Psych 100a midterm #2

Depth Perception

• Depth perception is crucial for understanding distances and spatial relationships in our environment.

• It relies on various visual cues:

  • Gestalt Grouping: Organizing visual information into holistic forms.

  • Shape Constancy: Perceiving objects as having a constant shape regardless of angle.

  • Distance Judgments: Estimating how far away an object is.

  • Gaps Filling: Completing incomplete figures visually.

• Notably, experiments involving reversed visual fields (e.g., wearing glasses that flip reality upside down) show that the brain can adjust after a period of adaptation.

  • This ability demonstrates neural plasticity and adaptability.

Nonvisual Senses

Hearing (Audition)

• Sound waves and their properties:

  • Pitch: Related to the frequency of sound waves (shorter waves = higher pitch).

  • Loudness: Determined by the amplitude of sound waves (higher amplitude = louder sound).

• Hearing plays an essential role in communication and social interactions:

  • People often find others more appealing when they hear their voices rather than simply read their words.

  • Hearing loss, often termed the "great invisible disability," can lead to social isolation, anxiety, and depression.

• Hearing Sensitivity: Humans can detect a wide range of sounds, particularly in the frequency range of human voices.

  • Distant ancestors relied on acute hearing for survival.

  • The brain processes sound much faster than visual stimuli.

Characteristics of Sound Waves

• Sound waves are variations in air pressure:

  • Amplitude: Determines loudness.

  • Frequency: Determines pitch (higher frequency = higher pitch).

  • Decibels: Measure of sound intensity (e.g., normal conversation = 60 dB).

• Hearing Damage: Prolonged exposure to sound levels above 85 dB can cause hearing loss.

• Anatomy of Ear: Sound waves vibrate the eardrum and are amplified by the middle ear's bones (hammer, anvil, stirrup) before reaching the cochlea where sound waves trigger nerve impulses.

Transduction in Hearing

• Transduction: The process of converting sound waves into electrical signals for the brain.

• Outer Ear: Channels sound to the eardrum.

• Inner Ear (Cochlea): Fluid motion within the cochlea causes hair cells to bend, triggering neural impulses that travel to the auditory cortex.

• Hair Cells: Extremely sensitive; their movements can initiate neural responses.

  • Up to 16,000 hair cells exist, but their sensitivity can diminish with age or exposure to loud sounds.

Hearing Loss Types

• Sensorineural Hearing Loss: Damage to the inner ear or auditory nerve.

• Conduction Hearing Loss: Damage to the mechanical parts conducting sound.

• Cochlear Implants: Devices that stimulate the auditory nerve in cases of severe hearing loss.

Theories of Pitch Perception

• Place Theory: Different pitches stimulate different places on the cochlea's basilar membrane.

• Frequency Theory: The rate of nerve impulses matches the frequency of the sound wave, especially for lower frequencies.

• Volley Principle: Neurons work in succession to exceed the firing rate limit of individual neurons.

Locating Sounds

• Binaural hearing allows for sound localization through:

  • Intensity Difference: Sounds reach one ear slightly more intensely than the other.

  • Time Lag: Sounds reach one ear slightly sooner than the other, aiding in spatial awareness.

Touch and Pain

Touch Sensations

• Touch is a mix of four basic sensations: pressure, warmth, cold, and pain.

  • Each area of the skin has differing sensitivity and responses to pressure.

• Comforting touch promotes physical and mental well-being throughout life.

Understanding Pain

• Biological, psychological, and social-cultural factors influence pain experiences:

  • Pain functions as an alarm, directing attention to possible injuries.

  • Gate-Control Theory: Suggests a neurological gate in the spinal cord that either allows or blocks pain signals to the brain.

• Coping Mechanisms:

  • Distraction can reduce pain sensitivity.

  • Expectations and psychological contexts can significantly alter pain perception.

Taste and Smell

Taste (Gustation)

• Involves five basic tastes: sweet, sour, salty, bitter, umami.

• Taste receptors are renewed frequently but become less sensitive with age.

• Taste and Smell Connection: Aroma significantly influences taste perception.

Smell (Olfaction)

• Smell is another chemical sense, relying on olfactory receptors that detect airborne molecules.

• The olfactory bulb transmits signals to brain areas connected to memory and emotion, explaining why certain smells can evoke vivid memories.

• Unlike other senses, smell bypasses the thalamus and communicates directly to the cortex.

Kinesthesia and Vestibular Sense

• Kinesthesia: Awareness of body position and movement, crucial for coordination and balance.

• Vestibular Sense: Detects head position and movement through structures in the inner ear.

Sensory Interaction and Embodied Cognition

• Sensory interaction refers to how one sense can influence another, exemplified by the interplay of taste and smell.

• Embodied Cognition: Physical sensations and experiences can affect cognitive judgments and preferences.

• Example: Warmth can elicit social warmth in interactions with others.

Extrasensory Perception (ESP)

• ESP claims, such as telepathy, clairvoyance, and precognition, lack scientific support and remain a subject of skepticism.

• Psychological science emphasizes empirical testing to investigate these claims, often yielding no reproducible results.