Human Sensory Capabilities

Barfield, W., Hendrix, C., Bjorneseth, O., Kaczmarek, K.A., and Lotens, W. 1996. Comparison of human sensory capabilities with technical specifications of virtual environment equipment. Presence 4 329-356. 

Sensory Reception of Information For a display to be useful, information must be in a form that an operator can sense. If it is outside human sensory capabilities, the display is useless. For example, humans cannot see wavelengths in the infrared or ultraviolet region. Few can hear frequencies near or above 20,000 Hz. 

Yet even primate studies cannot tell us anything about the interplay between emotion and cognition that is a crucial aspect of emotions in humans. One reason is that the range of beliefs that can be held by other animals is so limited. We can distinguish objects of beliefs along three dimensions. First, the objects may be observable or unobservable. Second, they may be physical or mental. Third, they may be real or imagined. As far as I know, animals can only form beliefs about real, physical objects. These need not be observable. We know from many studies that animals are capable of forming mental representations of physical objects that are absent from the present sensory field.3 But there is no evidence that animals can form the more complex beliefs of which humans are capable, such as beliefs about mental states (beliefs, emotions, motivations) and counterfactual beliefs. I discuss these beliefs in IV.2. In particular, animals cannot form beliefs about their own emotions. Nor does there seem to be any evidence that animal beliefs can be distorted by emotion, in the ways that 1 discuss in II.3 and IV.3. 

This chapter will consider methods and devices used to present visual, auditory, and tactual (touch) information to persons with sensory deficits. Sensory atigmentation systems such as eyeglasses and hearing aids enhance the existing capabilities of a functional human sensory system. Sensory substitution is the use of one human sense to receive information normally received by another sense. Braille and speech synthesizers are examples of systems that substitute touch and hearing, respectively, for information that is normally visual (printed or displayed text). 

Humans possess many useful senses touch, hearing, sight, taste, and smell. Humans can also sense pressure, vibration, temperature, acceleration (shock), rotation, linear motion, and position. In the area of patient safety, a better understanding of sensory capabilities of humans can be useful to reduce the occurrence of human errors. Four human sensory-related capabilities are described below [8,27,28]. 

Presently, most robotic applications require control of position only for assembly purposes. They are not suitable for operations requiring control of contact forces such as mating of parts with dose tolerances. Future rotetic applications will require sensory capabilities that are functionally equivalent to human senses, induding vision and touch. Important to robotic ap dications are the ability to sense when an objed comes in contact with another. Ibuch sensors are able to provide sensing over an area in which there is spatial resolinion. such as the posture rehahilitatioo sensor described in Section 1I1.A.3. 

Two ears. Our ability to determine the direction from which a sound is coming is partly based on the difference in time at which our two ears detect the sound. Given the speed of sound (350 meter/second) and the separation between our ears (0.15 meter), what difference is expected in the times at which a sound arrives at our two ears How does this difference compare with the time resolution of the human hearing system Would a sensory system that utilized 7TM receptors and G proteins be capable of adequate time resolution ... 

Effects observed in humans following neurotoxic exposure include modification of motor and sensory activities, emotional states, integrative capabilities such as learning and memory, adverse effects on sensory systems (including sight, hearing, smell, touch, and pain sensation), behavior modification, sleep loss, speech impairment, delirium, hallucinations, convulsions, and deaths1-4 ... 

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