• Reaction time: The time between the presentation of a stimulus and an appropriate response can indicate differences between two cognitive processes, and can indicate some things about their nature. For example, if in a search task the reaction times vary proportionally with the number of elements, then it is evident that this cognitive process of searching involves serial and not parallel processing.
• Psychophysics: Psychophysical experiments are an old psychological technique which have been adopted by cognitive psychology. They typically involve making judgements of some physical property, e.g. the loudness of a sound. Correlation of subjective scales between individuals can show cognitive or sensory biases as compared to actual physical measurements.
  1. sameness judgements for colors, tones, textures, etc.
  2. threshold differences for colors, tones, textures, etc.
• Brain imagery: analyzing activity within the brain while performing various cognitive tasks. Different types of imaging techniques vary in their temporal (time-based) and spatial (location-based) resolution.
  1. EEG: Electroencephalography (EEG) measures the electrical fields generated by large populations of neurons in the cortex by placing a series of electrodes on the scalp of the subject. This technique has an extremely high temporal resolution, but a relatively poor spatial resolution.
  2. fMRI: fMRI measures the relative amount of oxygenated blood flowing to different parts of the brain. More oxygenated blood in a particular region is correlated with an increase in neural activity in that part of the brain. This allows us to localize particular functions within different brain regions. fMRI has moderate spatial and temporal resolution.
  3. Positron emission tomography PET uses a radioactive isotope, usually in the form of glucose, which is injected into the subject's bloodstream and taken up by the brain. By observing which areas of the brain take up the radioactive isotope, we can see which areas of the brain are more active than others. PET has similar spatial resolution to fMRI, but it has extremely poor temporal resolution.
  4. Optical imaging: This technique uses infrared transmitters and receivers to measure the amount of light reflectance by blood near different areas of the brain. Since oxygenated and deoxygenated blood reflect light by different amounts, we can study which areas are more active (those that have more oxygenated blood). Optical imaging has moderate temporal resolution, but poor spatial resolution. It also has the advantage that it is extremely safe and can be used to study infants' brains.
• Scores/wins/losses in games
• Recording bodily movements in response to a task (e.g. walking towards an object)
• Eye tracking: This methodology is used to study a variety of cognitive processes, most notably visual perception and language processing. The fixation point of the eyes is linked to an individual's focus of attention. Thus, by monitoring eye movements, we can study what information is being processed at a given time.

Key findings (partial list)
Discovery of systemic human cognitive bias, usually credited to Amos Tversky and Daniel Kahneman, 1967. Basis of behavioral finance.

Assertion of equivalence of Euler's identity (basis of complex analysis in mathematics) with basic cognitive processes, George Lakoff and Rafael E. Núñez, 2000. Basis of the cognitive science of mathematics.

Theories

1. Response theory
2. Cognitive dissonance theory
3. Cognitive consistency theory
4. Cognitive science of mathematics
5. Propaganda
6. Attitudes and Affection

Linguistics:

Linguistics was traditionally studied as a part of the humanities, including studies of history, art and literature. In the last fifty years or so, more and more researchers have studied knowledge and use of language as a cognitive phenomenon, the main problems being how knowledge of language can be acquired and used, and what, precisely it consists of. Linguists find that, on the one hand, humans—even the young and the uneducated—form sentences in ways apparently governed by very complicated rule systems. On the other hand, the same people are remarkably inept at identifying the rules that lie behind their own speech. Thus, linguists must resort to indirect methods to determine what those rules might be. If speech is indeed governed by rules, they appear to be opaque to any conscious consideration.

One framework, favored by Noam Chomsky, usually referred to as generative grammar is that knowledge of language forms a separate module of the mind/brain, while other frameworks, such as functional-cognitive linguistics, hold that knowledge and use of language can be understood in terms of general-purpose cognitive mechanisms. The debate is still very much alive, and is ultimately an empirical question which will require more research before it can be settled.