IB Psychology HL

Rogers and Kesner (2003) Aim: To investigate the role of acetylcholine on memory encoding and memory retrieval. Method: It was a laboratory experiment using rats. Rats were trained to learn a simple maze, but before the memories could be learned well-enough to be transferred from short-term memory to long-term memory, the rats were divided into groups and injected with drugs: Group 1 was injected with scopolamine, which is known to block the reception of acetylcholine by the post-synaptic neurons. This means that acetylcholine, a neurotransmitter expected to help form memories, cannot travel from one neuron to another. This was the no acetylcholine condition. Group 2 was injected with physostigmine, a drug that blocks cholinesterase, which is what cleans up the acetylcholine from receptor proteins on the post-synaptic neurons, returning the neurons to their resting potential, where no nerve impulse is being sent. Therefore the acetylcholine continued to act. This was the h...

Bouchard et al. (1990) Aim:  To investigate the relative influence of environment and genetic factors on human characteristics and behaviours, including intelligence. Method: A cross-cultural correlational study of more than 100 pairs of reared-apart twins and siblings whose data was compared with twins and siblings reared together. The participants comprised identical (monozygotic/MZ) twins and non-identical (dizygotic/DZ) twins, with an average age of 41 years. MZ twins are often used in genetic research because they have identical or almost identical genes. Each participant underwent over 50 hours of psychological testing and interviews. In twin research, the correlation found between each twin and therefore presumable between genetic inheritance and a particular behaviour is called the concordance rate. Results: The concordance rates for IQ were: MZ twins reared together: 86% (0.86) MZ twins reared apart: 76% (0.76) DZ twins reared together: 55% (0.55) Biologi...

2.4 Explain, using examples, the function of two hormones on human behaviour Cortisol and memory Cortisol is a hormone produced by the adrenal cortex in response to stress and to restore homeostasis. Chronic stress may result in prolonged cortisol secretion and this can lead to physiological changes such as damaged immune system and impairment of learning and memory. This is because high amounts of cortisol results in atrophy of the hippocampus (Sapolsky, 1996). Newcomer et al. (1999) Aim: To investigate whether high levels of the stress hormone cortisol interfere with verbal declarative memory. Method: It was a laboratory experiment. A self-selected sample (recruited through advertisement) of 51 normal and healthy people aged  18-30 was used. It was a randomized, controlled, double-blind experiment running for four days. All participants gave informed consent. Participants were split into three groups. Group 1 (high dose cortisol) had tablets containing 160 mg o...

2.3 Explain, using one or more examples, the effects of neurotransmission on human behaviour. When a nerve impulse reaches the end of the neuron, the neuron fires and neurotransmitters are released into the synaptic gap where they travel to the neuron at the other side of the synaptic gap. If the neurotransmitter is not absorbed it can be re-uptaken, diffused out or destroyed. The neurotransmitter then binds to specific receptors at the other side. If a neurotransmitter is blocked or replaced (e.g. because another chemical interferes) then the messages change. This affects the physiological system, cognition, mood, or behaviour. Dopamine Dopamine is a neurotransmitter involved in goal-directed behaviour (motivation) such as pleasure seeking, control of movement, emotional response, and addictive behaviour. Dopamine is released in the brain’s reward system. Dopamine is released in the brain’s reward system and has been associated with pleasure seeking and addictive behaviou...

2.1 Outline principles that define the biological level of analysis and explain how these principles may be demonstrated in research Principle 1 : There are biological correlates of behaviour. This means that there are physiological origins of behaviour such as neurotransmitters, hormones, specialized brain areas, and genes. The biological level of analysis is based on reductionism, which is the attempt to explain complex behaviour in terms of simple causes. Newcomer et al. (1999) Aim: To investigate whether high levels of the stress hormone cortisol interfere with verbal declarative memory. Method: It was a laboratory experiment. Participants were split into three groups. Group 1 (high dose cortisol) had tablets containing 160 mg of cortisol for four days. Group 2 (low dose cortisol) had tablets with 40 mg of cortisol for four days. Group 3 (control) had placebo tablets. Participants listened to a prose paragraph and had to recall it as a test of verbal declar...

exploringmetro.wordpress.com Brefczynski-Lewis et al. (2007) Aim: To investigate the brain regions that are involved in meditation and which brain regions might show the effects of training Procedure: The researchers compared brain activity of highly-experienced Tibetan monks during meditation with the activity of novice meditators. To see the brain activity they used fMRI scans. They also played sounds to test how distractible the participants were during the meditation. Results: They found that meditations activated attention-related brain regions in both expert meditators and novices. Meditators with more practice showed more activity in attention regions, however the ones with the most practice had activity drop after less than half a minute, when their concentration may have settled into a tranquil but alert awareness. The most practised meditators showed the least reaction to the distracting sounds. Conclusion: The results from this study give evidence that conce...

Martinez and Kesner (1991) Aim: To determine the role of the neurotransmitter acetylcholine on memory Procedure: Rats were trained to go through a maze and find the end, where food was located. When the rats learned how to get through the maze, he divided them into three groups. The first group was injected with scopolamine, which blocks the acetylcholine receptor sites. The second group was injected with physostigmine. Physostigmine blocks the production of cholinesterase which does the “clean-up” of acetylcholine from the synapse and returns the neuron to its “resting state”. The third group was not injected because they were the control group. Results: The results showed that the group that had been injected with scopolamine were slower and made more errors than the two other groups. The physostigmine group was faster than both groups and also made less errors when running through the maze. Conclusion: The researchers could from the results conclude that the neurotr...

Aim: To investigate if schema processing influences both encoding and retrieval Procedure: The participants were given one schema at the encoding stage and one schema at the retrieval stage, to see if they were influenced by the last schema when they had to recall the information. The participants heard a story that was based on 72 points. Half of the participants were asked to read the story for the point of view of a house-buyer and the other half from the point of view of a burglar. After a break, half of the participants were given a different schema, so the burglars switched to the buyers and vice versa. The other half were tested on their original schema again. Results: The researchers found that the group of participants in the changed schema group were able to recall 7 percent more points on the second test than on the first one. Recall of points that were directly linked to the new schema increased by 10 per cent, whereas recall of points that were important to the pr...