物體為基注意力作用是否反射優勢或代價？

Does the Object-Based Attention Effect Reflect a Benefit or a Cost?

在無效線索的情況下，當目標與線索的距離維持相同時，如果目標與線索出現在相同物體時，目標偵測所需的時間，比當目標與線索出現在不同物體，還要來得快（例如Egly, Driver, & Rafal, 1994），稱之為物體為基注意力效果。我們以三個實驗來檢驗導致物體為基注意力效果之兩個可能性：注意力分佈在與線索相同之物體的優勢，抑或是注意力在兩個物體間移動所產生的代價。我們採用Egly、Driver及Rafal（1994）的實驗典範，並加入了無物體的情境，藉由比較有物體與無物體兩個情境，來區分代價與優勢這兩種可能。本研究發現物體為基注意力主要導因於注意力在兩個物體間移動所產生的代價。

Object-based attention would result if target appearing at an invalid location on the same object is detected more quickly than target on an equidistant location on different object (e.g., Egly, Driver, & Rafal, 1994). Three experiments examined the form of object- based attention typical object- based attention paradigms elicit (object- based benefits from the spread of attention across objects or object- based costs for switching attention between objects). Without a measurement of the time to switch attention from one location to another in the absence of objects, it is not possible to assess the relative costs or benefits of objects on attention. By adding an object- absent condition to typical object- based attention paradigms, the present experiments found that object-based attention is best described in terms of the cost to switch attention between objects.