Psychology Study Notes: Sensation, Perception, and Social Psychology

Psychology Study Notes: Sensation and Perception Key Concepts from Class Lecture

Sensation: Detecting Stimuli

• Definition of Sensation:

  • Sensation refers to the process by which our sensory systems and nervous system receive stimuli from the environment. For example, our taste buds detect flavors, and our skin senses touch.

  • Sensory neurons are activated by these stimuli, which are then converted into neural activity so our brain can interpret them.

Just Noticeable Difference (JND)

• Definition of JND:

  • The just noticeable difference is the minimum amount by which two stimuli must differ for us to notice the difference 50% of the time.

  • This concept helps us understand how we detect changes in our environment, such as noticing a stronger scent or a louder sound.

  • The scientist Weber described this as requiring a constant percentage difference, not a constant amount, for a difference to be noticeable.

Absolute Threshold

• Definition of Absolute Threshold:

  • The absolute threshold is the smallest amount of sensory input required for a person to detect its presence at all.

  • Examples include the faintest sound a person can hear or the weakest light they can see.

  • This threshold can vary from person to person depending on their physical and psychological state.

Signal Detection Theory

• Definition of Signal Detection Theory:

  • Signal detection theory explains how detection of a stimulus depends both on the strength of the signal and the individual’s physical and psychological context.

  • Example: Someone who is distracted or anxious may be less likely to notice a stimulus, even if it is present.

The Eye and Color Vision

• Components of the Eye:

  • Cornea: The outer layer of the eye where light first enters.

  • Iris and Pupil: The iris is the colored part of the eye; it regulates the size of the pupil, which controls the amount of light entering the eye.

  • Lens: Focuses light onto the retina; becomes less flexible with age, making focusing harder.

  • Retina: Contains photoreceptor cells for vision.

• Photoreceptors:

  • Rods: Detect black and white; useful in low light; respond slowly.

  • Cones: Detect color; respond quickly; three types for different colors.

Theories of Color Vision

• Trichromatic Theory:

  • Proposes three types of cones (red, green, blue). Color vision results from the combination and relative strength of stimulation of these cones.

• Opponent Process Theory:

  • Suggests three pairs of cells in the retina (red/green, blue/yellow, black/white). When one color in the pair is stimulated, the other is inhibited.

  • Explains phenomena like negative afterimages (seeing the opposite color after staring at one color for a while).

Color Blindness

• Types of Color Blindness:

  • Monochromatism: No functioning cones; only sees shades of gray (rare).

  • Dichromatism: One type of cone is missing or defective; for example, red-green color blindness. More common in males due to genetic inheritance patterns.

Taste and Smell

• Papillae: Small bumps on the tongue where taste buds are located.

• Taste Buds: Barrel-shaped structures inside papillae containing sensory cells for detecting taste.

• Variation in Taste Sensitivity:

  • People vary in their sensitivity to certain tastes (e.g., supertasters, non-tasters).

  • Genetic factors influence taste sensitivity.

  • Flavor is a combination of taste and smell; holding your nose while eating can reduce the ability to identify flavors.

Perception: Interpreting Sensory Information

• Definition of Perception:

  • Perception is the process of organizing and interpreting sensory input to make it meaningful.

  • It involves both bottom-up and top-down processing:

• Bottom-Up Processing:

  • Starts with raw sensory input and builds up to perception (e.g., a baby encountering something new).

• Top-Down Processing:

  • Uses prior experience and expectations to interpret sensory information.

Perceptual Set

• Definition of Perceptual Set:

  • Perceptual set is the tendency for our expectations and previous experiences to influence how we perceive things.

  • Example: If two groups see the same ambiguous image, one might see a person and the other a rat, depending on their prior context.

Examples and Demonstrations

• Holding your nose while eating candy demonstrates how smell influences taste perception.

• Negative afterimages and color blindness illustrate how different theories of color vision work.

• Group experiments show how expectations can change perception of ambiguous images.

Key Terms to Know

• Just Noticeable Difference (JND)

• Absolute Threshold

• Signal Detection Theory

• Trichromatic Theory

• Opponent Process Theory

• Perceptual Set

• Bottom-Up Processing

• Top-Down Processing

• Papillae

• Taste Buds

Quick Review Questions

• What is the minimum difference required to notice a change in stimulus? Just Noticeable Difference

• What is the first structure of the eye that contacts light? Cornea

• What theory explains negative afterimages? Opponent Process Theory

• What is the difference between bottom-up and top-down processing?

