for charity. As a result, he began having hallucinations, became psychotic and could not complete mentally simple challenges. This proves how we need sleep to function because without it he ended up a permanently changed man. He was more irratible, he lost his wife and his job, although he could sleep fine from then on, he was a very changed man.
Although he volunteered, and ethics of this study were satisfactory, he did use a drug to keep him awake for the majority of the time, so we are unsure as to whether they had a baring on his mental state as apposed to the lack of sleep.

Randy Gardner was a 17 year old who also tried going without sleep for a cause - a science project. Like Tripp, he was perfectly happy and healthy, however after 10 days, he was much more alert than Tripp ever was. Even on the 11th day, he saw some hallucinations, but was able to give a word perfect conference to people. But aside from slight brain lapses, researches said Randy had no psychiatric issues, and slept for fourteen hours after, mostly in NREM stage 4 and REM.
These two studies will contrast due to arguable individual differences such as age or drug use. Although both were mildly ethical, it was odd how one came out worse than the other.

Horne added onto Oswald’s theory stating that sleep deprivation affects cognitive processing.

Jouvet confirmed this by conducting an experiment using cats, he placed a cat onto of a pot, which was surrounded by water. When the cats went into REM, their muscles relaxed, they fell off the pot into the water and woke up. After several times of this, they had become conditioned not to fall into REM. As a result, they died 35 days after the experiement, with erratic behaviour leading up to thier death.

On average, people will have spent around a third of their life asleep. All living creatures sleep, therefore we come to the conclusion that sleep must be a necessary function, but after 50 years of research, we still cannot explain a few factors regarding sleep, such as variations is sleep/wake cycles between different species, and whether sleep serves the same purpose for every creature.

There are two main explanations towards the evolutionary theory of sleep:

• Meddis’ Predator / Prey Status
• Webb’s Hibernation Theory

Essentially, these are very simular explanations, as they both describe sleep as more of a survival precaution, rather than a nessecity to live and function properly.
Meddis’ theory explains how sleep has evolved as a way of keeping vunerable and dirunal animals safe, because it would be impossible to safely complete normal tasks such as collecting food in the night and safely. Animals who were more at risk of becoming prey would have evolved to sleep less and would need a reliable, safe sleep site to keep them out of harm’s way.
Webb’s theory explains the importance of energy conservation. It states that animals will sleep and hibernate during inactive periods such as in the night or in winter to conserve their energy. This is moreso for smaller animals which have higher metabolic rates, who will therefore burn energy quicker.

Alison and Cicchetti opposed the theory of Meddis by finding that over 39 species of animals, prey slept for alot less than predators did.
Lesku on the other hand, found how the safety of the sleep site was postively correlated with the amount of REM, which could support Meddis’ theory of saftey. He also found that brain mass was postively correclated with time spent in REM as did trophic position.

In taking these conclusions, it explains why animals sleep for the amount of time they do, for example, taking from Lesku’s study, the prey are usually herbivore’s, causing them not to use as much energy, confirming Webb’s theory, but it does not explain why sleep hasn’t been selected out for humans, and why we feel so tired when sleep is depreived if we don’t need it.

Pilleri completed a study on Indus dolphins which swum along the Indus river in Pakistan. They had evolved blindness as good eyesight was not needed in a poor visibilty river due to debris. Due to the constant danger of debris being erdicated by their excellent sonar sensors, sleep has not dissapeared; they sleep for 4-60 second bursts for up to 7 hours each day.

As a newborn, a person is in REM for 50% of their sleep cycle, with premature babies as high as 80%. From age 5, our time in REM reduces to 25%, because our brain has less need for development.

As a young toddler (up to 2 years) they will achieve the full amount of sleep needed per day via naps in addition to their large proportion of night time sleep. However, as we age, we tend to nap less on a regular basis and sleep longer through the night. As we age even more into senior years, this almost reverses and night sleep becomes fragmented and shorter, hence why older people nap more during the day, which in turn doesn’t help to sustain a full night’s sleep in the evening. It turns into a vicious cycle.

