Biology Flashcards
Social Intelligence Hypothesis/Social Brain Hypothesis
(Humphrey, 1976)
Evolutionary pressures to adapt to the complexities of social life (i.e., to facilitate co-operation with others), consequentially brought about the development of improved intellect more generally (superior intellectual abilities to that of other species)
(Dunbar, 1992)
Evidence in support of this hypothesis comes from a study that demonstrated that the greater the brain mass of a species, the larger the groups are that that species operates within.
Machiavellian Intelligence Hypothesis
(Whiten, 1988)
Competition was the key pressure driving the evolution of superior intellectual skills, as a greater level of social intelligence would have enabled one to outwit others in the battle to obtain their share of a limited resource pool.
Theory of Mind/Mentalization
(Gallup, 1985)
Sometimes referred to as theory of mind, mentalization is the process through which one infers the goals and beliefs of others; or reflects upon their own beliefs, goals or emotions.
(Gergely et al., 2002)
This capacity is observed in humans as early as infancy. Infants directly imitated an adult with free hands who pushed a button using their forehead, but pushed the button with their hands when an adult with bound arms did the same. This would suggest that the infants understood that the adult’s intent was to push the button and that they likely would have achieved this goal using their hands had they been able. [also observed in chimpanzess - Buttelmann et al., 2007]
Mirror Neuron System
(di Pellegrino et al., 1992)
Incidentally discovered what would later be termed the mirror neuron system in a sample of monkeys (i.e., identified a set of neurons in the rostral part of inferior premotor cortex (area F5) in monkeys that fired both when observing and when executing a series of goal-directed actions). Influential discovery with reference to the neuronal basis of imitative behaviours.
(Gallese et al., 1996)
Later proposed that these neurons may be of relevance to action recognition and social learning through imitation.
(Iacoboni et al., 2005)
Such neurons appear not to discharge when exposed to actions without purpose (i.e. grasping actions without the presence of an object) - hence the mirror neuron system may also be involved in the detection of intent.
One prominent methodological constraint for mirror neuron research in humans is that the invasiveness of the procedures required to carry out single-cell recordings often mean that such studies can only be performed within a very narrow set of circumstances - Mukamel et al., 2010 did with epileptic participants who had intracranial depth electrodes implanted in advance of surgery, and observed neurons that fired in response to both the observation and the performing of grasping tasks and facial expressions (in the medial frontal and medial temporal lobe)
Neural Basis of Empathy
(Gallagher, 2007)
Broadly, it is proposed that empathy may be achieved explicitly through narratively recreating the circumstances of another, or implicitly through the automatic activation of the relevant brain areas responsible for that emotion in ourselves.
(Wicker et al., 2003).
Self-other matching on a seemingly emotional level is accompanied by by a higher-order emotional component, as opposed to merely an autonomic response. Activation in the anterior insula has also been recorded via fMRI both for experiencing and witnessing disgust.
Implicit emotional contagion is considered one of the simplest forms of empathy (de Waal, 2007), and physiological/behavioural responses characteristic of fear and pain in monkeys when observing another member of the species experiencing these emotions (Parr, 2001)
The Value of Human Language
(Fitch, 2010)
Language is a more advanced system of communication than has been observed in any other species.
(Dunn & Brophy, 2005)
Language ability has also been identified as a predictor of other social competencies in humans, such as performance on a false belief task.
(Tomasello, 2009)
Language is a uniquely powerful tool for information transmission; and therefore enables teaching behaviours on a level not seen in any other species.
(Boyd et al., 2011)
The superior capacity to teach and learn from one another is what enables humans to accumulate knowledge of a greater complexity than could ever be obtained without such collaboration.
(Freiwald et al., 2009; Kanwisher et al., 1997).
Regions in the temporal lobe have been implicated in the processing of faces for both humans and macaques.
Prosocial Behaviour
(Pfattheicher et al., 2022).
Prosocial behaviour is a behavioural manifestation of social cognition (behaviours that benefit another conspecific, like resource sharing or comforting)
(Preston, 2013)
The drive to promote the wellbeing of another observed across mammals may have a common evolutionary origin in the desire to care for one’s dependent offspring.
(Burkart et al., 2014)
The extent of allomaternal care observed across primate species has been identified as a significant predictor of unsolicited prosocial behaviours.
(Tusche et al., 2016)
Charitable giving task. Activation in the anterior insula was associated with empathy for the receiver, and activation in the temporoparietal junction with perspective-taking - suggesting a role played by both cognitive perspective taking and affective empathetic processes in altruistic decision-making in humans.
Enhanced Plasticity during Adolescence
(Fuhrmann et al., 2015)
The enhanced plasticity observed in the brain during adolescence provides greater opportunities for development, but may also contribute to heightened vulnerability.
(Paus et al., 2008)
The peak age of onset for many psychiatric disorders occurs during adolescence.
