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Hyperconjugation can be used to rationalize a variety of chemical phenomena, including the anomeric effect, the gauche effect, the rotational barrier of ethane, the beta-silicon effect, the vibrational frequency of exocyclic carbonyl groups, and the relative stability of substituted carbocations and substituted carbon centred radicals, and the thermodynamic Zaitsev's rule for alkene stability.
This phenomenon, a type of resonance, can stabilize the molecule or transition state. [2] It also causes an elongation of the σ-bond by adding electron density to its antibonding orbital. [1] Negative hyperconjugation is seldom observed, though it can be most commonly observed when the σ *-orbital is located on certain C–F or C–O bonds ...
Negative hyperconjugation is a theorized phenomenon in organosilicon compounds, in which hyperconjugation stabilizes or destabilizes certain accumulations of positive charge. The phenomenon explains corresponding peculiarities in the stereochemistry and rate of hydrolysis .
The Cieplak effect relies on the stabilizing interaction of mixing full and empty orbitals to delocalize electrons, known as hyperconjugation. [2] When the highest occupied molecular orbital of one system and the lowest unoccupied molecular orbital of another system have comparable energies and spatial overlap, the electrons can delocalize and sink into a lower energy level.
The following is a formulaic description of Hebbian learning: (many other descriptions are possible) = where is the weight of the connection from neuron to neuron and the input for neuron . Note that this is pattern learning (weights updated after every training example).
Lithuanian-Soviet psychologist Bluma Zeigarnik first studied the phenomenon after professor and Gestalt psychologist Kurt Lewin noticed that a waiter had better recollections of still unpaid orders. [2] However, after the completion of the task — after everyone had paid — the waiter was unable to remember any more details of the orders.
Furthermore, in all animals, the nervous system is the organ of behavior. Therefore, every biological and behavioral variable that influences behavior must go through the nervous system to do so. Present-day research in behavioral neuroscience studies all biological variables which act through the nervous system and relate to behavior. [10]
An example water jar puzzle. The water jar test, first described in Abraham S. Luchins' 1942 classic experiment, [1] is a commonly cited example of an Einstellung situation. . The experiment's participants were given the following problem: there are 3 water jars, each with the capacity to hold a different, fixed amount of water; the subject must figure out how to measure a certain amount of ...