Ohayon et al produced a review in 2004 of 65 people’s sleep cycles. The study showed that at age 5 you will spend on average 100 minutes more sleeping per night than at age 70. At aged 70 you will only spend a small percentage more in stages one and two than as a five year old, and 5 years old’s will spend a larger percentage in the deeper stages of NREM and REM.

This can prove alzhimers’ in older people and why babies sleep so much in the early stages of their life.

Sleep is measured by an EEG, which detects electrical impluses in the brain in Hrtz and also measures the amplitude (size of the wave or impulse.)
The sleep-wake cycle is an example of a carcadian rhythm, but the sleep cycle itself is an ultradian rhythm.
There are 5 sleep stages;

• Stages 1, 2, 3 & 4 (NREM)
• REM (Rapid eye movement)

There are usually 5 sleep cycles (each being around 90mins) within a night.
Stage 1 is the only stage which isn’t revisited throughout the sleep. Characterised by theta waves and hypnogogic hallucinations occur (involuntary twitches, feeling as though ‘falling.’)
Stage 2, the brain is still highly responsive. EEG readings indicate that during stage 2 the brain can still pick up external stimuli and process the information, such as someone calling your name. This is known as a K-complex and the readings on the EEG are known as ‘sleep spindles.’  
Stage 3 has less sleep spindles and are dominated by delta waves. Delta waves are larger and slower than theta waves.
Stage 4 is the deepest form of NREM sleep. The delta waes are even larger and slower. Other physiological changes occur in this stage, such as heart rate and body temperature dropping to thier lowest, and growth hormones are secreted. This is the stage in which sleepwalking occurs.

REM sleep is characterised by beta waves which also occur during a relaxed wake state, and the high levels of brain activity is linked to dreaming. A state of paralysis is definate, which is beneficial for the sleeper to prevent them from acting our their dreams.

Dement confirmed the sleep cycle. (In stages:) 1,2,3,4,3,2,rem,2,3,2,rem,2,rem,2,awake.

Sleep experiments measured in a laboratory has revolutionised research on sleep, but it could produce demand charateristics and somewhat lacks external validity due to the wires glued to the p’s head. However in spite of this they control many variables which could affect the outcome, despite individual differences.

‘A cyclical variation in physiological / psychological functioning.’

These rhythms are controlled by what are called endogenous pacemakers (EP’s) and exogenous zietgebers (EZ’s).

EP’s are internal rhythms or more commonly known as a ‘body clock.’
EZ’s are external clues within our environment to help sync our bodies with the rest of the world.

These control 3 different types of biological rhythm (or 3 different time scales):

• Carcadian (24hr rhythms)
• Infradian (More than a day)
• Ultradian (Less than a day)

Carcadian studies:
Silver Removed the superchiasmatic nucleas (SCN) of some hamsters, which resulted in their EP’s becoming out of sync with the rest of the world, despite the EZ’s, so they did not know what time of day it was, when to eat, when to sleep, ecetera.  
Siffre locked himself in a cave in texas for several months, taking important readings of his body, but shutting himself off from any EZ’s. By doing this, he found that the body prefers a 25 hour day.

Infradian studies:
Pengelly & Asmundson blinded a small handful of squirells, in order for them not to witness any EZ’s indicating their hibernation period. As predicted, they did not know when to hibernate due to the inability to see when the nights were getting darker.
Russell et al attempted to sync women’s menstrual cycles by making them lick the sweaty armpit of their flatmate. (Yes, you did read that right.) Strangely enough, it worked, but the main relevance of this study is proving that a menstrual cycle is an infradian rhythm.

The most obvious form of ultradian rhythm being sleep. Disrupting sleep can be bad for biological rhythms, as it disrupts psychological function and cognitive processes. These can be everyday disruptions such as jet lag and shift work.

