Sensory Process-Visual

Definition

Sensation – Sensing the external or internal stimuli.

Sensory Process - The process of detection of external or internal stimuli through the activation of sense organs (Eyes, ear, nose, skin and tongue).

Sensory Process

          Human activities are the results orders of brain which gets inputs from the various sense organs. The sense organs are the windows to the world. These organs are activated by stimuli from the internal as well as external environment. The collective efforts of sense organs, neurons, tissues, muscles, bones, brain and mind helps in receiving, organizing and finally interpreting the stimuli. The sensory receptors (Specialized cells) of sense organs transform external or internal physical stimuli into electro-chemical signals known as neural impulse that travels via various channels to specific brain centres for further processing. This whole process of converting stimuli into neural impulse is known as sensory process.

Sensory Limits

          Sense organs too have certain limitations such as eye cannot see beyond visible spectrum of 380-780 nm, ears cannot hear beyond 20 Hz to 20000 Hz etc. There a stimulus should have a minimum value to initiate sensation. The minimum value of a stimulus required to activate a given sensory system is known as ‘Absolute Threshold or Absolute Limen’ (NCERT).

Visual Sensory Process

          The visual sensory process means transducing the visual stimuli into neural impulse. ‘Light’ (electromagnetic radiation visible to human eye i.e. 380 – 780 nm) onsets the visual sensory process. The Light when reflected from an object and enters into the eye to initiates the process. Human eye is a specialized sense organ that detect light and transduce it into neural impulse. Light is a form of energy that travels at a speed of 299 792 458 m/s (Approximately 3 Lakh Km per sec). Natural light is a mixture of seven colours. Colours are the psychological property of sensory experience of human beings because it is the brain that interprets the light into different colours.

Colours have three basic properties i.e.

          (i)       Brightness,

          (ii)      Saturation  and

          (iii)     Hue.

          (i)       Brightness – The perceived intensity of light. It is an important           characteristic of visual perception. It is determined by Amplitude of the light           wave.

          (ii)      Saturation – The psychological attribute that defines the purity of that           colour. It refers to the intensity of colour in an image. Fully saturated colour is        the purest. When colour is fully saturated, the colour is considered in purest           (truest) version. The red, blue and green are considered  primary colours with    highest saturation.

          (iii)     Hue – Hue is the wavelength within the visible-light spectrum at which           the energy output from a source is greatest. The attribute of a colour by virtue       of which it is discernible as red, green, etc. and which is dependent on its       dominant wavelength and independent of intensity or lightness.

Reference:

1.       NCERT, XI Psychology Text book.

2.       Ciccarelli, S. K. & Meyer, G. E. (2016). Psychology. Noida: Pearson India.

3.       Baron, R. (1993).  Psychology.

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