most sighted humans can in fact learn to roughly detect large areas of polarization by an effect called haidinger's brush; however, this is considered an entoptic phenomenon rather than a separate sense. slit sensillae of spiders detect mechanical strain in the exoskeleton, providing information on force and vibrations. plant sensation by using a variety of sense receptors, plants sense light, temperature, humidity, chemical substances, chemical gradients, reorientation, magnetic fields, infections, tissue damage and mechanical pressure. the absence of a nervous system notwithstanding, plants interpret and respond to these stimuli by a variety of hormonal and cell-to-cell communication pathways that result in movement, morphological changes and physiological state alterations at the organism level, that is, result in plant behavior. such physiological and cognitive functions are generally not believed to give rise to mental phenomena or qualia, however, as these are typically considered the product of nervous system activity. the emergence of mental phenomena from the activity of systems functionally or computationally analogous to that of nervous systems is, however, a hypothetical possibility explored by some schools of thought in the philosophy of mind field, such as functionalism and computationalism. however, plants can perceive the world around them, and might be able to emit airborne sounds similar to "screaming" when stressed. those noises could not be detectable by human ears, but organisms with a hearing range that can hear ultrasonic frequencies—like mice, bats or perhaps other plants—could hear the plants' cries from as far as 15 feet (4.6 m) away. artificial sensation and perception machine perception is the capability of a computer system to interpret data in a manner that is similar to the way humans use their senses to relate to the world around them. computers take in and respond to their environment through attached hardware. until recently, input was limited to a keyboard, joystick or a mouse, but advances in technology, both in hardware and software, have allowed computers to take in sensory input in a way similar to humans. culture in the time of william shakespeare, there were commonly reckoned to be five wits or five senses. at that time, the words "sense" and "wit" were synonyms, so the senses were known as the five outward wits. this traditional concept of five senses is common today. the traditional five senses are enumerated as the "five material faculties" (pañcannaṃ indriyānaṃ avakanti) in hindu literature. they appear in allegorical representation as early as in the katha upanishad (roughly 6th century bc), as five horses drawing the "chariot" of the body, guided by the mind as "chariot driver". depictions of the five traditional senses as allegory became a popular subject for seventeenth-century artists, especially among dutch and flemish baroque painters. a typical example is gérard de lairesse's allegory of the five senses (1668), in which each of the figures in the main group alludes to a sense: sight is the reclining boy with a convex mirror, hearing is the cupid-like boy with a triangle, smell is represented by the girl with flowers, taste is represented by the woman with the fruit, and touch is represented by the woman holding the bird. in buddhist philosophy, ayatana or "sense-base" includes the mind as a sense organ, in addition to the traditional five. this addition to the commonly acknowledged senses may arise from the psychological orientation involved in buddhist thought and practice. the mind considered by itself is seen as the principal gateway to a different spectrum of phenomena that differ from the physical sense data. this way of viewing the human sense system indicates the importance of internal sources of sensation and perception that complements our experience of the external world. lairesse's allegory of the five senses detail of the senses of hearing, touch and taste, jan brueghel the elder, 1618 in this painting by pietro paolini, each individual represents one of the five senses.