HL Pysch SAQ answers November 7

Describe/Explain one value of animal research in the study of human behavior with reference to one example.

Value: Permits invasive procedures that are unethical on human subjects, allowing researchers high experimental control to investigate causality in biological mechanisms.

Study: Rogers and Kesner (1995) (Rats).

Link: Rats were injected with scopolamine (ACh antagonist) to study memory loss. Invasive manipulations involve stimulating, lesioning, or removing parts of the nervous system or injecting substances into the body. These manipulations provide physiological evidence for neurotransmission's role in behavior.

Describe/Explain one ethical consideration in the use of animals in research with reference to one example.

Ethic: The principle of Refinement requires minimizing pain, suffering, or distress during the experiment, balancing the predictable "harm done" against the unknown "benefit" of the study (Moral Dilemma).

Study: Merzenich et al. (1984) (Owl Monkeys).

Link: The study involved a severe, permanent procedure (amputation of the third digit) to test cortical remapping. This inflicted significant, permanent physical harm and distress, raising ethical concerns about whether the scientific knowledge gained justified the harm.

Describe/Explain biological reductionism, with reference to one example.

Definition: Explaining complex behavior (like disorders) by systematically breaking it down into the simplest biological parts (genes, neurotransmitters, brain regions).

Goal/Critique: It aims for high internal validity to determine causality, but critics argue it oversimplifies by suggesting complex behaviors "can solely be based on neurotransmitters" or genes.

Study: Kendler et al. (2006) (Twin Study).

Link: Reductionism is seen when MDD is attributed solely to genetic inheritance (e.g., 38% heritability) or specific genes (like 5-HTT). This approach fails to explain why MZ twins (100% genotype shared) have less than 100% concordance, necessitating holistic factors.

Describe/Explain the use of one brain imaging technique in the study of behavior with reference to one example.

Technique: Functional Magnetic Resonance Imaging (fMRI).

Use/Mechanism: Functional imaging measures changes in blood flow and oxygenation (neural activity). Used to observe which specific areas are active during a cognitive task. Note: The final fMRI image is a statistical compilation, not an image of the brain at a specific time.

Study: Harris & Fiske (2006) or Antonova et al. (2011).

Link (Harris & Fiske): fMRI was used to map brain activity when participants viewed images of out-groups. They found reduced activity in the medial prefrontal cortex (area for thinking about people) and activation of the insula (disgust response) when viewing the homeless/addicts, linking specific areas to complex social cognition (dehumanization).

Describe/Explain the role of one chemical messenger in human behavior.

Messenger: Acetylcholine (ACh) (a neurotransmitter).

Role: ACh is highly concentrated in the hippocampus and plays a key role in learning, cognition, and memory consolidation. Chemical messengers include both neurotransmitters and hormones.

Study: Antonova et al. (2011).

Link: Researchers used scopolamine, an antagonist drug that blocks ACh receptor sites. When participants were injected, they showed a significant reduction in hippocampal activation, leading to reduced spatial memory performance, confirming ACh's role in this cognitive process.

Describe/Explain the Diathesis-Stress Model with reference to one human behavior.

Definition: Framework explaining that psychological disorders result from an interaction between a genetic predisposition (diathesis) and environmental triggers (stressors).

Core Idea: The model integrates genetics and environment (gene-environment interaction). The genetic vulnerability is only expressed (or "turned on") if sufficient stress is present.

Study: Caspi et al. (2003).

Link: The short 5-HTT gene allele (diathesis) only significantly increased the risk of developing MDD (behavior) in individuals who also reported experiencing many stressful life events (stressor).

Describe/Explain one example of how behavior may be the result of genetic inheritance.

Concept: We inherit genes that serve as physiological (biological) building blocks for traits and complex behaviors. Heritability estimates how much variation in a trait is due to genetic differences.

Technique: Twin studies compare concordance rates (similarity) between MZ twins (100% shared genotype) and DZ twins (approx. 50% shared genotype).

Study: Kendler et al. (2006).

Link: Higher concordance rates for depression were found in MZ twins (e.g., 44% for female MZ) compared to DZ twins, supporting the idea that a genetic predisposition for MDD is inherited.

Describe/Explain localization of function with reference to one example of behavior or cognition.

Definition: The theory that specific cognitive processes, behaviors, or emotions originate in distinct regions of the brain. Evidence often comes from studying brain injuries.

Behavior/Area: Spatial Memory localized to the Hippocampus.

Study: Antonova et al. (2011).

Link: fMRI mapping showed that the hippocampus demonstrated significant activity during the spatial memory/navigation task ("Arena task"). When neurotransmission was blocked, the activity in this specific area was reduced, confirming its specialized function.

Describe/Explain neuroplasticity with reference to one example.

Definition: The brain is not static; it is constantly changing its structure and connections due to experience, learning, or injury.

Mechanism: This change involves new neural connections being made from experiences (or the strengthening of synapses through repeated use, known as long-term potentiation, per Hebb's Law: "Neurons that FIRE together, WIRE together").

Study: Merzenich et al. (1984) (Cortical Remapping) or Maguire et al. (2000) (Taxi Drivers).

Link (Maguire): Grey matter volume in the right posterior hippocampus was found to correlate with the amount of time spent as a taxi driver. This shows that intensive spatial navigation (environmental demand) led to physical changes and increased density/volume in the specialized brain region (neuroplasticity).

Describe/Explain neurotransmission with reference to one example of its role in human behavior or cognition.

Definition: Electrochemical process where an electrical impulse releases chemical messengers (neurotransmitters) across the synapse to bind to a postsynaptic receptor.

Mechanics: Chemicals may be agonists (activate the receptor/mimic action) or antagonists (block the receptor/prevent signal). This process underlies all cognition.

Study: Antonova et al. (2011).

Link: The study manipulated neurotransmission by injecting the antagonist scopolamine. By blocking the receptor sites for Acetylcholine (ACh), the normal signal transmission was prevented, which resulted in a functional impairment (reduced spatial memory) and decreased hippocampal activity.