Perrin S. Cohen

Aggression induced by intermittent positive reinforcement

Mammalian and non-mammalian species engage in aggressive behavior toward animate and inanimate targets when exposed to intermittent access to a positive reinforcer. This behavior, called extinction- or schedule-induced aggression, typically includes a biting or striking topography that inflicts damage on a target. This paper critically reviews research and theoretical issues concerning such aggression and suggests directions for future investigation.

The nature and determinants of spatial retreat in the pigeon between periodic grain presentations

Pigeons were exposed to fixed-time and fixed-interval schedules that ranged from 30 to 960 sec. The probability of a subject’s location in the rear of the chamber (away from the reinforcer dispenser) peaked during the postreinforcer period, and was referenced to proportional time between reinforcers. Increasing the interreinforcer interval generally increased time in the rear. In some sessions (Experiment 1), location in the rear produced an explicit stimulus change (altered the color and intensity of lights, i.e., time-out); this change increased time spent in the rear without affecting its temporal locus or its relation to the interreinforcer interval. During Experiment 2, a keypeck (near the reinforcer site) produced the explicit stimulus change used in Experiment 1. The characteristics of keypeck time-out resembled those of movement to the rear of the chamber (with and without an explicit stimulus change), suggesting that movement away from the reinforcer site is functionally homologous to keypeck time-out.

Temporal patterns of reinforcer-induced general activity and attack in pigeons

Three White King pigeons were exposed to fixed-time schedules ranging from 60 to 240 sec. General activity and attack against a conspecific target were measured separately at each interreinforcer interval value. Comparison of the temporal distributions of activity and attack revealed significant differences in their temporal locus and overall distribution between reinforcer presentations. At all interval values, attack was localized to the postreinforcer period, and peaked at the same absolute time (5-10 sec) following each reinforcer presentation. General activity was more uniformly distributed between reinforcers, and the peak level occurred later in the interval. As the interval length increased, peak levels of activity shifted to later times following reinforcement. These differences question traditional accounts which posit a unitary process underlying induced behaviors, while supporting Cohen, Looney, Campagnoni and Lawlers recent two-state model of induced behaviors.

Temporal patterns of schedule-induced drinking and pawgrooming in rats exposed to periodic food

Five rats were exposed to fixed-time food schedules, ranging from 30 to 480 sec. Three rats displayed a postfood pattern of schedule-induced drinking, with short latencies from food delivery to drinking at all interfood interval durations. In contrast, drinking for the other 2 subjects tended to occur at lower overall levels, and drinking bouts frequently began in the middle of the interfood interval, such that the latency from food delivery to drinking increased dramatically as the interfood interval increased. Observation of these 2 subjects revealed that another form of licking-pawgrooming-occurred reliably after food delivery and before drinking bouts. A between subject comparison of the 3 postfood drinkers and the 2 pawgroomers revealed that, in addition to a common topography (repetitive licking), pawgrooming and drinking were similar with respect to their temporal locus, relation to the interfood interval, and extinction baseline levels. These similarities suggest that drinking and pawgrooming are induced by a common mechanism. Cohen, Looney, Campagnoni, and Lawler’s (1985) two-state model of reinforcer-induced motivation provides a useful framework for the interpretation of these results.

AIR Model : A Teaching Tool For Cultivating Reflective Ethical Inquiry

The AIR model we describe in this article is a practical framework for cultivating reflective inquiry into ethical issues that students, faculty, and administrators experience in the midst of busy daily lives and encounter in classroom discussions in a discipline field. The model is highly adaptable to academic and workplace settings and enables students to clarify and refine their ethical thinking and make more caring, compassionate, and respectful choices. Quantitative and qualitative assessment indicates that students who use AIR as an organizing framework become more empowered and competent to engage in reflective ethical inquiry.

Visual target control of schedule-induced aggression in white king pigeons (columba livia)

Visual target control of schedule-induced attack was studied in domesticated pigeons by exposing them to successive and simultaneous target preference procedures involving a fixed-time food schedule and projected target images. Pigeons preferred attacking an image of a conspecific head over a headless bird regardless of the height of the latter. Images of an intact bird and of a head alone were equally effective in controlling attack and more effective than the headless bird. Neither the eye nor four. other head-related features exclusively controlled attack. The combined results suggest that the head of an intact conspecific target selectively controls schedule-induced attack and that the effectiveness of the head in directing attack is inversely related to its physical integrity as a unit without regard to specific features. These results are consistent with reports that the head and head-related features of an intruder control reproductive aggression in birds.

Organization of attack and other behaviors of White King pigeons exposed to intermittent water presentations

Six water-deprived pigeons were exposed to a fixed-time 90-sec water schedule with and without a conspecific target available. Target contacts and the pigeon’s location in the test chamber during the interreinforcement interval were recorded, and the results were compared with those previously obtained with food reinforcement. Prior to target introduction, water-reinforced birds spent more total time in the front near the reinforcer dispenser and less in the rear than food-reinforced birds and, unlike food-reinforced birds, exhibited postreinforcement drinking-like behaviors near the reinforcer dispenser before moving away from that area. With the target available, the level, topography, and duration of target-directed biting pecks were comparable for food- and water-reinforced pigeons. In contrast, the temporal organization of target pecks reflected the different temporal and spatial organizations of behavior prior to target introduction. For both food- and water-reinforced birds, the time between reinforcers at which a bird was spatially situated halfway between the front and rear of the chamber prior to target presentation was positively correlated with the time at which maximum target contact subsequently occurred.

Schedule-induced attack on a pictorial target in feral pigeons (Columba livia)

Two of three feral pigeons exhibited schedule-induced attack on a colored photograph of a conspecific during exposure to a fixed-time food schedule. The rate and pattern of attack were comparable to that observed with domesticated pigeons. Schedule-induced attack against a conspecific target image is not confined to domesticated birds.

Ethical Leadership The AIR Modelsm Empowers Moral Agency

The AIR Modelsm of Reflective Ethical Inquiry (Cohen et al. 2005) is a practical framework that leads toward more caring, compassionate and appreciative ethical actions in administration, teaching, research and student life. In this article, we consider a corollary of the model: AIR practitioners are prepared to effectively meet anticipated and unanticipated ethical challenges. By being present to, curious about and responsive to ethical concerns as they arise in everyday situations, AIR practitioners emerge as both ‘direct ethical leaders’ (Gardner 1995) who embody an ethical tone and set an ethical direction, as well as an ‘indirect leaders’ (ibid.) who exert an impact through personal and collective works. The underlying AIR process is the foundation for individual and shared ethical leadership and leadership training, both of which reduce costly mistakes and enhance productivity.

Mirror control of responding on fixed-ratio schedules in pigeons

One of three pigeons exposed to multiple FR FR reinforcement schedules attacked a mirror target during postreinforcement pauses preceding the higher fixed ratio schedule. The same mirror-image stimulation, on the other hand, reduced reinforcement rate for all three pigeons by selectively increasing postreinforcement pauses preceding the higher fixed ratio schedule. This indicates that in studies of reinforcement schedules with pigeons, mirror-image stimulation from surfaces commonly present in standard test chambers (e.g., one-way mirrors, metal walls) may interact with schedule parameters to control postreinforcement behavior other than attack.