Normative Data for the Hayling and Brixton Tests in an Italian Population.

OBJECTIVE: The Hayling and Brixton tests constitute a short test battery that quickly assesses verbal and spatial inhibition and flexibility. This battery has shown high construct validity and strong reliability in clinical and experimental settings. The aim of this study was to develop an Italian version of the Hayling and Brixton tests and obtain normative values. METHOD: We collected normative data from 301 healthy Italian participants aged between 16 and 94 years, taking into account all demographics. To maximize the sample size, we used the overlapping interval strategy. Adjusted scores for demographics were obtained by linear regression analysis. RESULTS: The performance on the Hayling and Brixton tests was influenced by age and education. In particular, age affected verbal accuracy and response time on the Hayling Sentence Completion Test, whereas education only affected the former. Differently, the spatial component, as measured by the Brixton Spatial Anticipation Test, was shaped only by age, which decreased the number of correct responses. CONCLUSIONS: Our study provides normative data that have been adjusted for relevant demographics and percentile grids in an Italian population. Our data support the use of the Hayling and Brixton tests as a valid instrument for performing neuropsychological evaluations and longitudinal analyses of executive functions in clinical practice and for research purposes.

An ecological approach to the behavioral assessment of executive functions in anorexia nervosa.

The use of ecological tests to assess executive functions (EFs) in patients with anorexia nervosa (AN) has not examined extensively. The objective of this study was to analyze and compare the performance of patients with AN and healthy controls (HCs) on standard versus ecologically valid tests on EFs. Sixty-two females aged between 16 and 42 who were diagnosed with AN and 70 matched HCs completed 2 neuropsychological test batteries: standard tests (WCST, TMT, Stroop, ToL, fluency test) and the Behavioral Assessment of Dysexecutive Syndrome (BADS). On the standard tests, patients with AN produced more perseverative response and were slower than HCs in the TMT; in contrast, they scored as well as HCs on tasks that assessed categorization, interference in color naming, planning and semantic fluency. Conversely, there were differences in the ecological tests with patients with AN systematically slower in the resolution of complex tasks. Results demonstrated the power of ecological tests in capturing selective impairments in multifaceted and unstructured tests. Patients with AN experienced systematic deceleration in the resolution of ecological tasks. Also, the increased time needed to solve the tasks, was not reflected in overall improvement in performance. This evidence is further discussed with respect to central coherence.

Macaque monkeys can learn token values from human models through vicarious reward.

Monkeys can learn the symbolic meaning of tokens, and exchange them to get a reward. Monkeys can also learn the symbolic value of a token by observing conspecifics but it is not clear if they can learn passively by observing other actors, e.g., humans. To answer this question, we tested two monkeys in a token exchange paradigm in three experiments. Monkeys learned token values through observation of human models exchanging them. We used, after a phase of object familiarization, different sets of tokens. One token of each set was rewarded with a bit of apple. Other tokens had zero value (neutral tokens). Each token was presented only in one set. During the observation phase, monkeys watched the human model exchange tokens and watched them consume rewards (vicarious rewards). In the test phase, the monkeys were asked to exchange one of the tokens for food reward. Sets of three tokens were used in the first experiment and sets of two tokens were used in the second and third experiments. The valuable token was presented with different probabilities in the observation phase during the first and second experiments in which the monkeys exchanged the valuable token more frequently than any of the neutral tokens. The third experiments examined the effect of unequal probabilities. Our results support the view that monkeys can learn from non-conspecific actors through vicarious reward, even a symbolic task like the token-exchange task.

Transfer of the nonmatch-to-goal rule in monkeys across cognitive domains.

To solve novel problems, it is advantageous to abstract relevant information from past experience to transfer on related problems. To study whether macaque monkeys were able to transfer an abstract rule across cognitive domains, we trained two monkeys on a nonmatch-to-goal (NMTG) task. In the object version of the task (O-NMTG), the monkeys were required to choose between two object-like stimuli, which differed either only in shape or in shape and color. For each choice, they were required to switch from their previously chosen object-goal to a different one. After they reached a performance level of over 90% correct on the O-NMTG task, the monkeys were tested for rule transfer on a spatial version of the task (S-NMTG). To receive a reward, the monkeys had to switch from their previously chosen location to a different one. In both the O-NMTG and S-NMTG tasks, there were four potential choices, presented in pairs from trial-to-trial. We found that both monkeys transferred successfully the NMTG rule within the first testing session, showing effective transfer of the learned rule between two cognitive domains.