Cerebral Mechanisms in Behavior the Hixon Symposium

By Lloyd A. Jeffress; California Institute of Technology Hixon Fund | Go to book overview
Save to active project

Relational Determination in Perception

WOLFGANG KöHLER Department of Psychology, Swarthmore College

It is the main purpose of this paper to discuss records of electric currents which have been taken from the heads of human subjects under conditions of pattern vision. We have recently turned to work in this field, because it seemed natural to do so in view of certain psychological observations. I will therefore first describe these psychological facts.

When visual objects, figures, dots, or lines have for some time occupied a given region of the field, other visual objects which are now shown in this region tend to be displaced or distorted. Phenomena of this kind are known as "figural after-effects." The objects which establish such effects are called "inspection (or I-) objects," and the objects which exhibit the effects, "test (or T-) objects" (13).

According to the definition of figural after-effects which has just been given, a T-object is affected only if it is located within or near the area in which the I-object has been shown. This area is defined in a retinal (or cortical) sense rather than in terms of "absolute" space. Suppose, for instance, that after the I-period the eyes of the subject turn to a new fixation mark. Under these conditions, an after-effect will be observed in the new direction if the retinal place of the T-object has the right relation to the retinal area previously occupied by the Iobject. The T-object need not differ from the I-object. When inspected for some time, many visual objects change their own spatial characteristics. In a way, they then serve both as I- and as T-objects.

Most figural after-effects can be derived from the following principle: T-objects recede from areas in which I-objects have been shown, particularly from the regions in which the contours of these objects have been located. As a result, T-objects may be simply dis


Notes for this page

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
Loading One moment ...
Project items
Cite this page

Cited page

Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

Cited page

Bookmark this page
Cerebral Mechanisms in Behavior the Hixon Symposium


Text size Smaller Larger
Search within

Search within this book

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

While we understand printed pages are helpful to our users, this limitation is necessary to help protect our publishers' copyrighted material and prevent its unlawful distribution. We are sorry for any inconvenience.
Full screen
/ 311

matching results for page

Cited passage

Citations are available only to our active members.
Sign up now to cite pages or passages in MLA, APA and Chicago citation styles.

Cited passage

Welcome to the new Questia Reader

The Questia Reader has been updated to provide you with an even better online reading experience.  It is now 100% Responsive, which means you can read our books and articles on any sized device you wish.  All of your favorite tools like notes, highlights, and citations are still here, but the way you select text has been updated to be easier to use, especially on touchscreen devices.  Here's how:

1. Click or tap the first word you want to select.
2. Click or tap the last word you want to select.

OK, got it!

Thanks for trying Questia!

Please continue trying out our research tools, but please note, full functionality is available only to our active members.

Your work will be lost once you leave this Web page.

For full access in an ad-free environment, sign up now for a FREE, 1-day trial.

Already a member? Log in now.

Are you sure you want to delete this highlight?