The Biological Approach Flashcards
Research support for neurotransmitters and behaviour
Rogers and Kesner 2003
Antonova 2011
Neurotransmitters and Behaviour
Describe the structure of the nervous system (2)
•Is a system of neurons
•Neurons consist of body, dendrites and axon
Neurotransmitters and Behaviour
Describe neurotransmitters (3)
•Chemical messengers
•Can be excitatory (increase likelihood of neural firing) or inhibitory (decrease)
•Their action can be affected by agonists or antagonist (either enhance or counteract action of neurotransmitters)
Neurotransmitters and Behaviour
Explain the role of neurotransmitters in neural firing (5)
•Transmission is partly electrical, partly chemical
•Synapse=junction between 2 neurons
•Electrical impulse builds up at synapse and travels across axon
•At end of axon, neurotransmitter released into synaptic gap
•When neurotransmitter binds to post-synaptic neuron’s receptors, it changes it’s electric potential helping to build next impulse.
Rogers and Kesner 2003
What is the role of acetylcholine?
Consolidation of memory in the hippocampus
Rogers and Kesner 2003
Aim
Determine the role of acetylcholine in the formation of spatial memory
Rogers and Kesner 2003
Sample
30 rats
Rogers and Kesner 2003
Method
Lab Experiment, Independent Measures Design
Rogers and Kesner 2003
Procedure (7)
•Rats acclimated to Hebb Williams Maze by placing food in one corner
•When all rats acclimated, experiment began
•Half of sample injected directly into hippocampus with scopolamine (acetylcholine antagonist)
•Other half injected w placebo because injections cause secretion of adrenaline which could become confounding variable
•Rats placed in maze and amount of mistakes made when navigating maze were counted
•Encoding of spatial memory measured by comparing no. of mistakes made in first 5 and last 5 trials of day 1
•Retrieval measured by comparing no of mistakes made in last 5 trials of day 1 and first 5 of day 2
Rogers and Kesner 2003
Results (1)
*Rats injected w/ scopolamine made more mistakes than those injected w placebo and took longer to navigate maze
Rogers and Kesner 2003
Conclusion (1)
Acetylcholine plays significant role in formation of spatial memory
Rogers and Kesner 2003
Strengths (3)
High Control of Variables, i.e use of placebo to prevent confounding variables = high internal validity therefore, strong cause and effect relationship
Reliable as study has been applied to humans and same results achieved
Research is useful as it could one day be used to develop treatments for alzheimers or dementia
Rogers and Kesner 2003
Weaknesses (3)
*Reductionist approach to understanding memory; there are so many different types of memory and memory consolidation is very complex
*No significant results for retrieval of memory
*Ethical concerns for use of animals, (could have used a smaller sample, could have administered acetylcholine through foods w choline instead of injecting)
Antonova et al 2011
What experiment did they replicate on humans?
Rogers and Kesners investigation into the role of acetylcholine on formation aof spatial memory
Antonova et al 2011
Aim
Determine if scopolamine affects hippocampal activity in creation of spatial memory
Antonova et al 2011
Sample
20 healthy males; mean age 28
Antonova et al 2011
Method
Lab Experiment; Double Blind, Repeated Measures
Antonova et al 2011
Procedure (8)
•Ps either injected w scopolamine or placebo 70-90 mins before
•Placed in an fMRI where they would complete a VR arena task
•Ps taken through the controls and how to operate the joystick
•Ps had to get to pole in the middle of an arena
•Once found, screen would go blank for 30 seconds in which ps were to rehearse route to pole
•When arena re-appeared, ps began in new starting position and had to use spatial memory to find pole
•Brain activity measure for 6 trials
•Ps returned 3-4 weeks later to repeat in alternative condition
Antonova et al 2011
Results
Ps injected w scopolamine had significantly lower hippocampal activity than placebo group.
Antonova et al 2011
Conclusion
Acetylcholine plays a key role in the encoding of spatial memories in humans as well as rats
Antonova et al 2011
Strength (3)
*Repeated Measures Design eliminated participant variability
*Counter-balancing used so order effects eliminated
*Double blind procedure so researcher bias eliminated
Antonova et al 2011
Weaknesses (3)
*Ps expressed feeling stress about injection of unknown substance so stress could have been a confounding variable
*Sample small; unrepresentative so less generalizable
*Sample only men; unrepresentative of women so ungeneralizable to women
Pheromones
What are pheromones?
Chemical messengers that communicate info between members of species
Pheromones
Discuss pheromones in humans and animals (2)
In animals: processed in accessory olfactory bulb
In humans: no functional vomeronasal organ or accessory olfactory bulb so no way to detect pheromones
Pheromones
Describe Androstedienone (4)
Putative human pheromone
*Steroid in male sweat and semen that increases sympathetic arousal, influences cortisol levels and promotes good mood in females
*Activates hypothalamus in heterosexual females and homosexual males but no effect on heterosexual males and homosexual females
*Female equivalent = estratetraenol
Pheromones
Evaluation on the theory (4)
Research is inconclusive and existence not scientifically proven
Contradictory findings: Zhou vs Hare
Research mostly conducted for commercial purposes, i.e perfumes, and formula not revealed so can’t be replicated
Methodological limitations, i.e demand characteristics, ecological validity
Research support for Pheromones
Zhou et al 2014
Hare et al 2017
Zhou et al 2014
Aim
Investigate the effect of AND and EST on heterosexual and homosexual males and females
Zhou et al 2014
Sample
24 hetero males
24 hetero females
24 homo males
24 homo females
Zhou et al 2014
Procedure (5)
*Ps given point light walker task (set of dots moving to represent human motion)
*Ps asked to observe moving stick figure and identify it’s gender
*Same time of day for 3 consecutive days while exposed to AND, EST and *Control mixed w cloves
*One solution a day + counterbalanced to eliminate order effects
Zhou et al 2014
Results (4)
Hetero females and homo males exposed to AND had higher rate of identifying figure as masculine
AND had no significant effect on hetero men and homo women
EST caused hetero males to identify figure as female
EST had no significant effect on homo/bi women
Zhou et al 2014
Conclusion (1)
AND and EST have some effect on human behaviour
Zhou et al 2014
Strength (1)
Study was counter-balanced preventing order effects
Zhou et al 2014
Weaknesses (2)
Hare et al (2017) failed to replicate the study so results are unreliable (researchers found that exposure to the pheromones had no significant effect on gender perception or attractiveness)
The dose of AND and EST used in this study was significantly higher than humans naturally secrete; low ecological validity as although Zhou’s study determined a significant effect, it is unlikely that this represents actual human behaviour.
Hare et al 2017
Aim
Investigate effect of AND and EST on mate perception and gender signalling
Hare et al 2017
Sample
140 heterosexual adults
Hare et al 2017
Procedure (5)
46 participants 24M 22F
Two computer tasks twice on consecutive days
Exposed to a control scent and putative hormone
Had to indicate the gender of 5 gender neutral face morphs while the proporti
Ps given computer task
Task 1: 46 Ps shown 5 gender neutral facial morphs and asked to indicate gender
Task 2: 94 Ps shown photos of opposite sex and asked to rate attractiveness (1-10) and probable sexual unfaithfulness
Done on 2 days; on day 1 ps exposed to either AND or EST masked w clove scent, on day 2 exposed to control scent - clove oil
Counterbalancing used to prevent order effects
Hare et al 2017
Results
No differences in gender assigned in pheromone vs. control conditions
No differences in attractiveness
Hare et al 2017
Conclusion
AND and EST don’t qualify as human pheromones
Hare et al 2017
Strength
Blind data recording eliminated unconscious bias
