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Sensations, Perceptions, and Attention

PSY/300

Carlton Bowden

March 15th 2015

 A. Definition

Attention is a term with different meanings and can be used in various fields. For psychology, it is a quality of perception that functions as a kind of filter environmental stimuli, evaluating which are the most relevant and giving them priority for further processing. Moreover, attention is also understood as the mechanism that controls and regulates cognitive processes. Psychologists address two types of determinants of attention: internal determinants (those that are unique to the individual and depend on him) and external determinants (coming from the middle). It is understood that attention is a perceptual quality that acts as a filter of sensory stimuli. Attention can evaluate and prioritize those stimuli they consider most important (Cohen, 1993).

Threshold is the lowest or small a magnitude that can generate a certain effect value. In another sense, the threshold is the smallest amount of signal that must exist to be warned by a system. The notion of threshold is linked to the physical possibilities of sensitivity. The threshold is determined as the smaller of the intensity of a stimulus that has a fifty percent chance of being recorded level. When the stimulus reaches transmit a nerve impulse, is considered the threshold. It’s called hearing threshold, therefore, the lower intensity of a sound that can detect the ear of a person. The normal value is between zero and twenty dB audiometric.

1. Auditory Stimuli

Auditory information is filtered redundant very different from the novel or unusual stimuli that have shaped environmental significance. "The beep of a car is an example of how a novel stimulus may evoke a motor response as turning the head," the researcher said. This type of reaction is important for the survival of animals and even people in contexts of sensory, auditory or visual stimuli complex (Ritter, Vaughan, & Costa, 1968).

Auditory system: this system, specializes in the perception of sounds. This is done through the ear, which is an organ, which also involves the maintenance of balance, this is composed of different sensory structures that identify sounds and emit impulses through the auditory nerve, reach the brain receptors such centers function. The human ear consists of three parts, the outer ear, which acts as a receiver and presents a distinction between pinna or ear and ear canal; the middle ear, the eardrum forms, which is externally bounded by the eardrum, sensitive membrane so slightly conical vibration communicating with ear icicles; The first is the hammer, attached to the tympanic membrane, as happens, is the anvil and the stirrup; this last statement with oral window marks the passage to the inner ear. The auditory system consists of the ear, with its three part, but the auditory pathways of the brain that allows us to translate the air pressure waves into sounds and localize sound sources.

Sound waves are the stimuli that excite mechanoreceptors, which are usually several different frequencies. This is the result of a complex system concerning some form of electronic transduction in the inner ear, together with brain neural systems comparing the signals from the ears. Thanks to the mechanical design of the ear, and the specificity of the wiring of the brain, because the human being is capable of detecting a range of sound between 20 and 20,000 Hz.

2. Dichotic Listening

The dichotic listening involves the simultaneous presentation of two different auditory stimuli, one in each ear. The stimuli presented may differ from words to syllables, letters and even musical sounds, may also vary other parameters such as inter and intra-stimulus interval, number of presentations or intensity. The projections of the auditory pathway to the cerebral cortex are ipsilateral and contralateral. This means that the information it receives each ear is finally projected in both cerebral hemispheres. During dichotic listening condition, the less abundant than the contralateral, ipsilateral pathways are inhibited. Therefore, the information received in one ear only happens in this case the opposite cerebral hemisphere through the corpus callosum. Thus, if there is a break in any of the hemispheres was observed deficiency in the ear contralateral to the lesion under the condition dichotic listening (Moray, 1959).

3. Dividing Attention

There are several classifications of attention in this regard, which also vary depending on what criteria is used. Divided attention is when one is able to pay attention to two or more stimuli at the same time, useful in the development of complex tasks such as driving. the division of attention, is to help us look closely at the things that are happening around and in one, divided attention when we cut to be objective and observe all without stopping to engage a personification of something (Hirst, Spelke, Reaves, Caharack, & Neisser, 1980).

4. Sensory Perception

Humans have always considered the senses a gateway to the outside world, through which we explored our environment and we obtained information about it, basic to ensure our survival. Aristotle classified these natural body radars five: sight, hearing, taste, touch and smell. And those, we have been adding recently, others like the sense of balance, temperature, pain, body position and movement.

The sensory system has two distinct characteristics, the first is that the somatic sensation receptors distributed throughout the body, the second, is that this system processes many different types of stimuli which have different energy. To be able to perceive and feel the stimulus, a minimal amount of energy stimulus is needed, what is called sensory threshold. These thresholds are not fixed because they may be influenced by: the experience, habit, fatigue, the context in which it is present, etc. thus being able to fall, for example, as we anticipate the appearance of a stimulus. It is also obvious that the stimulus could disappear more quickly, while softer the intensity of this, falling below the threshold and absolutely losing the sensation or perception of the stimulus. In addition to the sensory threshold, we can find another concept related to the perception of the stimulus, the right stimulus, which is the right amount of energy for the stimulus is perceived clearly (Granit, 1955).

References

Cohen, S. B. (1993). From attention-goal psychology to belief-desire psychology: The development of a theory of mind and its dysfunction. Retrieved from http://www.citeulike.org/group/890/article/633397

Granit, R. (1955). Receptors and sensory perception. Retrieved from http://doi.apa.org/index.cfm?fa=search.printFormat&uid=1955-06625-000&recType=psycinfo&singlerecord=1&searchresultpage=true

Hirst, W., Spelke, E. S., Reaves, C. C., Caharack, G., & Neisser, U. (1980). Dividing attention without alternation or automaticity. Journal of Experimental Psychology: General, 109(1), 98.

Moray, N. (1959). Attention in dichotic listening: Affective cues and the influence of instructions. Quarterly Journal of Experimental Psychology, 11(1), 56–60.

Ritter, W., Vaughan, H. G., & Costa, L. D. (1968). Orienting and habituation to auditory stimuli: a study of short terms changes in average evoked responses. Electroencephalography and Clinical Neurophysiology, 25(6), 550–556.