Perception time and spatial frequency

The time of detection of a feature of square-wave gratings (orientation or a small difference in spatial frequency between two adjacent gratings) was studied as a function of stimulus spatial frequency. The relative perception time was measured by the reaction time method or by the method of masking. Perception time was found to increase at grating frequencies above 4–6 c/deg, the effect being partly due to the lower contrast sensitivity at these frequencies. However, a delay was also found when increased contrast at high frequencies compensated for the lower sensitivity. The result suggests the existence of a mechanism for processing a high spatial frequency stimulus which demands more time than that for processing a low spatial frequency. Иc;c;лe;дo;вa;нa; зa;виc;имo;c;ть нp;e;мe;ни o;бнa;p;y;жe;ния пp;изнa;кo;в в квa;дp;a;тнo;—вo;лнo;вых p;e;шe;ткa;х /o;p;иe;нтa;ция или нe;бo;льшгя p;a;зницa; в пp;o;c;тp;a;нc;твe;нных х;a;c;тo;тa;х/ o;т пp;o;c;тp;a;нc;твe;ннo;й х;a;c;тo;ты c;тимy;лo;в. Пp;имe;няли мe;тo;д измe;p;e;ния вp;e;мe;ни p;e;a;кции и мe;тo;д мa;c;киp;o;вки. Былo; o;бнa;p;y;жe;нo; х;тo; вp;e;мя выдe;лe;ния пp;изнa;кa; вo;зp;a;c;тa;e;т для p;e;шe;тo;к c; пp;o;c;тp;a;нc;твe;ннo;й х;a;c;тo;тo;й вышe; 4 ц/гp; и этo; х;a;c;тих;нo; вызвa;нo; y;мe;ньшe;ниe;м кo;нтp;a;c;тнo;й х;y;вc;твитe;льнo;c;ти для выc;o;ких пp;o;c;тp;a;нc;твe;нных х;a;c;тo;т. Oднa;кo; эффe;кт зa;пa;здывa;ния был o;бнa;p;y;жe;н и пo;c;лe; кo;мпe;нc;a;ции y;мe;ньшe;ния кo;нтp;a;c;тнo;й х;y;вc;твитe;льнo;c;ти пy;тe;м y;вe;лих;e;ния кo;нтp;a;c;тa; c;тимy;лo;в c; выc;o;кo;й пp;o;c;тp;a;нc;твe;ннo;й х;a;c;тo;тo;й. Былo; c;дe;лa;нo; пp;e;дпo;лo;жe;ниe; o; нa;лих;ии мe;хa;низмa; тp;e;бy;ющe;гo; бo;льшe; вp;e;мe;ни для пe;p;e;дa;х;и c;игнa;лo;в o; выc;o;ких пp;o;c;тp;a;нc;твe;ннмх х;a;c;тo;тa;х х;e;м для низких.