Shift work late at night proves to provide increased risk to the average worker because it impairs mental functioning as it is more than likely the worker will be tired.
(This is due to the EZ of low light levels; also, when it is dark, melatonin is released, making us feel more lathargic with slow physical and psychological reactions, hence why we want to sleep. This is detected by light entering the eyes, then the SCN controls the pineal gland which is responsible for the release of melatonin.)
Czeisler’s study attempted to fix this frequent occurance of late shift accidents by introducing phase delay between shifts, and the Kentucky police department introduced permanent shifts so the officers could adjust permanently to the time they needed to be awake. Some companies also have introduced planned napping to try and combat this.

Jet lag is also a major disruption to biological rhythms as although it does not always mean a lack of sleep, the outside world is changing, so your body has been forced out of sync with it and needs to ‘catch up’ or ‘re-sync.’
East to west travel will provide a longer day, so it will be easier for our bodies to catch up as it already prefers a longer day, However east to west travel will provide a shorter day and henceforth jet lag.
Shwartz studied baseball teams who frequently travelled, and found this theory of jet lag imapiring us confirmed by the study. He found that east to west travellers played better than west to east, because players were subjected to jet lag.
The way for reducing jet lag has been suggested by adjusting to the local EZ’s. For example, if it is breakfast time locally, eat breakfast.

There are two different types of insomnia:

• Primary
• & Secondary

Both obviously result in the inability to get a decent night’s sleep, it’s the other factor which creates this result that is different.
Primary insomnia has no noticeable cause for the lack of sleep; no other conditions nor any obvious current life experiences such as stress or medication to suggest there is a cause for the insomnia had.
Secondary insomnia as you will probably guess is the opposite. There is an explanation for the lack of sleep. Be it obvious or not, there will be an alternate reason which is affecting sleep pattern in such a dramatic mannor. The main culprit is usually an additional condition, prior to the insomnia or perhaps some form of reaction or side-effect to some other substance, be it food, drugs or otherwise.

There is no form of cure for primary insomnia doctors can suggest apart from routine ‘drink more water, get more physical excercise…’ ecetera. Whereas secondary can begin to work on a cure because they will know what the problem is.

There are two types of aggression:

• Affective (Emotional harm)
• Instrumental (Means to an end, another intention than to harm)

The definition of aggression is:

The delivery of an aversive stimulus from one person to another, with intent to harm and expectations of causing such harm, when the victim is motivated to escape or avoid the stimuli.

Social learning theory suggests that aggression is learned in two different ways:

• Direct reinforcement
• Indirect reinforcement

Direct = Operant conditioning, association with rewards and punishment.
For example if a child pushes another child and gets something they want out of it, they are likely to repeat said action.
Indirect = Observing and modelling others’ behaviour to our own needs.
A child may observe an older sibling getting their own way by acting in a certain way or doing a certain something. They may attempt to recreate this behaviour in order to get something in which they desire.
The key to indirect reinforcement is the presence of a role model from which the behaviour can be copied or remodelled from.

Bandura suggests that there are 4 steps in the modelling process:

• Attention - Must mentally digest the behaviour, subject is more likely to pay attention if model is simular yet more powerful.
• Retention - Must remember the representation of the aggressor.
• Reproduction - Must be able to reproduce behaviour. More likely to reproduce if subject has low self esteem or is highly dependant on others.
• Motivation - Likelihood of imitation depends on reinforcement. Operant conditioning plays a role.

Bandura also performed a number of laboratory experiments involving children and a bobo doll.
66 nursery children between ages 3-5, were all placed into 3 groups, named conditions 1, 2 and 3.
They watched a video about an adult who responded aggressively towards a bobo doll. Condition 1 video’s conclusion ended with the adult being rewarded for their behaviour, condition 2 ended in the adult being punished and condition 3 had no consequence of their actions.
The results of 1 showed that the children repeated the behaviour when let into a room with a bobo doll, and 2 showed the children behaved least aggressively towards the doll. These are both due to the effects of operant conditioning. The results of condition 3 showed the children also behaving somewhat aggressively towards the doll, this is another aspect of social learning theory. They learn what they see becuase they believe this is how ‘things are meant to be.’ I.e: They believed it was the right thing to beat up the doll simply because an adult was doing it with confidence.

