Rats’ novel object interaction as a measure of environmental familiarity

Environmental familiarization is a learning phenomenon embedded within most tasks used to study learning and motivation. Given its prevalence there is surprisingly little systematic behavioral research on factors affecting familiarization. The six experiments reported in the present report used rats’ tendency to interact more with a novel object in a familiar than in a novel environment as a measure of environmental familiarization. We found that 3 min of exposure to the environment was sufficient to increase object interaction above unfamiliar controls even when testing occurred up to 48 h after initial exposure to the environment; 1 or 1.5 min of exposure was not sufficient. Also, in the brief 2 min test, 10 min of environment exposure did not appear to increase object interaction above the 3-min condition. The 3-min of environment exposure was sufficient for familiarization whether environment exposure occurred in one 3 min placement or two 1.5 min placements. Environmental familiarization as measured by object interaction was also sensitive to ‘interference’ manipulations. That is, a distinct object present during initial exposure to the environment produced a level of object interaction in testing comparable to an unfamiliar control. Similarly, exposure to a second distinct alternate environment immediately after, but not before, initial exposure to the test environment partially disrupted environmental familiarization. In sum, object interaction might serve as a useful measure for studying processes mediating environmental familiarity.     

Context dependency of conditioned aversions to familiar and novel fluids

Using a context discrimination procedure and rats as the subjects, the formation of context-dependent aversions to novel and familiar fluids was investigated. Experiment 1 revealed that context dependency could be established to a novel fluid (saccharin) after three cycles of context discrimination training and that the acquired context dependency was revealed also to a second familiar fluid (water) presented in the following test. Experiment 2 showed that the formation of the context-dependent aversion and its transfer to a second fluid was not affected by whether fluid presented during discrimination was novel (saccharin) or familiar (water). Experiment 3 demonstrated that when the same water was given both in the two training contexts and in the home cages of the subjects during discrimination, the context-dependent aversion formed was specific to it. These findings can be explained in terms of a simple summation effect of fluid-nausea and context-nausea associations.     

The resistance of renewal to instructions that devalue the role of contextual cues in a conditioned suppression task with humans

The renewal of extinguished conditioned behaviour appears to reflect context-dependent learning. The present research used a conditioned suppression task with humans to examine whether instructions concerning the context could influence renewal. Pairings of a conditional stimulus (CS) and unconditional stimulus (US) were made in one context, followed by extinction trials of CS alone in a second context, and test trials of CS alone upon return to the original learning context. Four experiments tested whether the renewal of conditioned suppression observed during test would be attenuated if participants were instructed that the context changes were irrelevant to the predictive relationship between the CS and US. Using a differential conditioning design, no attenuation was found when the instructions were given prior to conditioning (Experiment 1) or immediately prior to the test trials (Experiment 2). The latter result was replicated with a single-cue conditioning design and further controls for exposure to the extinction contexts (Experiment 3). The collection of on-line ratings about the relationship between the contextual changes and the predictive nature of the CS indicated that participants did attend to and believe the instructions (Experiment 4). The results point to the resistance of renewal to explicit instructions that attempt to devalue the role of the contextual cues.     

Context blocking in rat autoshaping: Sign-tracking versus goal-tracking

Prior experience of unsignaled food can interfere with subsequent acquisition by birds of autoshaped key-pecking at a signal light. This has been understood to indicate that unsignaled food results in context conditioning, which blocks subsequent learning about the keylight-food relationship. In the present experiment with rats lever insertion as the conditioned stimulus (CS) preceded sucrose delivery as the unconditioned stimulus (US). Half the rats initially received unsignaled USs in the conditioning context, while the remainder did not. Both lever-presses (sign-tracking) and magazine-entries (goal-tracking) were recorded. Under immediate reinforcement conditions, prior unsignaled US interfered with sign-tracking, but had no effect on goal-tracking. In two further groups, a trace condition prevented development of sign-tracking. In this case, prior context conditioning interfered with goal-tracking. These results suggest that interference with sign-tracking may reflect response competition, while interference with goal-tracking under trace conditions may reflect failure to acquire a CS-US association.     

Relativizing utterance-truth?

In recent years, some people have held that a radical relativist position is defensible in some philosophically interesting cases, including future contingents, predicates of personal taste, evaluative predicates in general, epistemic modals, and knowledge attributions. The position is frequently characterized as denying that utterance-truth is absolute. I argue that this characterization is inappropriate, as it requires a metaphysical substantive contention with which moderate views as such need not be committed. Before this, I also offer a more basic, admittedly less exciting alternative characterization of the position, in terms of departing from the Kaplan–Lewis–Stalnaker two-dimensional framework.     

