Limitations of a Bidirectional Control Procedure for the Investigation of Imitation in Rats: Odour Cues on the Manipulandum

Magazine-trained observer rats confronted a conspecific demonstrator pushing a joystick to the right or to the left for food reward before the observers were given access to the joystick from the position previously occupied by the demonstrator and rewarded for responses in both directions. For half of the observers (group 0), the joystick was in the same position when acted upon by demonstrators and observers; for the other half (group 180) the manipulandum was rotated 180 within its mounting between observation and test. As in previous experiments using this bidirectional control procedure, rats in group 0 showed demonstratorconsistent responding-that is, they pushed the joystick in the same direction, relative to the actor's body, as had their demonstrators. However, group 180 showed a reverse effect: reliable demonstrator-inconsistent responding. These results suggest that attractive odour or taste cues deposited by demonstrators on the side of the joystick contralateral to the direction of responding are sufficient to produce demonstrator-consistent responding in the bidirectional control procedure.     

Effects of adult age and working memory on reasoning and spatial abilities

Three predictions were derived from the hypothesis that adult age differences in certain measures of cognitive functioning are attributable to age-related reductions in a processing resource such as working-memory capacity. Each prediction received at least some degree of empirical support in a study involving 120 males ranging between 20 and 79 years of age. First, older adults exhibited greater impairments of performance than did young adults when task complexity increased and more demands were placed on the limited processing resources; second, the magnitudes of these complexity effects were highly correlated across verbal (reasoning) and spatial (paper folding) tasks. Finally, statistical control of an index of a working-memory processing resource attenuated the effects of age on the measures of cognitive performance. It was concluded that further progress in understanding the mechanisms of the relation between age and cognitive functioning will require improved conceptualizations of the nature of working memory or other hypothesized mediating constructs.     

Back to the future: Temporal perspective in the explanation of events

Prospective hindsight involves generating an explanation for a future event as if it had already happened; i.e., one goes forward in time, and then looks back. In order to examine how shifts in perspective might influence people's perceptions of events, we investigated two possible factors: temporal perspective (whether an event is set in the future or past) and uncertainty (whether the event's occurrence is certain or uncertain). In the first experiment, temporal perspective showed little influence while outcome uncertainty strongly affected the nature of explanations for events. Explanations for sure events tended to be longer, to contain a higher proportion of episodic reasons, and to be expressed in past tense. Evidence from the second experiment supports the view that uncertainty mediates not the amount of time spent explaining, but rather subjects' choice of explanation type. The implications of these findings for the use of temporal perspective in decision aiding are discussed.     

Predictors of peer helpfulness: Implications for youth in residential treatment

Sociometric measures were used to predict peer helpfulness of youth in a residential treatment center. Seventeen female adolescents with conduct disorders were asked to choose three peers in their group who were most popular, similar, well-liked, and competent. These sociometric measures were correlated with the frequency in which each peer was nominated as most and least helpful in several problem scenarios representing actual situations encountered in residential settings. A multiple linear regression analysis indicated that “popularity” was the best predictor of peer helpfulness across the problem scenarios. Discussion focused on the impact of popularity on treatment strategies for youth in residential placement.     

Perspective-Taking Judgments of Medication Acceptance: Inferences from Relative Importance about the Impact and Combination of Information

Perspective-taking judgments of medication acceptance were studied for hypothetical mental health treatment scenarios. Three types of information were manipulated in all possible subsets: level of trust in the medication prescriber, severity of the hypothetical mental health condition being experienced, and the potential side effects of the medication. Subjects made judgments from four perspectives: self perspective and that of three other hypothetical people who were each said to place the most importance on one of the three cues. The results showed individual differences in self-reports of the relative importance of the cues which, in turn, predicted differences in judgment patterns. Subjects modified their cue use when making judgments from the perspectives of hypothetical others. The interaction patterns and rank orders of the perspective-taking judgments resembled the individual differences in judgments made from subjects’ own perspectives, but the perspective-taking judgments showed extreme effects of the most important cue. There was also some influence of subjects’ own perspectives on their perspective-taking judgments. When only a subset of the three cues was given, the judgment pattern depended on the importance of the cue that was omitted. The relative weight averaging model accounted for the judgments of only a minority of the subjects. Models which propose that subjects infer the value of missing information were also unsuccessful in explaining the data of the majority. Modifications of those models are proposed.