ブルーギルの食餌条件反応と強化スケジュールの関係について

本研究では貯水池より捕獲したbluegill sunfishを用いて、輪くぐりを使った条件反応の形成過程を解析し、4タイプの強化スケジュール(CRF、FR、VR、EXT)で形成された反応の特性について、次の知見を得た。1) CRFによる条件反応の形成過程では、反応形成が進むにつれて初期の反応速度は上昇し、また初回の輪くぐりに要する時間は数秒の値まで短縮した。その後の反応速度は約5反応/分で安定した。2) FRにより形成された反応では強化した直後には休止が認められた。VRの場合、強化を伴わない反応速度は一定であった。3) CRFにより反応が形成された実験魚のEXTでは消去が速やかに進行する傾向が見られたが、FRを経験した個体のEXTでは反応の低下は著しくなかった。

Bluegill sunfish, which were collected from the Kumano reservoir in Fukuyama, were conditioned so that they swam through a specified frame for obtaining a reward of food pellets. Process of the formation of conditioned response in the fish was analyzed. And also characteristics of the response aquired on 4 different types of reinforcement schedules were compared with each other. The results obtained were as follows; 1) When the fish were conditioned under the continuous reinforcement schedule (CRF), the initial rate of responding increased from a low level at early phase of formation to asymptotic ca. 5 resp./min, and moreover the time interval of initial response shortened from 5 min or so to few seconds. 2) When conditioned under the fixed ratio reinforcement schedule (FR), the acquired reponses were characteristic in that the responding following a reinforced responding took a rest. In the response formed on the variable ratio reinforcement schedule (YR), there was no such a rest but the responding without reward appeared at almost constant rate. 3) Extinction schedule (EXT) evidenced that the responses formed on CRF schedule tended to extinguish more easily than the responses formed on the other schedules.