Temporal discrimination learning of operant feeding in goldfish (Carassius auratus)

Operant temporal discrimination learning was investigated in goldfish. In the first experiment, there was a fixed daily change in illumination. Eight subjects were trained to operate a lever that reinforced each press with food. The period during which responses were reinforced was then progressively reduced until it was 1 hr in every 24. The final 1-hr feeding schedule was maintained over 4 weeks. The feeding period commenced at the same time each day throughout. The food dispensers were then made inactive, and a period of extinction ensued for 6 days. The pattern of responding suggested that the fish were able to exhibit temporal discrimination in anticipation of feeding time. This pattern of responding persisted for a limited number of days during the extinction procedure. The second experiment produced evidence that operant temporal discrimination could develop under continuous illumination.     

科学变革中的进化与连续性

一、不可通约性与意义 最有影响的实证主义的意义理论曾经认为,意义的基本单位就是个体的词项或陈述,到了本世纪50年代,这些理论转而认为,理论的或语言的关系域决定着个体词项的意义。     

Compliant in a moment: a commentary on nevin

Nevin's scholarly and timely discussion attempts to maintain the precarious union of the experimentally derived theory of behavioral momentum with applications of the behavioral momentum construct to human subjects in applied settings. Nevin's discussion adds much-needed clarification to a process that at times has proven to be awkward for applied researchers. In this commentary, we will address three general questions: (a) Can the applications of behavioral momentum be derived from the theory as conceptualized by Nevin? (b) Could those applications have been developed had the theory not been formulated? (c) Does behavioral momentum theory add significantly to the compliance literature?     

One-Handed Juggling: A Dynamical Approach to a Rhythmic Movement Task

The skill of rhythmically juggling a ball on a racket was investigated from the viewpoint of nonlinear dynamics. The difference equations that model the dynamical system were analyzed by means of local and nonlocal stability analyses. These analyses showed that the task dynamics offer an economical juggling pattern that is stable even for open-loop actuator motion. For this pattern, two types of predictions were extracted: (a) Stable periodic bouncing is sufficiently characterized by a negative acceleration of the racket at the moment of impact with the ball, and (b) a nonlinear scaling relation maps different juggling trajectories onto one topologically equivalent dynamical system. The relevance of these results for the human control of action was evaluated in an experiment in which subjects (N = 6) performed a comparable task of juggling a ball on a paddle. Task manipulations involved different juggling heights and gravity conditions of the ball. The following predictions were confirmed: (a) For stable rhythmic performance, the paddle's acceleration at impact is negative and fluctuations of the impact acceleration follow predictions from global stability analysis; and (b) for each subject, the realizations of juggling for the different experimental conditions are related by the scaling relation. These results permit one to conclude that humans reliably exploit the stable solutions inherent to the dynamics of the given task and do not overrule these dynamics by other control mechanisms. The dynamical scaling serves as an efficient principle for generating different movement realizations from only a few parameter changes and is discussed as a dynamical formalization of the principle of motor equivalence.