What is the Brain’s Purpose?
(Llinas, 2001)
One of the primary purposes of the brain is to enable movement. Living organs that do not move do not have a nervous system. The requisite for movement is the substratum on which evolution worked. For example, the Sea Squirt moves till it finds a location suitable for anchoring itself on, then digests its own brain. Without the need for movement, it no longer needs its brain.
The brain is also critical in helping us to adapt to changing environments. It is a “prediction machine” - reduced uncertainty by using information from the past to help predict the future.
What is Neuroplasticity? What are sensitive periods?
William James (1890) introduced the concept of plasticity (which is defined as the ability to be molded/shaped - coming from the Greek term plastos). He noted that brain functions are not fixed throughout our lives.
Neuroplasticity is the ability of the brain to modify its connections or rewire itself. Without it, we would never develop out of infancy, recover from brain injury etc.,
Plasticity is greatest during specific windows of development, known as sensitive periods, during which the acquisition of skills is easier (e.g., acquisition of language - if you are exposed to a second language before age 7, you will be as fluent as a native speaker - between 8 – 10 years, it will be harder to achieve fluency - after age 17, fluency will be low.)
Sensitive periods exist because there is a trade-off between plasticity and efficiency. As your brain gets better at some tasks, it becomes less able to perform others. Young animals display widespread plasticity without needing attentional focus – i.e., learning requires less attention and focus for a child than an adult (more automatic learning)
Phantom Limb Pain and Other Consequences of Changing Somatosensory Inputs
Phantom limb pain occurs because the somatosensory cortex region dedicated to the limb previously are now re-dedicated to an existing/retained area (e.g., some neurons in that area are still looking for input from the left hand but are now receiving input from the left foot). This process of reorganization can look different in the case of prosthetic limbs.
Cochlear implants bypass the ear and send electrical impulses directly to the cochlea. In adults they have to re-learn how to listen, which takes a year or so. Though the same brain region is recruited for listening, it will be now organized differently. We do it quickly in infants to expose babies to language learning in that critical period.
Changes to sensory input causes remapping, even if these changes are just temporary (e.g., using upside down goggles). The speed of such changes suggests that there are existing connections that are unmasked by the change; as it can’t be axonal sprouting or dendritic arborization because of the speed at which it occurs. This rapid reorganization has been observed in auditory and visual systems.
The Role of Behaviour in Neuroplasticity
Behaviour plays a critical role in neuroplasticity. For one, plasticity involves the ability to modify the brain, but also the ability to either retain or discard the changed structure. Adaptive coding, informed by behaviour, is used to alter the number of resources assigned to a function – depending on how important it is (i.e., tennis skills would be valued by a professional player).
Experience influences the brain. Rats in an enriched environment have more extensive dendrites, and neurons in Wernicke’s Area have more elaborate dendrites in college-educated individuals.
Lateralization of Brain Function - Case Studies that Inform Our Understanding
Certain brain functions or cognitive processes are controlled or influenced more by one cerebral hemisphere than the other (referred to as hemispheric lateralization or hemispheric specialization)
Patient W.J (Gazzaniga et al., 1962)
- Had his corpus callosum surgically removed to alleviate seizures, leaving the left and right hemisphere unable to communicate.
- Didn’t seem to be experiencing any difficulties, despite drastic shifts in brain function having been observed in animals.
- He couldn’t verbally identify images flashed to his left visual field (which would have been processed in his right hemisphere) but he could respond to them using morse code and his left hand - even though he would verbally report that he could not see an item.
Patient J.W (Turk et al., 2002)
- Was asked to identify whether a face (which was a morphed version of him and one of the researchers) was him or the researcher.
- The faces were flashed to either his left or right visual field.
- The right hemisphere was biased towards identifying other familiar faces while the left hemisphere had a bias for self-recognition of the face.
- He also did not show a letter priming effect (i.e., small h followed by capital H) in the right hemisphere, suggesting the left is more proficient at letter recognition.
- Right hemisphere could not judge whether two words were antonyms of one another.
Lateralized Functions Include:
- Language/Linguistic processing skills (left hemispheric mostly, but right-hemispheric specialisation for emotional prosody/tone in speech)
- Theory of Mind (lateralized to the right)
The Neural Basis of Confirmation Bias
(Westen et al., 2006)
This study used neuroimaging techniques (fMRI) to examine the neural responses associated with what they termed “motivated reasoning”. When participants were presented with evidence that did not align with their political beliefs, areas of the brain that showed high levels of activation during traditional reasoning tasks (DLPFC) showed significantly lower levels of activation - instead activation was observed in the ACC, PCC, insula.
The findings suggest that motivated reasoning is qualitatively distinct from reasoning when people do not have a strong emotional stake in the conclusions reached (participants were presented with reasoning tasks that contained information threatening to their preferred presidential candidate)
