Date of Award

12-1-1976

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Psychology

Abstract

When an observer views a picture, enough information processing occurs prior to the first eye movement to direct the eyes to an informative portion of the picture. This early processing is influenced by the overall coherency of the picture and the informativeness of the various sections of the picture. The present study tested the hypothesis that the processing of pictorial information proceeds in a hierarchical manner from the most informative sections of a picture to the least informative sections. The hypothesis was evaluated by observing changes in the recognition accuracy of high medium and low informative sections of a picture, located in either the center or periphery of the picture, at various exposure durations.

One hundred and twelve (56 female) undergraduates were randomly assigned to groups of 14 (7 female) subjects which saw the stimulus pictures for either 10, 30, 50, 75, 100, 150, 300, or 1000 milliseconds (msec). The individually tested subjects were shown a picture for the group appropriate exposure duration, followed by a visual noise mask, and finally a portion of a picture which served as a recognition probe. Subjects responded by indicating whether or not the probe was from the stimulus picture, and then rating their confidence in the decision.

The stimulus pictures had previously been divided into eight sections, four across by two down. They were rated such that the location of a high, medium, and low informative section was known for each picture. An equal number of pictures representing each level of informativeness in both the center and the periphery were selected for the stimulus set. For half of the trials, match trials, the probe was from the stimulus and for the remainder, mismatch trials, it was not.

Probes of medium informative sections of the stimulus picture were recognized better than probes of high and low informative sections. Sections at central locations were more accurately recognized than those at peripheral locations. Informativeness and location interacted such that medium informative sections had superior recognition at peripheral locations as opposed to central locations while high informative probes were recognized better centrally rather than peripherally.

Confidence ratings by the subjects followed essentially the same pattern of main effects and interactions. Medium informative sections were more confidently rated than high or low informative sections, particularly at the peripheral locations. Comparison of match and mismatch trials revealed significantly more confidence when the probe was from the stimulus picture than when it was not.

The findings appear to be explicable by a conceptualization derived from a synthesis of the levels of information concept of stimulus encoding and the dual informational model of perceiver experience. The levels of information concept proposes that the structure of information in a picture dictates the type of processing which will occur during encoding. The dual information model contends that the perceiver has explicit knowledge of two types of information available, a general characterization of the picture and a set of identified objects. The present formulation merely suggests that the levels of information encoding results in sufficient information for a dual information experience by the perceiver. This combination can explain the findings of the present study.

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