VISUAL SENSORY MEMORY EXPERIMENTS (CONTINUED):Psychological Time

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Cognitive Psychology PSY 504

Lesson 06

VISUAL SENSORY MEMORY EXPERIMENTS (CONTINUED)

Sperling (1967) & Neisser (1967)

Sperling made another variation and after that array disappeared, he made visual field dark

instead of white. This produced fascinating results and the retention power of the subjects was

increased to 5 seconds. He found that when the postexposure field was light the sensory

information remained for only a second, but when the field was dark it remained for a full 5

seconds.

Light post-exposure field 1 second

Dark post-exposure field 5 seconds

Ulric Neisser wrote first cognitive psychology book in 1957. He devised a word icon. It is a brief

visual memory revealed in these experiments. He devised the word iconic memory for short term

visual memory.

According to Neisser, the visual memory is neither short term memory nor long term memory but

it is very very short term memory and should b called as iconic memory. Without such a visual

icon, perception would be much more difficult. Many stimuli are of very duration. In order to

recognize them, the system needs some means of holding on to them for a short while until they

can be analyzed.

Neisser also reported that if another display is given during that one second when you are

already retaining an image it is like erasing or washing out the first and overwriting the second

one. Almost all the information is held for a very brief period (1 second). It is quickly washed out

after removal of stimulus unless attention is paid to it.

The sensory store is particularly visual in character and is sensitive to light. We cannot pinpoint

where sensory memory is located in brain (this is a software level description not hardware level

description). Sensory visual store is not physical but seems like physical phenomenon and is

sensitive to light.

Psychological Time

Are we living in every moment in this moment or are we living in the past? The conclusion is

drawn about that how we are judging that we are living in present not in past. Our new

information synthesis with our old information, as it is happening at the same time at the same

space. If we see the things that happen before one second we perceive it as it is happening here

and now. We are attending to the visual information after some delay no matter how brief that

period may be less than one second. And if we perceive the information after we have seen

something. We know that we are not living in past we are seeing things here and now. This is

called psychological time. We found that our perception is delayed by a second. Our visual

system is recombining things within a second and putting them together and constructing a visual

image based on the information we receive.

Auditory Sensory Memory

Evidence for an auditory sensory memory similar to the visual memory comes from the set of

experiments by

Moray, Bates and Barnett (1965), and

Cognitive Psychology PSY 504

Darwin, Turvey & Crowder (1972)

Moray, Bates and Barnett (1965)

Their experiment is copy of Sperling's experiments. But in this experiment instead of top, middle

and bottom, sounds were manipulated as coming from left, right or from the front side. The cue

was presented visual (opposite to the sperling's experiment, where the cue was auditory). In their

experiment, subjects listened to a recording over stereo headphones, hearing three lists of three

items read simultaneously. Because of stereophonic mixing, one list seemed to come from the

left side of the subjects head, one from the middle, and the one from the right side. The

investigators compared results from derived from a whole-report procedure, in which subjects

were instructed to report all nine items, with partial-report procedure, in which they were cued

visually after the presentation of the lists as to whether they should report the items coming from

the left, middle, or right locations. A greater percentage of the letters were reported in the partial-

report procedure than in the whole-report procedure. It was statistical significance. Statistical

significance means obvious, marked difference.

Thus all the information is available to the short term sensory storage, but it quickly decays. The

delay is significant but not striking as compared to visual sensation because visual sensation is

central and hearing only supports it. Neisser (1967) has called it echoic memory.

Neisser pointed out many things we understand, perceive but cannot perform them, like the

difference between competence and performance. This was a big blow to behaviorism. Cognitive

psychology scientifically proved that psychology is much more than observable behavior only.

Neisser conclusion was whole-report paradigm was a limit to our production not to our process.

We process every thing but we cannot produce all. Time delay, overwriting, light contrast

intervene in the production aspect not in the storage aspect.

Cognitive Psychology PSY 504

Psychological time

We all are living in the past. This past is not in passive term. Because we receive visual

information that is one second old. And we receive auditory information that is 5 seconds old.

Information is not only being received but also is being reconstructed. We are creating the reality

afresh, every moment. Every icon is separate entity. New information is different entity. It

reconstructs reality with combining other entity. The heart of cognitive psychology lies in its

experimentation.

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