Psychology Study Notes: The Power of the Situation in Social Psychology

• Understanding Attribution, Deindividuation, and the Fundamental Attribution Error

Introduction

• These notes focus on core social psychology concepts about how context and group dynamics shape our perceptions of and explanations for behavior, especially regarding negative behavior.

• Rather than immediately blaming an individual's personality, social psychology encourages consideration of situational factors.

• This approach aids in better understanding, predicting, and intervening in instances of negative behaviors.

Key Concepts

• Attribution:

  • An attribution is an explanation for why someone behaves a certain way.

  • Attributions can be categorized into:

  • Internal (dispositional) – based on personality or traits.

  • External (situational) – based on the environment or circumstances.

• Fundamental Attribution Error:

  • This is the common tendency to overemphasize personal characteristics and ignore situational factors when judging others’ behavior.

  • Example: If a student is late to class, one might quickly assume laziness (internal) rather than considering traffic or parking difficulties (external).

• Power of the Situation:

  • Social psychology research indicates that context and environment significantly influence behavior.

  • The same individual may act very differently depending on various situational factors.

• Deindividuation:

  • When people are in a group or feel anonymous, they may lose their sense of individual identity, leading to behavior they might not engage in if alone.

  • Examples include crowd behaviors at concerts or sporting events, or negative actions when hidden behind a screen on social media or while driving.

Illustrative Studies and Examples

• Halloween Candy Study (1976):

  • Researchers observed trick-or-treating children left alone with a bowl of candy and a sign that said "Take just one."

  • The study focused on how group presence and anonymity (deindividuation) increased the likelihood of bad behavior (taking extra candy).

• Group Influence:

  • Individuals often act in ways they might not if they were alone—sometimes due to group influence or perceived anonymity.

  • The loss of personal responsibility can lead to unexpected or even destructive actions.

• Modern Examples:

  • Social media and driving are scenarios where deindividuation can occur, leading individuals to act out in ways they otherwise wouldn’t due to anonymity or a detachment from consequences.

Why Is This Important?

• Social psychology teaches that when witnessing bad behavior, one should pause before labeling someone a "bad person."

• It is crucial to consider what situational factors might have contributed to their actions.

• Understanding the power of the situation can facilitate better interventions and compel us to show compassion or support, aiding individuals in changing their circumstances instead of merely attributing blame.

Application for Exams and Real Life

• Be prepared to identify examples of dispositional vs. situational attributions on exams.

• Classic studies in social psychology (like the Halloween candy study) reveal the mechanisms behind everyday group dynamics and individual behavior.

• Apply these concepts to real-world events and personal experiences; practice critical thinking about explanations for others' actions.

Summary

• Social psychology emphasizes the critical role of context in shaping behavior.

• The discipline highlights frequent errors in judgments (e.g., fundamental attribution error), the effects of groups and anonymity (e.g., deindividuation), and the necessity to look beyond the individual for a more comprehensive understanding of and strategies to change problematic behaviors.

Psychology Study Notes: Nervous System and Brain Structures

Organized Key Concepts and Explanations

I. Nervous System Overview

• Nervous System Breakdown:

  • Main focus: Central Nervous System, particularly the brain.

A. Central Nervous System: The Brain

1. Brain Evolution:

   • The brain evolved from basic structures that sustain life.

   • The earliest part of the brain controls survival functions.

2. Brain Structures:

   • Medulla:

     • Regulates breathing and heart rate.

     • Essential for survival; damage to this area is fatal.

   • Pons:

     • Active during sleep and dreaming.

     • Acts as a bridge connecting lower and upper brain structures.

   • Cerebellum:

     • Controls voluntary muscle movements and balance.

     • Alcohol impairs the cerebellum, affecting coordination (as seen in field sobriety tests).

     • Responsible for procedural memories (e.g., riding a bike).

   • Limbic System:

     • Responsible for emotional experiences; sometimes referred to as the emotional center.

   • Key Structures:

     • Hypothalamus:

     • Regulates stress, hunger, thirst, sex drive, and sleep; maintains homeostasis.

     • Thalamus:

     • Sensory relay station; directs sensory information (except smell) to the cortex.

     • Amygdala:

     • Central to fear and emotional responses.

