Quiz 3 - Short answer Flashcards
Third Variable Problem and Directionality Problem
The third variable problem arises when an unmeasured variable influences both the studied variables, creating a false impression of a causal relationship. For example, ice cream sales and drowning incidents may both increase due to a third variable: hot weather. The directionality problem occurs when it is unclear which variable is the cause and which is the effect. For instance, does stress cause poor sleep, or does poor sleep cause stress? Experimentation can address these issues by controlling variables and establishing temporal order. For example, to test if a new drug reduces anxiety, researchers can randomly assign participants to either the drug or a placebo group, ensuring any observed effects are due to the drug.
Roles of Neurotransmitters and Drug Effects
Neurotransmitters can be excitatory, increasing the likelihood of the receiving neuron firing, or inhibitory, decreasing this likelihood. For example, glutamate is excitatory, while GABA is inhibitory. Drugs can mimic (agonists) or block (antagonists) neurotransmitters. For example, morphine acts as an agonist for endorphins, enhancing pain relief and euphoria, while naloxone is an antagonist that blocks opioid receptors, reversing opioid overdose effects
Resting Potential, Action Potential, and Refractory Period
A neuron at rest has a resting potential of about -70mV, maintained by the sodium-potassium pump. When a stimulus exceeds the threshold, an action potential is triggered, causing a rapid influx of sodium ions, making the inside of the neuron positive. This depolarization travels down the axon. After the peak, potassium ions exit, repolarizing and eventually hyperpolarizing the cell during the refractory period, temporarily preventing further action potentials. Two properties of neural firing are the “all-or-none” principle, where neurons either fully fire or do not at all, and the “one-way direction” of action potentials, ensuring signals move from the cell body to the axon terminals.
Flow of Visual Information
Visual information from the left visual field is processed by the right hemisphere, while information from the right visual field is processed by the left hemisphere. Light enters the eyes and is focused on the retinas. The optic nerves partially cross at the optic chiasm, ensuring that information from each visual field is directed to the opposite hemisphere. This information travels through the lateral geniculate nucleus (LGN) of the thalamus and is then relayed to the primary visual cortex in the occipital lobe for processing
Types of Touch Receptors and Representation in the Brain
Under the skin, there are several types of touch receptors: mechanoreceptors (e.g., Meissner’s corpuscles for light touch, Pacinian corpuscles for pressure), thermoreceptors (for temperature), and nociceptors (for pain). Touch information is transmitted via sensory neurons to the spinal cord and then to the brain. In the brain, touch is represented in the somatosensory cortex, which has a somatotopic map known as the sensory homunculus. This map illustrates how different body parts are represented, with more sensitive areas like the lips and hands occupying larger cortical areas.
Properties of Consciousness
Consciousness has four basic properties: intentionality (the quality of being directed towards an object, e.g., focusing on a lecture), unity (resistance to division, e.g., integrating information from various senses), selectivity (the capacity to include some objects but not others, e.g., focusing on a conversation in a noisy room), and transience (the tendency to change, e.g., shifting thoughts during daydreaming). Each property exemplifies how consciousness allows for complex, adaptive interactions with the environment.
Iconic Memory and Echoic Memory
Iconic memory is a brief sensory memory of visual stimuli, while echoic memory is a brief sensory memory of auditory stimuli. A common paradigm for measuring iconic memory is the Sperling partial-report method, where participants are shown a grid of letters briefly and asked to recall one row indicated by a tone. This method reveals the capacity and duration of iconic memory. Sensory memory allows for the retention of sensory information long enough to be processed and integrated into short-term memory.
Classical Conditioning and Phobias
Classical conditioning explains how phobias can develop through the association of a neutral stimulus with a fearful response. In the “Little Albert experiment,” a white rat (neutral stimulus) was paired with a loud noise (unconditioned stimulus) that elicited fear (unconditioned response). Eventually, Albert exhibited fear (conditioned response) to the white rat alone (conditioned stimulus). This illustrates how repeated pairings can lead to the acquisition of phobias.
Memory Effect and September 11, 2001
The vivid memory of traumatic events like September 11 is explained by the phenomenon of flashbulb memories, which are detailed, long-lasting memories of significant events. Cognitive aspects include the emotional arousal and importance of the event, enhancing encoding and retrieval. Neural aspects involve the amygdala and hippocampus, which are crucial for emotional and episodic memory, respectively. The intense emotional response strengthens the consolidation of these memories.
Artificial Grammar and Implicit Learning
Artificial grammar learning studies how people unconsciously learn patterns and structures. Participants are exposed to strings of letters generated by a complex set of rules (artificial grammar) without being informed of these rules. Later, they can distinguish between grammatically correct and incorrect strings, demonstrating implicit learning. This research shows that people can acquire knowledge without conscious awareness, highlighting the role of implicit processes in learning and cognition.
