Stimuli


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Stimuli

 

in biology, various alterations in the external or internal environment of an organism that are capable, when acting on a biological system such as nervous, muscular, or glandular tissue, of altering the system’s original state, that is, of producing excitation. Stimuli may be physical, chemical, and physicochemical and adequate or inadequate. They affect specific nerve endings (receptors) and other cells of organs and tissues.

References in periodicals archive ?
The stimuli were presented in a random sequence of 270 trials in 30 blocks.
An unpaired / test showed the difference in the number of training trials for participants receiving different stimuli sets not to be significant, t(22) = 0.
Sosa (2014) recently has reviewed those kinds of procedures and their corresponding critiques regarding the demonstration of the conditioned reinforcement value by arbitrary stimuli.
However, some authors have argued that a simple discrimination procedure with a successive presentation of stimuli increases the probability of establishing a discriminated response that is controlled by aspects of the S+ and concurrently by aspects of the S- (Campos, Debert, Barros, & Mcllvane, 2011; Debert, 2003; Debert, Matos, & Mcllvane, 2007), which might not be the case in procedures with a simultaneous presentation of the stimuli.
After presenting students with all possible pairs of stimuli, educators determine preferences based on the proportion of times an item was selected from all presentations.
Squares of 10 x 10 cm made from commercially produced sandpapers (Debray, Barcelona, Spain) differing in roughness were used as the stimuli (grit grade "4" as the rougher surface, and grit grade "6" as the smoother surface).
The stimuli were presented in a random order, with the constraint that each 1-back-and-current luminance pair was presented with an equal frequency within a block.
The stimuli (boxes) were placed on wooden stands 40 cm in height so that the gull was unable to see the box's contents.
Non-smoking carriers of the risk gene, however, did not process stimuli much worse.
Instructional programs in educational settings often involve compound stimuli that are comprised of multiple relevant features, as well as other features not discriminative for reinforcement.
In sum, the findings seem to suggest that participants respond with respect to classes of stimuli in the absence of verbal rules or naming processes.
We used the smallest possible frequency of vibration to illicit a response from the millipedes since weaker stimuli require decreased time for habituation to occur compared to stronger stimuli (Koopowitz, 1974).