Billboards,bombs and shotgun weddings

It’s a presupposition of a very common way of thinking about context-sensitivity in language that the semantic contribution made by a bit of context-sensitive vocabulary is sensitive only to features of the speaker’s situation at the time of utterance. I argue that this is false, and that we need a theory of context-dependence that allows for content to depend not just on the features of the utterance’s origin, but also on features of its destination. There are cases in which a single utterance semantically conveys different propositions to different members of its audience, which force us to say that what a sentence conveys depends not just on the context in which it is uttered, but also on the context in which it is received.     

Two are better than one: comparison influences infants' visual recognition memory

Despite a large literature on infants’ memory for visually presented stimuli, the processes underlying visual memory are not well understood. Two studies with 4-month-olds (N = 60) examined the effects of providing opportunities for comparison of items on infants’ memory for those items. Experiment 1 revealed that 4-month-olds failed to show evidence of memory for an item presented during familiarization in a standard task (i.e., when only one item was presented during familiarization). In Experiment 2, infants showed robust memory for one of two different items presented during familiarization. Thus, infants’ memory for the distinctive features of individual items was enhanced when they could compare items.     

Unsanctioned aggression in rugby union: relationships among aggressiveness,anger, athletic identity,and professionalization

Aggressive players who intentionally cause injury to their opponents are common in many sports, particularly collision sports such as Rugby Union. Although some acts of aggression fall within the rules (sanctioned), others do not (unsanctioned), with the latter tending to be less acceptable than the former. This study attempts to identify characteristics of players who are more likely to employ unsanctioned methods in order to injure an opponent. Male Rugby Union players completed questionnaires assessing aggressiveness, anger, past aggression, professionalization, and athletic identity. Players were assigned to one of two groups based on self‐reported past unsanctioned aggression. Results indicated that demographic variables (e.g., age, playing position, or level of play) were not predictive of group membership. Measures of aggressiveness and professionalization were significant predictors; high scores on both indicated a greater probability of reporting the use of unsanctioned aggressive force for the sole purpose of causing injury or pain. In addition, players who had been taught how to execute aggressive illegal plays without detection were also more likely to report using excessive force to injure an opponent. Results provide further support that highly professionalized players may be more likely to use methods outside the constitutive rules of Rugby Union in order to intentionally injure their opponents. Results are discussed within the context of the increasing win‐at‐all‐cost attitude that is becoming more prevalent in sport and its implications for youth athletes. Aggr. Behav. 35:237–243, 2009. © 2009 Wiley‐Liss, Inc.     

Functional analysis and treatment of self-injury associated with transitions.

We applied functional analysis methodology to the assessment and treatment of 2 individuals' self‐injurious behavior (SIB), which was reported to be occasioned by transitions from one activity or location to another. A structural (task) analysis of activity transitions identified at least three separate components that might influence behavior either alone or in combination: (a) termination of a prechange activity, (b) initiation of a postchange activity, and (c) movement from one location to another. Results of preference and avoidance assessments were used to identify activities to which participants were exposed in varying arrangements during transitions in a functional analysis. Results of 1 participant's functional analysis indicated that his SIB was maintained by avoidance of having to change locations, regardless of the activity terminated prior to the change or the activity initiated following it. The 2nd participant's analysis revealed the same function but also an additional one: avoidance of certain task initiations. This information was used to identify transition contexts during intervention and to design treatment procedures appropriate for a given context and behavioral function. A procedure involving advance notice of an upcoming transition had no effect on SIB, and differential reinforcement of alternative behavior (DRA) had limited effects in the absence of extinction. Sustained decreases in SIB were observed when DRA was combined with extinction and response blocking. Further extensions of functional analysis methodology to the assessment of problem behavior in situations characterized by multiple or protracted stimulus changes are discussed.     

Response blocking with and without redirection for the treatment of pica.

Although response blocking can decrease problem behavior, one potential adverse side effect is the induction of aggression. In the current study, we report on a young adult who engaged in high rates of pica maintained by automatic reinforcement. Blocking pica, however, led to aggression. When redirection to an alternative preferred food item was added to an intervention consisting of response blocking, pica was effectively treated without increasing aggression.