Pepperberg (Evaluation Essay)

P – Point (Strength/Weakness)

E – Explain the point

E – Example from the study

R – Relate to the point on why is it a strength / weakness in the study

Low on ecological validity (mundane realism)

The extent to which the findings of research in one situation would generalize to other situations. This is either the situation represents the real world effectively or the task is relevant to real life.

For example Alex was trained and tested on objects that have similar and different properties with regard to colour, shape and material.

Additionally Alex was tested about his comprehension of abstract categories through questions such as ‘What’s same?’ and ‘What’s different?’.

The objects that Alex was tested and trained with are not natural for a parrot. The verbalization that was expected of Alex is also not a normal behavior for a parrot. These aspects of the task lacks in mundane realism. Hence, it could be argued that there findings of this study lacks ecological validity.

High in validity

The extent a researcher is testing what they claim to be testing.

The study controlled for several extraneous variables. For example, the testing was conducted by a secondary trainer who did not train Alex. Additionally, a student who was uninvolved in this research chose the objects to be paired and randomly ordered the questions to be asked.

The use of a secondary trainer during the testing procedure prevented Alex from responding to cues that could be present if his original trainer was used.

The use of a double blind procedure by ensuring an uninvolved student determined the object pairing and the order of the question meant that both Alex and the principal trainer did not know what was going to be asked reducing experimenter bias.

Low in validity

The extent to which a researcher is testing what they

claim to be testing.

The testing procedure went on for 26 months. In any week, testing was conducted between one and four times.


Testing Alex for the period of 2 years meant that the reported finding that Alex showed ability to comprehend ‘same’ and ‘different’ might not be due to learning but rather practice effect such that Alex knew what to expect and what responses were expected from him.

Low on generalisability

How widely findings apply to other settings and populations.

Alex was an African grey parrot bought by Pepperberg when he was a year old. Alex had been studied by Pepperberg for 10 years before this specific study.

The parrot in this study which was of a specific species was raised in a laboratory setting and was consistently exposed to similar experimental procedures. Hence, the behaviors reported about Alex might be due to his familiarization of the task and the environment rather than natural behavior we would expect from a parrot.

Therefore, the findings from this study might not generalize to other avian species in the wild.

Ethics (animals) (strength)

Housing refers to ensuring animals are not isolated or housed in an over-crowded environment.

In this study, Alex was housed in suitable accommodation. Alex had access to all parts of the lab for 8 hours a day. Alex was only caged during his ‘sleeping hours’ with fresh water and a standard seed mix was always available.

Because Alex was not deprived of his basic needs and was housed appropriately, it can be deduced that this study conformed to the ethical guideline of housing.

Nature vs. Nurture (Nurture) Strength

This debate focuses on whether particular behaviours are innate (nature) or learned (nurture). This study supports the nurture side of the debate.

For example, Alex received training on categorical labels, where Alex answered ‘What’s same’ or ‘What’s different’ about an object held by the trainer. Alex would receive a reward of the object and praise when the response is correct.

Thus this study provides evidence towards the nurture side of the debate as Alex’s behavior is shaped through operant conditioning from the positive reinforcement of praise and reward when Alex displays the desirable behavior (of correctly labeling an object)

Other analysis:

Case study: A case study is a detailed description of a particular individual or small group under study or treatment.


the one animal chose might be unusual; and so can’t generalise. e.g. more experience with experiments and the tasks associated, so the results would be unusual rather than typical


can study the individual in detail / can understand the ‘why’ behind behaviour; e.g. the training necessary to develop the ability to differentiate sameness and difference