Introduction to Sensation, Perception and Attention

INTRODUCTION TO SENSATION, PERCEPTION AND ATTENTION Dr. Debdulal Dutta Roy, Ph.D. (Psy.) Psychology Research Unit INDIAN STATISTICAL INSTITUTE Kolkata – 700108 Lecture at the PATC,Rabindrabharati university, Kolkata

SENSATION

What is sensation ?

It is defined as just awareness of stimulus. It is the stimulation of sensory receptors and the transmission of sensory information to the central nervous system (the spinal cord and brain).

Song: O ki elo, o ki elo na, bojha gelo na

Attributes of sensation

Quality : what distinguishes one sensation from another.

Generic and

specific

Intensity: strength of the stimulus

Duration : how long the sensation lasts

Localization:

Brain and sensation

Visual organ

Auditory organ

Nose and tongue

Skin

Spinal cord

Thresholds

Song: “Eso eso amar ghare eso, amar ghare. Bahir hoye eso”

Sensory receptors are located in sensory organs. Stimulus detection depends upon stimulus intensity. Stimulus intensity should cross the threshold.

There are three types of thresholds - absolute, differential and terminal thresholds.

Absolute threshold refers to the weakest amount of a stimulus that can be distinguished from no stimulus at all.

The level where in individual is able to make difference in magnitude of two stimuli is called difference threshold.

Terminal threshold refers to the very high intensity of stimulus, which is not able to detect by the individual.

Performing art therapy should study threshold of stimulus in customizing intensity of music so that client can detect its presence without any difficulty.

Signal detection theory

Signal detection theory considers human aspect of sensation and perception. This theory views that the signal can be distinguished from background noise through the interaction of physical (stimulus intensity), biological (sensory receptors’ limitation or fatigue) and psychological factors (motivation, expectations and learning). Therefore Performing art therapist should pay attention to the above three in presentation of stimuli to client.

Four conditions of signal detection

PERCEPTION

Have you heard any sound? Identify the sound and write

Perception

Perception is the brain’s process of organizing and interpreting sensory information to give it meaning.

Individual organizes perception according to certain principles of pattern perception. These are:

Figure and ground

We organize the perceptual field into stimuli that stand out(figure) and those that are left over (ground).

Closure

When individual sees a disconnected or incomplete figure, they fill in the spaces and see it as a complete figure.

Proximity:

When individual sees objects close to each other, they tend to group them together.

Similarity

the more similar objects are, the more likely we are to group them together

Linear perspective

The farther an object is from the viewer, the less space it takes up in the visual field. As an object recedes in the distance, parallel lines in the object converge.

Texture gradient

Texture becomes denser the farther away it from the viewer.

Relative size

Objects farther away create a smaller retinal image than those nearby.

Interposition

An object that partially conceals or overlaps another object is perceived as closer.

ATTENTION

Attention

Attention is the amount of effort exerted in focusing on certain portions of an experience: ability to sustain a focus on one activity; ability to concentrate.

Attention is of two types based on effort

Passive

Active or concentration

Focus Active attention Moderate Very high Passive attention Non-specific specific

Focus in Vivo

Think deeply some of the events happened in your life. You will be able to express all the incidents vividly because your focus of attention is in vivo.

Attention specificity

Non specific attention can be modified to specific through dance and movement therapy.

Attention is developed through play therapy

Follow client’s behaviour first and relate it to specific attention.

Selective attention changes perception

Attention difficulty can be controlled by movement therapy

Attention difficulty

using a 'behavioral approach' which you can divide into 5 steps:

Carefully observe the circumstances of your child's unacceptable behavior.

Try to understand why your child behaves as he does.

Set a reasonable goal for improvement based on his immediate needs and his developmental level.

Plan to work toward the goal in small steps, always rewarding 'good' behavior and making sure 'bad' behavior brings no pleasure, attention, or reward.

After the child's behavior has improved, gradually move toward a more natural (less planned) way of relating to him.

Disturbances in attention :

Distractibility: Inability to concentrate attention; attention drawn to unimportant or irrelevant external stimuli;

Selective inattention: Blocking out only those things that generate anxiety;

Hypervigilance: Excessive attention and focus on all internal and external stimuli secondary to paranoid stance.

Signs of ADHD children

Inattention

Hyperactivity

Impulsivity

Six or more of the following symptoms of inattention have persisted for at least 6 months to a degree that is maladaptive and inconsistent with developmental level.

Signs of Attention deficit/Hyperactivity disorder:

Attention deficit/Hyperactivity disorder:

Guidelines of Diagnostic and Statistical Manual of Mental Disorders (4 th Edition – Test revision, 2001) are as follows:

Either (1) or (2)

(1) Six or more of the following symptoms of inattention have persisted for at least 6 months to a degree that is maladaptive and inconsistent with developmental level:

Inattention:

often fails to give close attention to details or makes careless mistakes in schoolwork, work, or other activities;

often has difficulty sustaining attention in tasks or play activities;

often does not seem to listen when spoken to directly;

often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace (not due to oppositional behavior or failure to understand instructions)

often has difficulties organizing tasks and activities

often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort (such as schoolwork or homework)

often loses things necessary for tasks or activities (e.g., toys, school assignments, pencils, books or tools)

is often easily distracted by extraneous stimuli

is often forgetful in daily activities

Hyperactivity

(2) six ( or more) of the following symptoms of hyperactivity – impulsivity have persisted for at least 6 months to a degree that is maladaptive and inconsistent with developmental level.

Hyperactivity

often fidgets with hands or feet or squirms in seat

often leaves seat in classroom or in other situations in which remaining seated is expected

often runs about or climbs excessively in situations in which it is inappropriate (in adolescents or adults, may be limited to subjective feelings of restlessness)]

often has difficulty playing or engaging in leisure activities quietly

is often “ on the go” or often acts as if “driven by a motor”

often talks excessively

Impulsivity

Impulsivity

often blurs out answers before questions have been completed

often has difficulty awaiting turn

often interrupts or intrudes on others (e.g., butts into conversations or games)

Some hyperactive-impulsive or inattentive symptoms that caused impairment were present before age 7 years

Some impairment from the symptoms is present in two or more settings (e.g., at school [or work] and at home)

There must be clear evidence of clinically significant impairment in social, academic, or occupational functioning

The symptoms do not occur exclusively during the course of a pervasive developmental disorder, schizophrenia, or other psychotic disorder and are not better accounted for by another mental disorder (e.g., Mood disorder, Anxiety disorder, Dissociative Disorder or a Personality disorder).

Types