Testing Intelligence

INTELLIGENCE

Intelligence is the ability to reason, to understand, and to profit from experience.

The measure of intelligence is typically expressed as the intelligence quotient (IQ). A controversy that is critical to a biological understanding of intelligence is whether intelligence is a single capability or a collection of several independent abilities.

Lumpers or Splitters

Intelligence theorists tend to fall into one of two groups: lumpers or splitters.

· Lumpers claim that intelligence is a single, unitary capability, which is usually called the general factor, or simply “g”.

· Splitters hold that intelligence is made up of several mental abilities that are more or less independent of each other.

IQ Correlations

MRI studies of fraternal and identical twins found that general intelligence was correlated with both the volume of gray matter and the volume of white matter.

IQ scores are also correlated with nerve conduction velocity. In addition, people who are more intelligent excel on tasks in which stimuli are presented for an extremely short interval and on tasks that require choices. One way the brain could achieve greater efficiency is through enhanced myelination of its neurons.

Unanswered Questions

These are the findings of human intelligence that we have well established. However, many questions remained unanswered. For example, the etiology of autism and the reason for its increased prevalence remains unknown.

The relationship between the brain and behaviors under the specific topic of intelligence and cognitive functioning is being studied as are specific topics related to the neural characteristics that contribute to intelligence and the role of heredity and environment in forming intelligence. Additionally, relationships between brain size, neural conduction, processing speed, and processing efficiency and intelligence are also areas of inquiry.

Current Trends

Current trends in biopsychology research, such as sleep and consciousness, the sense of pain, and sex and gender, are interesting to explore.

· Age of puberty has steadily decreased over the past several decades. Puberty is generally defined as the point at which the brain completes maturation, and this process is largely orchestrated by steroid hormones. For some individuals, puberty comes long before the teenage years, prompting questions about the environmental and genetic signals that trigger this event.

· Testosterone is important for normal development and maturation in both males and females. In the developing male brain, the bulk of it is aromatized to estrogen. But androgens may also play an important role in shaping sexual preferences and behaviors, particularly in humans.

Consciousness

Much about what is known about consciousness comes from studying the nature of sleep and how our brains enter and awake from sleep. The concept of consciousness has intrigued neurobiologists and philosophers alike. New technology and a greater understanding of the brain has enlivened the debate about the nature of consciousness and led to new insight into this once largely inaccessible concept.

Pain

Finally, pain is both a necessary and troubling sensation. Without the sensation of pain, it is difficult to avoid injury, which is required for human survival.