In spite of this, beating the doll up was the only response to the doll they had, so it was more of a demand characteristic to beat the doll up. Consent and long term effects are issues with this study, as well as culture effects and to some extent age bias. However, it would have been tricky to get as true readings by doing it all ‘ethically.’ Bandura used children because they are ‘blank canvases’ as opposed to adults. Another critism is the fact that this agression may not be transferable towards other children, morals and teachings may kick in at that point before they would be a danger.

These factors are ones which are hereditary and inhertited from our biological parents and ancestors via their DNA / genes.

Psychologist Sandberg (1961) found that some men inherit to ‘Y’ chromosomes. So instead of being the standard male ‘XY’ they will be ‘XYY,’ equalling in a total in 47 chromosomes. It was given the name of the 47XYY Karyotype.
Court-Brown studied 314 XYY karyotype males and suggested that they should all be hospitalised because of their extremely aggressive nature on primary findings, however, the media picked up on these basic findings of the condition, and things blew out of proportion; the study was not continued, but the condition was not as serious as Court-Brown initially had believed.
Theilguard (1954) investigated XYY karyotypes and found there was 1 in every 1000 males with the condition. There was one common denominator between the karyotypes: Increased height. She found these karyotypes to give more of an aggressive outlook on life, and interpret images into aggressive pictures on the thematic apperception test. However, this did not prove that they would act out these mental interpretations.

Taking these findings into consideration, they are gender biased and would be hard to ignore all environmental factors in the males’ lives. It is a reductionistic and deterministic approach and relies on simply the ‘nature’ side of the nature vs. nurture debate.

Parts of the brain which are responsible for aggression.

Davidson et al suggested that serationin may serve to inhibit aggression. He found this in violent prisoners who had low levels of seratonin and monkeys who were given pills to lower their seratonin, who consequently became more aggressive.
Linnoila et al also suggested in realtion to this that low seratonin levels would result in ‘impulsive outbursts.’

The amino acid tryptophan is essential in the brain’s manufacture of seratonin, and has successfully been given to young offenders to make them less aggressive.
However, a silver fox study in Russia has found that silver foxes had lower levels of seratonin after they had been tamed as domestic pets.
These contrasting studies show that although there is a link between seratonin and aggression, there is no deterred cause and effect.

In terms of brain structure, animal research suggests that the hypothalamus and the amygdala are the the parts responsible for aggression.
The autopsy of the Charles Witman case study was found to have a tumour pressing against his amygdala. These days, we can have a procedure completed called an amygdalectomy which removes the amygdala and reduces aggression in extreme cases.

Pre-frontal cortex is connected closely to the functioning of the hypothalamus, and damage to it can result in impulsiveness, irritability and even personailty change.
Phineus Gage had an iron bar shot through his pre-frontal cortex and remarkably lived for 17 years longer, but had a massive personality change since the accident.

Charles Witman was a normal man. He had a normal life, and some would say he lead a happy one. Up until the age of around 25, he was fine. Then he gradually become very anxious in his day to day life. He went to visit a therapist, and often outlined very out-of-character scenarios, such as a fantasy killing spree.
The one day, he lost it.
He carried out said desired killing spree, and killed his mother and wife beforehand to ‘spare them the shame.’ He stood on the top of a university tower with a gun of some sorts, killed fifteen and injured thirty. Police had to shoot him down.
He was dead after the incident.
On autopsy, the doctors found a small pressing tumour on his brain, which had been growing. But at the time it was concluded this was ‘not enough’ to send him over the edge; this happened in the 1960’s.
Since then medical research has moved on, and whilst Witman’s body has not been knowingly re-diognosed, It has been found that tumours have been responsible for all types of unsuspected conditions and behaviours.
It has been linked to schitzophrenia, the pressing on certain parts of the brain causing hallucinations, for example.

We may never know what Charles Witman did have wrong with him, or that the tumour was the main cause, but it is certainly very likely. This also raises the nature v nurture debate and the fact that Witman had a relatively normal upbringing, shouldn’t or would have been highly unlikely to be a role in his actions.