     • Hippocampus:

     • Forms new long-term memories; affected by alcohol (can lead to blackouts).

B. Cerebral Cortex & Its Lobes

• Cerebral Cortex:

  • Outer layer of the brain; highly wrinkled to increase surface area and processing power.

  • Divided into left and right hemispheres, each with four lobes:

  • The Four Lobes:

  • Occipital Lobe:

    • Located at the back of the head; processes visual information from the eyes.

  • Temporal Lobe:

    • Located near the ears; processes auditory information; includes Wernicke’s area for understanding language.

    • The hippocampus is sometimes considered part of this lobe due to its role in memory formation.

  • Parietal Lobe:

    • Processes taste, temperature, and touch.

    • Somatosensory cortex interprets body sensations; larger cortex areas correlate with more sensory receptors (e.g., lips vs. elbow).

  • Frontal Lobe:

    • Manages planning, impulse control, and complex cognitive behaviors (prefrontal cortex).

    • Contains motor cortex (responsible for movement) and Broca’s area (involved in speech production).

    • Last part of the brain to develop, typically during adolescence to early adulthood.

C. Hemispheric Specialization & Split Brain Research

• Corpus Callosum:

  • A bundle of fibers that connects the left and right hemispheres, allowing communication between them.

• Contralateral Control:

  • Left hemisphere controls the right side of the body, while the right hemisphere controls the left side.

• Split Brain Patients:

  • In circumstances where the corpus callosum is severed (usually to treat severe epilepsy), the hemispheres show distinct functions:

  • Left Hemisphere:

    • Responsible for language (spoken/written), logic, mathematics, and detail-oriented processes.

  • Right Hemisphere:

    • Responsible for nonverbal tasks, visual-spatial perception, music, emotional processing, and pattern/facial recognition.

  • Experiments demonstrate each hemisphere has specialized abilities and limited communication post-surgery.

D. Neurons & Neurotransmitters

• Neuron Basics:

  • Neurons relay information throughout the nervous system.

  • Dendrites: Receive information.

  • Axons: Send information.

  • Note: Alphabetically, axon comes before dendrite.

  • Synapse: Gap between neurons where neurotransmitters are released.

  • Myelin Sheath: Covers axons to speed up impulse transmission.

• Neurotransmitter Types:

  • Excitatory:

  • Norepinephrine: Affects alertness, arousal, and mood.

  • Glutamate: Involved in learning and memory; levels are often high in migraines.

  • Dopamine: Related to pleasure, movement; implicated in schizophrenia and addiction.

  • Inhibitory:

  • Endorphins: Function as pain relief (often described as the "runners' high").

  • GABA: Plays a role in sleep regulation.

  • Both Excitatory & Inhibitory:

  • Acetylcholine: Crucial for muscle contraction, attention, memory; low levels are associated with Alzheimer’s disease.

  • Serotonin: Important for mood, arousal, sleep, and appetite; low levels are linked to depression and anxiety.

  • Agonists & Antagonists:

  • Agonist: Mimics a neurotransmitter and activates the receptor (e.g., nicotine).

  • Antagonist: Blocks a neurotransmitter, inhibiting activation (e.g., curare blocks acetylcholine, leading to paralysis).

  • Analogy: A wrong key fits ignition but won’t start the car (antagonist blocking the signal).

E. Neuroplasticity

• Definition of Neuroplasticity:

  • Neuroplasticity is the brain’s ability to change and adapt throughout life.

• Mechanism:

  • New neural pathways form with repeated thinking, feeling, or actions; old pathways weaken.

• Implication:

  • Changing habits, thoughts, and behaviors is possible by creating and reinforcing new brain pathways.

F. Review Tips

• Key Terms:

  • Medulla

  • Pons

  • Cerebellum

  • Limbic System (Hypothalamus, Thalamus, Amygdala, Hippocampus)

  • Cerebral Cortex and its lobes

  • Corpus Callosum

  • Neuron structure

  • Neurotransmitters

  • Neuroplasticity

• Mnemonic Devices:

  • Use mnemonic devices to remember functions of lobes and neurotransmitters.

• Understanding Split Brain Experiments:

  • Grasp what these studies reveal about hemisphere specialization.

• Explain Concepts in Your Own Words:

  • Practice describing concepts to deepen understanding.

Note:

These study notes summarize the material covered in class and should assist you in preparing for exams, quizzes, and study sessions.